Catalytically enhanced organic transistors for in vitro toxicology monitoring through hydrogel entrapment of enzymes

The regulation of cell metabolism is important for cell function and viability. In the presence of toxic compounds or pathogens, cell metabolism can change drastically because of excess stress on the cell. The monitoring of key metabolites, such as glucose and lactate, can provide insight into cellular function and can be used as a tool for toxicology studies. The development of enzymatic sensors based on organic electrochemical transistors (OECTs) was demonstrated in this study through the immobilization of enzymes in a photocrosslinkable hydrogel, which was, in turn, tethered to the platinum-modified gate of a planar OECT. The resulting sensors exhibited high stability, sensitivity, and selectivity. The sensing of relevant metabolites in complex media collected from live kidney epithelial cells was performed. As a proof of the principle, the monitoring of glucose and lactate was also performed from cells treated with cisplatin, a known nephrotoxicant. The glucose and lactate monitoring show that the metabolism of cells was significantly altered by the presence of cisplatin. These findings support the monitoring of cell metabolism as a good approach for toxicology studies. They also illustrate the need for the development of enzymatic sensors that can be used in situ to monitor cell viability and function.