A Facile and Versatile Approach to Construct Photoactivated Peptide Hydrogels by Regulating Electrostatic Repulsion

Abstract

Short peptides that can respond to external stimuli have been considered as the preferred building blocks to construct hydrogels for biomedical applications. In particular, photoresponsive peptides that are capable of triggering the formation of hydrogels upon light irradiation allow the properties of hydrogels to be changed remotely by precise and localized actuation. Here, we used the photochemical reaction of the 2-nitrobenzyl ester group (NB) to develop a facile and versatile strategy for constructing photoactivated peptide hydrogels. The peptides with high aggregation propensity were designed as hydrogelators, which were photocaged by a positively charged dipeptide (KK) to provide strong charge repulsion and prevent self-assembly in water. Light irradiation led to the removal of KK and triggered the self-assembly of peptides and the formation of hydrogel. Light stimulation endows spatial and temporal control, which enables the formation of hydrogel with precisely tunable structure and mechanical properties. Cell culture and behavior study indicated that the optimized photoactivated hydrogel was suitable for 2D and 3D cell culture, and its photocontrollable mechanical strength could regulate the spreading of stem cells on its surface. Therefore, our strategy provides an alternative way to construct photoactivated peptide hydrogels with wide applications in biomedical areas.

Designing Peptide-Based Nanoinhibitors of Programmed Cell Death Ligand 1 (PD-L1) for Enhanced Chemo-immunotherapy

“…The stability is crucial for application of peptide nanomaterials. 33 The FRS nanoparticles maintained their sizes without accumulation in PBS for 7 days, indicating the long-term dispersibility of the FRS (Figure 1H). Besides, FRS nanoparticles were also well-dispersed for 48 h under physiological conditions such as a cell culture medium, which was beneficial for improving the efficiency of cell delivery (Figure 1I).…”

“…The stability is crucial for application of peptide nanomaterials . The FRS nanoparticles maintained their sizes without accumulation in PBS for 7 days, indicating the long-term dispersibility of the FRS (Figure H).…”

Stimuli‐Responsive Peptide Self‐Assembly to Construct Hydrogels with Actuation and Shape Memory Behaviors

“…), the actuation of the peptide‐contained hydrogel is triggered by the assembly and disassembly of grafted MA‐FIID peptide in the polymer network, which would provide stronger deformation ability for the actuation behaviors since FIID assembly was triggered by the synergistic effect of H‐bonding, hydrophobic interaction, and π–π stacking interactions. Based on that peptide assembly and disassembly can be tracked by fluorescence and CD signal, the dynamic process of actuation can be explored, [ 43 ] which is difficult to achieve with other stimuli‐responsive materials. In addition, peptide‐based materials present great advantages due to their excellent biocompatibility and low immunogenicity, [ 24 ] which would endow the peptide‐based actuators with greater potential applications in biomedical areas.…”

Dynamic supramolecular hydrogels mediated by chemical reactions

“…4 In addition to the enzymatic hydrogelation, complete synthetic supramolecular hydrogel systems controlled by organic reactions have also been investigated. For example, catalytic formation of the hydrazone bond 14,[43][44][45][46] or photo-responsive cleavage of 2-nitrobenzyl ester group 47 have been demonstrated as effective ways to result in hydrogelation. Spatiotemporal control over the self-assembly of hydrogels can be achieved by controlling the spatial distribution of organocatalysts 18,48 or using light.…”