Development of an Anti-Idiotype Aptamer-Based Electrochemical Sensor for a Humanized Therapeutic Antibody Monitoring

Therapeutic monoclonal antibodies (mAbs) are currently the most effective medicines for a wide range of diseases. Therefore, it is expected that easy and rapid measurement of mAbs will be required to improve their efficacy. Here, we report an anti-idiotype aptamer-based electrochemical sensor for a humanized therapeutic antibody, bevacizumab, based on square wave voltammetry (SWV). With this measurement procedure, we were able to monitor the target mAb within 30 min by employing the anti-idiotype bivalent aptamer modified with a redox probe. A fabricated bevacizumab sensor achieved detection of bevacizumab from 1–100 nM while eliminating the need for free redox probes in the solution. The feasibility of monitoring biological samples was also demonstrated by detecting bevacizumab in the diluted artificial serum, and the fabricated sensor succeeded in detecting the target covering the physiologically relevant concentration range of bevacizumab. Our sensor contributes to ongoing efforts towards therapeutic mAbs monitoring by investigating their pharmacokinetics and improving their treatment efficacy.