Saya Comparative Analysis of Bovine Serum Albumin Detection Using Cuvettes, 1 Biofunctionalized, and Non-Biofunctionalized Tapered Optical Fiber

Advances in optical sensor technologies have been substantial in recent years, especially in the detection of biomolecules like Bovine 24 Serum Albumin (BSA), driven by the need for more sensitive and precise diagnostic tools. The detection of BSA plays a critical role, 25 particularly in the early diagnostic tools for chronic kidney disease. This work aims to investigate the performance of three different BSA 26 detection methods: biofunctionalized and non-biofunctionalized tapered optical fiber sensors and conventional cuvettes. This study 27 conducted an experimental investigation, utilizing a 3.5 ml cuvette and tapered optical fibers with design parameters including upper 28 and lower taper lengths of 10 mm, a waist length of 10 mm, and a waist diameter of 10 μm. The sensors were fabricated using the Vytran 29 GPX 3400 machine. Measurements of time response, intensity, and absorbance were carried out using a Deuterium-Tungsten DT-2-GS 30 light source and an Ocean Optics Flame spectrometer. The biofunctionalization of the sensing area involved three sequential steps: 31 hydroxylation with a 0.1M sodium hydroxide solution, salinization with a 2% (3-aminopropyl) triethoxysilane solution, and aldehyde 32 activation using a 2% glutaraldehyde solution. The experiment used 120 ml of BSA solutions at concentrations of 31.25 mg/dL, 62.5 33 mg/dL, and 125 mg/dL. Each method exhibits a unique spectral response across the ultraviolet, visible, and near-infrared regions. Both 34 intensity and absorbance assessments reveal a significant reduction in sensitivity when transitioning from the cuvette to the tapered 35 optical fiber. Notably, the sensitivity decreases by 99.96% for intensity measurements and by 97.76% for absorbance. Nonetheless, after 36 biofunctionalization, the tapered optical fiber's sensitivity increased, showing a 207.1% increase in absorbance and a 1494.72% increase 37 in intensity measurements compared to the non-biofunctionalized tapered optical fiber.