Hydrogels have become a popular material for new treatment strategies targeting a variety of diseases. They can deliver encapsulated therapeutic molecules, degrade in the body at a predefined rate, and can be biocompatible. However, each application requires the hydrogel to have appropriate strength, consistency, and the ability to carry growth factors or other molecules within itself.
Researchers at Rice University have now created a way to incorporate biomolecules intended for delivery to a target site in the body into structural components within an injectable hydrogel. These biomolecules give the hydrogel its unique pliability, and they can provide a therapeutic effect at the site of injection while simultaneously working as part of the hydrogel structure, which makes the whole process more efficient.
The researchers were able to attach molecules related to bone and cartilage growth to cross-linkers within a hydrogel. These molecules attract stem cells to move toward them, helping to heal any kind of damage close to the hydrogel. The material is injectable and the process to make a batch is performed at room temperature, which should facilitate its use in the clinic.
It should be possible to create bandages using this new material that would motivate the body’s own mesenchymal stem cells to gather around the bandage and quickly heal the wound beneath. The material would then degrade and disappear into the body, without having to be painfully pulled off as is common with most bandages.
Here’s a summary from the study’s abstract in Science Advances that briefly explains the process of creating these cross-linked bioactive hydrogels:
To introduce tissue-specific biochemical cues to these hydrogels, we have developed a modular hydrogel cross-linker, poly(glycolic acid)–poly(ethylene glycol)–poly(glycolic acid)-di(but-2-yne-1,4-dithiol) (PdBT), that can be functionalized with small peptide-based cues and large macromolecular cues simply by mixing PdBT in water with the appropriate biomolecules at room temperature. Cartilage- and bone-specific PdBT macromers were generated by functionalization with a cartilage-associated hydrophobic N-cadherin peptide, a hydrophilic bone morphogenetic protein peptide, and a cartilage-derived glycosaminoglycan, chondroitin sulfate. These biofunctionalized PdBT macromers can spontaneously cross-link polymers such as poly(N-isopropylacrylamide) to produce rapidly cross-linking, highly swollen, cytocompatible, and hydrolytically degradable hydrogels suitable for mesenchymal stem cell encapsulation.
Study in journal Science Advances: Modular, tissue-specific, and biodegradable hydrogel cross-linkers for tissue engineering