Figure 1.

The proposed multiplexed microfluidic biosensor (BiosensorX) within the envisioned POC scenario, monitoring the treatment of bacterial co- or superinfection in COVID-19 patients. BiosensorX is capable of harboring both, the CRISPR-powered assays for the detection of multiple COVID-19-specific RNA sequences, derived from nasal swabs, as well as a protein-based assay for ß-lactam antibiotic monitoring in serum samples. Simultaneous detection of the analytes is enabled by immobilization of different assays (light blue to black) onto the sequentially arranged incubation areas of the single-channel microfluidic chip. These incubation areas are each separated by two hydrophobic stopping barriers. The reaction solutions are then consecutively applied to their respective incubation areas, followed by application of glucose oxidase (GOx). The amount of GOx molecules in the incubation area is inversely proportional to the amount of detected viral RNA or ß-lactam, respectively. In order to perform the experimental readout, the entire microchannel is flooded with glucose solution which is converted into hydrogen peroxide by the immobilized GOx. The electrochemically active species oxidizes at the platinum working electrode, generating the amperometric signal. On-site patient monitoring could, hence, be performed by measuring ß-lactam antibiotic concentrations for personalized drug adjustment and screening for the abundance of the viral RdRP gene, to determine the end of isolation.