CN201732091U - Optical waveguide immunosensor - Google Patents

Abstract

The utility model discloses an optical waveguide immunosensor the basic structure of which includes an optical waveguide resonant cavity, a magnetic needle and an immunization reaction tank; the optical waveguide immunosensor implements specific surface decoration on nanometer magnetic beads and uses antibody and antigen reaction to capture a substance to be detected, uses the magnetic needle to orderly locate the nanometer magnetic beads on the surface of the annular or disc shape optical waveguide resonant cavity, uses evanescent field to sense the refractive index changes before and after immunization, and analyzes corresponding resonance spectrum changes to obtain the content of the substance to be detected in a sample. The optical waveguide immunosensor has a simple structure, and uses the magnetic needle to absorb the nanometer particles after the special immunization decoration to an optical waveguide surface based on the annular or disc shape optical waveguide resonant cavity with a compact structure to measure the excursion of the resonant frequency to realize accurate and sensitive immunization reaction detection. Apparatuses can be repeatedly used. The optical waveguide immunosensor has very good application prospect.

Description

Optical waveguide immunosensor

Technical field

The utility model relates to a kind of sensor, is specifically related to a kind of optical guided wave immunosensor.

Background technology

Along with growing continuously and fast of economy, people's living standard improves rapidly, and urbanization process is constantly accelerated, and living environment constantly changes.New environmental baseline has caused the appearance of new disease and disease variation, has brought new pressure for the medical department of China.Simultaneously, traditional major disease such as acquired immune deficiency syndrome (AIDS), tuberculosis, hepatitis etc. are also effectively contained, still the people's health in danger.Ensure health, carry out the work of prevention and treatment, press on molecular level the biological substance that human health is exerted an influence potential in human body, surrounding environment, the food is carried out accurate detection.But biological substance to be measured often content is small, the sample composition complexity, and it detects very difficulty.Utilize the Ag-Ab immune response of high selectivity to realize analytic target is caught, can significantly promote Selectivity of Sensor and sensitivity, this sensing equipment is called as immunosensor.Immunosensor is advanced detection, the core devices of diagnostic device, develops the high-performance immunosensor and has great significance.

Immunosensor combines highly sensitive sensing technology and specific immune response, now can be used for the detection of hormone, virus, cancer cell surface antigen, bacterium surface antigen etc.But traditional method often needs to carry out operations such as loaded down with trivial details biochemistry separation, sample culturing, purification amplification and biological concentration at micro-example the time, expends a large amount of time and cost, and delay treatment causes the further propagation of disease.Microflow control technique has been integrated into basic operations such as specimen preparation, reaction, detection on the very little chip, and the technology in fields such as biochemistry, ray machine electricity is organically combined.The miniflow immunoassay system combines immunization method with microflow control technique, promoted Selectivity of Sensor, accuracy, with the microminiaturization of biochemical analysis and checkout equipment, rapidly brought a brand-new era into.The miniflow immunosensor is one of developing direction of following immunosensor.

The method of immunoassay mainly can be divided into electricity and optics two classes by the physical quantity of its detection at present.Immune sensing technical pattern based on electricity is simple, easy to operate, but is subject to the influence of temperature, pH value of solution value, ion concentration, and inevitably can be subjected to electromagnetic interference (EMI).Immunosensor based on optics not only is not subjected to electromagnetic interference (EMI), and the measurement of multiparameter also can be provided on single device, and realizes remote sensing, has good application prospects.Especially combine with the integrated light guide technology, the volume of the biochemical sensitive device that can decline to a great extent improves integrated level, reduces cost.Owing to be based on the plane process technology equally, integrated light guide technology and microflow control technique are compatible fully.At present, the major technique of the immunoassay of integrated optics system has:

(1) marking type.Adopt special dyeing group that target molecule is carried out mark, utilize equipment such as fluorescent microscope to analyze then.Its sensitivity can reach individual molecule, and non-specific response is little.But testing process complexity, dying operation are difficult to accurate control, can't dye at individual molecule, and dye marker tend to biomolecule is produced certain influence.

1. laser-Induced Fluorescence Detection.Be one of at present the sensitiveest detection method, but the meeting of generation of the autofluorescence of many polymeric materials produces the lot of background noise, influences the selectivity of sensing, the purification of sample and the selection of material seem extremely important.

2. chemiluminescence detection.Need not excitation source, therefore the background interference that can avoid spontaneous radiation to bring still needs very sensitive detector.

(2) unmarked type.Can directly measure physics, the chemical change of Ag-Ab compound tense, preparation and operating process are simple, can realize dynamic, quantitative measurment, are one of important directions of immunosensor development.Refractive index or absorption variations around the evanscent field perceived light waveguide commonly used cause that corresponding the variation taken place for the output intensity of device or spectrum, detects the concentration that variable quantity can be calculated determinand.

1. interfere and detect.Simple in structure, be easy to realize, but the variations in refractive index that antigen-antibody reaction causes is very little usually, interfere the sensing unit of arm often to need suitable length, limited reducing of device size.

2. surface plasma resonant vibration detects.The sensitivity of the waveguide sensor of surface plasma body technique is very high, but its sensitivity is subjected to the influence of resonance peak width, makes operation wavelength limited, and it is less to can be used for making the material category of metal film, is difficult to further optimize performance.

3. resonance spectral detection.After refractive index around the resonator cavity waveguide changes, can cause moving of resonance frequency, can be used to analyze the concentration of test substance.Because length L eff ≈ LQ is surveyed in equivalence, wherein, L is a sensing unit length, and Q is the resonator cavity quality factor, and therefore the optical waveguide resonator cavity of high Q value can significantly increase the equivalence detection length and the action time of light and material, promotes sensing sensitivity.The primary structure of the resonator cavity of integrated light guide has Fabry-Parot chamber, dish and ring resonator.The Fabry-Parot chamber is important optical resonator, and is simple in structure, but needs to make reflecting surface, and high-quality reflecting surface is difficult to realize with the plane process technology.

By top comparison with analyze as can be seen, integrated light guide ring resonator type immunosensor need not mark, highly sensitive, compact conformation is flexible, can be applicable to be fit to pressing for of clinical treatment and Biomedical Development in convenient, fast, sensitive and the cheap molecular diagnosis and checkout equipment.

Optical waveguide immunosensor in the past generally is directly to carry out specific function in light guide surface to modify, but the complex process of surface-functionalized operation, difficulty are big, prices are rather stiff, and the resting period that can limit whole sensing chip, and do different modification operation easier on the same material surface big.This scheme regeneration difficulty is big, and regenerative operation causes the decline of device repeatability by meeting.Adopt magnetic separation technique, the surface that specificity is modified can be separated with sensing chip, and realize the regeneration of sensing chip.But the refractive index that immune antiboidy-antigen-reactive causes is very little usually, and the interference arm that utilizes the structure of light guide interference to need is very long, limiting device sensitivity.

The utility model content

For overcoming deficiency of the prior art, the purpose of this utility model is to provide a kind of optical waveguide immunosensor, this immunosensor, it is convenient to preserve, and need not fluorescence labeling, and size is little, it is integrated to be easy to, can realize accurate, sensitive quantitative measurment to biological substance, and reusable.

In order to solve the problems of the technologies described above, realize above-mentioned purpose, the utility model has adopted following technical scheme:

A kind of optical waveguide immunosensor, comprise a sensor substrate, described sensor substrate is provided with an immune response pond, there are an inlet and a liquid outlet in described immune response pond, top, described immune response pond is provided with a reaction tank upper caldding layer, the bottom in described immune response pond is provided with an optical waveguide resonator cavity, described optical waveguide resonator cavity top is provided with an optical waveguide upper limiting layer, described optical waveguide resonator cavity below is provided with an optical waveguide lower limit layer, between described optical waveguide upper limiting layer and the described optical waveguide lower limit layer coupled zone is arranged, described optical waveguide resonator cavity is connected with an optical waveguide by described coupled zone, and described optical waveguide has a light inlet and a light-emitting window.

Further, described optical waveguide immunosensor also comprises a needle, and described needle is placed on described optical waveguide resonator cavity below, and described optical waveguide resonator cavity is pointed at the tip of described needle.

Preferably, described needle is made of a needle-like magnetic material and a magnetic pole, or the needle of directly being made by a magnetic pole, is used for forming the magnetic induction line distribution of pointing to described optical waveguide resonator cavity center or being set out by described optical waveguide resonator cavity center.

Preferably, described optical waveguide resonator cavity is annular or dish-shaped resonator cavity.

Specify the detection principle of optical waveguide immunosensor of the present utility model below.

Light enters described coupled zone via input waveguide, part luminous power will be coupled into described optical waveguide resonator cavity, if optical wavelength is suitable, it is identical promptly to satisfy the light week back phase place that detours in described optical waveguide resonator cavity, light field forms stack and strengthens, so will form resonance in described optical waveguide resonator cavity.The wavelength of resonance takes place:

${\mathrm{\λ}}_{\mathrm{res}}=\frac{n_{\mathrm{eff}}{L}_u}{m}---\left(1\right)$

Wherein, m is a positive integer, n _EffBe effective refractive index, L _uIt is the girth of ring resonator.

The optical wavelength that resonance takes place will be assembled big energy in described optical waveguide resonator cavity, make the loss when light detours in described optical waveguide resonator cavity increase, if make the coupling ratio of described coupled zone satisfy certain relation, even can to make the luminous power of output optical waveguide be zero.This means that described optical waveguide resonator cavity can be at strong absorption point of resonance frequency place introducing.

After in solution, feeding test substance, will immune response take place on the nanometer magnetic bead surface, immune response will change the refractive index around the described optical waveguide resonator cavity, if the change of refractive index on every side, owing to the effect of evanscent field, the effective refractive index of described optical waveguide resonator cavity will change so.Effective refractive index is as follows with the relation of variations in refractive index on every side:

${\mathrm{\Δn}}_{\mathrm{eff}}=\frac{{\left({\mathrm{\Δn}}_M\right)}^2}{{\mathrm{\η}}_{0}P}\underset{M}{\∫}\∫{\left|\stackrel{v}{E}(x,y)\right|}^2\mathrm{dxdy}---\left(2\right)$

Wherein, Δ n _EffThe variation of effective refractive index, Δ n _MBe the variations in refractive index that takes place after immunoreactive, η ₀Be the characteristic impedance of free space, E is an electric field intensity, and P is the general power in whole cross section, and immunoreactive zone takes place M.

According to formula (2) as can be known, the variations in refractive index that immune response takes place on described optical waveguide resonator cavity surface will cause that the effective refractive index of overall optical waveguide changes, according to formula (1), this effective refractive index changes will cause change of resonance frequency again, therefore, the absorption point of output spectrum also will move thereupon.Its amount of movement Δ λ _ResChanges delta n with effective refractive index _EffThe pass be:

${\mathrm{\Δ\λ}}_{\mathrm{res}}=\frac{{\mathrm{\Δn}}_{\mathrm{eff}}{L}_u}{m}---\left(3\right)$

Suppose that immune response is complete, promptly the amount of acceptor is much larger than the amount of test substance, so the refractive index change delta n of waveguide surface _MJust can be expressed as with the relation of reactive material concentration:

Δn _M＝σρV (4)

Wherein, V is the liquor capacity that contains test substance that adds, and ρ is a test substance concentration, and σ is the variations in refractive index coefficient of the immune response generation that can take place.

Therefore,, utilize spectral analysis device to measure moving of resonance wavelength, just can calculate the content of test substance according to formula (1)-(4).

Utilize the detection method of optical waveguide immunosensor of the present utility model as follows:

Nano-beads is sneaked in the solution after the finishing, be input in the immune response pond by inlet again, with the close described optical waveguide resonator cavity of needle below, make magnetic nanoparticle be attracted to optical waveguide resonator cavity surface, utilize light inlet to import laser, utilize light-emitting window that light signal is sent into optical spectrum analyser, utilize inlet to import the solution that contains test substance then, import damping fluid after the reaction again, analysis is by the harmonic light spectral migration of array waveguide grating output, calculate corresponding variations in refractive index, and the testing concentration in the solution to be measured, needle is withdrawn resonator cavity, and utilize damping fluid flushing degaussing nano particle, can realize the regeneration of this sensor, in order to using next time.

Optical waveguide immunosensor of the present utility model is simple in structure, annular or dish-shaped optical waveguide cavity resonator structure based on compact conformation, utilize the nano particle after needle absorption immunologic opsonin is modified to arrive light guide surface, measurement is made in skew to resonance frequency, realize that accurate, sensitive immune response detects, device is reusable, has good application prospects.

Above-mentioned explanation only is the general introduction of technical solutions of the utility model, for can clearer understanding technological means of the present utility model, and can be implemented according to the content of instructions, below with preferred embodiment of the present utility model and conjunction with figs. describe in detail as after.Embodiment of the present utility model is provided in detail by following examples and accompanying drawing thereof.

Description of drawings

Fig. 1 is the basic structure vertical view of the optical waveguide immunosensor behind the removal reaction chamber upper caldding layer of the present utility model.

Fig. 2 is after adding the reaction chamber upper caldding layer on Fig. 1 structure, the A-A ' sectional view of Fig. 1.

Fig. 3 is after adding the reaction chamber upper caldding layer on Fig. 1 structure, the B-B ' sectional view of Fig. 1.

Fig. 4 is adsorbed on the nanometer magnetic bead behind the immune modification synoptic diagram of light guide surface for needle being placed near the below the optical waveguide resonator cavity center.

Fig. 5 feeds the output spectrum curve of determinand solution front and back for the utility model.

Number in the figure explanation: 1, optical waveguide resonator cavity, 2, the coupled zone, 3, with the waveguide of resonator cavity coupling, 4, optical waveguide upper limiting layer, 5, light inlet, 6, light-emitting window, 7, sensor substrate, 8, optical waveguide lower limit layer, 9, the immune response pond, 10, immune response pond upper caldding layer, 11, inlet, 12, liquid outlet, 13, needle, 14, nanometer magnetic bead after the finishing.

Embodiment

Below in conjunction with drawings and Examples technology implementation process of the present utility model is described further.

Referring to Fig. 1, Fig. 2, Fig. 3, shown in Figure 4, a kind of optical waveguide immunosensor, comprise a sensor substrate 7, described sensor substrate 7 is provided with an immune response pond 9, there are an inlet 11 and a liquid outlet 12 in described immune response pond 9,9 tops, described immune response pond are provided with a reaction tank upper caldding layer 10, the bottom in described immune response pond 9 is provided with an optical waveguide resonator cavity 1, described optical waveguide resonator cavity 1 top is provided with an optical waveguide upper limiting layer 4, described optical waveguide resonator cavity 1 below is provided with an optical waveguide lower limit layer 8, between described optical waveguide upper limiting layer 4 and the described optical waveguide lower limit layer 8 coupled zone 2 is arranged, described optical waveguide resonator cavity 1 is connected with an optical waveguide 3 by described coupled zone 2, and described optical waveguide 3 has a light inlet 5 and a light-emitting window 6.

Described optical waveguide immunosensor also comprises a needle 13, and described needle 13 is placed on described optical waveguide resonator cavity 1 below, and described optical waveguide resonator cavity 1 is pointed at the tip of described needle 13.

Preferably, described needle 13 is made of a needle-like magnetic material and a magnetic pole, or the needle of directly being made by a magnetic pole, is used for forming the magnetic induction line distribution of pointing to described optical waveguide resonator cavity 1 center or being set out by described optical waveguide resonator cavity 1 center.

Preferably, described optical waveguide resonator cavity 1 is annular or dish-shaped resonator cavity.

Utilize the testing process of optical waveguide immunosensor of the present utility model as follows:

1) nanometer magnetic bead of employing diameter 80nm, the magnetic quanta point material is Fe ₃O ₄, external cladding material is a polystyrene, utilizes the nanometer magnetic bead of surface-ready carboxyl and antibody crosslinked by EDC, obtains nanometer magnetic bead 14 after the finishing;

2) nanometer magnetic bead after the finishing 14 is mixed in the solution, and introduces in the immune response pond 9 by inlet 11;

3) needle 13 tips are placed on the position of optical waveguide resonator cavity 1 central lower, nanometer magnetic bead 14 can be attracted to optical waveguide resonator cavity 1 surface after the finishing, as shown in Figure 4;

4) laser with a certain infrared wavelength and intensity feeds light inlet 5, and the light signal of light-emitting window 6 outputs is imported spectral analysis apparatus;

5) feed damping fluid from inlet 11, nanometer magnetic bead 14 after the finishing that flushing goes not to be adsorbed feeds the solution that contains determinand again, feeds the damping fluid flushing at last and goes excessive solution;

6) utilize spectral analysis apparatus to measure the spectrum change that feeds the determinand front and back, (solid line partly represents to feed the preceding situation of determinand to change curve among the figure as shown in Figure 5, dotted portion represents to feed the situation behind the determinand), utilize formula (1)-(4) can calculate the concentration of determinand then;

7) detect to finish after, remove needle 13, feed buffer solution for cleaning and remove nanometer magnetic bead 14 after the finishing.

Claims (3)

1. optical waveguide immunosensor, comprise a sensor substrate (7), it is characterized in that: described sensor substrate (7) is provided with an immune response pond (9), there are an inlet (11) and a liquid outlet (12) in described immune response pond (9), top, described immune response pond (9) is provided with a reaction tank upper caldding layer (10), the bottom in described immune response pond (9) is provided with an optical waveguide resonator cavity (1), described optical waveguide resonator cavity (1) top is provided with an optical waveguide upper limiting layer (4), described optical waveguide resonator cavity (1) below is provided with an optical waveguide lower limit layer (8), between described optical waveguide upper limiting layer (4) and the described optical waveguide lower limit layer (8) coupled zone (2) is arranged, described optical waveguide resonator cavity (1) is connected with an optical waveguide (3) by described coupled zone (2), and described optical waveguide (3) has a light inlet (5) and a light-emitting window (6); Described optical waveguide immunosensor also comprises a needle (13), and described needle (13) is placed on described optical waveguide resonator cavity (1) below, and described optical waveguide resonator cavity (1) is pointed at the tip of described needle (13).

2. according to the described optical waveguide immunosensor of claim 1, it is characterized in that: described needle (13) is made of a needle-like magnetic material and a magnetic pole, or the needle of directly making by a magnetic pole, be used for forming the magnetic induction line distribution of pointing to described optical waveguide resonator cavity (1) center or setting out by described optical waveguide resonator cavity (1) center.

3. optical waveguide immunosensor according to claim 1 is characterized in that: described optical waveguide resonator cavity (1) is annular or dish-shaped resonator cavity.

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