Sensitive optical biosensors for unlabeled targets: a review

Area of Science:

• Biomedical Engineering
• Optoelectronics
• Nanotechnology

Background:

• Label-free biosensing allows for the detection of biomolecules in their native state, crucial for understanding biological interactions.
• Optical biosensors offer high sensitivity and specificity for detecting minute changes in biological samples.
• Refractive index (RI) changes are a common signal transduction mechanism in label-free optical biosensing.

Purpose of the Study:

• To review recent advancements in optical biosensors employing label-free detection strategies.
• To focus on biosensing platforms that utilize changes in refractive index for signal transduction.
• To compare the performance of various optical structures in terms of sensitivity and detection limits.

Main Methods:

• Review of scientific literature on optical label-free biosensors.
• Categorization of biosensing platforms based on optical structures (e.g., SPR, interferometers, waveguides, fiber gratings, ring resonators, photonic crystals).
• Analysis of sensing mechanisms and biomolecule detection examples.

Main Results:

• Detailed descriptions of various optical structures and their sensing mechanisms.
• Presentation of examples for detecting diverse biomolecules.
• Evaluation and comparison of sensing performance, including sensitivity and detection limits for different platforms.

Conclusions:

• Optical label-free biosensors leveraging refractive index changes represent a significant advancement in biomolecule detection.
• The reviewed platforms (SPR, interferometers, waveguides, etc.) offer distinct advantages for various applications.
• Further research can optimize these biosensors for enhanced sensitivity and broader applicability in diagnostics and research.