Plasma Surface Chemical Treatment of Electrospun Poly(l-Lactide) Microfibrous Scaffolds for Enhanced Cell Adhesion, Growth, and Infiltration

Abstract

Poly(l-lactide) (PLLA) microfibrous scaffolds produced by electrospinning were treated with mild Ar or Ar-NH 3 /H 2 plasmas to enhance cell attachment, growth, and infiltration. Goniometry, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) measurements were used to evaluate the modification of the scaffold surface chemistry by plasma treatment. AFM and XPS measurements showed that both plasma treatments increased the hydrophilicity without affecting the integrity of the fibrous structure and the fiber roughness, whereas Ar-NH 3 /H 2 plasma treatment also resulted in surface functionalization with amine groups. Culture studies of bovine aorta endothelial cells and bovine smooth muscle cells on the plasma-treated PLLA scaffolds revealed that both Ar and Ar-NH 3 /H 2 plasma treatments promoted cell spreading during the initial stage of cell attachment and, more importantly, increased the cell growth rate, especially for Ar plasma treatment. In vitro cell infiltration studies showed that both plasma treatments effectively enhanced cell migration into the microfibrous scaffolds. In vivo experiments involving the subcutaneous implantation of plasma-treated PLLA scaffolds under the skin of Sprague-Dawley rats also showed increased cell infiltration. The results of this study indicate that surface treatment of PLLA microfibrous scaffolds with mild Ar or Ar-NH 3 /H 2 plasmas may have important implications in tissue engineering. Further modifications with bioactive factors should improve the functions of the scaffolds for specific applications. Introduction Microfibrous structures synthesized by electrospinning are of particular interest in bioengineering due to their high porosity and biodegradability that make them ideal candidates for polymer scaffolds. However, because polymer surfaces (solid or fibrous), such as poly(llactide) (PLLA), are hydrophobic, cell attachment and growth on polymer scaffolds is limited. Therefore, various surface treatments have been used to modify the chemical behavior of PLLA surfaces in order to improve biocompatibility.1 Plasma-assisted surface modification is a common method of tuning biochemical surface properties to specific application needs. This method provides a wide range of surface functionalities, which can improve biocompatibility either directly or indirectly through biomolecule surface immobilization. For instance, surface functionalization with hydrophilic chemical groups (e.g., -COOH and -NH 2 ) by reactive gas plasma treatment or surface chemical modification by film deposition 2-11 and coating of polymer surfaces by various extracellular matrix proteins (e.g., collagen, gelatin, and laminin) [12][13][14][15][16][17][18] and other bioactive molecules by plasma treatment 19,20 have been shown to improve the biocompatibility of polymer materials.In addition to studies devoted to the increase of the surface hydrophilicity of biopolymers for promoting bioactive molecular and protein attachment, the direct effect of plasma surface treatment on biocompati...

Plasma surface functionalization of biodegradable electrospun scaffolds for tissue engineering applications

“…The visualization of the scaffold cross sections by fluorescent microscopy after DAPI staining revealed that both plasma treatments are efficient in improving BAEC infiltration into the scaffolds. In vivo subcutaneous implantation of PLLA scaffolds under rat skin also enhanced the cellular infiltration when plasmatreated [161]. Atmospheric pressure plasma was also employed to activate PLLA fibers and similar surface analysis techniques and cell tests were conducted.…”

Plasma Science and Technology - Progress in Physical States and Chemical Reactions

“…Whereas the smooth muscle cells showed no significant increase in proliferation in-vitro, in-vivo tests revealed that cells were able to penetrate the scaffolds more efficiently and at higher densities, mainly due to the increased wettability. Cheng et al [85] found similar results in-vivo for their Ar-/NH 3 -treated PLA scaffolds -indicating that for cell infiltration, wettability is most likely the critical factor. When it comes to mineralization, Yang et al [76] found similar results compared to Yildirim et al [86] in the rapid prototyping section: improved mineralization within the first few hours after immersion of Ar plasma-treated scaffolds into simulated body fluid (SBF) solution.…”

Immobilization of polyvinyl alcohol‐siloxane on the oxygen plasma‐modified polyurethane‐carbon nanotube composite matrix

“…The scaffolds structure and pattern (PC, PCO, PCOP, and PCOPG) along with their fiber diameters are presented in Figure 2(a-e). 43 The surfaces of electrospun poly(L-lactide) microfibrous scaffolds did not change after plasma treatment in their study, but the surface of the chemical altered with plasma modification has changed. Interconnected pores and network microstructure have been formed throughout the electrospinning technique, according to the SEM images.…”