Engineering Helical Modular Polypeptide-Based Hydrogels as Synthetic Extracellular Matrices for Cell Culture

Abstract

Expanding the toolkit of modular and functional synthetic material systems for biomimetic extracellular matrices (ECMs) is needed for achieving more predictable and characterizable cell culture. In the present study, we engineered a synthetic hydrogel system incorporating poly­(γ-propargyl-l-glutamate) (PPLG), an N-carboxy anhydride polypeptide with a unique α-helical secondary structure. PPLG macromers were cross-linked into poly­(ethylene glycol) (PEG) networks to form hybrid polypeptide-PEG hydrogels. We compared the properties of PPLG-PEG to systems where the PPLG macromers were replaced with 8-arm PEG or poly­(γ-propargyl-d,l-glutamate) (PPDLG), which has a flexible random-coil conformation. We evaluated each hydrogel system as synthetic ECMs for two-dimensional (2D) endothelial cell culture. Cells on PPLG-PEG displayed superior attachment and spreading at comparable adhesion ligand incorporation concentrations, demonstrating the unique benefit of combining the more rigid and hydrophobic α-helical PPLG within the more flexible and hydrophilic PEG matrix. The modular PPLG macromer is a promising building block for developing other types of PPLG-based hydrogels with favorable and tunable properties.

The Influence of Ligand Density and Degradability on Hydrogel Induced Breast Cancer Dormancy and Reactivation

“…A limitation of our polymerization scheme is that hydrogel degradability and elasticity are coupled, meaning that changing one changes the other. To independently tune these two parameters would require the implementation of multi-arm PEG chemistry to gain independent control over these parameters [66][67][68][69] and is of interest in future studies. While we anticipate elasticity played a minor role in influencing cancer cell fate, we found that ligand density had a significant influence on cancer cell phenotype.…”

Liquid–Liquid Phase‐Separated Systems from Reversible Gel–Sol Transition of Protein Microgels

“…[ 1–4 ] To date, sol–gel transitions (gelation) have been studied and utilized for the fabrication of materials like soft hydrogels in tissue engineering and also have high relevance for understanding the onset and development of protein‐aggregation diseases. [ 1–8 ] Recently, there is a growing interest in developing materials formed by liquid–liquid phase separation (LLPS), which is found at the heart of a range of biological processes connected to biological function and malfunction. [ 9–13 ] The processes underlying the formation of liquid‐state and gel‐state proteins can involve different physicochemical mechanisms, and liquid‐state materials are a key category of functional biological structures as well as an important complement of conventional solid or gel materials.…”

Smart Porous Multi-Stimulus Polysaccharide-Based Biomaterials for Tissue Engineering

“…The main efforts on engineered ECM in the biomedical field have been focused on the use and stimulation of pluripotent stem cells, which are special cells that have the ability to perpetuate themselves through a mechanism of self-renewal and to generate diverse types of cells through differentiation processes [15][16][17]. Nevertheless, osteoblasts [18], skeletal muscle cells [18], and endothelial cells [20] have been also studied.…”

“…Porous materials from polysaccharides have been used as extracellular matrices (ECM) in tissue engineering in order to generate diverse types of cell lineages, promoting regeneration [15,16], for instance, in stem cells [17], osteoblasts [18], skeletal muscle cells [19], and endothelial cells [20]. In the biomedical field, aerogels from different sources have found applications as implantable devices, dressings for wound healing, synthetic bone grafts, carriers for different drugs, biosensing, and biomedical imaging [6,21].…”