Impedimetric Immunosensor for On-Site Measurement of Rituximab from Invasive and Non-Invasive Samples

Abstract

Rituximab (RTX) is a specific monoclonal antibody for CD20 protein, which is mostly found in lymphocytes B. RTX is notably indicated for lymphomas, autoimmune disorders, leukemia, and transplant rejection. A higher efficiency is achieved by adjusted doses, which is tailored by individual body weight and RTX pharmacokinetic parameters. Therefore, individualized dosing is a usual practice to achieve therapeutic success with this expensive drug. Therapeutic monitoring of RTX is commonly performed by chromatographic methods or immunoassays. These methods, however, suffer from a lack of standardization in workflows, long turnaround times, and high instrumentation costs with complex sample preparation. In this regard, immunosensors emerge as a feasible alternative to overcome these limitations. Herein, we developed an immunosensor, which can detect RTX from both invasive and non-invasive samples. A linear correlation between the charge transfer resistance and RTX from 2 to 14 µg mL−1 (r2 of 0.99) along with limit-of-detection and limit-of-quantification of 0.13 and 0.40 µg mL−1, respectively, was obtained. The immunosensor implemented proved to have sufficient precision and accuracy for on-site RTX detection in both blood serum and urine samples. Such affordable, label-free, and highly sensitive electrochemical immunosensors could pave the way for on-site therapeutic drug monitoring, quality control.