Semiconductor-based biosensor exploiting competitive adsorption with charged pseudo-target molecules for monitoring 5-fluorouracil concentration in human serum

Rapid and simple monitoring of anticancer drug concentrations in blood is important for improving the efficacy of chemotherapeutic cancer treatment. In this study, we demonstrated the detection of 5-fluorouracil (5-FU) in human serum using a field-effect transistor (FET) biosensor with competitive adsorption between uncharged anticancer drugs and charged pseudo-targets. The target 5-FU and 5-FU-modified bovine serum albumin (BSA/5FU) were competitively adsorbed on the FET sensor surface using antigen-antibody reaction with antigen-binding fragment (Fab) receptor. FET responses to the target 5-FU concentrations were obtained via changes in the amount of negatively charged BSA/5-FU captured by Fab molecules. In addition, the influence of serum components could be suppressed by diluting the samples with a nonionic surfactant solution. As a result, the FET biosensing system was capable of quantitatively detecting 5-FU concentrations in serum. Therefore, the semiconductor-based sensing system could enable the adjustment of anticancer drug dosages and potentially lead to improvements in anticancer drug therapy.