Traditionally, scientists have diagnosed infectious diseases by testing various antibodies and antigens against the causative agent. These biomarkers are detected by immunoassays and tests such as ELISA and PCR. However, despite the multiple advantages of PCR and ELISA assays, next-gen bioanalytical tools are necessary to fulfill the increasing demands of synthetic and systems biology research. Multiplex biological assay development holds the key.
Today, several multiplex systems such as Meso Scale Discovery and multiplex ELISA assays are available to provide a comprehensive depiction of the underlying biological mechanism. Bead-based assay systems can detect multiple analytes of both immune response and target microbial pathogens. These assays are deployed successfully in cohort screening, diagnostic, and research setups. Therefore, this article focuses on multiplex ELISA development for infectious disease detection.
Multiplexed ELISA for infectious disease research
Evaluating different levels of antibodies and antigens as biomarkers for multiple diseases is a vital diagnostic and research tool. Today, ELISA assays have effectively replaced complement consumption, agglutination, immunodiffusion, and precipitation tests. The robustness of ELISA assays has allowed researchers to quantify the analyte of interest accurately in complex biological matrices. Besides, the ability to automate test systems is one of the primary reasons for establishing ELISA assays as a diagnostic and research tool.
Despite its advantages, singleplex ELISA can measure only one analyte at a time. This disadvantage may be a limiting factor in clinical settings where multiple markers require testing. Some clinical diagnostic protocols prefer test panels with multiple infectious agents. Multiple analyte test panels are crucial for saving time and costs and providing a more comprehensive clinical picture.
The real advantage of multiplex assays comes from miniaturized formats. Although multiplex assays involve antigen-antibody interactions, major applications have come from planar DNA microarrays.
Multiplex assays require physically addressing the capture molecules. Physicality is crucial for measuring specific interactions individually. Planar surfaces can be used to form a grid. On the other hand, bead-shaped surfaces can also be used to capture a library of molecules. Irrespective of the shape and size of the test surface, a mixture of fluorescent dyes is incorporated into the beads to generate a distinct gradient of hues. This multiplex technique involves sample and reporter molecule interaction in a suspension of bead library followed by flow cytometry detection to measure the assay signal.
Hence, multiplex ELISA offers simultaneous detection of numerous analytes. The gold standard for viral infection diagnosis involves the isolation of a causative pathogen in cell culture. This method requires highly specialized equipment and staff. Moreover, growing certain viruses may be challenging, making the entire process lengthy and resource and expert-intensive. Hence, rapid diagnostic tests such as multiplexed ELISA assays are favored for infectious disease research.
Viral and bacterial infections involve a series of immune responses, including chemokines and cytokines. Rapid and accurate profiling of immune responses and pathogens can help us better understand infectious diseases. Multiplex ELISA assays have become an ideal bioanalytical tool to detect these pathogens and immune responses for improving critical patient care and public health. Besides, the development of cost-efficient and reliable multiplex ELISA assays has the potential to kick-start the revolution in infectious disease research.