In vitro diagnostics (IVD) has moved from morphology based cellular analysis to incorporating molecular characterization. Biomarker analysis at the protein level provides a powerful approach to measuring biological process indicators in normal and pathological conditions or response to pharmacological intervention. Established techniques such as Microfluidics, Liquid Biopsy, Array Technique and perfect Diagnostic Platform at Creative Biolabs offer trustworthy systems on which to build and offer high-quality protein biomarker services for global clients.
A variety of protein assays for disease diagnosis, including those based on enzyme linked-immunosorbent assay (ELISA), immunohistochemistry (IHC), and flow cytometry (FC), are currently available in research use. At Creative Biolabs, work continues to be done to improve sensitivity and specificity as well as to improve the multiplexing and analysis capabilities for these methods. Some emerging protein analysis techniques such as mass spectrometry (MS), proximity assays are used extensively for research purposes.
Fig.1 The schematic representation of the immunoassay methods. (Manole, 2018)
One emphasis in IVD is the move to methods that use increasingly smaller sample sizes and more portable equipment. Miniaturization reduces cost and allows for easier multiplexing. Microfluidics reduces assay variability by controlling fluid flow and reduces labor through the possibility of automation. Micro and nanoparticles improve consistency between reactions and concentrate products. Colorimetric, fluorescent and electrochemical, chemiluminescence, electrochemiluminescence and other detection mechanisms have been extensively applied to disease biomarker detection.
To date, published examples of protein microarrays for IVD purposes have included tests for autoimmune, cancer, infectious, and cardiovascular diseases. In the context of infectious diseases, different types of protein-based laboratory tests can identify microorganisms such as bacteria, viruses, fungi, and parasites. There are two major types of diagnostic technologies: antibody test and antigen test. For instance, studies on the serum of recovered COVID-19 patients suggest that host-neutralizing antibodies primarily work against spike (S) and nucleocapsid (N) proteins. The likelihood of predicting immunity status could increase in serological tests that target various regions of S or N proteins. Among four major types of serological diagnostic tests, the rapid diagnostic test (RDT) is a simple and rapid test based on lateral flow immunoassay (LFIA) technology and can potentially be administered as a point-of-care (POC) test or self-test. As Fig.2 shown, RDT test strips use a drop of blood to detect the presence of patient antibodies (IgG, IgM, or IgA) produced against a specific SARS-CoV-2 antigen.
Fig.2 Overview of COVID-19 rapid diagnostic test for IgG and IgM detection. (Ghaffari, 2020)
Besides, the analytical protein array has been applied to identify biomarkers for a wide variety of cancers since it allows simultaneously monitoring hundreds of thousands of protein samples in cells or tissues. Taking breast cancer as an example, analytical protein arrays have been widely adopted as an unbiased screening tool for profiling the protein contents in cell lines, tissues, and patient sera. Some potential biomarkers, including p53 (TP53), annexin A11 (ANX11), mitogen-activated protein kinase 7 (MAPK7), cell division cycle 25C (CDC25C), and eukaryotic translation initiation factor 4E (EIF4E) were successfully identified to have increased expression levels in breast cancer.
Fig.3 Types of protein arrays (left) and scheme of the two-phase strategy for biomarker identification using functional protein arrays (right). (Huang, 2017)
Our scientists have extensive experience setting up biomarker assays to quantitate proteins in various biological matrices such as blood, plasma, serum, urine, cerebrospinal fluid (CSF), organ tissue homogenate, etc. These biomarker studies can be performed using a traditional ELISA assay or one of our advanced biomarker assay platforms (LC-MS/MS, MSD ECL). We offer these biomarker testing services for the analysis of your study samples through custom assay development or commercially available assay kits.
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