posted on 2022-12-19, 22:29authored bySuji Lee, Jinyoung Oh, Min Su Han
In this paper, we report a photoactivatable,
artificial peroxidase
system based on a photocaging approach. The photocaged Mn2(bpmp) (bpmp: 2,6-bis((bis(2-pyridylmethyl)amino)-methyl)-4-methylphenolate)
complex was developed by a simple design and synthesis of the corresponding
bpmp ligand via the introduction of the 1-(o-nitrophenyl)-ethyl
(NPE) group, a well-known photoremovable protecting group. Following
365 nm light irradiation of the resulting complex, the intrinsic peroxidase-like
activity of the raw Mn2(bpmp) was effectively restored.
Interestingly, the degree of activation of the raw Mn2(bpmp)
system was found to be altered by varying the irradiation time and/or
the light intensity, providing us with a method to tune the in situ
reaction kinetics ad libitum. The photocaged Mn2(bpmp)
complex was further utilized for light-controlled hydrogelation by
exploiting the ability of Mn2(bpmp) to catalyze the synthesis
of hydrogels under physiological conditions with a phenol-functionalized
hydrophilic polymer as a precursor, and the photocontrollability of
this catalytic activity using an external light source. Spatial control
of light irradiation using a photomask enabled site-specific activation
of peroxidase-like activity, allowing the preparation of a desired
shape of the hydrogel. In addition, the mechanical properties of the
resultant hydrogel, such as the adhesion strength, could be regulated
depending on the light exposure time of the pre-gel solution containing
the precursor, H2O2, and photocaged Mn2(bpmp). Furthermore, the biocompatibility of the hydrogel synthesized
using the photocaged Mn2(bpmp) was confirmed by an in vitro
assay.