Quantification of hCG Hormone Using Tapered Optical Fiber Decorated with Gold Nanoparticles

Area of Science:

• Biophotonics
• Nanotechnology
• Biosensing

Background:

• Accurate quantification of human chorionic gonadotropin (hCG) is crucial for various biomedical applications, including pregnancy testing and monitoring certain health conditions.
• Existing quantification methods may have limitations in sensitivity, speed, or cost.
• Development of novel, sensitive, and efficient biosensing platforms is an ongoing area of research.

Purpose of the Study:

• To develop and demonstrate a novel biosensor for the sensitive quantification of hCG hormone.
• To utilize localized surface plasmons on a tapered optical fiber decorated with gold nanoparticles for enhanced detection.
• To establish a correlation between optical power response and varying concentrations of hCG.

Main Methods:

• Fabrication of a tapered optical fiber using a flame-brushing system to a 3 μm waist diameter.
• Decoration of the tapered fiber with 100 nm gold nanoparticles (Au-NPs) via photodeposition using a 1550 nm radiation source.
• Verification of hCG presence using Fourier-transform infrared spectroscopy (FTIR).
• Quantification of hCG by measuring the optical power response of the Au-NP decorated tapered fiber across concentrations from 1 mIU/mL to 100,000 mIU/mL.

Main Results:

• Demonstrated a proportional relationship between measured optical power and hCG concentration.
• Observed a decrease in optical power from 4.45 mW to 2.5 mW as hCG concentration increased from 1 mIU/mL to 100,000 mIU/mL.
• Reported a spectral shift of 14.2 nm with increasing hCG concentration, indicating sensitivity to hormone levels.

Conclusions:

• The developed tapered optical fiber sensor functionalized with Au-NPs shows significant promise for hCG quantification.
• The sensor leverages localized surface plasmon resonance for enhanced evanescent field interaction, leading to sensitive detection.
• This novel system holds potential for future applications in biomedical diagnostics and industrial sensing.