Porous photonic crystal external cavity laser biosensor

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Photonic crystal (PC) biosensors offer high sensitivity for biomolecular detection.
• Optimizing surface area and electromagnetic field overlap is crucial for enhancing PC biosensor performance.
• Label-free detection methods are desirable for real-time monitoring of molecular interactions.

Purpose of the Study:

• To design, fabricate, and test a novel PC biosensor utilizing a porous TiO2 dielectric film.
• To enhance the surface area for protein immobilization within regions of strong electromagnetic fields.
• To leverage an external cavity laser (ECL) detection method for high-resolution wavelength shift measurements.

Main Methods:

• Fabrication of a photonic crystal (PC) biosensor with a porous, high refractive index TiO2 dielectric film.
• Immobilization of capture proteins within the porous structure to maximize interaction sites.
• Integration of the PC sensor into an external cavity laser (ECL) for sensitive detection.
• Testing the biosensor's response to small molecule interactions with immobilized proteins.

Main Results:

• The porous TiO2 PC structure exhibited narrowband and high-efficiency resonant reflection.
• The porous structure provided a 3.7× increase in biosensor signal compared to nonporous structures.
• The ECL detection method enabled sensing of picometer-scale wavelength shifts.
• The developed porous ECL biosensor achieved a record high figure of merit for label-free optical biosensors.

Conclusions:

• Porous TiO2 PC structures significantly enhance biosensor signal and sensitivity.
• The ECL detection method coupled with PC biosensors allows for highly sensitive, label-free detection.
• This technology represents a significant advancement in label-free optical biosensing for small molecule detection.