Nanofibrous and nanocomposite hydrogels formed by the self-assembly of a bis-urea low molecular weight gelator
Place: conference room, IMDEA Nanociencia.
Abstract:
Hydrogels are increasingly explored in tissue engineering and regenerative medicine to support cell growth and tissue regeneration. In particular, low molecular weight gelators (LMWGs) are a promising class of small molecules that can form hydrogels through self-assembly; however, hydrogels prepared from LMWGs, especially bis-urea-based gelators, are less well explored than those based on polymers. Key open questions include the biocompatibility and bioactivity of these hydrogels as well as the ability to tune their chemical and physical properties. The first part of this talk will explore the hypothesis that the incorporation of metal ions (Mg2+, Ca2+, Zn2+, Na+/K+) into bis-urea LMWG hydrogels can enhance their mechanical and biological properties. Rheological analysis reveals that the ion-modified hydrogels exhibit increased mechanical strength while still demonstrating shear-thinning and self-healing behavior, which makes the hydrogels suitable for applications such as injection for minimally invasive delivery and 3D bioprinting.
Furthermore, L929 fibroblasts demonstrate high viability and proliferation, both when cultured on the surface of the hydrogels and when encapsulated inside them in 3D, with these effects being further amplified by the presence of metal ions. As additional proof-of-concept, the ion-modified hydrogels are used to promote the in vitro differentiation of MC3T3-E1 pre-osteoblasts, with the hydrogels containing Ca2+ ions leading to robust collagen deposition and matrix mineralization. The second part of this talk will systematically investigate the incorporation of four nanoparticle types (carbon nanotubes, cellulose nanocrystals, hydroxyapatite nanoparticles, and magnesium carbonate nanoparticles) into the hydrogels at concentrations of 0.15, 0.5, and 1.0 wt.%. Rheological characterization reveals that all nanoparticle types enhance storage and loss moduli in a concentration-dependent manner, with carbon nanotubes producing the greatest effect. Biological assessment using L929 fibroblasts demonstrates high cell viability across all formulations, with a clear inverse relationship with nanoparticle loading. For example, metabolic activity and DNA quantification assays show that low nanoparticle concentrations (0.15 wt.%) support proliferation comparable to or exceeding controls while higher concentrations progressively reduce cell survival. An optimal concentration range of 0.15 to 0.5 wt.% nanoparticles is identified for balancing mechanical reinforcement with cellular compatibility. Overall, these findings suggest that ion-modified or nanoparticle-reinforced bis-urea LMWG hydrogels offer significant potential for applications ranging from advanced scaffolds for tissue engineering and regenerative medicine to drug delivery systems.
Dr. Jennifer Patterson joined IMDEA Materials as a Researcher in February 2021, and she heads the research group on Biomaterials and Regenerative Medicine. Originally from Philadelphia, USA, Dr. Patterson received a B.S.E. in chemical engineering from Princeton University in 1998 and a Ph.D. in bioengineering from the University of Washington in 2007. Her bachelor thesis research was on the characterization of self-assembled fibrils formed from combinatorially designed de novo proteins, working under the guidance of Prof. Michael Hecht, and her Ph.D. dissertation was on the development of hydrogel- and microsphere-based delivery systems to stimulate oriented bone regeneration, in the laboratory of Prof. Patrick Stayton. Dr. Patterson has worked internationally in both industry and academia, with previous positions at Therics, Inc. (USA – one of the first companies to develop 3D printing technology for medical applications), BIOFABICS LDA (Portugal), and EPFL (Switzerland) and as an assistant professor at KU Leuven (Belgium).
During her postdoc in the lab of Prof. Jeffrey Hubbell at EPFL, she gained experience in the molecularly engineered polyethylene glycol hydrogels pioneered by that group. At KU Leuven, she was the leader of a research group on biomaterials and was also a lecturer for master-level courses for the option in biomaterials within the materials engineering degree program. In the last 15 years, she has supervised or co-supervised 8 postdoctoral fellows (1 ongoing), 12 Ph.D. students (7 ongoing and 5 defended), 4 predoctoral students/research assistants, >30 master students, and >90 bachelor students. Her research activities and interests include (1) the synthesis of novel biomaterials, with a particular focus on hydrogels; (2) processing of biomaterials into complex 3D structures; (3) evaluation of physicochemical properties such as morphology and mechanical and surface properties; (4) characterization of cytocompatibility and biological functionality in vitro; and (5) preclinical evaluation in small animal models in vivo.
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