Real-time, in-situ analysis of silver ions using nucleic acid probes modified silica microfiber interferometry

A sensitive Ag + sensor based on nucleic acid probes modified silica microfiber interferometry is designed and developed. The probes on microfiber surface plays the part on catching Ag + as tentacles, while their conformation change from random coils to hairpins. It induces the fiber surface refractive index change, which is captured by the optical fiber and translated into a significant wavelength shift in the interferometric fringe. Such a combination enables an improved concentration sensitivity of 0.22   nm/log M and limit of detection of 1.36 × 10 −9   M, taking the advantage of real-time and in-situ analysis. It shows good selectivity in the present of many other metal ions and offers potential to analysis in real matrix, especially in the environmental samples must be analyzed in a short time. This may provide insights into the preparation of sensing platforms for optical quantification of other small molecular, supplementing the existing tools.