Biomimetic ultrathin pepsomes for photo-controllable catalysis

Artificial vesicles for mimicking the unique structures and functions of natural organelles represent a promising scientific object in biomimicry. However, the development of the stimuli-responsive and ultrathin vesicles assembled from sequence-defined biomimetic polymers for controllable applications is still a significant challenge. Herein, we report the self-assembly of azobenzene-based amphiphilic alternating peptoids to generate photo-responsive and ultrathin peptoid vesicle (pepsomes) with an average diameter of ∼180 nm. Both cryo-transmission electron microscopy (TEM) and dissipative particle dynamics simulation proved that the vesicular membrane was the ultrathin bilayer structure around ∼1.6 nm. The photo-responsive ability of pepsomes was demonstrated by the reversible size changes upon the alternative irradiation with ultraviolet (UV) and visible lights, which was attributable to the photoisomerization virtue of azobenzene moiety. As a proof-of-concept, the photo-controllable catalytic action of gold nanoparticles-decorated pepsomes was evaluated toward the borohydride-mediated reduction from 4-nitrophenol to 4-aminophenol. Photo-controllable reversible and recyclable catalytic activity was effectively modulated using the alternative irradiation with UV and visible lights for five cycles. Our work provides a simple strategy to prepare stimuli-responsive and ultrathin vesicles for potential application on nanocatalysis.