Surface plasmon resonance based fiber optic sensor for the detection of cysteine using diosmin capped silver nanoparticles

- Novel one pot synthesis of silver nanoparticles using diosmin.
- Cysteine sensing properties of green synthesized silver nanoparticles were investigated.
- Proposed sensor showed good sensitivity and selectivity towards cysteine.
- Fabricated an SPR based Fiber optic cysteine sensor utilizing the synthesized material.

A simple green method to synthesize silver nanoparticles (AgNPs) is described where diosmin acts as reducing and capping agent. Formation of diosmin capped silver nanoparticles (Dios-AgNPs) was characterized using UV-vis spectroscopy, X-ray diffraction, TEM, Raman imaging and FTIR analysis. Investigations on the biosensing of Dios-AgNPs among various amino acids showed excellent response towards cysteine. Further an SPR based fiber optic sensor for cysteine was fabricated and its sensitivity, selectivity and limit of detection were investigated and reported. The fiber optic sensor was developed by coating a thin film of silver over the unclad core of the fiber and then coated with Dios-AgNPs. The sensor has advantages of low cost of production, fast response, high selectivity and sensitivity. The sensor can be used for online monitoring and remote sensing applications.