Photodegradable Gelatin-Based Hydrogels Prepared by Bioorthogonal Click Chemistry for Cell Encapsulation and Release

Abstract

In this study, we present a method for the fabrication of in situ forming gelatin and poly(ethylene glycol)-based hydrogels utilizing bioorthogonal, strain-promoted alkyne-azide cycloaddition as the cross-linking reaction. By incorporating nitrobenzyl moieties within the network structure, these hydrogels can be designed to be degradable upon irradiation with low intensity UV light, allowing precise photopatterning. Fibroblast cells encapsulated within these hydrogels were viable at 14 days and could be readily harvested using a light trigger. Potential applications of this new class of injectable hydrogel include its use as a 3D culturing platform that allows the capture and release of cells, as well as light-triggered cell delivery in regenerative medicine.

Synthesis and characterization of thermosensitive gelatin hydrogel microspheres in a microfluidic system

“…Gelatin contains integrin binding peptide sequences (e.g., Arg-Gly-Asp (RGD)) that allow cells to bind to these networks. 24 To form polymer networks, a transition called 'gelation' from a sol, which is a mixture of polydisperse soluble branched polymers to gel that is percolated with finite branched polymers, is required. 25 Above the gelling point (i.e., approximately 30 o C), a gelatinwater mixture exists as a sol.…”

“…In particular, these properties are important for the feasibility of a hydrogel to be employed for a specific biological application. 24 For example, a hydrogel for use as a scaffold for cell adhesion and cell growth should possess an appropriate rigidity and mechanical stiffness. 43 In this study, we present a simple approach for the synthesis of the monodisperse gelatin hydrogels with a narrow size distribution in a droplet-based microfluidic system.…”

Spatiotemporal hydrogel biomaterials for regenerative medicine

“…Using a similar strategy, a photodegradable cell laden gel can be selectively eroded to produce microfluidic channels to produce vascularized hydrogel constructs. 193 The adaptation of natural ECM components to photodegradable networks also integrates intrinsic degradability and cell adhesion sites, and photodegradable gelatin hydrogels have been introduced by reacting clickable 212,213 or methacrylamide 191 modified gelatin with photodegradable PEGs.…”

“…222–224 Of these, the strain-promoted azide alkyne cycloaddition (SPAAC) has, so far, proven most useful. 88,96,150,192,207,212,213,220 …”

Spatially and temporally controlled hydrogels for tissue engineering

“…For example, Truong and Tsang et al investigated dynamic hydrogels based on gelatin and PEG crosslinkers [288, 289]. An organogel system containing the o -benzylether motifs based on ring opening metathesis polymerization (ROMP) was demonstrated to degrade into fluorescent polymer fragments upon UV irradiation [290].…”