B ₁₂ -dependent photoresponsive protein hydrogels for controlled stem cell/protein release

Abstract

Thanks to the precise control over their structural and functional properties, genetically engineered protein-based hydrogels have emerged as a promising candidate for biomedical applications. Given the growing demand for creating stimuli-responsive "smart" hydrogels, here we show the synthesis of entirely protein-based photoresponsive hydrogels by covalently polymerizing the adenosylcobalamin (AdoB 12 )-dependent photoreceptor C-terminal adenosylcobalamin binding domain (CarH C ) proteins using genetically encoded SpyTagSpyCatcher chemistry under mild physiological conditions. The resulting hydrogel composed of physically self-assembled CarH C polymers exhibited a rapid gel-sol transition on light exposure, which enabled the facile release/recovery of 3T3 fibroblasts and human mesenchymal stem cells (hMSCs) from 3D cultures while maintaining their viability. A covalently cross-linked CarH C hydrogel was also designed to encapsulate and release bulky globular proteins, such as mCherry, in a light-dependent manner. The direct assembly of stimuli-responsive proteins into hydrogels represents a versatile strategy for designing dynamically tunable materials.hydrogels | cell encapsulation | drug delivery | photoresponsive materials | protein engineering

Recent Advances in Photo-Crosslinkable Hydrogels for Biomedical Applications

“…Among various stimuli, light stimulus (e.g.,ultraviolet [UV] light and visible light) is considered as an ideal external control method to manipulate the properties of hydrogels owing to their several unique advantages. These include the abilities to: (i) control the stimulus easily by switching the light on and off; (ii) regulate light dosage precisely to achieve functional tunability; (iii) obtain independent spatial or temporal control of different biological processes in a wavelength-specific manner; (iv) direct the light to a confined location at user-defined times; as well as (v) to regulate a range of cellular processes in vivo in the optical tissue window [10,11]. These advantages have led to the extensive use of light for better control and modulation of hydrogels for numerous potential applications.…”

Design Principles for Aqueous Interactive Materials: Lessons from Small Molecules and Stimuli‐Responsive Systems

“…Controlled release using visible light as a trigger is becoming increasingly popular, shifting away from traditional UV stimuli. Wang et al recently designed a protein‐based hydrogel that was based on polymerized CarH c proteins using SpyTag‐SpyCatcher chemistry 49. If the CarH c ‐containing polymers were exposed to AdoB 12 (an adenosylcobalamin) in the dark, the CarH c domains formed tetramers, generating a stable hydrogel.…”

The Role of Photochemical Reactions in the Development of Advanced Soft Materials for Biomedical Applications

“…Consequently, the dimer is disassembled liquefying the hydrogel and releasing the encapsulated cells or proteins. A similar approach was developed using CarH C , a protein that readily forms tetramers in the presence of adenosylcobalamin and is able to revert to monomers under green light (522 nm) . Apart from being used to release biological material from hydrogels, photoresponsive proteins, such as Dronpa145N, have been also investigated to reversibly form hydrogels .…”