Development of an Optical Fiber Biosensor for the Detection of Vascular Endothelial Growth Factor (VEGF) for Synovial Fluid Application

Abstract

The detection of vascular endothelial growth factor (VEGF) plays a very important role in the research of joint-related diseases, especially osteoarthritis. In this work, a label-free optical fiber biosensor was designed based on the semi-distributed interferometric (SDI) system that can be used for highly sensitive measurements of VEGF. The optical fiber sensor was manufactured using the splice-and-cleave method of single-mode and enhanced backscattering fibers, and then anti-VEGF antibodies were attached to its surface. The fabricated sensors showed high sensitivity towards refractive index variations within the range of 137 to 207 dB/RIU. In the detection tests carried out in Phosphate Buffer Saline (PBS), there was a definite concentration-dependent response over the entire range from 1 fM to 100 nM, giving an output signal variation of around 1.7 – 1.8 dB with good linearity (R² = 0.94). It was also observed that the sensor could detect VEGF accurately at femtomolar concentrations, which clearly indicated its highly sensitive nature. Evaluation in simulated synovial fluid environment in a knee-joint phantom model also gave a positive result. The results show that the designed optical fiber biosensor based on SDI technique is a miniaturized, sensitive, and rapid system for detecting VEGF. The current research lays down the groundwork for future experiments that can be performed using biological samples and possibly even in vivo.