Lab-on-a chip electrochemical sensing platform for simultaneous, ultra-sensitive and on-spot detection of 4-aminosalicylic acid and 5-aminosalicylic acid based on synergistic potential of chitosan functionalized MWCNTs supported on Ni doped Bi2S3

Abstract

Mesalamine or 5-aminosalicylic acid (5-ASA) and its isomer 4-aminosalicylic acid (4-ASA), well known key therapeutic agents used to treat inflammatory bowel diseases (IBDs) can pose toxicity risks upon unregulated consumption. However, their simultaneous real-time detection from physiological fluids like urine remains unexplored. This study presents an innovative electrochemical sensing platform using modified screen-printed electrodes capable of simultaneous detection of both the drugs by harnessing the synergistic potential of a novel nanocomposite comprising chitosan functionalized multi-walled carbon nanotubes and nickel doped bismuth sulphide. Comprehensive optical and microstructural characterization validate the modified sensor platform's morphological characteristics. The sensor was evaluated using CV and DPV, exhibiting notably low detection limits which is of the value 39.559 μM for 5-ASA and 85.21 μM for 4-ASA. Sensitivity was found to be 0.174 μA μM⁻¹cm⁻² for the linear dynamic range (LDR) of 50 μM–5750 μM for 5-ASA and 0.139 μA μM⁻¹cm⁻² for the linear dynamic range (LDR) of 100 μM–2200 μM for 4-ASA. Moreover, the adaptability of the sensor for integration into hand-held point-of-care devices for practical application has been demonstrated in this paper. Experimental validation using real urine samples underscores the sensor's impressive recovery rate of 98–99.6 % for 5-ASA and 95.12–99.24 % for 4-ASA and its capability of detecting target drugs even when present with typical urinary constituents as interferences. The real-world applicability of this sensing platform is further emphasized by conducting experiments on miniaturized hand-held device thus making it a promising tool for on-the-spot detection, offering substantial potential for future integration into point-of-care diagnostic devices to monitor patients requiring precise medical monitoring. Our approach offers unprecedented real-time identification capabilities of 4-ASA and 5-ASA which has not been explored before.