Drip-Dry Strategy\nAssisted Blu-Ray Disc Biosensor\nfor Fast Point of Care Testing

Discs and numerous other consumer products have been\ndeveloped\nfor point of care testing (POCT) to replace traditional large and\nexpensive biochemical devices in certain scenarios. Herein, we propose\na drip-dry strategy (2D strategy) assisted Blu-ray disc (BD) biosensor,\ntermed BDB, for rapid and portable POCT within 30 min with the cost\nof a single test < $1. The platform utilizes the covered area formed\nby the deposition of the substance to be measured on the activated\nBD surface after the evaporation of water and realizes the quantitative\ndetection of the target through the error readout of free disc quality\ndiagnosis software. As a proof of concept, we first demonstrated the\nfeasibility of direct quantitative detection of substances in solution\nin a single system through the detection of pure proteins avoiding\ncolorimetric reagent used in traditional optical detection. For the\ncomplex mixed systems, we then innovatively utilize the principle\nthat soluble targets promote/inhibit the dissolution of insoluble\nprecipitates to achieve specific detection of targets and successfully\napply BDB to the indirect quantitative detection of glutathione (GSH)\nwith LOD of 0.447 mM in the range of 2–16 mM and organophosphorus\npesticides (OPs) with LOD of 2.122 × 10<sup>–7</sup> M\nin the range of 1.289 × 10<sup>–7</sup>–1.289 ×\n10<sup>–4</sup> M. The BDB is widely applicable, easy to operate,\nand less time-consuming, which is anticipated to provide an alternative\nmethod for early, on-site detection or screening.