Cell analysis requires increasingly more complex equipment to investigate cellular and molecular mechanisms. The goal of the present research is to develop a platform of integrated amperometric biosensors to better understand biological processes by real-time monitoring of different metabolites over the duration of a cell culture. The simultaneous use of carbon nanotubes (CNTs) to enhance the signal and oxidases to confer specificity can really lead to an innovative tool for several research activities. We propose an integrated electrochemical cell fabricated with CMOS compatible technology. The platform consists of five working electrodes, which are nanostructurated with CNTs, previously dispersed in Nafion, and functionalized with different oxidases. A microfluidic system on the top of the biosensor guarantees continuously fresh solution at the electrode surface. For measurements in culture medium, a microdialysis probe helps to limit interference from other electroactive species and to provide a broader linear range. Initially, CNTs-based biosensors are characterized in phosphate buffer saline (PBS) solution in terms of sensitivity and detection limit. Chronoamperometries are then performed in cell culture medium in a wider range of concentrations. Continuous measurements are also performed over 7 hours to validate operational stability. Considering calibration in PBS, our system shows 10x higher sensitivity compared to other works with similar nanostructuration. In fact, CNTs and Nafion form an optimal immobilization surface for enzymes. The detection of multiple metabolites is achieved in pure medium, while previous art requires dilution steps. Moreover, the biosensor covers the entire range of interest thanks to the microdialysis probe, a significant improvement as compared to our previous work. The operational stability exhibited during longer measurements leads us to conclude that the developed biosensor is highly suitable for cell line monitoring.