Long Period Grating Mach-Zehnder Interferometer Based Immunosensor with Temperature and Bulk Refractive Index...

Area of Science:

• Optoelectronics and Photonics
• Biomedical Engineering
• Chemical Sensing

Background:

• Interferometric fiber optic sensors offer high sensitivity for biosensing.
• Existing sensors often struggle with environmental fluctuations like temperature and refractive index changes.
• Long Period Gratings (LPGs) are versatile photonic components for sensing applications.

Purpose of the Study:

• To develop and characterize a Long Period Grating Mach-Zehnder Interferometer (LPGMZI) biosensor.
• To evaluate the LPGMZI's capability for compensating environmental variations.
• To demonstrate the LPGMZI platform for detecting immunoglobulin M (IgM).

Main Methods:

• Fabrication of a single-fiber LPGMZI with two identical LPGs.
• Analysis of spectral fringes and their envelope for sensing.
• Characterization of the sensor's response to external refractive index and temperature changes.
• Functionalization of the LPGMZI with anti-IgM for specific analyte detection.

Main Results:

• The LPGMZI exhibited distinct fringe shifts with changes in external refractive index and temperature.
• The interference envelope remained stable under specific immersion conditions, indicating potential for compensation.
• The sensor successfully detected varying concentrations of IgM, with fringe shifts correlating to analyte levels.
• The envelope remained static during IgM detection, confirming compensation for bulk effects.

Conclusions:

• The developed LPGMZI platform demonstrates robust performance for biosensing.
• The LPGMZI effectively compensates for bulk refractive index and temperature fluctuations.
• This technology holds promise for developing portable and reliable biosensor devices.