Harnessing Thiol-Tetrazine Bond Exchange for Engineering Dynamic Covalent Hydrogels for Cell Culture
Year: 2026
Type: preprint
Abstract: Dynamic covalent chemistry (DCvC) provides a versatile toolbox of reactions forming reversible covalent bonds that are strong yet dynamic. Implementing DCvC in hydrogel networks to engineer extracellular matrix (ECM) mimics improves their resemblance to natural tissues, by conferring dynamicity and time-dependent viscoelastic properties. In this work, the nucleophilic aromatic substitution of tetrazines with thiols (thiol-Tz) is proposed as a DCvC strategy to synthesize tunable, dynamic hydrogels under close-to-physiological conditions, which find value as scaffolds for cell encapsulation. The network design consists of a linear poly(ethylene glycol) (PEG) macromer end-functionalized with chloro-tetrazine groups (easily synthesized in good yield via a one-step reaction) and a commercially available multiarm PEG precursor terminated with thiols. Derived PEG thiol-Tz hydrogels form rapidly by mixing the two polymeric precursors under physiological conditions (in buffer, pH 7-8, room temperature). NMR spectroscopy analysis provides insight into the thiol-Tz coupling reaction and the subsequent thiol-Tz bond exchange. These results are correlated with macroscopic rheological characterization of derived thiol-Tz hydrogels to elucidate how such dynamic exchange impacts materials properties, including gelation kinetics, mechanical strength, stress relaxation and self-recovery. Thiol-Tz dynamic hydrogels demonstrate good cytocompatibility for encapsulation of human mesenchymal stem cells (hMSCs). These proof-of-concept findings showcase the potential of thiol-Tz DCvC as a novel strategy to manufacture mechanically tunable hydrogels for cell and bioengineering applications.
Source: ChemRxiv
Language: English
Subfield: Biomaterials
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7207768188