CN117607460A - Polypeptides for detecting PGI proteins and related products and uses thereof - Google Patents

Abstract

The invention discloses a polypeptide for detecting PGI protein, a related product and application thereof, and relates to the field of biomedical detection. The polypeptide for detecting the PGI protein provided by the invention comprises at least one of polypeptide probes 1-5, the polypeptide probes 1-5 have high specificity and high sensitivity for detecting the PGI protein, and the detection method established by combination can finish the accurate detection of the target protein under the condition of not expressing and purifying a large amount of protein or antibody probes and quantitatively fixing the protein or antibody probes on the surface of a support, and has the advantages of better stability, higher detection efficiency, low preparation cost and the like.

Description

Polypeptides for detecting PGI proteins and related products and uses thereof

Technical Field

The invention relates to the field of biomedical detection, in particular to a polypeptide for detecting PGI protein, a related product and application thereof.

Background

In clinical serological immunodiagnosis, proteins need to be measured as markers of a class of important diseases, and changes in levels can reflect the occurrence and progression of certain diseases, such as tumor markers, cardiac markers, inflammatory factors, thyroid function markers, and the like.

The current clinically conventional methods include: enzyme-linked immunosorbent assay (ELISA), chemiluminescent assay (RIA), immunoblotting (Western blotting) and immunofluorescent assay. The ELISA has high sensitivity, high specificity, simple operation and reliable result, can simultaneously measure a plurality of samples, but can be influenced by interfering substances, and needs a long time for marking and detection. The chemiluminescence method has the advantages of high sensitivity, long optical signal duration, wide linear range and high automation degree, but the signal generation is instantly completed, fission is easy to occur in the reaction process, the combined phase and the free phase are required to be separated, and the detection cost is relatively high. Radioimmunoassay (RIA) has very high sensitivity and specificity and can measure very low concentrations of protein, but the use of radioisotope labels can be potentially dangerous and require specialized equipment and personnel to perform. Immunoblotting (Western blotting) can be used to detect specific proteins in complex mixtures, results are reliable, and there is no limit to the size of the protein to be detected, but the procedure is complicated, requires a long time, and may risk false positive results when non-specific binding or lack of specific antibodies. Immunofluorescence is rapid, accurate, intuitive, sensitive, and allows simultaneous measurement of multiple proteins, but for some samples there may be background fluorescence interference, requiring specialized equipment and personnel to perform the procedure. The above methods are well-established, but have respective technical limitations.

There are also few companies that develop protein or antibody detection techniques based on biochips, and the advantage of using biochips for detection is mainly that multi-index combination achieves high throughput detection, one detection can achieve measurement of tens, hundreds, thousands or even more targets, and besides, the chip has a miniaturized feature, thus having less sample/reagent consumption. By combining the intersection and fusion of advanced materials science, information science and other technologies, the system detection with high sensitivity and high specificity can be achieved with lower unit cost. The technology is widely applied to the fields of scientific research of genomics and proteomics, clinical disease diagnosis, new medicine research and development, judicial identification, food safety and the like. The current protein chip relies on protein or antibody macromolecular probes (such as Olink, luminex, UNIarray and Huprot) in the process of capturing protein (or antibody) to be detected, and has challenges in expressing and purifying a large amount of protein, directionally fixing the protein on the surface of a support to form a high-flux chip, and keeping the activity of the protein in technical realization and cost control of transformation application.

Compared with a protein chip, the polypeptide chip can bear a large number of polypeptide fragments, can quickly, accurately and effectively find out corresponding binding sites/domains, has the general advantages of the biochip, and has the advantage of high-flux detection. The polypeptide fragments fixed on the polypeptide chip comprise protein complete sequences, are more stable relative to the original macromolecular proteins, are not easy to decompose and inactivate, acquire more accurate data, and are more reliable in production and manufacture. In addition, the polypeptide fragment can be not limited to a known protein structure, and amino acids forming the polypeptide molecule can be unnatural amino acids subjected to chemical modification, so that the polypeptide fragment has strong flexibility in drug development, screening and novel diagnostic marker search.

In the current research, the polypeptide chip is mainly used in the fields of antibody epitope analysis, multiple epitope analysis, protein interaction research, antibody spectrum research, immune monitoring and the like, but effective quantification of the protein based on the polypeptide chip technology is not realized.

In view of this, the present invention has been made.

Disclosure of Invention

The present invention provides polypeptide sequences useful for detecting PGI proteins, and uses of these sequences to arrive at polypeptide chips useful for detecting PGI and related products and applications.

The invention is realized in the following way:

in a first aspect, embodiments of the present invention provide the use of a polypeptide probe for the preparation of a product for detecting PGI, the polypeptide probe comprising: at least one of the polypeptide probes 1 to 5; the amino acid sequences of the polypeptide probes 1 to 5 are shown as SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4 and SEQ ID NO. 5 in sequence.

In a second aspect, embodiments of the present invention provide a polypeptide chip comprising: a chip carrier and polypeptide probes distributed on the chip carrier, the polypeptide probes comprising: at least one of the polypeptide probes 1 to 5; the amino acid sequences of the polypeptide probes 1 to 5 are shown as SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4 and SEQ ID NO. 5 in sequence.

In a third aspect, embodiments of the present invention provide a kit comprising: the polypeptide chip of the preceding embodiment.

In a fourth aspect, an embodiment of the present invention provides a method for detecting PGI protein, including: detecting a sample to be detected by adopting the polypeptide chip in the embodiment; the detection method is not directed to the diagnosis or treatment of a disease.

In a fifth aspect, embodiments of the present invention provide a polypeptide having an amino acid sequence as set forth in any one of SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4 and SEQ ID NO. 5.

In a sixth aspect, embodiments of the present invention provide a polypeptide composition comprising: the amino acid sequence is at least one of the polypeptides shown in SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4 and SEQ ID NO. 5.

The invention has the following beneficial effects:

the polypeptide chip provided by the invention comprises at least one of the polypeptide probes 1-5, wherein the polypeptide probes 1-5 have high specificity and high sensitivity when used for detecting PGI protein, and can finish the accurate quantification of target protein without expressing and purifying a large amount of protein or antibody probes and quantitatively fixing the protein or antibody probes on the surface of a support by combining the established detection method, and the polypeptide chip has the advantages of better stability, higher detection efficiency, low preparation cost and the like.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a protein competitive inhibition specific antibody binding polypeptide probe;

FIG. 2 is a diagram of the operational steps of two methods, direct signaling and indirect signaling;

FIG. 3 shows the results of the identification of antibodies and protein material;

FIG. 4 shows the antigen inhibition of PGI-specific peptides (pure buffer system); wherein a is negative control NTC (zLNKR) as a signal reference probe, b-f are signal inhibition signals of 5 specific polypeptides of PGI under different antigen concentrations, and the relative number of the signal inhibition signals and the reference probe is the relative signal value of the Y axis; the relative number of the antigen concentration on the x axis is calculated according to the initial concentration of the PGI antibody of 100ng/mL, the molecular weight of the antibody of 150KD and the molecular weight of the antigen of 42 KD;

FIG. 5 shows the efficacy of predicting PGI protein concentration by chip signals, and the accuracy of the predicted values and the actual values and CV values of the probe signals are used as evaluation indexes.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

In the verification research of detecting proteins by using a polypeptide chip, the inventor tries to directly utilize the affinity characteristics of a polypeptide probe and proteins on the polypeptide chip, and possible protein conformations in an actual sample are changeable, so that signals are unstable. Based on the research basis of the early antibody epitope, the inventor introduces a specific antibody corresponding to the protein, discovers high-affinity epitope peptide (polypeptide probe) of the target protein recognition antibody through a polypeptide chip, and realizes protein detection by using a specific binding site immunized by the antibody as a protein anchor point.

The polypeptide chip provided by the invention can be used for effectively detecting PGI protein in a complex sample, and has better background matrix interference resistance and cross reaction resistance between detection indexes during detection of the polypeptide chip synthesized in situ, so that the problems of large interference influence and inaccurate quantification during multi-protein joint detection are solved; in addition, the polypeptide chip provided by the invention does not need to rely on protein expression, coating or sample application (protein or antibody macromolecular probes are not required to be fixed on a solid support), only needs to screen out a specific polypeptide set (polypeptide probes) aiming at target detection proteins, and can finish the quantification of the proteins by taking signals of the polypeptide set as target data for analysis.

In one aspect, embodiments of the present invention provide an application of a polypeptide probe in preparing a product for detecting PGI, the polypeptide probe comprising: at least one of the polypeptide probes 1 to 5; the amino acid sequences of the polypeptide probes 1 to 5 are shown as SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4 and SEQ ID NO. 5 in sequence.

The polypeptide probes 1-5 are obtained by screening 13 ten thousand polypeptides by the inventor, and compared with other polypeptide probes, the polypeptide probes 1-5 obtained by screening have better detection specificity and sensitivity.

In some embodiments, the product includes any one of a reagent, a kit, and a chip.

In another aspect, embodiments of the present invention further provide a polypeptide chip, which includes: a chip carrier and polypeptide probes distributed on the chip carrier, the polypeptide probes comprising: at least one of the polypeptide probes 1 to 4; the amino acid sequences of the polypeptide probes 1 to 5 are shown as SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4 and SEQ ID NO. 5 in sequence.

In some embodiments, the assay of the polypeptide chip comprises PGI.

In some embodiments, the polypeptide probes are present on the polypeptide chip in the form of clusters of polypeptide probes.

In some embodiments, the polypeptide probe clusters are 7 μm to 1cm in size on the chip carrier. The size may be any one or more of 7 μm, 10 μm, 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1mm, 5mm, 10 mm.

In some embodiments, the method of immobilizing the polypeptide probe on a chip carrier comprises: any one of in situ SPPS (solid-phase polypeptide synthesis), SPOT (SPOT synthesis), and covalent binding.

The polypeptide chip synthesized by the in-situ SPPS has the characteristics of extremely stable probe signals and no mutual interference, and the polypeptide chip probe synthesized by the in-situ solid phase has higher purity and consistency, because each probe is formed by gradually assembling amino acid monomers which are accurately measured on the surface of the chip; in addition, since the condensation reaction of the probes is performed on the surface of the chip, the position and density of each probe can be accurately controlled and adjusted, thereby avoiding cross reaction and interference between different probes.

SPOT synthesis is a reliable and fast technique for synthesizing polypeptide libraries based on membranes, especially cellulose membranes.

In some embodiments, the chip carrier is selected from: cellulose acetate film, glass sheet, nitrocellulose film, nylon film and SiO ₂ Any one of the chips.

In another aspect, an embodiment of the present invention further provides a kit, including: the polypeptide chip of any preceding embodiment.

In some embodiments, the kit further comprises: any one or more of a fluorescent label, an antibody against PGI protein, and a fluorescently labeled antibody against PGI protein. Optionally, the kit further comprises: fluorescent markers and antibodies against PGI proteins; optionally, the kit further comprises a fluorescently labeled antibody against PGI protein.

In some embodiments, the kit further comprises: any one or more of a fluorescent label, a primary antibody against PGI protein, an antibody against said primary antibody, a fluorescently labeled antibody against said primary antibody (secondary antibody). Optionally, the kit comprises a fluorescent label, a primary antibody against PGI protein, and an antibody against the primary antibody; optionally, the kit further comprises: a primary antibody against PGI protein and a fluorescently labeled antibody against said primary antibody.

In some embodiments, the fluorescent marker comprises: at least one of fluorescein-based dye, rhodamine-based dye, cy-based cyanine dye, alexa-based dye, protein-based dye, radioisotope, chemiluminescent reagent and nanoparticle-based label. Wherein the fluorescein dye comprises Fluorescein Isothiocyanate (FITC), hydroxyfluorescein (FAM), tetrachlorofluorescein (TET) and the like and analogues thereof. Rhodamine dyes include red Rhodamine (RBITC), tetramethyl rhodamine (TAMRA), rhodamine B (TRITC), and the like. Cy-series cyanine dyes, which generally consist of two heterocyclic systems, include Cy2, cy3B, cy3.5, cy5, cy5.5, cy7, and the like. Alexa series dyes, including Alexa Fluor 350, 405, 430, 488, 532, 546, 555, 568, 594, 610, 633, 647, 680, 700, 750. Dyes for proteins include Phycoerythrin (PE), phycocyanin (PC), allophycocyanin (APC), polymethine-chlorophyll protein (precP), etc. Chemiluminescent reagents include luminols and acridine ester luminescent agents. Nanoparticle labels including semiconductor quantum dots, carbon quantum dots, AIE nanoparticles, semiconductor nanoparticles, and upconversion nanoparticles, and the like.

In some embodiments, the kit further comprises detection reagents for the polypeptide chip.

In some embodiments, the detection reagent comprises: any one or more of a sample diluent, a buffer, and a washing solution.

In another aspect, an embodiment of the present invention further provides a method for detecting PGI protein, including: detecting a sample to be detected by using the polypeptide chip described in any of the foregoing embodiments; the detection method is not directed to the diagnosis or treatment of a disease.

In some embodiments, the condition not directly aimed at diagnosis or treatment of the disease includes the condition that the sample to be tested is an environmental sample or a manually made sample.

The detection method or the detection principle of the polypeptide chip provided by the embodiment of the invention is to competitively inhibit specific antibody binding to the polypeptide probe on the polypeptide chip according to target protein (protein to be detected), and specifically reference can be made to fig. 1: no target protein is in the control hole, and the initial signal of the polypeptide probe is detected; the test wells have the target protein competitively bound to its corresponding antibody, and the presence of the target protein reduces the signal value of the polypeptide probe, and the decrease in signal correlates with the abundance level of the target protein. Detection of the target protein can be achieved by comparing the control wells by incubating with antibodies specific for the selected target protein, and calculating the difference in signal from the control wells.

In some embodiments, the detection method comprises: either direct signaling or indirect signaling. The direct signal method and the indirect signal method are based on the same detection principle (according to the competitive inhibition of specific antibody of target protein and the polypeptide probe on the polypeptide chip), and are different in that the specific antibody is slightly different in use in the operation steps, the direct signal method directly detects the content of target protein through the reduction of fluorescent labeled antibody signals, and the indirect signal method does not label the specific antibody of target protein, but completes the signal detection of target protein through fluorescent labeled secondary antibody. Reference is made to fig. 2.

In some embodiments, the indirect signaling method comprises:

obtaining an antibody resisting PGI protein as a primary antibody, and using a fluorescent labeled antibody resisting the primary antibody as a fluorescent secondary antibody;

the polypeptide chip is adopted to be respectively mixed with the primary antibody and a mixture obtained by mixing and incubating the primary antibody and a sample to be tested, the fluorescent secondary antibody is respectively added after rinsing, and signal detection is carried out after rinsing, so that a detection result of the primary antibody and a detection result of the mixture are obtained;

based on the difference between the detection result of the primary antibody and the detection result of the mixture, analyzing whether PGI protein exists in the sample to be tested and/or analyzing the PGI protein concentration.

In the field of high-throughput biochip protein detection, a large amount of protein or antibody is usually used for solid phase capture, and the protein or antibody needs to be marked or modified, so that the conformation and activity of the protein or antibody are changed, the manufacturing process is difficult, and the cost is high. According to the invention, the principle advantage of the immunospecific combination of the antibody antigen and the technological advantage of the polypeptide array chip (the same polypeptide chip) are combined ingeniously, and the specific antibody is introduced, but the modification of the specific antibody is avoided, the natural conformation and the binding activity of the liquid free state of the specific antibody are reserved, and the effectiveness and the specificity of the innovative detection method established by the invention are ensured.

In some embodiments, the antibody (primary antibody) against the PGI protein is a CNPAIR M3116 anti-PGI antibody.

In some embodiments, the secondary antibody is: thermofiser A21424 coat anti-Mouse IgG (H+L) Cross-Adsorbed Secondary Antibody, alexa Fluor 555.

On the other hand, the embodiment of the invention also provides a polypeptide, the amino acid sequence of which is shown in any one of SEQ ID NO. 1 and SEQ ID NO. 2.

In addition, the embodiment of the invention also provides a polypeptide composition, which comprises: at least one of polypeptides with the amino acid sequences shown as SEQ ID NO. 1 and SEQ ID NO. 2;

in some embodiments, the polypeptide composition further comprises: at least one of the polypeptides shown in SEQ ID NO. 3, SEQ ID NO. 4 and SEQ ID NO. 5.

The features and capabilities of the present invention are described in further detail below in connection with the examples.

Example 1

The present embodiment provides a polypeptide chip for detecting PGI protein.

1. Polypeptide chip

The polypeptide chip adopted in the embodiment is a polypeptide chip which is intelligently supplied by China carbon cloud and is synthesized in situ based on mask lithography, has the technical advantages of small physical size (7-14 mu m) of single characteristic points, realization of high-density chip preparation, more matching of complexity of biomolecular interaction and the like.

The present example provides a polypeptide chip comprising polypeptide probes 1-5, wherein each probe has 6 technical replicates. The sequence information of the probe is shown in the following table.

The general reagents for polypeptide chip detection are as follows:

reagent name	Model/goods number	LOT number
			D-Mannitol (D-Mannitol)	63560-250G-F	BCCC4152
Casein sodium salt from bovine milk(Casein)	C8654-500G	WXBC8228V
			20×PBS with 1％TWEEN-20(PBST，20×)	P1192	P119204C2101
Proclin 950	46879-U	/
			LC/MS Grade Isopropanol (isopropanol)	A461-4	190658

Example 2

The present example provides a method for detecting PGI protein (indirect signaling method), which uses 5 peptides in the polypeptide chip provided in example 1 to detect PGI protein.

(1) Samples used in this example:

the results of the identification of antibodies and protein material are shown in FIG. 3.

As shown in the result of the electrophoresis of PGI antigen protein (the loading concentration is 25. Mu.g/mL) in FIG. 3, the band position was correct and single, and the purity was high. The ELISA result of PGI antibody antigen binding shows that the antigen-antibody material to be used later has better affinity, and the ELISA test can screen the available antibodies of the polypeptide chip competition method for detecting the protein.

Chip test general purpose reagents the same as in example 1.

(2) Detection method (indirect signal method):

1. sample processing

1.1 antibody treatment: the secondary fluorescent antibody was diluted with secondary antibody (0.75% Casein in PBST, proclin 950) at 1: 3000-fold dilution the primary antibody was diluted to near saturation (500 ng/mL) with a sample diluent (PBST containing 1% D-mannitol and 0.05% Casein, plus Proclin 950).

1.2, the molar ratio of the target protein PGI to be detected to the antibody is 0: 1. 2: 1. 4: 1. 8: 1. 16: 1. 32: 1. 64: 1. 128:1 preparing corresponding concentration of antigen protein, and preparing samples by sample diluent and 2 human negative serum diluted 1000 times respectively.

2. Off-chip mixing incubation of sample (primary antibody and analyte)

And adding the primary antibody and the protein mixture to be tested into a 100 mu L-96-well plate, sealing the membrane, shaking and uniformly mixing, centrifuging, and incubating for 1h at the temperature of 37 ℃ of an oven.

3. Chip loading

And adding 90 mu l of the incubated samples (protein-antibody complex to be detected) into corresponding holes of the polypeptide chip fixed by the clamp.

4. First incubation and washing plate

And (3) sealing the membrane by Cassette, placing the membrane in a constant temperature oscillator for incubation for 1 hour at 37 ℃, placing the membrane into a plate washer after incubation is completed, washing the membrane for 3 times by using phosphate buffer solution, and fully removing unbound molecules and reagents.

5. Second incubation and washing plate

A2 nM solution of fluorescent secondary antibody was prepared with 0.75% Casein (Casein) solution and added to the clip-immobilized polypeptide chip at 40. Mu.L/well and incubated at 37℃for 1 hour with a constant temperature shaker. After the incubation is completed, the plate washer is put into the plate washer, and the plate washer is washed for 3 times by phosphate buffer solution, so that unbound molecules and reagents are fully removed.

6. Chip drying

The polypeptide chip was removed from the clip, sprayed with 90% isopropyl alcohol for washing, and then spin-dried in a centrifuge.

7. Imaging scan

A chip fluorescence imager (ImageXpress) scans and images the polypeptide chip by using a fluorescence channel corresponding to the excitation wavelength, and each chip hole site obtains a TIFF image file which is original data.

8. Image processing

And converting the pictures obtained by fluorescence imaging into fluorescence intensity values to obtain corresponding numerical matrixes.

The method specifically comprises the following steps:

the fluorescence intensity values of the features were extracted and 1 GPR5 data file and 1 corn images file were output. Wherein the GPR5 file contains all information of one sample and fluorescence intensity information of all features;

characteristic fluorescence intensity information is extracted from the GPR5 data file of all samples, generating a raw fluorescence intensity (FG) data matrix.

9. Preliminary data processing and quality control

And carrying out logarithmic conversion and normalization processing on the sample values, and outputting a normalization matrix. And performing single-sample intrinsic control and system stability quality control.

10. Data analysis

The inhibition of 5 specific polypeptide probes of PGI and control probe NTC (CGSC) on antigens with different concentrations in a pure buffer system is shown in FIG. 4. As can be seen from the results, the signal values of the 5 probes selected on the polypeptide chip had a gradient response to the concentration of PGI antigen compared to the control probe NTC, with potential efficacy of the constant PGI antigen.

The quantitative efficacy of polypeptide probes of PGI antibodies against antigen concentrations in complex systems with interference of serum matrices (diluted with defined negative serum as diluent, diluted with different concentrations of antigen) was verified, the results are shown in fig. 5 and the following table.

Reference formula: b= (M-T)/t×100%; wherein B is the relative deviation, M is the test value, and T is the calibration value. Generally less than.+ -. 10% is excellent in quantitative accuracy performance.

Reference formula: cv=sd/m×100%; where SD and M are standard deviations and averages of the signal values of the plurality of repeated probes, and CV is the coefficient of variation. Generally, CV values of less than 10% are excellent in quantitative reproducibility.

The result shows that the polypeptide probe in the polypeptide chip can be used for determining the concentration of the PGI protein.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. Use of a polypeptide probe for the preparation of a product for detecting PGI, the polypeptide probe comprising: at least one of the polypeptide probes 1 to 5; the amino acid sequences of the polypeptide probes 1 to 5 are shown as SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4 and SEQ ID NO. 5 in sequence.

2. A polypeptide chip, comprising: a chip carrier and polypeptide probes distributed on the chip carrier, the polypeptide probes comprising: at least one of the polypeptide probes 1 to 4; the amino acid sequences of the polypeptide probes 1 to 5 are shown as SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4 and SEQ ID NO. 5 in sequence.

3. The polypeptide chip of claim 2, wherein the polypeptide and the detector of the polypeptide chip comprises PGI;

optionally, the polypeptide probes are present on the polypeptide chip in the form of clusters of polypeptide probes;

optionally, the size of the polypeptide probe clusters on the chip carrier is 7 μm-1 cm;

optionally, the method for immobilizing the polypeptide probe on the chip carrier comprises: any one of in situ SPPS, SPOT, and covalent bonding;

optionally, the chip carrier is selected from: cellulose acetate film, glass sheet, nitrocellulose film, nylon film and SiO ₂ Any one of the chips.

4. A kit, comprising: a polypeptide chip according to claim 2 or 3.

5. The kit of claim 4, further comprising: any one or more of a fluorescent label, an antibody against PGI protein, and a fluorescently labeled antibody against PGI protein;

optionally, the kit further comprises: any one or more of a fluorescent label, a primary antibody against PGI protein, an antibody against said primary antibody, and a fluorescently labeled antibody against said primary antibody.

6. A method for detecting PGI protein, comprising: detecting a sample to be detected by using the polypeptide chip according to claim 2 or 3;

the detection method is not directed to the diagnosis or treatment of a disease.

7. The method of detection according to claim 6, wherein the method of detection comprises: either direct signaling or indirect signaling.

8. The method of detection according to claim 7, wherein the direct signaling method comprises:

obtaining a fluorescence-labeled anti-PGI protein antibody as a fluorescence primary antibody;

detecting the first fluorescent antibody and a mixture obtained by mixing and incubating the first fluorescent antibody and a sample to be detected by adopting the polypeptide chip to obtain a detection result of the first fluorescent antibody and a detection result of the mixture;

based on the difference between the detection result of the fluorescent primary antibody and the detection result of the mixture, analyzing whether PGI protein exists in the sample to be tested and/or analyzing the concentration of PGI protein.

9. The method of detection according to claim 7, wherein the indirect signaling method comprises:

obtaining an antibody resisting PGI protein as a primary antibody, and using a fluorescent labeled antibody resisting the primary antibody as a fluorescent secondary antibody;

the polypeptide chip is adopted to be respectively mixed with the primary antibody and a mixture obtained by mixing and incubating the primary antibody and a sample to be tested, the fluorescent secondary antibody is respectively added after rinsing, and signal detection is carried out after rinsing, so that a detection result of the primary antibody and a detection result of the mixture are obtained;

based on the difference between the detection result of the primary antibody and the detection result of the mixture, analyzing whether PGI protein exists in the sample to be tested and/or analyzing the PGI protein concentration.

10. A polypeptide composition, comprising: at least two of polypeptides 1 to 5; the amino acid sequences of the polypeptides 1-5 are shown as SEQ ID NO. 1, SEQ ID NO. 2, SEQ ID NO. 3, SEQ ID NO. 4 and SEQ ID NO. 5 in sequence.