Tapered Side-Polished Microfibre Sensor for High Sensitivity hCG Detection

A high sensitivity human chorionic gonado-tropin (hCG) detection was conducted by a tapered side-polished (TSP) optical fiber sensor. Experimentally, the TSP sensor made side polishing short section of single mode to D shape structure and tapering small diameter ( $ < 10~\mu \text{m}$ in experiments). By functionalizing primary antibody hCG onto surface, used for detecting concentration. Experimental results show that when concentration is 0.1 mIU/mL, has an average wavelength shift 0.82 nm. The limit (LoD) estimated 0.058 assuming three times maximum variation notation="LaTeX">${3}\times {0}.{15}=0.45$ nm) Phosphate buffer saline (PBS) measurement limit. specificity also been tested immersing into mixed biomaterial solution (hCG - 1 pig-IgG notation="LaTeX">$\mu \text{g}$ /mL, Staphylococcus aureus notation="LaTeX">$-{6}\times {10}^{{5}}$ CFU/mL Escherichia coli notation="LaTeX">${2.5}\times CFU/mL). result showed excellent specificity. biosensor potential application clinical/medical diagnostics, health, environmental quality food safety monitoring.