Advances in Terahertz Spectroscopy for Biomedical and Biophysical Sensing

Terahertz (THz) radiation occupies the spectral gap between microwave and infrared and interacts uniquely with the collective vibrational and rotational modes of biomolecules, hydration water, and intermolecular networks. Over the past two decades this has made THz spectroscopy and imaging an increasingly powerful, label-free, non-ionising tool for biophysics and biomedicine - from resolving the hydration shells of proteins and nucleic acids, to fingerprinting sugars, amino acids and metabolites, to characterising tissues, cells and biofluids for diagnostics. The field now stands at an inflection point, with advances in sources and detectors, metamaterial and metasurface enhancers, microfluidic and on-chip platforms, and computational/AI methods pushing sensitivity and specificity toward clinically and physiologically relevant levels. However, central challenges remain insufficiently resolved - water absorption, weak signals, in-vivo variability, and the translation gap between laboratory measurement and point-of-care device - as seen most tangibly in non-invasive glucose monitoring.

The goal of this Research Topic is to advance the fundamental understanding and translational capabilities of THz spectroscopy and sensing for biophysics and biomedicine. We seek to bring together researchers and engineers working at the intersection of THz photonics, biophysics, metamaterials, microfluidics, computational analysis, and clinical/physiological sensing to address the key challenges in this field.

Specific objectives include:

• elucidating the physical mechanisms of biomolecular fingerprinting, hydration, protein dynamics and self-assembly at THz frequencies;
• developing improved sources, detectors, metamaterial/metasurface enhancers, on-chip platforms and machine-learning methods to raise sensitivity and specificity;
• establishing robust approaches for non-invasive and continuous metabolic/physiological sensing and for THz characterisation of tissues, cells and biofluids;
• translating fundamental measurement into clinically and physiologically relevant, point-of-care-ready methods, and defining data-analysis and reporting standards for the field.

By achieving these goals, this collection aims to crystallise the state of the art, surface the key bottlenecks to clinical and physiological translation, and stimulate cross-disciplinary dialogue between physicists, engineers and life scientists - providing both a reference map and a forward-looking agenda for THz-enabled biophysics and biomedical sensing.

This Research Topic welcomes contributions addressing the biophysical and biomedical application of THz spectroscopy and sensing.
Themes of interest include but are not limited to:

• Molecular fingerprinting of biomolecules (sugars, amino acids, proteins, nucleotides, metabolites) and the role of hydration;
• Metamaterial/metasurface-enhanced THz biosensors, plasmonic and anapole-mode designs, and machine-learning-enabled recognition;
• Non-invasive and continuous glucose monitoring and other metabolic/physiological sensing with THz waves;
• THz characterisation of tissues, cells, biofluids and phantoms for cancer, burn, skin, corneal and other diagnostics;
• Fundamental biophysical studies of water, protein dynamics, and biomolecular self-assembly at THz frequencies;
• Instrumentation, on-chip/mm-wave, near-field and imaging advances that enable biomedical translation;
• Data analysis, modelling, and standards for THz biophysics.

We invite Original Research, Review, Methods, Perspective and Opinion articles. All contributions must advance the physical understanding or biomedical application of THz spectroscopy and sensing and demonstrate clear relevance to biophysics and biomedicine.