MEMS based microfluidic system for HIV detection

ART guidelines of World Health Organization recommend a series of tests for HIV diagnostics (HIV antibody test, CD4 cell count and HIV viral load count). There are several modern technologies that are available to ensure reliable HIV diagnosis employing various principles. However, there is a need for point-of-care system that will eliminate the requirement of the patient to visit a hospital for initial diagnosis. In this paper, a novel design and analysis of MEMS based microfluidic chip facilitating point-of-care diagnostics is presented. The chip is based on the CD4 T⁺ cell count in blood. The device involves an array of silicon micro-needles each of length 250 microns, that would remove blood directly from the veins and feed it to a silicon micro-channel with alternating constrictions. These constrictions are coated with anti-CD4 Ab molecules to selectively adsorb CD4 T⁺ cells. An alternating current (AC) impedometric method is then used for discrimination and enumeration of these immobilized cells. The results strongly indicate the reliability of low-cost point of care diagnostics for HIV diagnosis.