Development of Uric Acid Biosensor Using Gold Nanoparticles and Graphene Oxide Functionalized Micro-Ball Fiber Sensor Probe

A highly sensitive and selective optical fiber-based enzymatic biosensor has been proposed in the present study for detection of uric acid (UA) in human serum. The working mechanism of sensor depends on surface plasma property and localized surface plasmon resonance technique. For this purpose, a micro-ball fiber sensor probe of $350 similar to\mu \text{m}$ diameter was fabricated using advanced fusion-splicer and coated with gold nanoparticles (AuNPs) and graphene oxide (GO) in order to enhance its sensitivity. UV-Visible spectrophotometer and high-resolution transmission electron microscope (HR-TEM) were used to characterize the AuNPs solution and GO aqueous dispersion. The absorbance spectrum of AuNPs and GO are recorded at 519 nm and 230 nm, respectively. The coating of AuNPs and GO over fiber surface were verified by using a scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX). Thereafter, sensor probe was functionalized with the specific enzyme i.e. uricase for the UA detection. The linearity response of uricase/GO/AuNPs-coated micro-ball optical fiber sensor is reported in the range of $10 similar to\mu \text{M}$ -1 mM UA concentrations. The reflectance of sensor linearly decreases with the increasing UA concentrations. Sensitivity of the sensor is 2.1 %/mM with a good slope of linearity with detection limit of $65.60 similar to\mu \text{M}$ . To test the accuracy of proposed sensor, UA concentration in serum samples have also tested by using proposed sensor and A5800 Automatic Biochemical Analyzer. The results of the developed sensor are consistent with the results of A5800 Automatic Biochemical Analyzer. Thus, proposed sensor can be successfully utilized for UA detection in human serum samples.