In situ biosensing with a surface plasmon resonance fiber grating aptasensor

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Optoelectronics

Background:

• Established biosensor platforms can be costly and complex.
• Optical fiber biosensors offer a promising alternative for in situ and in vivo monitoring.
• Surface Plasmon Resonance (SPR) is a label-free technique for detecting biomolecular interactions.

Purpose of the Study:

• To develop and characterize a cost-effective optical fiber SPR biosensor.
• To demonstrate label-free detection of biomolecular interactions using aptamer functionalization.
• To evaluate the sensor's performance in detecting thrombin in complex solutions.

Main Methods:

• Fabrication of an in-fiber tilted Bragg grating for SPR excitation.
• Functionalization of the gold-coated fiber with aptamers for specific target binding.
• Real-time monitoring of aptamer functionalization and target detection using SPR.
• Analysis of binding kinetics and determination of dissociation constants (Kd).

Main Results:

• The fiber biosensor achieved SPR excitation over a wide refractive index range.
• Minimal cross-sensitivity to temperature was observed, maintaining fiber structural integrity.
• Successful real-time monitoring of aptamer functionalization and thrombin detection in buffer and serum.
• Accurate determination of the dissociation constant (Kd) for thrombin binding, consistent with literature values.

Conclusions:

• The developed optical fiber SPR biosensor is a cost-effective and sensitive platform for label-free biomolecular detection.
• Aptamer functionalization enables specific and real-time monitoring of target analytes.
• The sensor demonstrates robust performance in complex biological samples, with potential for in situ and in vivo applications.