Stretch activated molecule immobilization in disulfide linked double network hydrogels.

Inspired by how forces facilitate molecule immobilization in biological tissues to provide localized functionalization, tough hydrogel networks with stretch activated mechanochemistry are developed by utilizing disulfide bonds as dynamic covalent crosslinks. Specifically, disulfide linked polyethylene glycol hydrogels are reinforced with a second ionically bonded sodium alginate network to simultaneously achieve stretchability and mechanochemical functionalization. To demonstrate and quantify the mechanochemical response, thiols produced by disulfide bond rupture are sensed during stretching using a reaction activated fluorophore dissolved in the hydrating solution.

Improving the bioactivity and mechanical properties of poly(ethylene glycol)-based hydrogels through a supramolecular support network.

Most synthetic hydrogels are formed through radical polymerization to yield a homogenous covalent meshwork. In contrast, natural hydrogels form through mechanisms involving both covalent assembly and supramolecular interactions. In this communication, we expand the capabilities of covalent poly(ethylene glycol) (PEG) networks through co-assembly of supramolecular peptide nanofibers.

Mechanical and biological behavior of double network hydrogels reinforced with alginate versus gellan gum.

Alginate and gellan gum have both been used by researchers as reinforcing networks to create tough and biocompatible polyethylene glycol (PEG) based double network (DN) hydrogels; however, the relative advantages and disadvantages of each approach are not understood. This study directly compares the mechanical and biological properties of polyethylene glycol di-methacrylate (PEGDMA) hybrid DN hydrogels reinforced with either gellan gum or sodium alginate using PEGDMA concentrations from 10 to 20 wt% and reinforcing network concentrations of 1 and 2 wt%. The findings demonstrate that gellan gum reinforcement is more effective at increasing the strength, stiffness, and toughness of PEGDMA DN hydrogels.