A Study On Fluorescnt Materials Incorporated Hydrogel Optical Fiber For Fluorescence Sensing

Fluorescence sensing technology has been widely applied in measurement of environmental parameters,micro or trace analysis of ions,recognition of biomedical molecules because of its high sensitivity,high selectivity and fast response.On the basis of its small size,light weight,insulation,high temperature resistance,corrosion resistance,long distance propagation and anti-electromagnetic interference,it may achieve remote,real-time,on-site and even in-vivo sensing based on fluorescence effects.However,it is still in the early stage,where exists many problems limiting further development of all fiber-optic fluorescence sensing technology,such as the difficulty of integration of fluorescence probe into optical fiber,low excitation or fluorescence collection efficiency.To address the aforementioned problems,this paper has investigated the integration of fluorescent materials into hydrogel optical fiber and high-performance fluorescence sensing,which are listed as followings:(1)Design and preparation of permeable hydrogel optical fiber.This paper has explored factors influencing swelling ratios,refractive indexes and optical transmission of bulky hydrogels.We have prepared permeable hydrogel optical fibers according to two-step method by using poly(ethylene glycol)diacrylate and sodium alginate as core and clad respectively,and propagation loss of the prepared hydrogel optical fiber was as low as 0.5 dB/cm.The prepared hydrogel optical fiber possessed quite good permeability meanwhile guaranteeing the adequate interaction between the fluorescent materials robustly embedded in the core and the surrounding analytes,and this has paved the way for design of fluorescent materials incorporated hydrogel optical fiber.(2)Study on design of fluorescent materials integrated hydrogel optical fiber for highly selective explosive fluorescence sensing.We have synthesized metal-organic framework material EuNDC for highly selective sensing of picric acid.We have fabricated EuNDC incorporated hydrogel optical fiber,which has enhanced effective interaction length to several centimeters because of its good light-guiding ability.We have achieved highly selective,quantitative detection of explosive molecule according to the principle of turn-down.This has improved environment adaptability and further demonstrated its feasibility as a fluorescence sensing platform applied in solutions.(3)Study on design of fluorescent materials incorporated hydrogel optical fiber for pH sensing with high precision.Large measuring errors will be brought into systems for conventional fluorescence sensing technology based on intensity because of light source instability and environment perturbance.Thus we choose FITC、PtTPTBP as pH sensitive fluorescent material and reference dye,respectively.We then have constructed double-doped hydrogel optical fiber used as a ratiometric pH fluorescence sensor,which could respond to pH in the range of 3.79-10 and enhanced accuracy.Furthermore,we have also investigated the ratiometric sensing performance of ANNA doped hydrogel optical fiber,which achieved detection of pH in the physiological range and improved the repeatability.For monitoring pH changes in vivo,fluorescent materials incorporated hydrogel optical fiber may be a hopeful candidate.