Highly sensitive and label-free detection of biotin using a liquid crystal-based optofluidic biosensor

Area of Science:

• Optofluidics
• Biosensing
• Liquid Crystal Technology

Background:

• Whispering gallery mode (WGM) resonators are sensitive to refractive index changes.
• Liquid crystals (LCs) exhibit orientation changes in response to molecular interactions.
• Biotin detection is crucial in various biological and medical applications.

Purpose of the Study:

• To develop an ultrasensitive optofluidic biosensor for biotin detection.
• To utilize the synergistic effects of LC orientation and WGM resonance for enhanced sensitivity.
• To establish a real-time monitoring platform for biomolecular interactions.

Main Methods:

• Fabrication of an optofluidic resonator incorporating liquid crystals.
• Immobilization of streptavidin (SA) as a recognition element for biotin.
• Monitoring of WGM spectral shifts caused by biotin-streptavidin binding and subsequent LC reorientation.
• Quantification of biotin concentration based on wavelength shift linearity.

Main Results:

• Achieved an ultra-low detection limit of 0.4 fM for biotin.
• Demonstrated excellent linearity between biotin concentration and WGM spectral shift (0-0.1 pg/ml).
• Reported a seven-order-of-magnitude improvement in detection limit compared to conventional methods.
• Exhibited high reproducibility and potential for real-time monitoring.

Conclusions:

• The developed LC-based optofluidic WGM biosensor offers unprecedented sensitivity for biotin detection.
• This technology provides a robust platform for ultrasensitive, real-time biomolecular detection.
• The approach holds promise for broader applications in detecting other receptor-ligand interactions.