The choice of biopolymer is crucial to trigger angiogenesis with vascular endothelial growth factor releasing coatings

Abstract

Bio-based coatings and release systems for pro-angiogenic growth factors are of interest to overcome insufficient vascularization and bio-integration of implants. This study compares different biopolymer-based coatings on polyethylene terephthalate (PET) membranes in terms of coating homogeneity and stability, coating thickness in the swollen state, endothelial cell adhesion, vascular endothelial growth factor (VEGF) release and pro-angiogenic properties. Coatings consisted of carbodiimide cross-linked gelatin type A (GelA), type B (GelB) or albumin (Alb), and heparin (Hep), or they consisted of radically cross-linked gelatin methacryloyl-acetyl (GM5A5) and heparin methacrylate (HepM5). We prepared films with thicknesses of 8–10 µm and found that all coatings were homogeneous after washing. All gelatin-based coatings enhanced the adhesion of primary human endothelial cells compared to the uncoated membrane. The VEGF release was tunable with the loading concentration and dependent on the isoelectric points and hydrophilicities of the biopolymers used for coating: GelA-Hep showed the highest releases, while releases were indistinguishable for GelB-Hep and Alb-Hep, and lowest for GM5A5-HepM5. Interestingly, not only the amount of VEGF released from the coatings determined whether angiogenesis was induced, but a combination of VEGF release, metabolic activity and adhesion of endothelial cells. VEGF releasing GelA-Hep and GelB-Hep coatings induced angiogenesis in a chorioallantoic membrane assay, so that these coatings should be considered for further in vivo testing.

Soft Sub‐Structured Multi‐Material Biosensor Hydrogels with Enzymes Retained by Plant Viral Scaffolds

“…[ 46 ] Isothiouronium groups may interact with GM by ionic interactions, similar to the isothiouronium‐functional dye alcian blue that is well known to stain GM‐based materials. [ 47 ] Thiol groups may react with methacrylate and methacrylamide groups in GM via a thiol‐Michael reaction to form covalent bonds between the hydrogel surface and the GM spots. [ 48 ]…”

“…[46] Isothiouronium groups may interact with GM by ionic interactions, similar to the isothiouronium-functional dye alcian blue that is well known to stain GM-based materials. [47] Thiol groups may react with methacrylate and methacrylamide groups in GM via a thiol-Michael reaction to form covalent bonds between the hydrogel surface and the GM spots. [48] Properties of the distinct PEGDA substrates with regard to their wetting behavior, spot cross-linking, and surface adhesion will be described and discussed in the following two sections.…”

Which Gelatin and Antibiotic Should Be Chosen to Seal a Woven Vascular Graft?

“…Gelatin A is obtained from porcine skin by acid hydrolysis, resulting in an isoelectric point (pIE) of about 9.0, and is called basic gelatin. Gelatin B (acidic, pIE = 5.0) is obtained from bovine skin or bones via alkaline hydrolysis [14,33,34]. Gelatins A and B differ radically in terms of hydrodynamic radius, viscosity, linear viscoelastic range, equilibrium degree of swelling, etc.…”

“…For woven and knitted aortic prostheses, various compositions and methods of sealing have been developed, including those containing antibacterial drugs. Gelatin-based (Gel) sealants are most popular due to their ability to form low-viscosity hydrogels [13,14], which form a thin elastic film on the inner and outer surfaces of a porous prosthesis after drying [15,16]. Gelatin sealing techniques vary widely, but they all require that the coating be elastic, uniform in thickness, firmly bonded to the surface, not peeled off during storage and intraoperative manipulation, and also do not significantly increase the rigidity of the graft.…”

Optimization of Technological Parameters of the Process of Forming Therapeutic Biopolymer Nanofilled Films

“…In addition, the complexity of the production technology and the high cost of the components restrain their wide implementation. It is assumed that biopolymer coatings will reduce the organism’s reaction to a foreign body and thus increase its biocompatibility [ 25 , 26 ]. Infections associated with orthopaedic implants can have catastrophic consequences for patientsA promising direction in preventing surgical infections and accelerating wound healing is the use of therapeutic nano-containing biopolymer films [ 27 , 28 ] To effectively use biopolymer films, it is necessary to carefully study their physical, mechanical and therapeutic properties and ways to correct them.…”