ZIF-8/Lipase Coated Tapered Optical Fiber Biosensor for the Detection of Triacylglycerides

A novel method for the detection of triacylglycerides was reported with a pure, stable, label-free enzyme functionalized optical fiber detector. This method has been accomplished by immobilizing Zeolitic imidazolate framework-8 (ZIF-8) packaged lipase on the tapered optical fiber. The evanescent field is generated by tapering the optical fiber birefringent interferometer (BFI). Usage of ZIF-8/lipase as a biosensing film on optical fiber has not previously been reported. 4-nitrophenyl palmitate (4-NP) is used to determine the stability of the lipase encapsulated in ZIF-8. Tapered BFI works at a refractive index (RI), which matches the turning point to provide high sensitivity. The wavelength shift has a quadratic polynomial response relationship with the concentration of triacylglycerol, showing enhanced sensitivity and bio-selectivity. LOD (Limit of detection) of 0.17 μM and 0.23 nM is obtained with diameters of 10 μm and 7 μm, respectively. This sensor can be applied to triacylglycerides detection, requiring a low volume of blood for each sample.