Analytics with blood on hybrid paper-rotating disc device

Abstract

Active and passive flow control via combining hybrid centrifugal devices holds decisive advantages in microfluidic manipulation. These advantages include but are not limited to multiplexing via single actuation, non-mechanical valving over a wide operational window, ultra low-cost fabrication, complex flow manipulation without requiring specialized surface treatments or surface patterning, and translating established test protocols to a high-throughput analytical platform. However, despite such promises, the complex interplay of various forces makes it extremely difficult to manipulate fluids on such a complex device in a programmable manner. To circumvent these deficiencies, here we present a novel design framework for fluidic manipulation of a drop of blood sample on a hybrid paper – spinning disc device, and translate the concept into a miniature device technology for quantifying blood haematocrit content (volume fraction of red blood cells) as a representative point-of-care hematological testing platform. Exploiting the characteristics of lateral motion under preferential design conditions, we establish a wider window of the capillary flow saturation dynamics as compared to that obtained in standard capillary or centrifugal microfluidics, thereby favouring bio-analytical procedures with high sensitivity and enhanced limit of detection. In a reagent-free framework, this not only puts forward a new detection paradigm for extreme point of care settings but also opens up avenues for advancing the development of novel porous media based on compact disc platforms in the realm of medical diagnostics for the low resource settings, with no impact of an otherwise inevitable weak supply chain and storage facilities of sensitive reagents.