Diagnosis of age-related macular degeneration (AMD) using optical fiber sensor
Muhamad Nur Azhar Noordin
Date of Issue2016-05-27
School of Chemical and Biomedical Engineering
Age-Related Macular Degeneration (AMD) has been a lingering problem for late adults, which contributes to loss of central vision thus reducing their ability to focus on an object. The exact cause of AMD is still unknown; but it starts with the degeneration of macula cells which often result to extensively secretion of Vascular Endothelial Growth Factor-A (VEGF-A) in the eye. In this report, the application of Fabry-Perot Interferometer (FPI) and Fiber Bragg Gratings (FBG) to detect VEGF-A concentration were evaluated. The FPI consists of a standard single-mode fiber spliced with 1mm of hollow-core fiber and 0.8mm of no-core fiber. Both optical fiber tip were coated with the crosslinked poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) hydrogel and functionalized with VEGF-A detection antibody, prior to the VEGF-A antigen detection. Following, the coated tip was exposed to seven solutions of increasing concentration. It is observed that FBG sensor demonstrated a high increment change of 5.657dB between the smallest and highest concentration, compared to the FPI sensor which shows only 0.634dB change. Further evaluation was performed on the FBG sensor to identify the response time where it concluded to require 8 minutes for a stabilized output. The FBG also provides relatively high signal-to-noise ratio to impede inaccuracy that may arises due to external factors. The mentioned sensor also has a sensitivity of 5.1 × 10−3dB/pg/ml. Even though only two control proteins were utilised in its specificity test, it still shows a recognizable difference between their refractive powers, proving its vulnerability to VEGF-A concentrations.
Final Year Project (FYP)
Nanyang Technological University