Title: Non-thermal acceleration of DNA base pairing by sub-terahertz irradiation

We report a non-thermal mechanism by which sub-terahertz (sub-THz) radiation accelerates DNA base pairing in aqueous environments. By using a randomized 40-mer DNA pool as a model system, we investigated the effects of 0.1 THz continuous-wave irradiation on rehydration-coupled structural reorganization. UV absorption spectroscopy revealed a selective enhancement of the G:C base pairing-associated spectral component under this irradiation, in contrast to conductive heating, which suppressed this component. Fluorescence correlation spectroscopy using a base-pair-sensitive dye further demonstrated that 0.1 THz irradiation increased the population of base-paired DNA molecules, while heating induced the opposite effect. These findings indicate that sub-THz waves promote nucleobase-specific hydrogen bonding, potentially by altering non-specific base-stacking interactions, in a manner inconsistent with thermal activation. This study provides mechanistic insight into the physical basis of sub-THz radiation-mediated modulation of nucleic acid structure and dynamics, with implications for the noninvasive manipulation of biomolecular processes.