Immunoassays identify disease biomarkers in patient samples and enable the detection of viruses, cancers and various other pathogens by exploiting the relationship between antibodies and antigens . Widely used diagnostic immunoassays such as enzyme-linked immunosorbent assay (ELISA), fluorescent immunoassay (FIA) and chemiluminescence immunoassay (CLIA) are limited in their capacity to curtail rapidly advancing diseases . ELISA, the gold standard of immunoassays, requires several days to provide diagnostic results as it requires specialists and large equipment . In that time frame, disease spread through communities can be exponential and the advancement of disease in patients can be deadly. As a result, numerous research efforts are directed towards the development of rapid, highly sensitive, point of care devices. In some cases, new devices have reduced result waiting times to less than an hour .
Plasma Treatment for Immunoassay Development
Harrick Plasma cleaners are used in immunoassay development to improve device sensitivity and to enable microfluidic device fabrication. Plasma cleaning oxidizes material surfaces, introducing reactive polar functional groups. By increasing the hydrophilicity of inherently hydrophobic materials, plasma cleaning can enhance antigen or antibody immobilization . As a result, more antigens or antibodies can be loaded onto the material surface, thereby enhancing device sensitivity . Additionally, increasing surface wettability prevents the formation of air pockets within devices, providing more contact between samples and immunoassay receptors . Immunoassay materials treated to improve device sensitivity include PDMS, glass capillaries, polystyrene fibers, and cotton fibers.
Coronavirus related Work
Recently, Harrick Plasma cleaners have been used in the development of immunoassays directed at viruses in the coronavirus family. These include Middle East respiratory syndrome coronavirus (MERS-CoV) , avian coronavirus (AvCoV)  and Murine coronavirus . In one example, microfibers were patterned with oxygen plasma to create hydrophilic zones with different antigens, creating a device capable of detecting multiple antibodies in the same test .
Covid-19 (Sars-Cov-2) immunoassay development is currently in its initial stages. While Harrick Plasma cleaners have not yet been reported for use specifically with Covid-19, the methodologies and fabrication techniques presented in the following papers may be similarly applied.
For more information regarding microfluidic device fabrication, visit our PDMS Bonding page.
Relevant Articles from Harrick Plasma Users
 Hoy CFO, Kushiro K, Yamaoka Y, Ryo A, Takai M. “Rapid multiplex microfiber-based immunoassay for anti-MERS-CoV antibody detection.” Sensing and Bio-Sensing Research. 2019;26 https://doi.org/10.1016/j.sbsr.2019.100304
 Lin YH, Wu CC, Chen WL, Chang KP. “Anti-p53 Autoantibody Detection in Automatic Glass Capillary Immunoassay Platform for Screening of Oral Cavity Squamous Cell Carcinoma.” Sensors (Basel). 2020;20(4) https://doi.org/10.3390/s20040971
 Weng X, and Neethirajan S. “Immunosensor Based on Antibody-Functionalized MoS for Rapid Detection of Avian Coronavirus on Cotton Thread”. IEEE Sens. J. 2018 18: 4358-4363 https://doi.org/10.1109/JSEN.2018.2829084
 Li Y, Kang Q-S, Sun G-P, Su L-J, Zheng Z-H, Zhang Z-F, Wang H-Z, He Z-K, and Huang W-H. “Microchip-based immunoassays with application of silicon dioxide nanoparticle film”. Anal. Bioanal. Chem. 2012 403: 2449–2457 10.1007/s00216-012-5952-4
 Wippold JA, Wang H, Tingling J, Leibowitz JL, De figueiredo P, Han A. “PRESCIENT: platform for the rapid evaluation of antibody success using integrated microfluidics enabled technology”. Lab Chip. 2020 https://doi.org/10.1039/C9LC01165J