What is Peptide Microarray?

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Definition of peptide microarrays

Peptide microarrays (also commonly called peptide chips or peptide epitope microarrays) are designed based on protein-protein interactions, and a known protein array is immobilized on a carrier to detect paired unknown proteins. The protein immobilized on the carrier can be antibodies, antigens, receptors, ligands, enzyme substrates, and protein binding factors. This new technology can detect the relative abundance of hundreds of proteins in biological samples in a single experiment. Its core technologies include: design, modification, and high-purity synthesis of new peptide molecules that specifically bind to the target protein; high-precision, high-throughput peptide array chip design and synthesis of the target protein binding site; peptide and peptide-protein reactions detection system; antibody-specific epitope original discovery system; target protein binding peptide discovery system; and huge epitope element-binding sample library and peptide molecule sample library.

Peptide microarrays can effectively find disease-specific markers from patient biological samples and can be used for the early diagnosis of various diseases including tumors. At the same time, the use of peptide microarray technology can screen out effective substances from a large number of pharmaceutical ingredients, which is of vital significance for the design and development of new drugs and targeted individual treatment.

Determination guidelines for peptide microarrays

The determination criteria for peptide microarrays are similar to the enzyme-linked immunosorbent assay (ELISA) protocol. The peptides (thousands of several copies) are attached to the surface of the glass chip. This peptide chip can be directly cultivated with various biological samples, such as purified enzymes or antibodies, patient or animal serum, cell lysates, etc. After some washing steps, a secondary antibody with the required specificity (for example, human/mouse anti-IgG or anti-phosphotyrosine or anti-myc) is used. Typically, the secondary antibody is labeled with a fluorescent label that can be detected by a fluorescent scanner. Other detection methods include chemiluminescence or autoradiography. By analyzing the differences in the results of microarray screening of patient samples and healthy human samples, we can obtain biomarkers that are highly related to the disease, and further use these biomarkers to assist in the diagnosis, monitoring, and treatment effect evaluation of the disease.

Features of peptide microarrays

  1. High-throughput and systematic: a large number of different types of peptides are carried on a detection array, which can easily cover many components in the product, beyond the limitations of traditional chemical analysis methods.
  2. Scientificity and objectivity: Produce clear quantitative analysis results and evidence, and get rid of the subjectivity and ambiguity of empirical analysis.
  3. High efficiency and low cost: Thousands of peptide reagents are tested at one time, and to achieve the same results, traditional analysis methods are incomparable in terms of time and cost.

Application of peptide microarrays

  1. Epitope mapping: Host humoral immunological response plays an essential role in protection against pathogens. Identification of B-cell epitopes on antigens is required for accurate diagnosis and vaccine development. To map SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) spike linear epitopes, Li developed a protocol of profiling sera from patients with COVID-19 (coronavirus disease 2019) via a peptide microarray designed according to spike protein. The qualified peptide microarray exhibited bright, uniform, organized, and regular features. Using peptide microarray technology, this study provided a detailed scheme for mapping the linear epitope of SARS-CoV-2 spikes and may be applicable to linear epitope mapping of other antigens.
  2. Screening of epitopes: The epitope has rich biological information, which is of great value for the diagnosis of disease and the development of new vaccines. At present, the epitope research of PPRV mostly focuses on N protein and H protein. Liu used the peptide microarray technology, using the PPRV Nigeria 75/1 strain as the reference sequence, selected the full gene sequence of the four structural proteins of PPRV N, M, H, F, and combined the peptide fragments. And then they used PPRV negative-positive serum for antigen epitope screening and analyzed the response rate correlation, stability, and three modes of the obtained data.
  3. Rapid screening: Researchers have developed a new, simple and rapid screening method with the help of peptide microarrays to detect cell behavior in the three-dimensional tissue microenvironment. The method used electrospun fiber (polyethylene glycol) hydrogel and peptide microarray platform. The researchers studied the utility of this platform using five different peptide motifs and ten cell types. These cells included stem cells, terminally differentiated cells, cancer cells, and immune cells. These cells come from original sources or cell lines of different species. The ability of an array composed of multiple peptide motifs and concentrations to screen cell adhesion and morphology has been verified in many ways.
  4. Virus detection: Zhou et al. cut the extracellular sequence of 7 proteins from the HPV-16 virus in a shingled manner, constructed a microarray chip based on 241 fine peptide libraries, and performed large-scale serological screening on 75 prostate cancer patients and 80 prostate hyperplasia patients diagnosed by pathology. The significance analysis of microarrays (SAM) was used to screen the differentially expressed polypeptides (specific polypeptides) in the serum of prostate cancer patients and benign prostatic hyperplasia patients and the receiver operating characteristic curve was used to evaluate the diagnostic value of these peptides for prostate cancer and compared with PSA.

References:

  1. Li Y, Lai D, Tao S. SARS-CoV-2 Spike linear epitope scanning via a peptide microarray through sera profiling[J]. STAR protocols, 2021: 100707.
  2. Liu H. D. Screening and preliminary application of peptide epitopes of Peste des ruminants virus [D]. Gansu Agricultural University, 2018.
  3. Zhou Z. Application of iPDMS-based human papillomavirus type 16 (human papillomavirus, HPV-16) peptide microarray technology in the screening of serum antibodies in prostate cancer patients[D]. Soochow University, 2017.