Custom-designed hydrogels offer effective inflammation control

“This understanding of the immune response to peptide biomaterials improves our ability to design effective materials and to tailor their use for specific biomedical applications”Jeffrey Hartgerink

A team from Rice University and the Texas Heart Institute have shown how hydrogels synthesized from bioengineered molecules are able to control inflammation and assist the healing process. They achieved this by modeling how multidomain peptide hydrogels can tune the body’s inflammatory response, establishing a baseline set of injectable hydrogels that holds potential for the healing of wounds, delivering drugs and treating cancer.

As reported in the journal Biomaterials [Lopez-Silva et al. Biomaterials (2019) DOI: 10.1016/j.biomaterials.2019.119667], to understand the best way to develop materials around the inflammatory responses they provoke, they examined a sample of chemically distinct, synthetic and biocompatible hydrogels to identify how tuning them could influence the body’s inflammatory response, eventually developing around 100 different types.

The hydrogels, which are also compatible with a variety of cell types, offer a copy of cellular scaffolds in particular locations, as well as acting as placeholders while new blood vessels and cells are naturally fed into the scaffold. This gradually degrades to leave just natural tissue. The hydrogels can also carry chemical or biological triggers to ascertain the scaffold’s structure and affinity to the surrounding tissue, assisting the objective of tailoring therapeutic delivery that is functionally relevant and predictable.

The body’s inflammatory response is key for wound healing and clearing infection, and achieving the most appropriate inflammation is therefore crucial – for instance, in wound healing inflammation is beneficial as it triggers the process of rebuilding vasculature and recruits regenerative cells to that site. They tested four basic hydrogel types, two with positive charge and two with negative, to distinguish the kind of inflammation they might trigger, with the positively charged hydrogels being shown to provide a much stronger inflammatory response than negatively charged ones.

For the positive materials, and contingent on the chemistry generating the charge, either a strong or a moderate inflammatory response can be generated. For wound healing, it is preferable to have a moderate response, which was demonstrated in one of the four materials. However, for the treatment of cancer a higher inflammatory response is more useful, while for drug delivery, where inflammation is not effective, a negatively charged material can be preferable.

While the study does not aim at a particular application, it could help bring synthetic hydrogels into the clinic. As study leader Jeffrey Hartgerink said, “This understanding of the immune response to peptide biomaterials improves our ability to design effective materials and to tailor their use for specific biomedical applications”.