Photonic detection and characterization of DNA using sapphire microspheres

Area of Science:

• Optical biosensing
• Biomaterials science
• Nanotechnology

Background:

• Optical biosensors offer high sensitivity for detecting biological molecules.
• Sapphire is a biocompatible and chemically resilient material suitable for biosensor fabrication.

Purpose of the Study:

• To demonstrate a microcavity-based DNA optical biosensor using synthetic sapphire.
• To analyze the performance of sapphire microspheres for DNA detection.
• To investigate DNA immobilization and hybridization on a sapphire surface.

Main Methods:

• Fabrication of a sapphire microsphere optical cavity.
• Functionalization of the microsphere with probe DNA.
• Hybridization with target DNA and monitoring of whispering gallery modes (WGMs).
• Analysis of WGM shifts and quality factors.

Main Results:

• Successful detection of DNA hybridization via WGM shifts.
• Correlation between WGM shifts and DNA layer thickness.
• Demonstration of uniform ssDNA orientation compared to dsDNA.
• Preservation of high-quality factor (Q) of sapphire microspheres after DNA functionalization.

Conclusions:

• Sapphire microcavities are effective for DNA optical biosensing.
• The developed biosensor shows promise for sensitive and specific DNA detection.
• Sapphire's properties make it an excellent material for advanced biosensor development.