Affimer-based impedimetric biosensors for fibroblast growth factor receptor 3 (FGFR3): a novel tool for detection and surveillance of recurrent bladder cancer

Fibroblast growth factor receptor 3 (FGFR3) is a transmembrane tyrosine kinase protein in the fibroblast growth factor receptor family, which plays a key role in many biological processes. Over-expression and activating mutations in FGFR3 are frequent in non-invasive bladder cancer, highlighting this protein as a potential biomarker for recurrent bladder cancer detection. Affimer reagents isolated against recombinant FGFR3 were assessed for their affinity using double-sandwich ELISA and SPR. Anti-FGFR3-14 and FGFR3-21 Affimer proteins showed strong binding to FGFR3 and were used for fabrication of impedimetric electrochemical biosensors. A decrease in impedance was observed when the sensors were exposed to increasing concentrations of FGFR3. The successful impedimetric biosensors were capable of detecting sub-pM to nM concentrations of recombinant FGFR3 protein in phosphate buffered saline as well as in synthetic urine.