Label-free Electrochemical Immunosensor for Monitoring Kidney Transplant Rejection with Electroactive Antibiofouling Hydrogel

Diagnosing acute rejection of kidney transplant remains challenging as standard practice relies on monitoring serum creatinine levels and performing biopsies. The former lacks sensitivity, while the latter is invasive. Monitoring Chemokine IP-10 (or CXCL10) in patient samples has shown promising results in addressing these bottlenecks but is measured with expensive and time-consuming protocols such as enzyme-linked immunosorbent assay (ELISA). This does not allow for an individualized approach. The present work describes the development of a novel screen-printed electrode-based electrochemical biosensor for IP-10 detection using an electroactive anti-biofouling hydrogel. The electrode coating is based on glutaraldehyde (GA)-crosslinked 3D nanostructured bovine serum albumin (BSA) hydrogel, whose pores are filled with a highly conductive Ti3C2Tx MXene. The formulation is water-based and avoids the use of toxic solvents. The crosslinking mechanism, anti-biofouling characteristics, and electroactivity were characterized by UV-VIS spectroscopy, contact angle measurement, and cyclic voltammetry tests, respectively. The antibody-functionalized MXene/BSA/GA nanocomposite-based sensor allows the detection of IP-10 spiked in human serum by achieving an LOD of 3.3 pg/ml with a linear range across 1-200 pg/ml and a response time of 30 min. The study paves the way toward developing a highly specific multiplexed chemokine profiling platform for point-of-care diagnostics applications to monitor kidney transplant rejection.