Abstract Description

The quantification of circulating blood cells expressing the Cluster of Differentiation 4 (CD4 + ) glycoprotein by flow cytometry is used for the diagnosis and monitoring of several diseases, including HIV and certain haematopoietic cancers. Due to the high capital costs and the complexity of operation, access to flow cytometry remains out of reach for many routine diagnostic applications, especially for patients residing in low-income, resource-limited, and/or remote areas. Paper-based lateral flow sensors, utilising aptamers or antibodies as biorecognition molecules, have emerged as low-cost alternative point-of-care sensors for CD4 detection and for CD4 + cell quantification. We report on the fabrication of a colorimetric aptamer-antibody composite lateral flow biosensor for CD4, comparing the ability of two previously-reported aptamers – U26 and U20 – to function in the sensor. The development of a low-cost hybrid aptamer-antibody lateral flow sensor for CD4 detection has the potential to improve HIV-infected patient care. Future work will evaluate the sensor’s ability to detect CD4-expressing cells in complex matrices similar to human serum.