Fabrication of a paper-based facile and low-cost microfluidic device and digital imaging technique for point-of-need monitoring of hypochlorite?

Analyst Pub Date: 2023-07-24 DOI: 10.1039/D3AN00533J

Abstract

Lab-on-a-paper-based devices are promising alternatives to the existing arduous techniques for point-of-need monitoring. The present work reports an instant and facile method to produce a microfluidic paper-based analytical device (μPAD). The fabricated μPAD has been used to detect hypochlorite (OCl?) by incorporating newly synthesized chromo-fluorogenic ratiometric probes 1 and 2 into the sample reception zone. The probes showed high selectivity and fast response (<10 s) toward OCl? with an excellent linear relationship in the concentration range of 0–100 μM. The concentration-dependent fluorometric change driven by the reaction of 1@μPAD with OCl? has been monitored using gel-doc imaging systems, which is unprecedented. Digitizing the intensity of the colour solution with different mathematical models of colour has developed a straightforward method for monitoring OCl? without any interference from its competitors. 1@μPAD can detect OCl? at ～10 times lower than the WHO recommended limit. The detection limit of 1@μPAD via a digital camera-based fluorescence technique was found to be better over digital camera-based cuvette assays. Therefore, 1@μPAD has been successfully utilized to monitor OCl? in actual environmental water samples with portability, ease of use, and sensitivity. The analytical RSD was found to be ≤3% based on fluorimetric detection using 1@μPAD. The chemodosimetric reaction between OCl? and the probe was evidenced by UV-vis and fluorescence spectroscopy, 1H NMR, and ESI-MS. The rapid response time, biocompatibility, low cytotoxicity, 100% aqueous solubility, ratiometric feature, and exclusive OCl? selectivity over other competitive ROS/RNS successfully lead to the application of the probes for bioimaging of exogenous as well as endogenous OCl? in normal cells (HEK293) and cancerous cells (HeLa).

Graphical abstract: Fabrication of a paper-based facile and low-cost microfluidic device and digital imaging technique for point-of-need monitoring of hypochlorite
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