Fully integrated lab-on-a-chip on standard 4-layer printed circuit board incorporating DNA amplification and detection on reduced graphene oxide sensors

Integration is one of the most challenging issues in Lab-on-a-Chip (LOC) devices and a major hurdle for transforming LOCs into practical applications. To date, cumbersome solutions have been proposed involving either heterogeneously integrated cartridges or various microfluidic components interconnected via various types of tubing and microfluidic fittings. In this work, we present a fully integrated LOC in which key components required to perform a complete analysis of biological samples such as heating elements, microfluidic channel networks and biosensors are seamlessly integrated on a single printed circuit board (PCB). This approach allows for the implementation of complicated functions such as nucleic acid amplification and detection on the same low cost, mass producible chip. In our realization, graphene oxide (GO) is deposited as a multilayer stack and then reduced via a mild thermal treatment on predefined Au plated electrodes as a means to straightforward implement highly sensitive biosensors on the chip. As a proof-of-concept application, a specific DNA region of BRCA1 gene is successfully amplified on-chip using recombinase polymerase amplification (RPA) and subsequently detected by the on-chip GO biosensors. The success of the DNA amplification is verified off-chip via gel electrophoresis, whereas the entire amplification and detection procedure is completed within 40 min.