UCLA researchers in the Department of Bioengineering have developed a novel polypeptide-based hydrogel mixture that offers a large degree of biocompatibility and biodegradability while also offering the ability to tune mechanical properties. Specifically, these compositions allow for high hydrogel stiffness at low polymer concentrations, while retaining injectability of these physical hydrogels.
BACKGROUND:
The use of hydrogels has found applications in several products: personal care, food, cosmetics, and biomedical. The greatest interest has been focused for the use of injectable hydrogels for biomedical applications. These hydrogels are particularly appealing for biomedical applications due to favorable properties: high biocompatibility, good biodegradability, and adjustable mechanical properties. However, the first generation of injectable hydrogels only possessed one of these favorable characteristics. Future generations of hydrogels utilized peptide structures to increase biocompatibility and biodegradability properties, but these self-assembled hydrogels possessed low stiffness, characteristic of physical hydrogels. Due to the good injectability, biocompatibility and breakdown properties of these polypeptide-based hydrogels, much attention has been given to the ability to improve mechanical properties: limited success has however been found.
INNOVATION:
UCLA researchers in the Department of Bioengineering have developed novel polypeptide-based hydrogel mixtures that offer a large degree of biocompatibility and biodegradability while also obtaining high hydrogel stiffness at low polymer concentrations, while retaining injectability of these physical hydrogels. These researchers have previously discovered a series of diblock copolypeptide hydrogels (DCH) that were able to form new supramolecular architectures that were cell compatible for biomedical applications. These researchers have now developed physical mixtures of DCH that result in a synergistic increase in mechanical stiffness of the hydrogels, while retaining hydrogel injectability through small needles/catheters. Along with this increase in mechanical properties, the DCH mixtures retain advantageous features such as: biocompatibility, resistance to dilution/swelling, and the ability to load larger cell cargos. These newly developed formulations may allow the ability to overcome some of the limiting factors to clinical use of hydrogels already on the market.
POTENTIAL APPLICATIONS:
• Injectable, tissue compatible, degradable depots for delivery of drugs, biologics and/or cells into target tissues
• Use as tissue regeneration scaffolds
• Ability to strengthen currently marketed hydrogels
• Use in thickening/structuring agents in personal care products
ADVANTAGES:
• Allows for the adjustment of several hydrogel properties (stiffness, biocompatibility, resistance to dilution, and cargo encapsulation/retention) via novel formulation process and tunable copolypeptide compositions
• Ability to form hydrogels at low concentration in water (<10 wt%)
• Non-Toxic and Biodegradable
• Simple and direct hydrogel formulation in water. no cosolvents, heating, pH adjustments, etc. required.
• The amphiphilic nature of the DCH polymers allows them to carry and deliver both hydrophobic and hydrophilic payloads
DEVELOPMENT-TO-DATE:
The physical crosslinking of the DCH mixture has been accomplished, and shown to increase: stiffness, biocompatibility, resistance to dilution, and greater potential cell cargo capacity, while retaining injectability of these physical hydrogels.
RELATED PAPERS:
1) Yintao Sun, Alexander L. Wollenberg, Timothy Mark O’Shea, Yanxiang Cui, Z. Hong Zhou, Michael V. Sofroniew, and Timothy J. Deming. Conformation-directed formation of self-healing diblock copolypeptide hydrogels via polyion complexation (2017). Journal of the American Chemical Society Article 2017, 139, 15114–15121. DOI: 10.1021/jacs.7b08190.
2) Sun, Y.; Bentolila, L. A.; Deming, T. J. Self-sorting microscale compartmentalized block copolypeptide hydrogels. ACS Macro Lett., 2019, 8, 1275-1279. online 9-14-19. DOI: 10.1021/acsmacrolett.9b00669.