An official website of the United States government
Cells encapsulated in 3D hydrogels exhibit differences in cellular mechanosensing based on their ability to remodel their surrounding hydrogel environment. Although cells in tissue interfaces feature a range of mechanosensitive states, it is challenging to recreate this in 3D biomaterials. Human mesenchymal stem cells (MSCs) encapsulated in methacrylated gelatin (GelMe) hydrogels remodel their local hydrogel environment in a time-dependent manner, with a significant increase in cell volume and nuclear Yes-associated protein (YAP) localization between 3 and 5 days in culture. A finite element analysis model of compression showed spatial differences in hydrogel stress of compressed GelMe hydrogels, and MSC-laden GelMe hydrogels were compressed (0–50%) for 3 days to evaluate the role of spatial differences in hydrogel stress on 3D cellular mechanosensing. MSCs in the edge (high stress) were significantly larger, less round, and had increased nuclear YAP in comparison to MSCs in the center (low stress) of 25% compressed GelMe hydrogels. At 50% compression, GelMe hydrogels were under high stress throughout, and this resulted in a consistent increase in MSC volume and nuclear YAP across the entire hydrogel. To recreate heterogeneous mechanical signals present in tissue interfaces, porous polycaprolactone (PCL) scaffolds were perfused with an MSC-laden GelMe hydrogel solution. MSCs in different pore diameter (~280–430 μm) constructs showed an increased range in morphology and nuclear YAP with increasing pore size. Hydrogel stress influences MSC mechanosensing, and porous scaffold-hydrogel composites that expose MSCs to diverse mechanical signals are a unique biomaterial for studying and designing tissue interfaces.
more »
« less
Development and characterization of Factor Xa ‐responsive materials for applications in cell culture and biologics delivery
Abstract Stimuli–responsive biomaterials may be used to better control the release of bioactive molecules or cells for applications involving drug delivery and controlled cell release. In this study, we developed a Factor Xa (FXa)‐responsive biomaterial capable of controlled release of pharmaceutical agents and cells from in vitro culture. FXa‐cleavable substrates were formed as hydrogels that degraded in response to FXa enzyme over several hours. Hydrogels were shown to release both heparin and a model protein in response to FXa. Additionally, RGD‐functionalized FXa‐degradable hydrogels were used to culture mesenchymal stromal cells (MSCs), enabling FXa‐mediated cell dissociation from hydrogels in a manner that preserved multicellular structures. Harvesting MSCs using FXa‐mediated dissociation did not influence their differentiation capacity or indoleamine 2,3‐dioxygenase (IDO) activity (a measure of immunomodulatory capacity). In all, this FXa‐degradable hydrogel is a novel responsive biomaterial system that may be used for on‐demand drug delivery, as well as for improving processes for in vitro culture of therapeutic cells.
more »
« less
- Award ID(s):
- 1648035
- PAR ID:
- 10397452
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Biomedical Materials Research Part A
- Volume:
- 111
- Issue:
- 5
- ISSN:
- 1549-3296
- Page Range / eLocation ID:
- p. 634-643
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Neural progenitor cells (NPCs) are a promising cell source to repair damaged nervous tissue. However, expansion of therapeutically relevant numbers of NPCs and their efficient differentiation into desired mature cell types remains a challenge. Material‐based strategies, including culture within 3D hydrogels, have the potential to overcome these current limitations. An ideal material would enable both NPC expansion and subsequent differentiation within a single platform. It has recently been demonstrated that cell‐mediated remodeling of 3D hydrogels is necessary to maintain the stem cell phenotype of NPCs during expansion, but the role of matrix remodeling on NPC differentiation and maturation remains unknown. By culturing NPCs within engineered protein hydrogels susceptible to degradation by NPC‐secreted proteases, it is identified that a critical amount of remodeling is necessary to enable NPC differentiation, even in highly degradable gels. Chemical induction of differentiation after sufficient remodeling time results in differentiation into astrocytes and neurotransmitter‐responsive neurons. Matrix remodeling modulates expression of the transcriptional co‐activator Yes‐associated protein, which drives expression of NPC stemness factors and maintains NPC differentiation capacity, in a cadherin‐dependent manner. Thus, cell‐remodelable hydrogels are an attractive platform to enable expansion of NPCs followed by differentiation of the cells into mature phenotypes for therapeutic use.more » « less
-
This study investigates the development of a supramolecular peptide amphiphile (PA) material functionalized with phenylboronic acid (PBA) for glucose-responsive glucagon delivery. The PA-PBA system self-assembles into nanofibrillar hydrogels in the presence of physiological glucose levels, resulting in stable hydrogels capable of releasing glucagon under hypoglycemic conditions. Glucose responsiveness is driven by reversible binding between PBA and glucose, which modulates the electrostatic interactions necessary for hydrogel formation and dissolution. Through comprehensive in vitro characterization, including circular dichroism, zeta potential measurements, and rheological assessments, the PA-PBA system is found to exhibit glucose-dependent assembly, enabling controlled glucagon release that is inversely related to glucose concentration. Glucagon release is accelerated under low glucose conditions, simulating a hypoglycemic state, with a reduced rate seen at higher glucose levels. Evaluation of the platform in vivo using a type 1 diabetic mouse model demonstrates efficacy in protecting against insulin-induced hypoglycemia by restoring blood glucose levels following an insulin overdose. The ability to tailor glucagon release in response to fluctuating glucose concentrations underscores the potential of this platform for improving glycemic control. These findings suggest that glucose-stabilized supramolecular peptide hydrogels hold significant promise for responsive drug delivery applications, offering an approach to manage glucose levels in diabetes and other metabolic disorders.more » « less
-
Abstract Understanding mesenchymal stromal cells (MSCs) growth mechanisms in response to surface chemistries is essential to optimize culture methods for high‐quality and robust cell yields in cell manufacturing applications. Heparin (HEP) and collagen 1 (COL) substrates have been reported to enhance cell adhesion, growth, viability, and secretory potential in MSCs. However, the biomolecular mechanisms underlying the benefits of combined HEP/COL substrates are unknown. This work used HEP/COL bilayered surfaces to investigate the role of integrin‐HEP interactions in the advantages of MSC culture. The layer‐by‐layer approach (LbL) was used to create HEP/COL bilayers, which were made up of stacks of 8 and 9 layers that combined HEP and COL in an alternate arrangement. Surface spectroscopic investigations and laser scanning microscopy evaluations verified the biochemical fingerprint of each component and a total stacked bilayer thickness of roughly 150 nm. Cell growth and apoptosis in response to IC50and IC75levels of BTT‐3033 and Cilengitide, α2β1 and αvβ3 integrin inhibitors respectively, were evaluated on HEP/COL coated surfaces using two bone marrow‐derived MSC donors. While integrin activity did not affect cell growth rates, it significantly affected cell adhesion and apoptosis on HEP/COL surfaces. HEP‐ending HEP/COL surfaces significantly increased FAK‐ERK½ phosphorylation and endogenous cell COL deposition compared to COL, COL‐ending HEP/COL and uncoated surfaces. BTT‐3033 but not Cilengitide treatment markedly affected FAK‐ERK½ activity levels on HEP‐ending HEP/COL surfaces supporting a major role for α2β1 activity. BTT‐3033 treatment on HEP‐ending bilayers reduced MSC‐mediated macrophage inhibitory activity and altered the cytokine profile of co‐cultures. Overall, this study supports a novel role for HEP in regulating the survival and potency of MSCs via enhancing the α2β1‐FAK‐ERK½ signaling mechanism.more » « less
-
Finding the sweet spot: a library of hydrogels with tunable degradation for tissue model developmentIn vitro models are valuable tools for applications including understanding cellular mechanisms and drug screening. Hydrogel biomaterials facilitate in vitro models by mimicking the extracellular matrix and in vivo microenvironment. However, it can be challenging for cells to form tissues in hydrogels that do not degrade. In contrast, if hydrogels degrade too much or too quickly, tissue models may be difficult to assess in a high throughput manner. In this paper, we present a poly(allylamine) (PAA) based synthetic hydrogel system which can be tuned to control the mechanical and chemical cues provided by the hydrogel scaffold. PAA is a polycation with several biomedical applications, including the delivery of small molecules, nucleic acids, and proteins. Based on PAA and poly(ethylene glycol) (PEG), we developed a synthetic non-degradable system with potential applications for long-term cultures. We then created a second set of gels that combined PAA with poly- l -lysine (PLL) to generate a library of semi-degradable gels with unique degradation kinetics. In this work, we present the hydrogel systems’ synthesis, characterization, and degradation profiles along with cellular data demonstrating that a subset of gels supports the formation of endothelial cell cord-like structures.more » « less
