posted on 2021-11-29, 19:13authored byZheng Zhang, Bofeng Pan, Luxin Wang, Gang Sun
Photoactivities and photoinduced
antibacterial functions of two
vitamin B2 (VB2) derivatives, riboflavin (RF)
and flavin mononucleotide (FMN), were investigated by computational
modeling and various experimental evaluations. Under photoirradiation,
the ground state of both VB2 derivatives could be excited
to generate different reactive oxygen species (ROS) by undergoing
different reaction paths. The formed ROS could nonselectively inactivate
microorganisms. However, both RF and FMN exhibited negligible photoinduced
antimicrobial activity in phosphate-buffered saline (PBS) solutions
even at high concentrations. The study revealed that the affinity
of both RF and FMN to microorganisms in different application media
plays a key role due to the very short lifetime of the generated ROS.
The speculation was proven by the preparation of a poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membrane
blended with RF or FMN, which could enhance the contact of the agents
with microorganisms. The fabricated nanofibrous membranes containing
both VB2 derivatives (VBNFMs) showed great photoinduced
antibacterial activity against Gram-negative Escherichia
coli (E. coli) (99.999%
bacterial reduction) and Gram-positive Listeria innocua (L. innocua) (99% bacterial reduction)
under 20 min of ultra-violet A irradiation. The photoinduced antimicrobial
performances of RF/PVA-co-PE and FMN/PVA-co-PE nanofibrous membranes were comparable. Interestingly,
the durability of the photoinduced antibacterial functions of the
prepared VBNFMs was questionable, due to the photodegradation of VB2 in nanomaterials.