Conclusions

This study demonstrates that modification of a disposable screen-printed electrode with TiO2 nanoparticles yields a highly sensitive electrochemical sensor (TiO2NP@SPE) for the determination of erlotinib, with SEM-EDAX, FTIR, and XRD characterization confirming successful nanoparticle deposition. The sensor exhibited diffusion-controlled oxidation kinetics with a LOD of 9.15 μM, LOQ of 30.52 μM and sensitivity of 1.775 μA μM-1 cm⁻2, alongside excellent selectivity against physiological interferents and structurally related anticancer agents, and intra- and inter-day serum recovery of 98.56 to 102.54 % (RSD <2.7 %). Despite the improved sensitivity, the TiO2NP modification resulted in a higher LOD compared to the bare SPE, owing to elevated background capacitance inherent to nanomaterial-modified electrode surfaces. Future work will explore TiO2-carbon nanotube or molecularly imprinted TiO2 composite modifications to synergistically lower the detection limit and enhance selectivity, alongside integration into a miniaturized lab-on-chip platform for on-chip sample preparation and point-of-care therapeutic drug monitoring of erlotinib in clinical settings.