Abstract

Plasma is a complex aqueous biofluid consisting of numerous proteins. The plasma of individuals affected by certain types of cancer and harmful pathogens contains antibodies, antigens and free nucleic acids, which are biomarkers of such diseases. The presence of blood cells in plasma interferes with assay reproducibility and clogs channels in microfluidic diagnostics, that is replacing conventional tests in clinical laboratories1. Therefore, the separation of blood cells is inevitable for accurate diagnosis. Furthermore, plasma biomarkers are present at sub-nanomolar concentrations, requiring highly sensitive detection techniques. More recently, the localized surface plasmon resonance (LSPR) realized using metallic nanostructures has shown great promise for such applications, by offering label-free detection and consuming low volume of reagents2. In this presentation, we will discuss a microfluidic approach to separate plasma from whole blood and detect biomarkers via LSPR downstream. Previously, we developed microfluidic devices that employ capillary force and hydrophobic patch filtration mechanism to separate upto 2 microlitres of plasma from whole blood within 15 minutes, and detect millimolar levels of glucose in the separated plasma3,4. By fabricating metallic nanostructures within our separation channels, we anticipate to improve our detection limit by few orders of magnitude via LSPR.