CN104083780A - Medical contrast agent containing unsaturated polymer - Google Patents

Abstract

The invention discloses a medical contrast agent containing unsaturated polymer. A microsphere, namely the medical contrast agent is of a hollow inorganic/organic/inorganic three-layer structure, a cavity is formed in the center of the microsphere, and air is filled inside the cavity; the outer layer of the cavity is provided with alpha-Fe2O3 magnetic particles; the intermediate layer is a core/shell polymer nanomicrosphere which is obtained by copolymerizing a polybutadiene-polyacrylic acid random copolymer, polyacrylic acid and divinyl benzene by means of free radicals, and the copolymer is stable because a coordinate bond or ionic bond can be formed between the copolymer and the alpha-Fe2O3 magnetic particles on the inner layer through carboxyl and ferric salt on the inner surface; the outer layer is silicon dioxide, and is connected with the silicon hydroxyl on the surface of the silicon dioxide through carboxyl on the surface of the microsphere by generating a hydrogen-bond interaction with the silicon hydroxyl on the surface of the silicon dioxide. The medical contrast agent has the advantages that the copolymer microsphere belongs to nano-grade particles, targeted location of the contrast agent can be realized by means of the alpha-Fe2O3 magnetic particles on the inner layer, the silicon dioxide hollow microsphere has good biocompatibility and mechanical stability, and the inner cavity can generate a strong echo signal under a radiography mode.

Description

A kind of containing unsaturated high molecular medical contrast medium

Technical field

The present invention relates to a kind of medical treatment detection contrast agent, relate in particular to a kind of Nano microsphere with the multilamellar organic/inorganic composite construction of magnetic function, belong to medicine technology field.

Background technology

In recent years, molecular image technology is because it can provide important information to be paid close attention to widely (Campbell R. E., Chang C. J. for medical diagnosis on disease and the monitoring of biological tissue curr Opin Chem Biol, 2010,14 (1): 1-2.).In numerous imaging patterns, ultra sonic imaging is as a kind of AT biomedical imaging pattern, because it has imaging and diagnosis safety is timely, cheap, light and fast, utilization are extensive etc. that advantage has important researching value.Yet between different biological tissues, the difference of echo-signal usually can hinder the accuracy of diagnosis; in order to obtain better the accurate information of particular organization; people conventionally adopt (the R. D í az-L ó PBz that adds the method for ultra sonic imaging contrast agent to realize; Tsapisa N.; Libong D., et al. biomaterials, 2009,30 (8): 1462-1472.).

Conventionally contrast agent used is mainly microvesicle, and its shell is that the amphipathic small molecules such as saccharide, protein or polymer form, the inner C that fills ₃f ₈, SF ₆deng gas, form vesicle (Ferrara K. W., Borden M. A., Zhang H. acc Chem Res, 2009,42 (7): 881-892.).These contrast agent can change or strengthen ultrasound echo signal and better surface or organizational information are provided.Yet due to laplace pressure, blood pressure, oxidative metabolism and hyperacoustic effect, these gas microbubbles are to inject blood just dissolved and break several seconds after, and particle diameter is difficult to control (Schutt E. G., Klein D. H., Mattrey R. M., et al. angew Chem Int Ed, 2003,42 (28): 3218-3235.).SiO 2 hollow microsphere has good biocompatibility and mechanical stability, and has larger cavity, under radiography pattern, can produce stronger echo-signal, can address the above problem.(Lin P. L., Eckersley R. J., the Elizabeth A. H. such as Hall adv Mater2009,21 (38-39): 3949-3952.) take PB ball as template, by polyene acid propyl hydrochlorate (PAH) change surface charge, having prepared particle diameter is the tiny balloon of 2.8 μ m, shell thickness is less than 30nm, and has studied its ultra sonic imaging effect under different mechanical index conditions.Linear ultrasonic imaging (B-model) result shows, this hollow SiO ₂bead has very strong ultrasonic signal under water environment.Yet these class methods still have certain limitation, as hollow SiO ₂the size of bead is too large, does not reach nanoscale structures, is difficult to for living imaging, and does not carry out modified with functional group and be difficult to further connect.Therefore, the contrast agent of clinical middle use at present can't be taken into account good biocompatibility, mechanical stability, Targeting Performance, nanostructured simultaneously, can be carried out the requirements such as modified with functional group.

Summary of the invention

The present invention is directed to above problem, provide a kind of containing unsaturated high molecular medical contrast medium, it is a kind of multilamellar organic/inorganic composite construction magnetic Nano microsphere, have hollow type inorganic/organic/inorganic three-layer composite structure:

What be positioned at microsphere center is cavity, the inner air of filling;

Intermediate layer is macromolecule layer, is the copolymer of polyacrylic acid and divinylbenzene;

Between cavity and intermediate layer, be -Fe ₂o ₃magnetic nano-particle, is deposited on macromolecule layer inner surface by coordinate bond or ionic bond;

Outer for there being mesoporous Nano particles of silicon dioxide, by hydrogen bond action, adsorb with macromolecule layer outside.

The technical solution adopted for the present invention to solve the technical problems is:

1) preparation of core/shell polymer microsphere double-layer nanometer microsphere

This microsphere is prepared based on a kind of core/shell polymer microsphere double-layer nanometer microsphere.First utilize butadiene and acrylic acid to carry out copolymerization and obtain dispersed nano microsphere, it is structure shown in following chemical formula:

The integer that wherein x is 5 ~ 50;

Y is 0 ~ 15 integer;

2) prepare the outer cross-linked structure of double-layer nanometer microsphere

Then by above-mentioned dispersed nano microsphere and polyacrylic acid, divinylbenzene, by Solution Free Radical copolymerization process, obtain microsphere layer structure, it is structure shown in following chemical formula:

The integer that wherein n is 0 ~ 50

3) by " certainly disperseing " polyreaction, prepare core/shell polymer microsphere double-layer nanometer microsphere

Utilize the surperficial carboxyl of double-layer nanometer microsphere to produce hydrogen bond action with the silicon hydroxyl of silica surface, make silicon dioxide form shell structurre in aggregate surface hydrolysis polycondensation.Its interaction chemical formula is as follows:

4) preparation of hollow macromolecule-silicon dioxide nanosphere

Utilize acetone to extract kernel and form hollow macromolecule-silicon dioxide nanosphere structure.In reaction system, add chloroform to dissolve, stirred for several hour, obtains SiO after utilizing chloroform to dissolve PB core ₂tiny balloon, its form keep stable and structural integrity, there is good spherical structure.Preparation process schematic diagram is as shown in Figure of description 4;

5) preparation of magnetic macromolecular microsphere

Because Nano microsphere inside prepared in above-mentioned steps exists a large amount of carboxyls, at silica surface, there are a large amount of micropores simultaneously.Therefore, can utilize this micropore as passage, by Fe ³⁺add after reaction system, utilize microchannel to enter hollow ball inside, add PEG simultaneously, NaOH, regulates pH value, makes internal layer combination -Fe ₂o ₃magnetic particle.Nano microsphere internal layer macromolecule exists -Fe ₂o ₃surface has formed Fe-O-C key, and forms internal magnetization particle layer.

By above technical scheme, tool of the present invention has the following advantages: 1) containing unsaturated high molecular medical contrast medium, have good biocompatibility;

2) containing unsaturated high molecular medical contrast medium, there is volume little, there is nanoscale structures, can be by various human body barriers;

3) containing unsaturated high molecular medical contrast medium owing to containing superparamagnetism -Fe ₂o ₃, therefore there is Targeting Performance;

4) high containing unsaturated high molecular medical contrast medium Stability Analysis of Structures, mechanical stability.

This type of can overcome the problems such as traditional contrast agent poor stability, echo signal is weak, biocompatibility is poor containing unsaturated high molecular medical contrast medium.

Accompanying drawing explanation

Fig. 1 is this structural representation containing unsaturated high molecular medical contrast medium;

Fig. 2 is this particle diameter test pattern containing unsaturated high molecular medical contrast medium;

Fig. 3 is this AFM scintigram containing unsaturated high molecular medical contrast medium;

Fig. 4 is the preparation flow schematic diagram of hollow polymer microsphere.

The specific embodiment

For making enforcement object of the present invention, technical scheme and advantage more clear, below in conjunction with the drawings and specific embodiments of the present invention, the present invention is described in detail:

As shown in Figure 1, be the structural representation containing unsaturated high molecular medical contrast medium.This Nano microsphere has hollow type machine/organic/inorganic three-layer composite structure, has successively: outermost layer be Nano particles of silicon dioxide 1.; Intermediate layer be macromolecule layer 2.; Internal layer is -Fe ₂o ₃magnetic nano-particle 3.; Be positioned at microsphere center be cavity 4., the inner air of filling.Wherein Nano particles of silicon dioxide layer should have meso-hole structure in 1..

As macromolecule layer 2., silicon dioxide granule is adsorbed in outside 1. to polyacrylic acid-divinylbenzene crosslinking copolymerization macromolecule simultaneously, and internal layer combination -Fe ₂o ₃magnetic nano-particle is 3. as an embodiment preferably: utilize butadiene and polyacrylic acid to carry out copolymerization and obtain internal layer microsphere, then internal layer is carried out to copolymerization by polyacrylic acid and divinylbenzene, obtain double-deck solid nano polymer microspheres.Utilize the surperficial carboxyl of double-layer nanometer microsphere to produce hydrogen bond action with the silicon hydroxyl of silica surface, make silicon dioxide form shell structurre 1. in aggregate surface hydrolysis polycondensation.Meanwhile, utilize the meso-hole structure of Nano particles of silicon dioxide, with an organic solvent method (acetone) extracts kernel and forms hollow macromolecule-silicon dioxide double-layer nanometer micro-sphere structure.Finally, utilize microsphere inner surface carboxyl and iron salt can form coordinate bond or ionic bond, by adsorption and permeation, enter the Fe of hollow ball inside ²⁺and Fe ³⁺deng reactant, make internal layer combination -Fe ₂o ₃magnetic particle 3..

Figure 2 shows that and utilize the particle diameter test pattern of dynamic light scattering method to magnetic Nano microsphere, can find out, Nano microsphere particle diameter is less than 1 micron, and particle size distribution is narrower, proves that this Nano microsphere volume is little, good dispersion.

Figure 3 shows that the AFM scanogram containing unsaturated high molecular medical contrast medium.Proof macromolecule forms globular micelle structure homogeneous, and good dispersion is not reunited in aqueous solution.Be conducive to targeting location and the dispersion of contrast agent in body fluid.

Provide embodiment below so that the present invention is specifically described; but it is worthy of note that following examples are only used to further illustrate the present invention; can not be interpreted as limiting the scope of the invention, some nonessential improvement that the person skilled in the art in this field makes the present invention according to the invention described above content and adjustment still belong to protection scope of the present invention.

Embodiment 1:

1. the preparation of core/shell polymeric Nano microsphere

Step 1: single (PB-PAA) copolymer microsphere that disperses of method preparation that first adopts " certainly disperseing " polymerization.In tri-mouthfuls of round bottom reaction bulbs of 500mL, add butadiene and each 0.2mol of acrylic acid, AIBN(azo-bis-isobutyl cyanide) 0.98g, butyl acetate 280 mL; under nitrogen protection; 70 ℃ of reactions of constant temperature 12 hours, product is dried in 55 ℃ of baking ovens, obtains single dispersion (PB-PAA) copolymer microsphere.

Step 2: " certainly disperse " polyreaction to prepare core/shell polymer microsphere with seed.By (PB-PAA) copolymer microsphere 3.65g, acrylic acid and each 0.038mol of divinylbenzene, AIBN 0.09 g, butyl acetate 100 mL, normal hexane 35 mL; add in reaction bulb; under nitrogen protection, 75 ℃ of reactions of constant temperature 13 hours, obtain two-layer core/shell polymeric Nano microsphere.

2. silicon dioxide is assembled and is formed shell structurre at microsphere surface

Two-layer core/shell polymeric the Nano microsphere prepared in above-mentioned steps of take is template, by sol-gel process, at PAA surface in situ, generates thickness homogeneous and the regular SiO of pattern ₂shell.Adopt St ber method (St ber W., Fink A., Bohn E. j Colloid Interface Sci, 1968,26 (1): 62-69.), adding 55mL ammonia is catalyst, utilize ethyl orthosilicate (TEOS) 16.5g, synthetic SiO after hydrolysis and polycondensation reaction ₂.

With PAA surface PB core, as template, deposit SiO ₂time, generally can generate the independent SiO about 35nm ₂particle.Because PB checks SiO ₂adsorptivity a little less than, if directly precipitate SiO with PB as masterplate ₂, be difficult to obtain uniform SiO ₂shell structurre.And after the surface and copolymerized PAA of PB core, because of the carboxyl on PAA chain or carboxylate radical can with hydrolyzate and the SiO of ethyl orthosilicate ₂the hydroxyl of particle surface forms hydrogen bond, thus induction SiO ₂nucleating growth, finally forms regular shell structurre.

3. hollow type polymer-SiO ₂the preparation of Nano microsphere

Get the SiO preparing in 2.7g above-mentioned steps ₂core/shell polymeric Nano microsphere adds 15mL chloroform to dissolve in reaction system, stirs 7 hours, obtains SiO after utilizing chloroform dissolving PB core ₂tiny balloon, its form keep stable and structural integrity, there is good spherical structure.

4. the preparation of hollow type magnetic Nano microsphere contrast agent

The hollow polymer microsphere 1g, the FeCl that in tri-mouthfuls of round bottom reaction bulbs of 250mL, add gained in above-mentioned reactions steps ₃6H ₂o 6g, deionized water 150mL, then add 5 mL PEG-400, under magnetic agitation, with dilute NaOH solution, the pH value of mixed solution is adjusted to 3.After reaction finishes, product is through centrifugalize, and by distilled water and washing with alcohol repeatedly, in 60 ℃ of vacuum tanks, dries.Above-mentioned microsphere is added in bag filter, with 1000 mL pure water dialysis, refresh the water periodically.Dialysis solution is with after membrane filtration, and lyophilization obtains hollow type magnetic Nano microsphere contrast agent.

Finally it should be noted that, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although the present invention is had been described in detail with reference to preferred embodiment, those of ordinary skill in the art should understand, can a minute technical scheme for invention be modified or be replaced on an equal basis, and not departing from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of claim scope of the present invention.

Claims (5)

1. containing a unsaturated high molecular medical contrast medium, it is characterized in that having hollow type inorganic/organic/inorganic three-layer composite structure:

1) what be positioned at microsphere center is cavity, the inner air of filling;

2) intermediate layer is macromolecule layer, is the copolymer of polyacrylic acid and divinylbenzene;

3) between cavity and intermediate layer, be -Fe ₂o ₃magnetic nano-particle;

4) skin is Nano particles of silicon dioxide.

2. according to claim 1 a kind of containing unsaturated high molecular medical contrast medium, this material is prepared as follows:

1) prepare polybutadiene-acrylic acid random copolymerization list diffuse nuclei/shell polymeric Nano microsphere;

2) silicon dioxide is assembled at microsphere surface;

3) prepare hollow type polymer-SiO ₂nano microsphere;

4) preparation of hollow type magnetic Nano microsphere contrast agent.

3. according to claim 1 and 2 a kind of containing unsaturated high molecular medical contrast medium, be further characterized in that above-mentioned steps 1) in formed core/shell polymeric Nano microsphere be double-decker, and be all to adopt polyacrylic acid as hydrophilic segment, it is characterized in that:

1) its internal layer is polybutadiene-acrylic acid random copolymer;

2) its skin is polyacrylic acid and divinyl benzene crosslinked polymer.

4. according to claim 1 and 2 a kind of containing unsaturated high molecular medical contrast medium, be further characterized in that: in outermost Nano particles of silicon dioxide, there is meso-hole structure.

5. according to claim 1 and 2 a kind of containing unsaturated high molecular medical contrast medium, be further characterized in that: macromolecule layer is the copolymer of polyacrylic acid and divinylbenzene, macromolecule has double-deck polyacrylic acid structure, utilizes divinylbenzene bridging between molecule.