A hollow core photonics crystal fiber based miniaturized sensor for detection of aggregation-induced emission molecules.

A miniature sensor for detection of aggregation-induced emission (AIE) molecule is proposed in this work. The sensing head is fabricated by use of hollow core photonic crystal fiber with a core diameter of about 4.8 μm. The cladding holes are sealed by fusion splicing technique while the central hole remains open to allow the filtration of solution with AIE molecules. When the solution is excited by ultraviolet lamp, the fluorescence light is received by a fiber optic spectrometer. The fluorescence intensity is associated with the concentration of AIE molecules and the infiltrated core length. In the whole process of the experiments, the output peak wavelength is stable which indicates that the existing forms of AIE particles are stable and the fluorescence reabsorption can be neglected. The experimental results obtained are in accordance with the traditional microplate spectrophotometer methods. The most exciting result is the amount of sample measured can be as low as 0.36 nL, which allows detection of AIE molecules at only 0.02 pmol. In addition, the miniature sensor was successfully applied to detect an AIE-based bio-probe for evaluating the activity of DPP-4 inhibitor sitagliptin with IC50 of 69.32 nM. The advantage of small device size and nanoliter scale sample volume suggested the proposed sensor is promising in many biosensing applications.