Nanomaterial-Enhanced Fiber Optofluidic Laser Biosensor for Sensitive Enzyme Detection

A novel fiber optofluidic laser biosensor based on nanoparticle-functionalized thin-walled hollow optical fiber is developed for sensitive detection of enzyme horseradish peroxidase (HRP). High sensitivity is achieved thanks to the high surface-to-volume ratio of the nanomaterials. Two kinds of attractive nanomaterials, i.e., Au nanorods and SiO
₂
nanoparticles, are selected as demonstrative models to be coated onto the inner surface of thin-walled hollow fiber through electrostatic adsorption and biochemical cross-linking, respectively, while the streptavidin-biotin conjugation mechanism acts as a bridge for the specific recognition of enzyme. The nanoparticle-functionalized fiber optofluidic lasers have lower lasing threshold, compared to the control group without nanomaterial. We experimentally demonstrate that the nanomaterials enhanced fiber optofluidic laser biosensors can detect HRP in the range of 75–15 000 pM with a good linearity in semi-logarithmic scale, and with a sensitivity enhancement of 57.4% by using the SiO
₂
nanoparticles. We believe that this nanoparticle-enhanced fiber optofluidic laser biosensor could provide an efficient strategy for biomolecule detection such as enzyme-linked immunosorbent assay (ELISA).