# Optical Waveguide Lightmode Spectroscopy: A Versatile Technique for Real-Time, Label-Free Biosensing

**Authors:** Jeremy J. Ramsden

PMC · DOI: 10.3390/s26041183 · Sensors (Basel, Switzerland) · 2026-02-11

## TL;DR

OWLS is a powerful biosensing technique that allows real-time, label-free monitoring of structural changes at interfaces with high precision.

## Contribution

This review provides a comprehensive overview of OWLS fundamentals, configurations, data interpretation, and biosensing applications.

## Key findings

- OWLS offers sub-ångström spatial resolution for interface probing.
- The technique enables real-time monitoring of structural changes.
- Applications in biosensing demonstrate OWLS's versatility and potential.

## Abstract

Optical waveguide lightmode spectroscopy (OWLS) is an integrated-optical technique for probing structures at the solid/gas and solid/liquid interface. Spatial resolution perpendicular to the interface is sub-ångström. Thanks to good time resolution, processes involving structural change can also be investigated. This review covers the fundamentals of the technique, the various measurement configurations that are used, interpretation of the primary data received, applications in biosensing, and future prospects.

## Full-text entities

- **Genes:** ALB (albumin) [NCBI Gene 213] {aka FDAHT, HSA, PRO0883, PRO0903, PRO1341}
- **Diseases:** oxide (MESH:D028361), injury to (MESH:D014947), cancer (MESH:D009369), diabetes (MESH:D003920), infectious diseases (MESH:D003141)
- **Chemicals:** silica (MESH:D012822), oxygen (MESH:D010100), metal (MESH:D008670), OWLS (-), ITO (MESH:C109984), phosphatidylcholines (MESH:D010713), polymer (MESH:D011108), polyelectrolyte (MESH:D000071228), nitrogen (MESH:D009584), POPC (MESH:C065191), urea (MESH:D014508), carbon nanotube (MESH:D037742), lipid (MESH:D008055), phospholipid (MESH:D010743), Water (MESH:D014867), polystyrene (MESH:D011137), carbon dioxide (MESH:D002245), titania (MESH:C009495), cholesterol (MESH:D002784), Glucose (MESH:D005947), oxide (MESH:D010087), blood glucose (MESH:D001786), hydrogen (MESH:D006859)
- **Species:** Canis lupus familiaris (dog, subspecies) [taxon 9615], Leishmania major (species) [taxon 5664], Homo sapiens (human, species) [taxon 9606], Bacteriophage sp. (species) [taxon 38018]

## Full text

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## Figures

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## References

128 references — full list in the complete paper: https://tomesphere.com/paper/PMC12944548/full.md

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Source: https://tomesphere.com/paper/PMC12944548