A Self-Contained System With CNTs-Based Biosensors for Cell Culture Monitoring

Biosensors have been applied to disparate fields, especially for endogenous compounds such as glucose and lactate. The main areas of application are certainly related to medical and diagnostic purposes. However, metabolic monitoring can be also of interest in cell analysis. Cells can be cultivated for several purposes, such as understanding and modeling some biological mechanisms, the development of new drugs and therapies, or in the ήeld of regenerative medicine. All the aforementioned applications require a thorough knowledge of the biological system under study. In this paper, we propose the development of a self-contained system based on electrochemical biosensors for cell culture monitoring. The detection is based on oxidases immobilized onto carbon nanotubes. We also develop an architecture to record the signal generated by the biosensor and transmit it to a remote station by means of a Bluetooth module. We calibrate the system for glucose and lactate detection in phosphate buffer solution. We achieve a sensitivity of 55.5 μA/mM cm^-2 and a detection limit of 2 μM for glucose, as well as a sensitivity of 25.0 μA/ mM cm^-2 and a detection limit of 11 μM for lactate. We finally validate the two biosensors for metabolic monitoring in culture medium and we detect lactate production in neuroblastoma cells after 72 h of cultivation. The integrated system proposed in the present work opens new opportunities towards the development of novel tools for cell analysis.