Plasma surface modification technique–induced gelatin grafting on bio-originated polyurethane porous matrix: Physicochemical and in vitro study

Abstract

In this study, polyurethane (TPU) scaffolds were fabricated using freeze-drying technique and gelatin macromolecules immobilized on the activated surface by oxygen plasma treatment. Scanning electron microscopy (SEM) micrographs indicated an interconnected porous microstructure with randomly oriented pores. According to the results, the diameter of pores increased after plasma treatment and gelatin grafting. Fourier transform infrared spectroscopy illustrated that there is no inappropriate interaction between materials during processing; furthermore, attenuated total reflection Fourier transform infrared spectroscopy confirmed the immobilization of gelatin molecules on the surface of the plasma-treated polymeric scaffolds. Waterdrop contact angle analysis presented that wettability and hydrophilicity of constructs increased after grafting gelatin on the activated surface. Phosphate-buffered saline absorption and hydrolytic biodegradation enhanced after surface modification of the polymeric samples. Cellular behavior demonstrated better adhesion and spreading after grafting gelatin of oxygen plasma-treated constructs. No evidence of toxicity was observed for 7 days. DNA content determined that the number of viable cells increased in TPU-gelatin matrixes after 1 day in contrast with TPU scaffolds. Based on results, oxygen plasma treatment can create an activated surface to graft gelatin macromolecules and achieve optimum physicochemical, mechanical, and biological features for the neo-tissue formation.

Hydrophilic Surface Functionalization of Electrospun Nanofibrous Scaffolds in Tissue Engineering

“…This type of grafting uses all kinds of polymerization, including atom-transfer radical-polymerization (ATRP), controlled free-radical polymerization (CFRP), or anionic polymerization [ 47 , 48 ]. Covalent grafting was used for hydrophilic surface functionalization on PCL, PLLA, or polysulfone (PSU) and many copolymers described below [ 49 , 50 , 51 , 52 ]. “Grafting to” is a method that might be used for a wide range of materials, for instance, various monomers, such as acrylonitrile [ 22 ], acrylate, acrylamide, and many others [ 47 , 48 , 53 ].…”

“…In this method, the macromolecular backbone is modified with the purpose of introducing reactive functional groups on the surface. This method requires an initiator, which might be introduced to the surface through post-polymerization, copolymerization, or polycondensation [ 51 , 52 ]. For instance, “grafting from” might take place using an atmospheric pressure plasma jet (APPJ) with argon as processing gas and in open-air.…”

“…The MTS cell viability assay also confirmed that the modified surface created a more preferred environment for ECM production and chondrocytes proliferation even after 28 days [ 62 ]. Hesari et al [ 51 ] incorporated plasma treatment with covalent grafting of gelatin to modify a PU scaffold. The surface was activated with oxygen plasma, and then gelatin macromolecules were incorporated into the surface.…”

“…On the other hand, it significantly impairs the mechanical properties of the material. Another thing is that gelatin increases the hydrolytic degradation rate, which might be favorable unless the process might be controlled [ 51 ]. On the other hand, surface graft polymerization usually requires plasma initiation to generate free radicals.…”

PCL/Gelatin/Graphene Oxide Electrospun Nanofibers: Effect of Surface Functionalization on In Vitro and Antibacterial Response

“…Positively charged cationic nanofibers have been shown to increase antimicrobial potency, as they can attract negatively charged bacteria cells [ 61 , 62 , 63 ]. Post-electrospinning surface treatments can be optimized to introduce suitable moieties on the surface of nanofibers using several approaches, including wet chemical functionalization, covalent grafting, physical adsorption, and plasma treatment [ 64 , 65 , 66 , 67 , 68 ]. Among these methods, plasma treatment is favorable, as it is the fastest method for surface functionalization with a high stability effect [ 69 , 70 ].…”