Terahertz Modulation of Biomolecular Dynamics: Physical Mechanisms, Biological Implications, and Future Challenges.

With the rapid expansion of terahertz (THz) technologies across communications, imaging, sensing, and biomedicine, defining their biological effects, safety boundaries, and controlled intervention has become a critical scientific priority for their responsible deployment. Although diverse biological responses have been observed at different levels of biological organization, the findings are highly dependent on exposure parameters and biological models. Moreover, how molecular perturbations propagate across scales to produce higher-order biological effects remains poorly understood. Because biomacromolecules and their hydration environments constitute the primary interface which THz radiation interacts with biological systems, elucidating THz bioeffects at the molecular scale is essential for mechanistic understanding. Here, we systematically review recent advances in THz interactions with key biological targets, including proteins, nucleic acids, ion channels, and biological membranes, and examine how local molecular perturbations translate into higher-level phenotypes. On this basis, we critically assess the major challenges facing the field and propose an integrative framework for mechanistic validation. By consolidating dispersed findings and emphasizing methodological standardization, this review provides a coherent conceptual basis for interpreting THz bioeffects and guiding their biomedical translation.