Smartphone-based portable biosensing system using cell viability biosensor for okadaic acid detection

•A smartphone-based biosensing system using CVBS was developed for OA detection.•The system presented the good robustness in long-term image capture and analysis.•The system achieved label-free, non-invasive and long-term monitoring of cell viability.•The cost-effective CVBS was constructed by HepG2 cells, MTP and CCK-8 kit for OA detection.•The iPlate Monitor used traversal algorithm to obtain the best detection point-in-time.

Okadaic acid (OA), as a diarrheic shellfish poisoning toxin, had wide distribution and frequent occurrence. Therefore, low-cost, high-throughput, wide-range and portable detection of OA was in high demand for food safety and environmental monitoring. In this study, a novel and portable smartphone-based system using cell viability biosensor (CVBS) was developed for label-free, non-invasive and long-term monitoring of cell viability. The variation of cell viability reflected the changes of cell morphology, cell count and cell proliferation indirectly. And this system applied the combination of image analysis and cell counting kit-8 assay (CCK-8) to monitor the reflection. The biosensing system chose HepG2 cells as sensing elements to build CVBS and used it in OA detection. Results showed this system could synchronously detect OA in 96 channels. And this biosensor presented a good performance to various OA concentrations, with a wide linear detection range (10-800 μg/L). Moreover, the point-in-time having best detection performance could be located by the traversal algorithm in the monitoring duration. Thus, this cell-based biosensor system provided a convenient and efficient approach in seafood safety testing such as OA screening.