A portable medical diagnostic device utilizing free-standing responsive polymer film-based biosensors and low-cost transducer for point-of-care applications

The development of medical diagnostic devices for point-of-care applications (PoC) is a key demand towards the establishment of decentralized health-care systems. The cost of miniaturized transducers, the need for elaborated modification of the sensing surface and the complexity of the assay workflow impede the widespread use of current biosensing technologies to PoC applications. Herein, we describe a portable medical diagnostic device (we call it BioPoC), which employs free-standing enzyme-modified responsive polymer membrane-based biosensors and a newly devised low-cost transduction principle. The device includes a single vertical channel with an integrated sample dosing well. Its operation is based on the measurement of the time required the originally infinite electric resistance between two, separated by the enzyme-modified responsive polymer membrane, conductive strips to reach a finite value (typically< 20 MOhm) as a result of the target-triggered degradation of the polymer membrane and the ensuing vertical flow of the sample, which thus establishes an electrical communication between the conductive strips. The time (R-infinity -> R-20MOhm) is proportional to the concentration of the target. By proper combination of different responsive polymers and enzyme(s), BioPoC device can enable the drop-volume, one-step biosensing of a variety of biomarkers. Data demonstrate an outstanding selectivity against the components of the matrix, while the detection range can be tuned over the normal range of the analyte of interest. As part of the proof-of-concept, BioPoC device was employed for the determination of urea in undiluted human urine and the near-patient detection of Helicobacter pylori in gastric antrum bioptic samples.