Considerable effort has been invested in developing salicylic acid (SA) biosensors for various application purposes. Here, by engineering the sensing modules and host cell chassis, we have gradually optimized the NahR-Psal/Pr-based SA biosensor, increasing the sensitivity and maximum output by 17.2-fold and 9.4-fold, respectively, and improving the detection limit by 800-fold, from 80 μM to 0.1 μM. A portable SA sensing device was constructed by embedding a gelatin-based hydrogel containing an optimized biosensor into the perforations of tape adhered to glass slide, which allowed good determination of SA in the range of 0.1 μM–10 μM. Then, we developed a customized smartphone App to measure the fluorescence intensity of each perforation and automatically calculate the corresponding SA concentration so that we could detect SA concentrations in real cosmetic samples. We anticipate that this smartphone-based imaging biosensor, with its compact size, higher sensitivity, cost-effectiveness, and easy data transfer, will be useful for long-term monitoring of SA.

中文翻译：

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一种灵敏、便携式、基于智能手机的全细胞生物传感器设备，用于水杨酸监测

人们投入了大量精力来开发用于各种应用目的的水杨酸（SA）生物传感器。在这里，通过设计传感模块和宿主细胞底盘，我们逐步优化了基于 NahR-Psal/Pr 的 SA 生物传感器，将灵敏度和最大输出分别提高了 17.2 倍和 9.4 倍，并将检测限提高了800 倍，从 80 μM 到 0.1 μM。通过将含有优化生物传感器的明胶基水凝胶嵌入到载玻片上的胶带穿孔中，构建了便携式SA传感装置，可以很好地测定0.1 μM–10 μM范围内的SA。然后，我们开发了定制的智能手机App来测量每个穿孔的荧光强度并自动计算相应的SA浓度，以便我们可以检测真实化妆品样品中的SA浓度。我们预计，这种基于智能手机的成像生物传感器具有紧凑的尺寸、更高的灵敏度、成本效益和易于数据传输，将有助于长期监测 SA。