ph-triggered cross-reactivity for visual pattern recognition of antidepressant drugs

Abstract: pattern-based sensing with multi-component sensor arrays, despite its merits, may be laborious and time-consuming. as an alternative approach, herein, a condition-based single component sensor array has been provided which represents an elegantly simple, low cost and minimally instrumented format for the quantification and classification of antidepressant drugs. tuning the ph and ionic strength enabled the single component probe to interact with the target analytes through different binding modes, providing the required cross-reactivity. gold nps are promising candidates for the design of colorimetric sensor arrays and have been widely applied in this field due to their facile surface functionalization, tunable surface plasmon band and ease of control over their size, shape, morphology and aggregation state during the synthesis step or post modifications [1]. to date, a high number of aunp-based colorimetric sensor arrays have been developed with the aim of addressing important analytical challenges [2-3]. none of them have yet reported the array-based sensing of antidepressant drugs. to generate the array, a single aunp was embedded into six experimental conditions: three different buffers each at two concentration levels. the analytical figures of merit of the sensor array exhibited excellent sensitivity and selectivity results towards antidepressants and low limit of detections (as low as 0.009 μg ml-1). the prediction accuracy (r2pred) for the identification and determination of the antidepressants over their wide concentration ranges were all above 0.99. these metrices verified that the condition-based multiplex sensing approach is precise and accurate for both the discrimination and quantification of the anti-depressant drugs. the results of multivariate calibration (r2cal> 99% and r2cv> 99%) and discrimination (r2cv> 98%) of antidepressants in human urine ensured the practicability of the array in complex biological fluids. furthermore, the wide-ranging colorimetric responses that appeared due to different aggregation patterns allowed visual detection.