Label-free optical biosensing: going beyond the limits.

Area of Science:

• Optics and Photonics
• Biomedical Engineering
• Materials Science

Background:

• Label-free optical biosensing offers real-time analysis for diagnostics and safety but lacks sensitivity compared to labeling methods.
• Current limitations restrict label-free biosensing primarily to research applications.
• Existing platforms struggle to meet the sensitivity demands of various critical applications.

Purpose of the Study:

• To explore advanced label-free optical biosensing strategies that overcome current sensitivity limitations.
• To review emerging technologies enabling detection limits superior to traditional labeling methods.
• To discuss novel approaches for enhancing biosensor performance and expanding their practical utility.

Main Methods:

• Review of emerging optical implementations utilizing novel structural architectures and artificial materials.
• Elucidation of plasmonic phase biosensing mechanisms.
• Investigation of hyper-sensitive transducers and advanced optical layouts.

Main Results:

• Novel structural architectures and artificial materials (metamaterials, hetero-metastructures) enhance sensitivity.
• Plasmonic phase biosensing and hyper-sensitive transducers achieve single-molecule detection limits (<1 fg mm⁻²).
• Emerging layouts based on dielectric nanomaterials, bound states in continuum, and exceptional points show significant promise.

Conclusions:

• Advanced optical biosensing designs can surpass the sensitivity of conventional labeling techniques.
• Emerging technologies enable detection of analytes at significantly lower concentrations.
• These advancements position label-free optical biosensing for broader applications in diagnostics and safety monitoring.