Complexed Photosensitizer of Hypericin with G-Quadruplex: Structure-Dependent Behavior

• DOI: 10.1021/acs.jpcb.3c07307
• Publication Date: 2024-01-08T10:10:42Z
• Authors: Zheng Hu; Danfeng Wang; Qian Zhou; Jialong Jie; Hongmei Su
• Keywords: Hypericin; Quantum yield; G-quadruplex; Antiparallel (mathematics)

Despite the increased interest of visible-light-absorbing compound Hypericin (Hyp) in photodiagnosis, photocatalysis, and photodynamic therapy (PDT) applications, a major obstacle still exists; i.e., photoactivity is diminished due to facile aggregation Hyp aqueous environment that induces excited-state quenching. Herein, we explore property bound DNA G-quadruplex by combining multiple steady-state time-resolved spectroscopy. We find aggregation-induced quenching effect can be successfully prevented appropriate binders disperse into monomer. The binding Hyp/G-quadruplex selective, however, exhibiting preferential toward parallel G-quadruplexes (c-kit2, C14B1, STAT3, S50, PS2.M), over antiparallel or hybrid (Tel22, TBA). highly related behavior, showing consistent trend better binding, longer triplet 3Hyp* lifetime higher efficiency produce 1O2. For Hyp/c-kit2, mode 5′-end stacking, which offers protection from collisional reactions ensures stable photocycle 3Hyp*-O2 energy transfer forming 1O2, leading highest 1O2 quantum yield (0.67) with superior photostability. These findings open possibilities developing complex as biocompatible photosensitizer for PDT etc.