Automation of multi-analyte prostate cancer biomarker immunoassay panel from whole blood by minimum-instrumentation rotational flow control

Abstract

Early diagnosis and prognosis of prostate cancer (PCa) is increasingly moving towards evaluations based on a strategic combination of biomarkers. The ability to parallelize multi-parameter detection on the same device is hence considered as a substantial improvement compared to conventional, single-marker methods such as total prostate-specific antigen (t-PSA). We demonstrate full rotational control of a centrifugal microfluidic system which is geared to automate multi-step/multi-reagent protocols underlying PCa detection based on a multi-marker panel on a widely autonomous, cost-efficient and rugged point-of-care instrument. Such comprehensive fluidic integration is enabled by a novel type of dissolvable-film (DF) valve which significantly enhances the definition of its critical release frequency by a factor of more than 3 (average spread of ±1.8Hz), and thus substantially enhances process reliability and integration density on our “Lab-on-a-Disc” (LoaD) platform. This siphon-based centrifugo-pneumatic flow control scheme can be attuned merely by temporal modulation of the spin rate to parallelize three assay protocols in a sample-to-answer fashion; in addition, we demonstrate flexibility of application without redesigning of the cartridge towards variants of the common Enzyme-Linked Immuno-Sorbent Assay (ELISA) format. As a pilot application, we further implement liquid handling automation for the detection of two distinct PCa markers, free PSA and human epidermal growth factor receptor-type 2, (HER2), using two types of ELISA i.e. sandwich and competitive, respectively.