Background technology
In recent decades, immuno analytical method combines characteristics such as the sensitivity, convenience of technology such as specific recognition reaction between antigen, antibody molecule and galvanochemistry, spectroscopy, acoustics, with its high selectivity and high sensitivity to analytes such as tumor markerses, become clinical, biological chemistry, one of analysis means that every field such as environmental analysis are important.Conventional immune analysis method mainly contains: radio immunoassay, enzyme-linked immunosorbent assay, fluoroimmunoassay, chemiluminescence immunoassay etc.These methods are mainly by mark radioactive isotope, enzyme molecule, fluorescent material etc. on antibody, when determined antigen and labelled antibody through specific reaction, wash plate and separate after, measure the radioactive isotope of mark or the signal of fluorescent material, or measure that marker enzyme acts on the signal of electroactive material that substrate produces, luminescent substance etc. and the concentration that obtains determinand; Operation steps comprises that mainly first antibody to measuring antigen recognizing, washing, resists reaction, washes plate with mark two, adds substrate mensuration etc.These conventional method of analysis complex operation step, analysis time is longer, and the sample consumption is big, and cost of determination is higher.At present, some in conjunction with or the self-reacting device that improves these methods be widely used in clinical detection.
Chemiluminescence detection has no radiocontamination, required instrument is simple, detectability is low, the advantages such as dynamics range of sensitivity height and width, can combine neatly with multiple different pattern; And the Flow Injection Analysis method have convenient and flexible operation, analysis speed fast, be easy to robotization and accuracy advantages of higher.The flow injection immuno analytical method that the flow injection technology is combined with immunoassay and chemical luminescence detection method and grow up has been proved to be a kind of strong analysis tool, and is widely used in environmental monitoring, Pharmaceutical Analysis, Food Inspection and clinical analysis.
In order to prepare portable injection chemiluminescence immune detection pond, a lot of solid phase materials comprise that inorganic material, organic high molecular polymer and some commercial materials (as the magnetic microsphere of silicon dioxide, agarose, glucosan and polystyrene bag quilt) are attempted.In actual applications, cost is low and material is inexpensive, to be easy to get also be the key factor that solid phase carrier is selected.
Summary of the invention
The present invention seeks to, develop a kind of new immune sensor of utilizing crosslinked with silicane chitosan film immobilized antigen, a kind of novel portable injection chemiluminescence immune detection pond and the method for preparation thereof are provided.Can be successfully used to the detection of tumor markers.
The present invention utilizes the silylating reagent cross-linked chitosan, at the carrier surface crosslinked chitosan film that silylating reagent is handled, immobilized antigen molecule, structure new immune sensor, this sensor is combined preparation portable injection chemiluminescence immune detection pond with the chemiluminescence flow cell.The chemiluminescence flow cell is to be made of plastic plate such as polyfluortetraethylene plate, transparent panel such as organic glass and silicone rubber gasket.Plastic plate on the upper strata has two passages, as the import and the outlet of liquid transfer; Side is carved with a groove within it, is used for embedding immunosensor; Lower floor is better glass of light transmission or poly (methyl methacrylate) plate, and directly is placed on the photomultiplier top; The middle silicone rubber gasket that adopts forms reaction tank, and immune response and luminous detection all take place in this reaction tank.
The method that the present invention constructs new immune sensor is: the slide carrier surface is carried out pre-service, and configuration epoxypropane base trimethoxy silane (GPS) solution pipettes drips of solution then in carrier surface, drying; Drip chitosan-acetic acid solution on the slide that the GPS silanization was handled, dry again silane crosslinked chitosan film; Determined antigen is dissolved in buffer solution; Antigenic solution is dripped on the crosslinked with silicane chitosan film slowly volatilization under 0-10 ℃ of condition; Drip on above-mentioned steps gained film with serum albumin solution, the sealing active site gets the immunologic function film.Above-mentioned immunologic function film is placed in the groove of chemiluminescence flow cell immunosensor.
Application of the present invention is: the testing process of this detection cell is at first with testing sample and excessive slightly horseradish peroxidase-labeled antibody off-line incubation, then this immune potpourri is fed detection cell, unconjugated enzyme labelled antibody is by antigen capture fixing in the immunosensor in the back incubation, and determined antigen-enzyme labelled antibody immune complex then is rushed out.Based on the enzyme labelled antibody of catching to luminol-H
2O
2Chemiluminescence detection is carried out in the catalytic action of chemiluminescence reaction.Typical enzyme labelled antibody is a horseradish peroxidase-labeled.
The invention has the beneficial effects as follows: the technology that apparatus of the present invention and application process utilize specific immune response and portable injection chemiluminescence analysis to combine, developed non-competing method portable injection chemiluminescence immuno analytical method, and prepared immunosensor based on the novelty of crosslinked chitosan film immobilized antigen.The more existing immune analysis method of this method has the following advantages:
1) analysis speed is quicker, is applicable to clinical on-line quick detection;
2) favorable reproducibility, the injection of sample and analytic process all adopt automation mechanized operation, have reduced the personal error analysis, and have simplified the operation steps of immunoassay;
3) utilize this natural macromolecular material immobilized antigen of shitosan molecule, material is cheap and easy to get, nontoxic, good biocompatibility;
4) this sensor sheet reveals good accuracy, and repeated and stable, the preparation method is simple, can develop into the immunoassays sensor and to marketing.
The present invention will have convenient and flexible operation, analysis speed flow injection immuno analytical method and non-competing immune analysis method fast, that be easy to robotization and accuracy advantages of higher combine, simplify analytical procedure, shorten analysis time, reduce reagent consumption, and then the reduction cost of determination, to realize online express-analysis clinically.Chitosan film after adopting the process silylating reagent crosslinked fixes antigen molecule, the immunoassays film that makes has excellent biological compatibility, Yan Zhi portable injection chemiluminescence immune detection pond can make things convenient for, be used at an easy rate flow injection immuno analytical method immunoassay based on this.
Embodiment
1. chemiluminescence flow cell
As shown in Figure 1, this chemiluminescence flow cell is to be made of polyfluortetraethylene plate, poly (methyl methacrylate) plate and silicone rubber gasket.Polyfluortetraethylene plate (45mm * 30mm * 8mm) go up two passages of cutter, on the upper strata as the import and the outlet of liquid transfer; Side is carved with a groove (20mm * 10mm * 1.5mm), grow and the wide positive and negative 3mm of size the positive and negative 1mm of high size within it.Being used for embedding the microslide that is modified with the antigen molecule functional membrane is immunosensor (Fig. 2; Lower floor is the better poly (methyl methacrylate) plate of light transmission (45mm * 30mm * 8mm), directly be placed on the photomultiplier top; The middle silicone rubber gasket that adopts forms reaction tank, and immune response and luminous detection all take place in this loop.
2. the preparation of immunosensor
(1) determined antigen is dissolved in buffer solution, selected buffer solution is different because of antigen type, and standard is to make immunoreactive activity and chemiluminescence signal response maximum.
(2) the slide carrier surface is carried out pre-service, obtain smooth, clean, hydrophilic surface.
(3) configuration finite concentration epoxypropane base trimethoxy silane (GPS) solution is placed and was made its abundant hydrolysis in 60 minutes, pipettes 50 microlitre drips of solution then in carrier surface, heats 60 minutes down at 93 ℃.Drip 50 microlitres, 1% chitosan-acetic acid solution on the slide that the GPS silanization was handled, place baking oven to heat 60 minutes down again, get the crosslinked with silicane chitosan film at 105 ℃.
(4) 50 microlitre antigenic solutions are dripped on the crosslinked with silicane chitosan film, in 4 ℃ of refrigerators, slowly volatilize, spend the night.
(5) drip on (4) step gained film with 50 microlitre serum albumin solutions, the sealing active site gets the immunologic function film.
(6) above-mentioned immunologic function film is placed in the groove of the chemiluminescence flow cell shown in the last figure immunosensor.
The immunologic function film that influence is obtained and the principal element of immunosensor performance have three aspects:
(1) time: time enough makes the GPS hydrolysis reaction abundant.
(2) preparation of immunosensor is subjected to the influence of crosslinked chitosan film surface topography, this depends primarily on the consumption of GPS and shitosan in the preparation process, have only consumption proportion suitable, just can obtain rule, even, present the cross linking membrane of mesh-like structure, thereby prepare the immunologic function film that stability is high, performance is good.
(3) the pH value of buffer solution: only under certain acidity, antigen just has optimum activity.If acidity departs from this numerical value, the performance of immunologic function film and immunosensor will be influenced.
3. the mensuration of determined antigen
The optimization of (1) immunoassays condition.
(2) under optimum determining condition, after will containing variable concentrations antigen standard solution or sample and fixed amount enzyme mark antibody solution off-line incubation 30min, be injected in the immunosensor by the flow injection current system, resolvase labeling antibody not combined in the incubation immune response in early stage is by antigen capture fixing in the sensor, and immune conjugate is then taken out of reaction tank.When chemical luminous substrate injected sensor, captive enzyme labelled antibody carried out catalytic reaction to chemical luminous system, obtains luminous signal, drew the typical curve of measuring, and obtained antigen concentration in the sample by typical curve.
The optimization of immunoassays condition comprises following three aspects:
(1) the incubation time: immune response (identification between antigen, antibody, combination) needs certain hour to finish usually, and accuracy and sensitivity for guaranteeing to measure require the control certain reaction time.
(2) amount of enzyme labelled antibody in the reaction solution: this is measured and adopts non-competing immune analysis method, be about to the reaction solution off-line incubation of determined antigen and fixed amount enzymic-labelled antibody, immune response finishes the back and comes separating and combining and free enzyme labelled antibody by the antigen that is fixed on the immunosensor, by the enzyme labelled antibody catalytic chemistry luminescence-producing reaction that is fixed on the antigen capture on the immunosensor, reduce the amount of coming the indirect determination determined antigen thereby produce signal.The optimization of the amount of enzyme labelled antibody is standard to obtain maximum detection range and to detect the sensitiveest in the reaction solution.If the amount of enzyme labelled antibody is worth less than this, sensing range is dwindled; If the amount of enzyme labelled antibody is worth greater than this, background signal is increased, measurement result is less than normal.
(3) immune complex flows through the flow velocity of immunosensor behind the incubation: immune complex is long more in the time that sensor is detained, and promptly flow velocity is slow more, and the amount of resolvase labeling antibody that then is fixed on the antigen capture on the immunosensor is many more, and separating effect is just good more; Otherwise then the quantity of the catch of resolvase labeling antibody is just few, and the effect of separation is just weaker.Take into account the demand of fast detecting clinically, the flow velocity that immune complex flows through immunosensor behind the incubation is optimized the influence of combination and free enzyme labelled antibody separating effect.
Detect Application Example
1.CA19-9 the preparation of immunosensor
Select microslide (20mm * 10mm * 1.0mm) makes carrier matrix, is example as fixed object with tumor associated antigen CA19-9:
(a) slide is handled: wash respectively with secondary water and acetone.1%GPS solution (3: 1 ethanol/water mixed solvents) is placed after 60 minutes and is made its abundant hydrolysis, pipette the 40-60 microlitre then, as 50 microlitre drips of solution on glass sheet, 93 ℃ of heating 60 minutes down, make GPS and glass surface that silane coupled reaction take place; Pipette the 40-60 microlitre, as 50 microlitres, 1% chitosan-acetic acid solution on the slide that the GPS silanization was handled, again 105 ℃ of down heating 60 minutes, the amino on this moment shitosan is crosslinked with the epoxypropane base functional group that the silane coupling agent on the slide passes through GPS.
(b) immunologic function film preparation: get the 40-60 microlitre, as the 120U/ml CA19-9 solution of 50 microlitres, drip on above-mentioned crosslinked chitosan film, in 4 ℃ of refrigerators, slowly volatilize, spend the night.Seal active site with above-mentioned same step with bovine serum albumin(BSA) more afterwards.
(c) slide that will be coated with the CA19-9/ chitosan film places in the groove of polyfluortetraethylene plate, and lower floor is a poly (methyl methacrylate) plate, and the middle packing ring that adopts forms reaction tank.Experiment finishes, and immunosensor is full of with 0.1M pH7.0PBS damping fluid, preserves down at 4 ℃.
Certainly, under size condition of the present invention, choosing 40-60 microlitre solution is suitable selection, does not exceed scope of the present invention and choose extraneous situation at present embodiment.
2. testing process
(d) adopt non-competing flow injection immune response pattern, the CA19-9 antibody-solutions of the horseradish peroxidase-labeled of 50 microlitres dilution in 1: 7.5 and 50 microlitre CA19-9 standard solution or blood serum sample mix, and at room temperature (25 ± 2 ℃) incubation is 30 minutes.This mixed liquor is injected in the stream, flows through immunosensor, simultaneously luminol and iodophenol, hydrogen peroxide also mixed with a three-way pipeline with the flow velocity of 0.1ml/min.When incubation not combined resolvase labeling antibody by sensor in fixing antigen capture and being trapped in the sensor, bond is rushed out.Inject reaction tank with 100 microlitre chemical luminous substrates this moment, the luminescence-producing reaction of captive enzyme labelled antibody catalytic chemistry, thus detect chemiluminescence signal.Detection finishes, and with glycocoll-HCl eluent of 0.1M pH2.2 immunosensor is regenerated 1 minute, again with the flushing of 0.1M pH7.0 PBS damping fluid, balance 1 minute.The experiment that next round is new just can begin.
3.CA19-9 mensuration
(a) optimization of condition determination: change the flow velocity that immune complex behind the amount of horseradish peroxidase-labeled CA19-9 antibody in incubation time, the reaction solution and the incubation flows through immunosensor respectively, measure accordingly as optimum determining condition when selecting the maximum chemical luminescence response, experimental result shows, as incubation 30min under room temperature (25 ± 2 ℃), selection is with 1: 5 HRP mark CA19-9 antibody-solutions of 0.1M pH7.0 PBS damping fluid dilution, and immune mixed liquor obtains maximum chemiluminescence signal response when flowing through immunosensor with the flow velocity of 0.1ml/min.
(b) mensuration of CA19-9: under the optimization experiment condition, utilize non-competing immune analysis method, measure series of standards CA19-9 antigen concentration, determine the typical curve that CA19-9 measures, utilize calibration curve method again, the concentration of CA19-9 antigen in the working sample.