Biocompatibility of two model elastin‐like recombinamer‐based hydrogels formed through physical or chemical cross‐linking for various applications in tissue engineering and regenerative medicine

Abstract

Biocompatibility studies, especially innate immunity induction, in vitro and in vivo cytotoxicity, and fibrosis, are often lacking for many novel biomaterials including recombinant protein‐based ones, such as elastin‐like recombinamers (ELRs), and has not been extensively explored in the scientific literature, in contrast to traditional biomaterials. Herein, we present the results from a set of experiments designed to elucidate the preliminary biocompatibility of 2 types of ELRs that are able to form extracellular matrix‐like hydrogels through either physical or chemical cross‐linking both of which are intended for different applications in tissue engineering and regenerative medicine. Initially, we present in vitro cytocompatibility results obtained upon culturing human umbilical vein endothelial cells on ELR substrates, showing optimal proliferation up to 9 days. Regarding in vivo cytocompatibility, luciferase‐expressing hMSCs were viable for at least 4 weeks in terms of bioluminescence emission when embedded in ELR hydrogels and injected subcutaneously into immunosuppressed mice. Furthermore, both types of ELR‐based hydrogels were injected subcutaneously in immunocompetent mice and serum TNFα, IL‐1β, IL‐4, IL‐6, and IL‐10 concentrations were measured by enzyme‐linked immunosorbent assay, confirming the lack of inflammatory response, as also observed upon macroscopic and histological evaluation. All these findings suggest that both types of ELRs possess broad biocompatibility, thus making them very promising for tissue engineering and regenerative medicine‐related applications.

Production, purification and characterization of an elastin-like polypeptide containing the Ile-Lys-Val-Ala-Val (IKVAV) peptide for tissue engineering applications

“…These observations, coupled with the absence of any major inflammatory response, suggest a suitable biocompatibility for our material in vivo. This supports previous reports showing that ELP-based hydrogels do not trigger important cytotoxicity or inflammatory response after their in vivo implantation (Ibáñez-Fonseca et al, 2018;Nettles et al, 2008;Testera et al, 2015;Zhang et al, 2015).…”

Layer-by-layer biofabrication of coronary covered stents with clickable elastin-like recombinamers

“…Here, we propose the elastin-like recombinamers, as the biopolymers of choice for covering coronary stents. The ELRs have shown their potential in a wide range of applications due to their good biocompatibility [38,39], low thrombogenicity [23,24] and their elastic properties [40]. Specifically, we have used two ELRs that were chemically modified with cyclooctyne and azide to enable their stable crosslinking via catalyst-free click-chemistry reaction.…”

Random and oriented electrospun fibers based on a multicomponent, in situ clickable elastin-like recombinamer system for dermal tissue engineering

“…The recombinant DNA technology used for the biosynthesis of ELRs also allows the inclusion of bioactive peptides or proteins that may improve the biocompatibility of this type of biomaterials, such as cell adhesion domains comprising the tri-peptide Arg-Gly-Asp (RGD) [46]. It should be noted that hydrogels formed by the cross-linking of RGD-containing ELRs following the aforementioned "click" methodology have recently been shown to be cytoand biocompatible using several methods [47], thereby anticipating the good biocompatibility of ELR-based "clickable" electrospun fibers.…”