A self-calibrating and multiplexed electrochemical lab-on-a-chip for cell culture analysis and high-resolution imaging.

In vitro analysis requires cell proliferation in conditions close to physiological ones. Lab-on-a-chip (LoC) devices simplify, miniaturize and automate traditional protocols, with the advantages of being less expensive and faster due to their shorter diffusion distances. The main limitation of current LoCs is still the control of the culture conditions. Most LoCs employ off-chip equipment to determine cell culture activity, which confers limited monitoring capacity. The few systems integrating transducers on-chip present important functional problems mostly associated with the attachment of biomolecules to the transducer surface (i.e., biofouling) and the impossibility of re-calibrating the sensors during cell culturing. This limitation is addressed in the present LoC containing a network of micro-channels and micro-chambers, which allows (i) cell seeding and cultivation, avoiding biofouling risk, (ii) multiplexed analysis of cell culture, reactivation and recalibration of the (bio)sensors without compromising cell viability, (iii) cell imaging and (iv) reference electrode compartmentalization to guarantee stability. The activity of the culture is monitored with four independent electrochemical micro-electrodes for glucose, hydrogen peroxide, conductivity and oxidation reduction potential. Electrochemical analysis is complemented with high-resolution confocal microscopy analysis. This paper demonstrates the suitability of the current configuration for cell culture monitoring and future applications in drug screening or organ-on-a-chip development.