A highly sensitive magnetic nano-fluorescent probe for singlet oxygen detection and screening of natural photosensitizers

In this study, a magnetic nano-fluorescent probe was designed and synthesized. The probe has a high sensitivity and good selectivity for singlet oxygen (O-1(2)), and it was successfully used to screen natural photosensitizers (TSF-OH, TSF-CHO, and TSF-COOH) isolated and purified from the traditional Chinese medicine Eclipta herba when combined with chromatography. The photosensitivity was confirmed by the O-1(2) generation ability of the compound and photodynamic antibacterial experiments. To improve the absorption wavelength and O-1(2) generation efficiency, five derivatives (L-A to L-E) with lower energy gaps, longer wavelengths, and higher O-1(2) -generation ability were designed and synthesized using a LUMO-HOMO energy gap (& UDelta;EL-H) and singlet-triplet energy gap (& UDelta;E-ST) as design strategies and TSF-CHO as skeleton by Gaussian calculation. The minimum bactericidal concentration of the L-E compound to Pseudomonas aeruginosa was 6.6 x 10(-6) M, and the minimum bactericidal concentration of TSF-CHO was 4.5 x 10(-5) M. The NMF-RP probe offers a new strategy for screening natural photosensitizers from plants, and the design of derivatives offers directions for the modification of photosensitizers.

Automated summary

A magnetic nano-fluorescent probe with high sensitivity and selectivity for singlet oxygen was designed and synthesized in this study. It was used to screen natural photosensitizers from traditional Chinese medicine and derivatives were designed to improve their efficiency. The probe offers a new strategy for screening photosensitizers and the derivatives provide directions for modification.