WO2014123847A1

WO2014123847A1 - Compositions and methods for inhibiting contamination of cytological samples

Info

Publication number: WO2014123847A1
Application number: PCT/US2014/014576
Authority: WO
Inventors: William Alan Fox
Original assignee: Tripath Imaging, Inc.
Priority date: 2013-02-05
Filing date: 2014-02-04
Publication date: 2014-08-14

Abstract

The present subject matter is directed to compositions and methods for inhibiting or preventing contamination of a cytological sample for analysis, wherein the sample is associated with a substrate. The methods disclosed herein are directed to contacting a polyanionic polymer material with a sample that is affixed to a substrate, which has a net cationic charge density. Upon contacting the sample with the polyanionic solution, contamination of the sample by other biological material, particularly cells, is inhibited or prevented.

Description

COMPOSITIONS AND METHODS FOR INHIBITING CONTAMINATION OF

CYTOLOGICAL SAMPLES

FIELD OF THE INVENTION

The subject matter disclosed herein relates generally to compositions and methods of preparing cytological samples that inhibit contamination of the prepared cytological samples.

BACKGROUND

Cytology is the branch of biology dealing with the study of the formation, structure, and function of cells. As applied in a laboratory setting, cytologists, cytotechnologists, and other medical professionals make medical diagnoses of a patient's condition based on visual examination of a specimen of the patient's cells. A typical cytological technique is a "Pap smear" test, in which cells are scraped from a woman's cervix and analyzed in order to detect the presence of abnormal cells, a precursor to the onset of cervical cancer. Cytological techniques are also used to detect abnormal cells and disease in other parts of the human body.

Cytological techniques are widely employed because collection of cell samples for analysis is generally less invasive than traditional surgical pathological procedures such as biopsies, whereby a tissue specimen is excised from the patient using specialized biopsy needles having spring loaded translatable stylets, fixed cannulae, and the like. Cell samples may be obtained from the patient by a variety of techniques including, for example, by scraping or swabbing an area, or by using a needle to aspirate body fluids from the chest cavity, bladder, spinal canal, or other appropriate area. The cell samples are placed in solution and subsequently collected and transferred to a glass slide for viewing under magnification. Fixative and staining solutions are typically applied to the cells on the glass slide, often called a cell smear, for facilitating examination and for preserving the specimen for archival purposes.

However, cells can slough off the substrate during subsequent washes. As is common in this field, the cells are washed by dipping the cell-containing substrate into a solution. Cells can easily dissociate from the substrate and remain in the wash solution. Subsequent dips of different cytological samples can pick up such cells and result in a contaminated the sample. What is therefore needed is a composition and method for inhibiting contamination of a cell sample with unwanted cells.

BRIEF SUMMARY

The present subject matter is directed to compositions and methods for inhibiting or preventing contamination of a cytological sample for analysis, wherein the sample is associated with a substrate. In preferred embodiments, the methods disclosed herein are directed to contacting a polyanionic polymer material with a sample and a substrate, where the sample is associated with the substrate, where the substrate has a net cationic charge density. Upon contacting the sample with the polyanionic solution, contamination of the sample by other biological material, particularly cells, is inhibited or prevented.

In an aspect, the subject matter described herein is directed to a method of inhibiting contamination of a cytological specimen, comprising: contacting the cytological specimen with a polyanionic polymer composition for a period Ti to prepare a cytological sample having a coating of the polyanionic polymer on at least a portion thereof, where the cytological sample is associated with a substrate, where the substrate has a net cationic charge density prior to contact with a polyanionic polymer solution, and where the cytological sample and the substrate are inhibited from associating with additional biological material.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood and features, aspects and advantages other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such detailed description makes reference to the following drawings, wherein:

Figure 1 is a flow chart for an embodiment as described herein. A biological sample is associated with a coated substrate and the sample and substrate are contacted with a polyanionic solution without incubation. Consequently, the resulting sample and substrate are inhibited from associating with additional biological material.

Figure 2 shows sample cells associated with a glass slide.

Figure 3 shows inhibition of additional cells to associate with the substrate slide on the lower portion of the slide that has been dipped for 1-5 seconds in a polyanionic polymer solution disclosed herein. Figure 4 shows a stained sample. Note that the portion that has been inhibited from associating with additional cells shows no appreciable staining except for the sample cells. Importantly, the process does not inhibit the staining of the target cells. DETAILED DESCRIPTION

The subject matter disclosed herein is directed to compositions and methods for inhibiting the contamination of a biological sample. Advantageously, in preferred embodiments, the compositions and methods described herein are employed with a substrate having a net cationic charge. The net cationic charge provides an electric potential that increases the association of a biological sample to the substrate. At this point, however, the substrate and sample may be vulnerable to cross-contamination from extraneous cells in a community well or dip tank.

As is typical in the field of cytology, biological samples are prepared in community wells or dip tanks. In other words, the sample and substrate are dipped into wells or tanks of solutions that have previously or simultaneously been used for preparing other biological samples, i.e., samples from other subjects. As a result, biological material from one sample can dissociate from the substrate and enter the solution. The solution is then contaminated with biological material. As more samples are processed using the same solution or well, this dissociation process can repeat, which results in a solution or well that contains numerous cells and other biological materials from any number of different samples and subjects. These dissociated cells in solution can then become associated with subsequent substrates causing contamination of the samples. Though high throughput screening is an indispensable tool, it is hampered by the possibility of cross-contamination. Unfortunately, all too often this can lead to the determination and reporting of a false-positive result. The presently described methods solve this shortcoming in the current technology. The use of cytological samples prepares by the present methods solve the contamination problem and allow for the high throughput screening of samples. Because the present methods inhibit contamination, the methods also decrease false-positives.

While blocking solutions are known to limit background noise, the methods employed require sufficiently long incubation periods (30 minutes) to reduce background noise. In contrast, the present methods preferably utilize charge density to quickly form an inhibitory coating on a cytological sample such that the sample is inhibited from becoming contaminated with additional biological material. As used herein, the term "contaminant" or "contaminated" and variations thereof refer to unwanted material, in particular, unwanted biological material associating with the substrate or the sample. This biological material includes material from a subject other than the subject whose sample has been purposefully affixed on the substrate. The term includes "extraneous biological material," "unwanted biological material" or "additional biological material." In particular, the material is a material that originated from one subject and may contaminate another subject's sample. The contamination of a subject's sample in this way is often the result of high throughput processing of cytological samples using community wells or dip tanks of solutions during preparation of the samples for analyses.

The term "biological material" refers to material that is biological in origin and comprises tissue, cell or a population of cells, cell extracts, DNA, RNA, cell homogenates, exudate, biological markers, purified or reconstituted proteins, recombinant proteins, bodily and other biological fluids, viruses or viral particles, prions and subcellular components. Biological material can refer to a biological fluid such as whole blood, plasma, senim, nasal secretions, sputum, saliva, urine, sweat, transdermal exudates, cerebrospinal fluid, or the like. Biological fluids also include tissue and cell culture medium wherein an analyte of interest has been secreted into the medium. The origin can be derived from organs, tissue or cells from the animal.

Examples of sources of such samples include muscle, eye, skin, gonads, lymph nodes, heart, brain, lung, liver, kidney, spleen, thymus, pancreas, solid tumors, macrophages, mammary glands, mesotheiium, and the like. Cells include without limitation prokaryotic cells such as bacteria, yeast, fungi, mycobacteria and mycoplasma, and eukaryotic cells such as nucleated plant and animal ceils that include primary cultures and immortalized cell lines. Prokaryotic ceils include E. coli and S. aureus. Eukaryotic ceils include without limitation ovary cells, epithelial cells, circulating immune cells, β cells, hepatocytes, and neurons. Since an aim of the methods is to determine the presence or absence of abnormal biological material, such as abnormal cells, the material can include cancerous and pre-cancerous biological material. The biological material is preferably a prokaryotic cell.

As used herein, the tern "contacting" refers to allowing the sample to come into physical contact with a polymer solution by dipping, immersing and the like the sample in a solution of the polymer. As used herein, contacting is performed for a period of time, Tj . Because the time period is relatively short, the term contacting does not include incubating.

As used herein, the term "inhibited" or "inhibiting" means a reduction in the amount of unwanted biological material that becomes associated with the cytological sample and/or substrate that would associate in the absence of the inhibitory coating, such as the polyanionic polymer material coating. This inhibition may be from a partial to a complete reduction in the association of unwanted biological material.

As used herein, the term "inhibitory coating" means at least a portion of the substrate and/or sample associated with the substrate has an amount of polyanionic polymer solution covering it. Preferably, the coating substantially or completely covers the substrate and/or sample associated with the substrate.

As used herein, the term "cytological sample" means an amount of biological material that has been coated on at least a portion thereof with a polyanionic solution, wherein the material is associated with a substrate.

As used herein, "specimen" means an amount of biological material that has been obtained or is derived from a subject.

As used herein, the term "subject" refers to any plant or animal from which a sample can be obtained. Preferably, the subject is a mammal, which includes humans as well as all other mammalian animals. As used herein, the term "mammal" includes a patient and refers to a warm blooded animal. It is understood that guinea pigs, dogs, cats, rats, mice, horses, goats, cattle, sheep, zoo animals, livestock, primates, and humans are all examples of animals within the scope of the meaning of the term. As used herein, "a subject in need thereof can be a subject whom may be suspected of suffering from a condition and is need of a diagnostic assay that can identify whether the condition exists. Alternatively, the subject may merely be susceptible to a condition where determining the presence or absence of abnormal cells is desirable. In another aspect, "a subject in need thereof can be a subject that is suffering from a condition and the condition can be assessed, such as in the clinical staging of disease, e.g., cancer.

As used herein, the term "net cationic charge density" refers to a property of a substrate or coating on a substrate to contain excess positive charge on the surface. Methods for determining charge density are described in PCT/US2005/033938

(WO/2006/034385), herein incorporated by reference in its entirety. Briefly, one method suitable for use in quantifying charge density of the coated substrate would directly measure charge density in terms of charge density per area of coated substrate. Another method would indirectly measure charge density by correlation to another measurable property. For example, the charge density of the polymeric coating material coated on the substrate can be quantified through spectrographic measurement of a dye associated with the coated substrate (e.g., adsorbed thereon).

The ability of a coated substrate to adhere or associate with a biological sample (generally being negatively charged) is directly related to the quantity of excess positive charge on the slide surface. When a negatively charged dye is associated with the slide surface, the excess positive charge on the slide surface can be quantified through spectrographic analysis of the dye. It is well known in the art that the absorption of electromagnetic radiation at a given wavelength by a dye is directly proportional to the concentration of the dye. Therefore, given a proportional relationship between the anionic dye and the cationic coating material, a measurement of absorbance of the dye associated with the coating material is a reliable indicator of the quantity of excess positive charge on the surface of the coated substrate. In other words, the greater the charge density, the greater the concentration of the dye adsorbed on the coated substrate, and the greater the dye's absorption of electromagnetic radiation at a given wavelength. Such a measurement technique is described by Tadao Sakai and Akihiko Hirose (Talanta 59 (2003) 167-175), which is incorporated herein by reference. The charge density of a pre-coated substrate, through quantitative measurement, can easily be seen to be much greater than the charge density of a substrate that does not have a net cationic charge density.

The term "abnormal cell" refers to any diseased or pathological cell. Abnormal cells demonstrate abnormal morphological characteristics when viewed

microscopically. These abnormal morphological characteristics can be observed by employing the cytological staining compositions disclosed herein and simple light microscopy. Non-limiting examples of abnormal cells include pre-cancerous changes as well as true cancerous cells.

In embodiments, the abnormal cell is a cancerous, pre-cancerous or atypical cell. Cells of the following types of cancers are of particular interest: a solid tumor, such as cervical or cancer of the reproductive system, brain, lung, liver, spleen, kidney (such as renal cell and renal pelvis), lymph node, small intestine, pancreas, blood cells, bone, colon/colorectal, stomach, breast, endometrium, prostate, testicle, ovary, central nervous system, skin, head and neck, esophagus, or bone marrow, or a hematological cancer, such as leukemia, acute promyelocyte leukemia, lymphoma, multiple myeloma, myelodysplasia, myeloproliferative disease, or refractory anemia. In particular, the cancer cell is cervical or an atypical cell associated with cervical cancers or disorders or correlated to the incidence of such cancers or disorders.

In an embodiment, the subject matter described herein is directed to a method of inhibiting contamination of a cytological specimen, comprising: contacting the cytological specimen with a polyanionic polymer composition for a period Ti to prepare a cytological sample having an inhibitory coating on at least a portion thereof, wherein the cytological sample is associated with a substrate, wherein the substrate has a net cationic charge density prior to contact with a polyanionic polymer solution, wherein the cytological sample and the substrate are inhibited from associating with additional biological material. The method further comprises removing the sample from the polyanionic polymer solution immediately upon the expiration of the time period TV A subsequent immediate rinse step in all embodiments is also contemplated.

Useful periods of time, Ti, are less than 10 minutes and do not require a longer period of time, such as an incubation step. Preferably, the period of time, T_ls that the polyanionic polymer solution is contacted with the sample is less than five minutes. More preferably, the period of time, T_ls that the polyanionic polymer solution is contacted with the sample is less than one minute. Most preferably, the period of time, Ti, that the polyanionic polymer solution is contacted with the sample is from about 1 second to about 60 seconds. In this aspect, the period of time, T_ls is 1-5 seconds; 1-10 seconds; 1-20 seconds; 1-30 seconds; 1-40 seconds or 1-50 seconds. For a number of reasons, the period of time, T_ls is optimally from about 1 to about 5 seconds. Unlike known methods that require substantially long incubation periods with a blocking solution to reduce background noise, in embodiments, the present methods

advantageously use a substrate having a net cationic charge that significantly reduces the amount of time for forming an inhibitory coating on a sample. Methods described in the art are only concerned with limiting background staining rather than inhibiting contamination of a sample with unwanted biological material. This unwanted biological material poses a significant problem since it can lead to false-positive test results and incorrect diagnoses. Accordingly, the methods employing short periods of time, Ti, are highly efficient and applicable to high through-put screening protocols. Additionally, the brief period Ti has the advantage of reducing the time of overall exposure that the sample could be contaminated. In embodiments, the cytological sample is associated with a substrate. Though standard substrates, such as glass slides, generally have a net anionic charge, the preferred substrate employed in the present methods will have a cationic coating that provides a net cationic charge density. Such a coating provides a charge potential that binds biological samples of interest to the substrate. Cells have a net negative charge on their outer surface. This charge difference between the cells and the treated slides creates the electrostatic adhesion to immobilize the cells on the slide surface. However, a pre-coated microscopic slide can have a coating that facilitates fixation of the sample to the slide. An exemplary substrate of this kind is described in PCT/US2005/033938 (WO/2006/034385).

In a preferred embodiment, the substrate has a coating that exhibits a net positive (cationic) charge and the surface of the cytological specimen exhibits a net negative (anionic) charge. The net positive charge of the slide coating associates with the negatively charged sample cells. This cell adhesion property of the coating solution allows the immobilization of the sample material during all subsequent processing.

However, unbound cells from other samples can bind to exposed cationic sites on these slides when multiple sample slides are processed in the same container, such as is commonly found in many automated cytology processing devices. This cross- contamination can make diagnosis more difficult and can potentially result in false positive results. In fact, any negatively charged material, such as biological materials including nucleic acids and many proteins, can be non-specifically bound to these coated slides and result in equally undesirable effects. The cationic nature of the substrate allows for a very short period, Ti, for preparing an inhibitory coating to inhibit contamination. A significant feature of the present methods is this shortened time required for preparing the cytological sample for further processing. This was not thought possible since long incubation periods have been reported for the purpose of limiting background staining such that the time required made it inefficient, undesirable and impractical for high throughput screenings methods.

The pre-coated substrates comprise a polycationic coating. Preferably, the polycationic coatings are as described in PCT/US2005/033938 (WO/2006/034385). However, immobilization of biological materials using pre-coated slides may be susceptible to the non-specific binding of extraneous negatively charged materials. To inhibit contamination after the cytological specimen has been immobilized, most, if not all, remaining cationic sites can be neutralized or de-activated using the methods described herein.

Useful polyanionc polymer materials include synthetic polymers. The polyanionic polymer is selected from the group consisting of a polystryrene or copolymer thereof; a polyacrylamide or copolymer thereof; a polyvinylene or copolymer thereof; a polyacrylate or copolymer thereof; a polyalkaiene or copolymer thereof; a polyaniline or copolymer thereof; a polypbenylalkylene of copolymer thereof; a giycosaminoglycan or derivative thereof; a heparin or derivative thereof; a dextran or derivative thereof; a suramin or derivative thereof; carrageenan or derivative thereof; a cyclodextrin other than sulfobutylether beta-cyclodextrin or derivative thereof; a cellulose or derivative thereof; a pentosan or derivative thereof; a dextrin or derivative thereof; a laminarin or derivative thereof; a dermatan or derivative thereof; a chitin or derivative thereof; a ehitosan or derivative thereof; a curd! an or derivative thereof; a pullulan or derivative thereof; a keratan or derivative thereof; a fucoidan or derivative thereof; a ficoll or derivative thereof, a xylan or derivative thereof; an amylose or derivative thereof; a galactan or derivative thereof; a mucin or derivative thereof; a galactomannan or derivative thereof; a mannan or derivative thereof; a glucaii or derivative thereof; a fucan or derivative thereof; a heparaosan or derivative thereof; a rhamnan or derivative thereof; a catechin or derivative thereof; or, a calixarene or derivative thereof, or a combination or mixture thereof.

In more particular embodiments, the polymeric material is a sulfonated polystyrene or copolymer thereof. These include poly(sodium 4-styrenesulfonic acid), poly(4-styrenesulfonic acid-co-maleic acid), sulfonated poly(4-methylstyrene), sulfonated poly(alpha-methylstyrene), sulfonated poly(styrene-block-ethyleneoxide- block-styrene), sulfonated poly(ethyleneoxide-block-styrene-block-ethyleneoxide), sulfonated poly(4-methoxystyrene), sulfonated poly(ethyleneoxide-block-styrene), sulfonated poly(styrene-block-ethylene), sulfonated poly(styrene-co-butadiene), sulfonated poly(styrene-block-(ethylene-co-butylene)-block-styrene,

poly(styrenesulfonate-co-styrene), poly(styrenesulfonate-co-acrylic acid),

poly(styrenesulfonate-co-methacrylic acid), poly(styrenesulfonate-co- acrylamidomethylpropanesulfonate), poly(styrenesulfonate-co-itaconic acid), poly(styrenesulfonate-co-vinylbenzoic acid), poly(styrenesulfonate-co- octylstyrenesulfonamide), polystyrenesulfonate-co-menthylstyrenesulfonate), poly(styrenesulfonate-co-lithocholic acid styrenesulfonate), poly(styrenesulfonate-co- diallylmethylammonium chloride), poly(styrenesulfonate-co-diallyidimethylammonium chloride), poly(styrenesulfonate-co-diallylmethyloctylammonium chloride),

poly(styrenesulfonate-co-allylamine), poly(styrenesulfonate-co-vinylamine) and poly(styrenesulfonate-co-vinylbenzyltrimethylammonium chloride).

Useful concentrations of the polyanionic polymer solution include from about

0.001 % to about 20 % (w/v). Preferably, the concentration of the polyanioinic polymer solution is from about 0.001 % to about 10 % (w/v). More preferably, the concentration of the polyanioinic polymer solution is from about 0.01 % to about 5 % (w/v). Most preferably, the concentration of the polyanioinic polymer solution is from about 0.1 % to about 1 % (w/v). In a preferred embodiment, the methods described herein employ poly(sodium 4-styrene-sulfonate) at a concentration of 0.25%

weight/volume. The polyanionic polymer material can be dissolved in the solvent at a concentration that is selected for particular results or applications, such as a

concentration from about 0.1 mg/mL to about 20 mg/niL, for example, a concentration from about 0.5 mg mL to about 10 mg/mL such as a concentration from about 1 mg/mL to about 5 mg/mL.

The polyanionic polymer material may be supplied in the form of a liquid, solid, gel or powder. When necessary, the polyanionic polymer material can be contacted with a solvent to prepare the solution that will be used in the present methods. The solvents can be water-based or organic solvents. The term "organic solvent" refers to an organic compound with solvent properties or a mixture of organic compounds with solvent properties. Generally, in the field of the invention, organic solvents belong to various chemical classes such as hydrocarbons, ketones, alcohols, carboxylic acid esters, and the like. Preferably, the cytological staining solutions described herein are water-based and contain low, trace or zero amounts of organic solvents. The term "water-soluble solvent" means a liquid that solvates the components of the

composition, is substantially inert and will dissolve in water. This is intended to mean that the solvent does not affect pH or any other property of the composition. A water- soluble solvent may also be an organic solvent.

The polyanionic polymer solutions may further contain a buffer which refers to a liquid medium that mimics the salt balance and pH of the cytoplasm of a cell or of the extracellular milieu. Examples of buffers include phosphate buffers (PB), Tris buffers, acetate buffers, bicarbonate buffers, carbonate buffers, borate buffers, citrate buffers, phosphate buffered saline (PBS) buffers and the like. Other examples of buffers include BES, Bicine, EPPS, HEPES, MES, MOPS, MOPSO, PIPES, TAPS, TAPSO, TES, Tricine, Trimethylammonium acetate, ADA, ACES, DIPS, DIPSO, AMPS, AMPSO, CAPS and the like. Particular examples of physiological buffers include phosphate-, Tris- or borate-buffered saline (PBS, TBS or BBS) with pHs ranging from 6.5 to 8.0, or non-saline buffers such as acetates, bicarbonates, or citrates within this pH range. In a particular embodiment, the buffer comprises a PBS buffer, for example, 0.01M phosphate buffer, 0.15M NaCl, at pH 7.2. The polyanionic polymer solutions can have any pH between 0 and 14 established by a particular buffer.

The polyanionic polymer solution may further include a surfactant. Suitable surfactants are typically any nonionic biological surfactant useful for solubilization of proteins and membrane components. Polyoxyethylenesorbitans and polyoxyethylene ethers are examples of such non-ionic surfactants, and specific examples include polyoxyethylenesorbitan monolaurate and polyoxyethylene 23 lauryl ether. The surfactant is generally used at a concentration of from about 0.01 to about 5% (v/v), more typically from about 0.05 to about 1% (v/v), such as from about 0.05 to about 0.5% (v/v).

The polyanionic polymer solution can also include a preservative. The solutions can include an antimycotic or antimicrobial agent in an effective

concentration to inhibit growth of microorganisms in the solution. Preservatives that do not interfere with specific binding reactions, such as immunochemical reactions, are well known. The preservative can be a broad spectrum preservative, such as one that is effective against both bacteria (both gram positive and gram negative) and fungi, or a limited spectrum preservative, such as one that is only effective on a single group of microorganisms. A limited spectrum preservative can be used in combination with a broad spectrum preservative or other limited spectrum preservatives with

complimentary and/or supplementary activity. Preservatives are typically effective at concentrations in the range of from about 0.001% to 0.1%, more typically at about 0.01 to about 0.1%, and even more typically at about 0.05%.

Exemplary preservative agents include azides, metal chelating agents, gentamycin, penicillin, streptomycin, thimerosal, and a mixture of 2-chloro-2-methyl-4- isothiazolin-3-one, 2-methyi-4-isothiozoiiii-3-one and triethylorthoformate in dipropylene glycol. In some embodiments, merthiolate (ihimerosol) or sodium azide is added, for example, at 0.01 to 0.05%, to retard microbial growth. In some cases where a specific group of microbial contaminants is problematic (such as Gram negatives), aminocarboxylate chelators may be used alone or as potentiators in conjunction with other preservatives. These chelators include, for example, ethylenediaminetetraacetic acid (EDTA), ethylene glycol-bis(2-aminoethyl)-N,N,N',N''-tetraacetic acid (EGTA, o- pbenanthroline hydroxyethylenediamineiriacetic acid, diethylenetriaminepentaacetic acid, and other aminocarboxylate chelators, and mixtures thereof, and their salts, and mixtures thereof.

Procurement of the sample material from the subject for the cyto logical evaluation utilizes any methods known in the art. In conjunction with sample collection, samples may be exposed to other agents such as buffers, diluents, extraction or chromatographic media, cross-linking agents, blocking agents, denaturing agents, etc., to stabilize or otherwise prepare the sample for processing within a desired assay.

Specimens can be associated with useful substrates that are selected from the group consisting of, but not limited to, a microscope slide, a cuvette, microtiter trays, tissue typing trays, films and standard cover slides. Preferably, the substrate is a microscopic slide. In a preferred embodiment, the method does not comprise associating a standard cover slide with the sample that is associated with the substrate. A standard cover slip is a plastic, glass or other material that is transparent and can be hard or flexible. A standard cover slip does not include a liquid cover slip.

After the cytological sample material has been associated, e.g., immobilized or affixed, on the substrate, such as a pre-coated slide, the slide can simply be contacted with the polyanionic polymer solution. In this aspect, the cytological sample associated with a substrate can simply be dipped into the polyanionic polymer solution or the polyanionic polymer solution can be rinsed over the cytological sample that is associated with a substrate. This dipping or rinsing only requires one second or a few seconds of contact to prepare a cytological sample having a polyanionic polymer coating on at least a portion thereof. Accordingly, in the most preferred methods, the period of time, Ti, for contacting the sample with the polyanionic polymer solution is only one second to about five seconds. This relatively short dipping or rinsing step can advantageously provide a methodology that can be employed with high through-put screening protocols. After exposure to the polyanionic polymer solution, the slide can be subjected to a rinse. Rinsing and washing solutions are known in the art; however, preferably the solution is DI H₂0. The slide is now ready for further processing.

Further processing steps can include contacting the prepared cytological sample with a solution to further rinse, stain, fix, etc. the cytological sample. Preferably, the methods described herein can be incorporated as an exceedingly efficient step in a cytological sample preparation protocol. In customary cytological protocols, the sample must first be immobilized on a substrate. Only then is it practical to stain or further process the immobilized sample. In customary protocols in particular, any step that employs a common dip tank or well can introduce unwanted biological material to the desired sample. In other protocols, cytological staining compositions can advantageously be used in a solution that immobilizes the sample and concurrently stains the nuclear and/or cytoplasmic structures of the cells. The polyanionic polymer solution can be employed at any point after the sample is associated with the substrate. It will be most advantageous to employ the polyanionic polymer solution prior to exposing the sample to any conditions that can cause unwanted biological materials to also associate with the sample or the substrate. As discussed above, these conditions include community dip wells that are ubiquitous in the field of cytological preparation.

Dye solutions are known in the art. Most cytology staining techniques rely on

"acid ionized" stains that contain negatively charged functional groups. As such, these stains can compete with the negative charged cell surfaces for binding sites on the positively charged glass slides. Many of these stains are also alcohol based and considered a hazardous material due to the corrosive qualities of the low pH (acid) and the flammability due to the high alcohol content. Preferably, the stain used in this process is from a class of "basic ionized" stains and contains positively charged functional groups. These charges do not compete for the negative binding sites on the positively charged slide surface. Therefore, cells stained with these types of stains bind readily and strongly adhere to the positively charged slides. As these stains are aqueous based and are used at a relatively neutral pH of 6.0 - 8.0, they would not be considered corrosive.

Cationic dyes are preferred. Useful cationic dyes include crystal violet, acriflavine, bismarck brown, malachite green, methyl green, Victoria pure blue BO, and Azure C, and analogues thereof. Examples of cationic dyes include those listed in Table 1 :

Table 1. Cationic dyes

A particularly useful dye is Azure C. Azure C has the following chemical structure:

Anionic dyes can also be used in the cytological staining compositions described herein. However, because of the convenience and oftentimes necessity for a one-step, straightforward cytological preparation, the cationic dyes disclosed herein are preferred.

Staining the target cells with standard biological dyes provides important morphological detail that assist in the identification of abnormal cells. Other critical information useful for a more thorough diagnosis, such as the presence or absence of specific protein markers within the cell can also be obtained using the methods described herein. To ascertain such protein marker details from these abnormal cells, the presently described methods can incorporate known immunochemistry techniques. These techniques involve the application of specific antibodies designed to detect the protein markers of interest, along with some type of signaling entity to indicate that the antibody has indeed attached to the proteins of interest in the cells. These signaling entities can include, but are not limited to, conjugated dyes, fluorochromes, chemilluminescent reactants, and radioactive isotopes. The compositions and methods described herein provide inhibition of the association of unwanted materials to the substrate while still allowing staining of the target cells with biological stains, which includes staining using known immunochemistry compositions and techniques.

Fixing solutions and rinsing solutions are known in the art. Fixing solutions contain fixatives that are well-known in this field. Rinsing and fixing solutions are preferably water-based but can contain polyols and hygroscopic polyols. As used herein, the term "hygroscopic" is intended to mean a property of a polyol to attract and hold water molecules from the surrounding environment. This can be achieved by absorption or adsorption. The polyol may physically change as it absorbs or adsorbs water, for example, by an increase in its volume, stickiness or ability to hydrate substances that the polyol is contacting. As used herein, the term "polyol" is intended to encompass aliphatic diols and triols and derivatives thereof. Preferably, the polyol is a liquid. Useful hygroscopic polyols include glycerol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 2,3- butanediol, 1 ,4-butanediol, 3 -methyl- 1,3-butanediol, 1,5-pentanediol, tetraethylene glycol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, polyethylene glycol, 1,2,4- butanetriol, 1,2,6-hexanetriol, 2-ethyl-2-methyl-l,3-propanediol, 3,3-dimethyl-l,2- butanediol, 2,2-diethyl-l,3-propanediol, 2-methyl-2-propyl-l,3-propanediol, 2,4- dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene-l,2-diol, 2-ethyl-l,3- hexanediol or 2,2,4-trimethyl- 1 ,3-pentanediol, butylene glycol, pentaerthyritol, mannitol, sorbitol, di-glycerol, tri-glycerol, tetra-glycerol, erythritol, 2-hydroxymethyl- 2-methyl-l,3-propanediol (trimethylolethane), 2-ethyl-2-(hydroxymethyl)-l,3- propanediol (trimethylolpropane), 1,2,4-hexanetriol and mixtures thereof. Preferably, the glycol is glycerol or sorbitol. Most preferably, at least one of the polyol(s) contained in the composition is glycerol. Most preferably, the only polyol contained in the composition is glycerol.

As used frequently in this field, staining, rinsing and fixing solutions will have been exposed to many samples since the solution is contained in a community well or dip tank. Consequently, the solutions can comprise unwanted biological material. This biological material can then associate with any of the samples that are contacted with the solution. This can lead to contamination of one subject's sample with biological material from another subject. The result can lead to false-positive results.

To inhibit or prevent this from happening, the present methods prepare a cytological sample that is inhibited from associated with additional biological material. Thus, the cytological samples prepared suing the present methods are particularly useful in protocols that employ community wells or dip tanks. These protocols are often employed in high throughput screenings.

In another embodiment, a pre-coated substrate that has a net-positive charge is first coated with a polyanionic polymer material as described herein. A sample that has a net positive charge is then contacted with the net-negative charged substrate to adhere the sample to the substrate. The adhered sample and substrate are then contacted with a cationic polymer solution.

Cationic polymers include those derived from at least one monomer selected from the group consisting of diallyldimethylammonium, allylamine, methylacrylamidopropyltrimethylammonium, acrylamide, acrylic acid,

methacryloyloxyethyltrimethylammonium, 4-vinyl-benzyltrimethylammonium, methacrylic acid, hydroxyethylacrylate, methacrylate, methylmethacrylate,

hydroxyethylmethacrylate, 4-vinylpyridinium, 4-vinyl-l-methylpyridinium, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethyl hexyl acrylate,

dimethylaminoethylacrylate, dimethylaminoethylacrylate methyl chloride quaternary, dimethylaminopropylacrylamide, dimethylaminopropylacrylamide methyl chloride quaternary, acryloxyethyldimethylbenzyl ammonium, acryloxyethyltrimethyl ammonium, dimethylaminoethylmethacrylate, methacryloxyethyldimethylammonium, methacryloxyethyltrimethylbenzylammonium, ethene, ethyleneimine, propene, styrene, vinyl chloride, isobutylene, trimethyl-2-methacryloylethylammonium, trimethyl-2- methacrylaminopropylammonium, and mixtures thereof.

In another preferred embodiment, the polymeric coating material comprises a copolymer of a cationic monomer and at least one additional monomer. Preferentially, the polymeric coating material comprises a copolymer of diallyldimethylammonium and at least one additional monomer. Most preferably, the at least one additional monomer comprises a vinylic monomer. In one embodiment, the polymeric coating material comprises a copolymer comprising diallyldimethylammonium and acrylic acid monomer units. In another embodiment, the polymeric coating material comprises a copolymer comprising diallyldimethylammonium and acrylamide monomer units. In another embodiment of the invention, the polymeric coating material comprises a terpolymer comprising diallyldimethylammonium, acrylic acid, and

hydroxyethylmethacrylate monomer units.

Preferably, the polymeric coating material according to the present invention is "non-peptidic", meaning the linkages between monomer units are predominately and, preferably substantially, non-peptidic in nature.

In an embodiment, the methods described herein further comprise subjecting the prepared cytological sample to an assay to determine the presence or absence of abnormal cells. Once the sample has been prepared as described herein, any known method of analyses can be employed. Such methods include visual assessment with or without the aid of a magnifying device such as a microscope. A system for imaging a cytological sample including nuclear material and cytoplasmic material that includes an optical instrument and one or more light sources can be employed. Other equipment and techniques are known to those of skill in this field such as cytologists, technicians and pathologists, and can be used in combination with the compositions and methods disclosed herein.

The assay can be any analyses or evaluation employed to determine the presence or absence of abnormal cells. These analyses are known in the art and can be automated or can be performed by a human such as a technician, cytologist or pathologist. Preferably, since the methods described herein require as little as seconds to complete, the methods are incorporated into a high through-put screening protocol.

In an embodiment, the subject matter described herein is directed to a method of preparing a cyto logical sample comprising:

a. Depositing cells onto a substrate, such as a microscope slide, wherein the slide has a polycationic coating;

b. Rinsing excess cells from the substrate;

c. Contacting the sample associated with a substrate to a polyanionic polymer solution for a period of time, T_ls wherein the period is from about 1 second to less than 10 minutes, preferably only 1 second to less than one minute; d. Staining the cells with an appropriate dye;

e. Optionally, contacting the sample on the slide with a liquid cover slip (about 25μ1);

f. Subjecting the sample to analyses.

b. Staining the cells and rinsing excess cells from the substrate;

c. Contacting the stained sample associated with a substrate to a polyanionic polymer solution for a period of time, T_ls wherein the period is from about 1 second to less than 10 minutes, preferably only 1 second to less than one minute;

d. Optionally, contacting the sample on the slide with a liquid cover slip (about 25μ1);

e. Subjecting the sample to analyses.

Additional specific embodiments of the subject matter described herein include the following: Embodiment 1 : A method of inhibiting contamination of a cytological specimen, comprising:

i. contacting the cytological specimen with a polyanionic polymer composition for a period Ti to prepare a cytological sample having a coating of the polyanionic polymer on at least a portion thereof,

wherein Ti is less than ten minutes;

wherein the cytological sample is associated with a substrate, wherein the substrate has a net cationic charge density prior to contact with a polyanionic polymer solution, and

wherein the cytological sample and the substrate are inhibited from associating with additional biological material.

2. The method of embodiment 1, wherein Ti is less than 5 minutes.

3. The method of embodiment 1, wherein Ti is less than 1 minute.

4. The method of embodiment 1, wherein Ti is from 1 second to 50 seconds.

5. The method of embodiment 1, wherein Ti is from 1 second to 40 seconds.

6. The method of embodiment 1, wherein Ti is from 1 second to 30 seconds.

7. The method of embodiment 1, wherein Ti is from 1 second to 20 seconds.

8. The method of embodiment 1, wherein Ti is from 1 second to 10 seconds.

9. The method of embodiment 1 , wherein the polyanionic polymer is a sulfonated polystryrene or copolymer thereof.

10. The method of embodiment 9, wherein the sulfonated polystyrene or copolymer thereof is selected from the group consisting of poly(sodium 4- styrenesulfonic acid), poly(4-styrenesulfonic acid-co-maleic acid), sulfonated poly(4- methylstyrene), sulfonated poly(alpha-methylstyrene), sulfonated poly(styrene-block ethyleneoxide-block-styrene), sulfonated poly(ethyleneoxide-block-styrene-block- ethyleneoxide), sulfonated poly(4-methoxystyrene), sulfonated poly(ethyleneoxide- block-styrene), sulfonated poly(styrene-block-ethylene), sulfonated poly(styrene-co- butadiene), sulfonated poly(styrene-block-(ethylene-co-butylene)-block-styrene, poly(styrenesulfonate-co-styrene), poly(styrenesulfonate-co-acrylic acid), poly(styrenesulfonate-co-methacrylic acid), poly(styrenesulfonate-co- acrylamidomethylpropanesulfonate), poly(styrenesulfonate-co-itaconic acid), poly(styrenesulfonate-co-vinylbenzoic acid), poly(styrenesulfonate-co- octylstyrenesulfonamide), polystyrenesulfonate-co-menthylstyrenesulfonate), poly(styrenesulfonate-co-lithocholic acid styrenesulfonate), poly(styrenesulfonate-co- diallylmethylammonium chloride), poly(styrenesulfonate-co-diallyidimethylammonium chloride), poly(styrenesulfonate-co-diallylmethyloctylammonium chloride), poly(styrenesulfonate-co-allylamine), poly(styrenesulfonate-co-vinylamine) and poly(styrenesulfonate-co-vinylbenzyltrimethylammonium chloride).

11. The method of embodiment 10, wherein the polyanionic polymer is poly(sodium 4-styrenesulfonic acid).

12. The method of embodiment 1, further comprising:

ii. contacting the cytological sample with one or more solutions.

13. The method of embodiment 12, wherein the solutions are selected from the group consisting of staining, fixing and rinsing solutions.

14. The method of embodiment 12, wherein the contacting comprises dipping or rinsing the sample.

15. The method of embodiment 12, wherein the solution has been previously contacted with a cytological specimen from another subject.

16. The method of embodiment 12, wherein the solution comprises the additional biological material.

17. The method of embodiment 1, wherein the cytological sample comprises abnormal cells.

18. The method of embodiment 17, wherein the abnormal cells comprise a cancer cell.

19. The method of embodiment 18, wherein the cancer is selected from the group consisting of cervical, cancers of the reproductive system, brain, lung, liver, spleen, kidney, renal cell and renal pelvis cancers, lymph node, small intestine, pancreas, blood cells, bone, colon/colorectal, stomach, breast, endometrium, prostate, testicle, ovary, central nervous system, skin, head and neck, esophagus, bone marrow, hematological cancers, leukemia, acute promyelocytic leukemia, lymphoma, multiple myeloma, myelodysplasia and myeloproliferative disease.

20. The method of embodiment 18, wherein the cancer is cervical. 21. The method of embodiment 1 , wherein the substrate is selected from the group consisting of a microscope slide, a cuvette, microtiter trays, tissue typing trays, films and coverslips.

22. The method of embodiment 21, wherein the substrate is a microscopic slide.

23. The method of embodiment 1, wherein the substrate has a coating of a non-peptidic cationic polymer on at least a portion thereof.

24. The method of embodiment 23, wherein the non-peptidic polymer comprises at least one monomer selected from the group consisting of

diallyldimethylammonium, allylamine, methylacrylamidopropyltrimethylammonium, acrylamide, acrylic acid, methacryloyloxyethyltrimethylammonium, 4-vinyl- benzyltrimethylammonium, methacrylic acid, hydroxyethylacrylate, methacrylate, methylmethacrylate, hydroxyethylmethacrylate, 4-vinylpyridinium, 4-vinyl-l- methylpyridinium, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethyl hexyl acrylate, dimethylaminoethylacrylate, dimethylaminoethylacrylate methyl chloride quaternary, dimethylaminopropylacrylamide, dimethylaminopropylacrylamide methyl chloride quaternary, acryloxyethyldimethylbenzyl ammonium, acryloxyethyltrimethyl ammonium, dimethylaminoethylmethacrylate, methacryloxyethyldimethylammonium, methacryloxyethyltrimethylbenzylammonium, ethene, ethyleneimine, propene, styrene, vinyl chloride, isobutylene, trimethyl-2-methacryloylethylammonium, trimethyl-2- methacrylaminopropylammonium, and mixtures thereof.

25. The method of embodiment 23, wherein the non-peptidic cationic polymer is polydiallyldimethylammonium.

26. The method of embodiment 1, further comprising:

iii. contacting the cytological sample with a composition comprising a dye, a polyol and a solvent.

27. The method of embodiment 1 or 26, further comprising:

iv. subjecting the cytological sample to an assay to determine the presence or absence of abnormal cells.

28. A kit comprising a polyanionic polymer material and a substrate for a cytological sample, wherein the substrate has a net cationic charge density.

29. The kit of embodiment 28, wherein the substrate is coated with a non- peptidic cationic polymer on at least a portion thereof. 30. The kit of embodiment 28, wherein the polyanionic polymer material is a liquid.

In all embodiments, there is no need for an incubation period. In certain protocols, for example in an automated system, the period Ti may be as long as is needed to hold the sample until the equipment is ready to take the cytological sample and process it further. However, it is noted that in all embodiments, Ti is

advantageously kept to a short period of time so that throughput screenings can be employed when desired or to minimize processing time by eliminating unnecessary procedures.

The methods described herein are combinable with aspects of known cytology preparation processes to simplify the entire sample preparation process, save considerable time, and substantially increase processing throughput.

In an embodiment, the subject matter disclosed herein is directed to kits comprising the polyanionic polymer material and a substrate having a net cationic charge density. The kit can also include components, accessories, reagents and other related materials for practicing the sample preparation methods. These kits are clinically useful for preparing the sample to identify the presence or absence of an abnormal cell. The foregoing kit components are generally assembled in a collective packaging unit, which may include written or otherwise user-accessible instructions detailing the sample collection, handling and/or processing methods of the invention.

Kits for practicing the cytological preparation methods can include a suitable container or other device for collecting, storing, handling and/or processing a biological sample and the polyanionic polymer solution. A range of suitable collection devices is contemplated. For example, simple sterile containers or reservoirs are provided. A variety of solid phase devices, including microscopic glass slides, membranes, filters and like media, are provided to receive or partition selected liquid or solid fractions of the sample or the polyanionic polymer solution, or to receive or partition cells or cellular constituents from the sample. A wide variety of such sample collection devices are widely known or described in the literature, which can be readily adapted for use within specific embodiments. The following examples are offered by way of illustration and not by way of limitation.

EXAMPLES

1. Preparation of a Cytological Sample that is Inhibited from Associating with

Additional Biological Material

Figures 2, 3 and 4 show an actual substrate slide that has been prepared according to a preferred embodiment. Figure 1 shows a sample of cells associated with a substrate slide. This slide was dipped for 1 to 5 seconds in a polyanionic polymer solution, poly(sodium 4-styrenesulfonic acid), followed by a water rinse (deionized water, 1-5 seconds). The slide was then contacted with additional non-target cells. Figure 4 shows that the additional cells were inhibited from associating with the portion of the neat substrate and the cell sample that had been contacted with the polyanionic polymer solution. Figure 5 shows the treated slide after staining with a stain solution. Note that the sample cells that had been contacted with the polyanionic polymer solution do not show contamination with the non-target cells. Importantly, the process does not inhibit the staining of the target cells. Thus, the cells of the prepared sample has not been obscured or contaminated with non-target cells and materials.

As used herein, "about" means within a statistically meaningful range of a value such as a stated concentration range, time frame, molecular weight, volume, temperature or pH. Such a range can be within an order of magnitude, typically within 20%, more typically still within 10%, and even more typically within 5% of a given value or range. The allowable variation encompassed by "about" will depend upon the particular system under study, and can be readily appreciated by one of skill in the art.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art to which the invention pertains. Although any methods and materials similar to or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein.

All publications and patent applications mentioned in the specification are indicative of the level of those skilled in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the appended claims.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A method of inhibiting contamination of a cytological specimen,

comprising:

i. contacting said cytological specimen with a polyanionic polymer composition for a period Ti to prepare a cytological sample having a coating of said polyanionic polymer on at least a portion thereof, wherein said Ti is less than ten minutes;

wherein said cytological sample is associated with a substrate, wherein said substrate has a net cationic charge density prior to contact with a polyanionic polymer solution, and wherein said cytological sample and said substrate are inhibited from associating with additional biological material.

2. The method of claim 1, wherein said Ti is less than 5 minutes.

3. The method of claim 1, wherein said Ti is less than 1 minute.

4. The method of claim 1, wherein said Ti is from 1 second to 50 seconds.

5. The method of claim 1, wherein said Ti is from 1 second to 40 seconds.

6. The method of claim 1, wherein said Ti is from 1 second to 30 seconds.

7. The method of claim 1, wherein said Ti is from 1 second to 20 seconds.

8. The method of claim 1, wherein said Ti is from 1 second to 10 seconds.

9. The method of claim 1, wherein said polyanionic polymer is a sulfonated polystryrene or copolymer thereof.

10. The method of claim 9, wherein said sulfonated polystyrene or copolymer thereof is selected from the group consisting of poly(sodium 4- styrenesulfonic acid), poly(4-styrenesulfonic acid-co-maleic acid), sulfonated poly(4-methylstyrene), sulfonated poly(alpha-methylstyrene), sulfonated poly(styrene-block-ethyleneoxide-block-styrene), sulfonated poly(ethyleneoxide-block-styrene-block-ethyleneoxide), sulfonated poly(4- methoxystyrene), sulfonated poly(ethyleneoxide-block-styrene), sulfonated poly(styrene-block-ethylene), sulfonated poly(styrene-co-butadiene), sulfonated poly(styrene-block-(ethylene-co-butylene)-block-styrene, poly(styrenesulfonate-co-styrene), poly(styrenesulfonate-co-acrylic acid), poly(styrenesulfonate-co-methacrylic acid), poly(styrenesulfonate-co- acrylamidomethylpropanesulfonate), poly(styrenesulfonate-co-itaconic acid), poly(styrenesulfonate-co-vinylbenzoic acid), poly(styrenesulfonate- co-octylstyrenesulfonamide), polystyrenesulfonate-co- menthylstyrenesulfonate), poly(styrenesulfonate-co-lithocholic acid styrenesulfonate), poly(styrenesulfonate-co-diallylmethylammonium chloride), poly(styrenesulfonate-co-diallyidimethylammonium chloride), poly(styrenesulfonate-co-diallylmethyloctylammonium chloride), poly(styrenesulfonate-co-allylamine), poly(styrenesulfonate-co-vinylamine) and poly(styrenesulfonate-co-vinylbenzyltrimethylammonium chloride) .

The method of claim 10, wherein said polyanionic polymer is poly(sodium 4-styrenesulfonic acid).

The method of claim 1, further comprising:

ii. contacting said cytological sample with one or more solutions.

The method of claim 12, wherein said one or more solutions are selected from the group consisting of staining, fixing and rinsing solutions.

The method of claim 12, wherein said contacting comprises dipping or rinsing said sample.

The method of claim 12, wherein said solution has been previously contacted with a cytological specimen from another subject.

16. The method of claim 12, wherein said solution comprises said additional biological material.

17. The method of claim 1, wherein said cytological sample comprises

abnormal cells.

18. The method of claim 17, wherein said abnormal cells comprise a cancer cell.

19. The method of claim 18, wherein said cancer is selected from the group consisting of cervical, cancers of the reproductive system, brain, lung, liver, spleen, kidney, renal cell and renal pelvis cancers, lymph node, small intestine, pancreas, blood cells, bone, colon/colorectal, stomach, breast, endometrium, prostate, testicle, ovary, central nervous system, skin, head and neck, esophagus, bone marrow, hematological cancers, leukemia, acute promyelocytic leukemia, lymphoma, multiple myeloma, myelodysplasia and myeloproliferative disease.

20. The method of claim 18, wherein said cancer is cervical.

21. The method of claim 1 , wherein said substrate is selected from the group consisting of a microscope slide, a cuvette, microtiter trays, tissue typing trays, films and covers lips.

22. The method of claim 21, wherein said substrate is a microscopic slide.

23. The method of claim 1, wherein said substrate has a coating of a non- peptidic cationic polymer on at least a portion thereof.

24. The method of claim 23, wherein said non-peptidic polymer comprises at least one monomer selected from the group consisting of

diallyldimethylammonium, allylamine,

methylacrylamidopropyltrimethylammonium, acrylamide, acrylic acid, methacryloyloxyethyltrimethylammonium, 4-vinyl- benzyltrimethylammonium, methacrylic acid, hydroxyethylacrylate, methacrylate, methylmethacrylate, hydroxyethylmethacrylate, 4- vinylpyridinium, 4-vinyl-l-methylpyridinium, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethyl hexyl acrylate, dimethylaminoethylacrylate, dimethylaminoethylacrylate methyl chloride quaternary,

dimethylammopropylacrylamide, dimethylammopropylacrylamide methyl chloride quaternary, acryloxyethyldimethylbenzyl ammonium,

acryloxyethyltrimethyl ammonium, dimethylaminoethylmethacrylate, methacryloxyethyldimethylammonium,

methacryloxyethyltrimethylbenzylammonium, ethene, ethyleneimine, propene, styrene, vinyl chloride, isobutylene, trimethyl-2- methacryloylethylammonium, trimethyl-2- methacrylaminopropylammonium, and mixtures thereof.

25. The method of claim 23, wherein said non-peptidic cationic polymer is polydiallyldimethylammonium.

26. The method of claim 1, further comprising:

iii. contacting said cytological sample with a composition comprising a dye, a polyol and a solvent.

27. The method of claim 1 or 26, further comprising:

iv. subjecting said cytological sample to an assay to determine the presence or absence of abnormal cells.

28. A kit comprising a polyanionic polymer material and a substrate for a

cytological sample, wherein said substrate has a net cationic charge density.

29. The kit of claim 28, wherein said substrate is coated with a non-peptidic cationic polymer on at least a portion thereof.

30. The kit of claim 28, wherein said polyanionic polymer material is a liquid.