Plasma-induced polymerization as a tool for surface functionalization of polymer scaffolds for bone tissue engineering: An in vitro study

Abstract

A commonly applied strategy in the field of tissue engineering (TE) is the use of temporary three-dimensional scaffolds for supporting and guiding tissue formation in various in vitro strategies and in vivo regeneration approaches. The interactions of these scaffolds with highly sensitive bioentities such as living cells and tissues primarily occur through the material surface. Hence, surface chemistry and topological features have principal roles in coordinating biological events at the molecular, cellular and tissue levels on timescales ranging from seconds to weeks. However, tailoring the surface properties of scaffolds with a complex shape and architecture remains a challenge in materials science. Commonly applied wet chemical treatments often involve the use of toxic solvents whose oddments in the construct could be fatal in the subsequent application. Aiming to shorten the culture time in vitro (i.e. prior the implantation of the construct), in this work we propose a modification of previously described bone TE scaffolds made from a blend of starch with polycaprolactone (SPCL). The modification method involves surface grafting of sulfonic or phosphonic groups via plasma-induced polymerization of vinyl sulfonic and vinyl phosphonic acid, respectively. We demonstrate herein that the presence of these anionic functional groups can modulate cell adhesion mediated through the adsorbed proteins (from the culture medium). Under the conditions studied, both vitronectin adsorption and osteoblast proliferation and viability increased in the order SPCL << sulfonic-grafted SPCL < phosphonic-grafted SPCL. The results revealed that plasma-induced polymerization is an excellent alternative route, when compared to the commonly used wet chemical treatments, for the surface functionalization of biodevices with complex shape and porosity.

Phosphorous-containing polymers for regenerative medicine

“…Many phosphorous-containing polymers have been reported to adsorb proteins, which can improve their biological function. [7,11,15,52–55] However, in vascular applications, protein adsorption can lead to thrombus formation that can prevent blood flow. MPC incorporation in a variety of co- polymers has been reported to result in decreased protein adsorption and blood cell adherence.…”

“…[13] Phosphorylation of poly(vinyl alcohol) has been reported to increase adherence, proliferation, and osteoblastic differentiation of human osteoblast-like cells, as well as increase mineralization of the scaffold. [15] Similarly, the presence of VPA has exhibited improved osteoblast- like cell adhesion and proliferation both as a homo-polymer[11] and in co-polymers with acrylamide. [54,59] Likewise, phosphorylation of chitosan nanofibrous scaffolds has been shown to improve proliferation and osteogenic differentiation of human osteoblast-like cells.…”

Investigation of silk fibroin nanoparticle-decorated poly(L-lactic acid) composite scaffolds for osteoblast growth and differentiation

“…These data can be correlated with the scaffold structure that can improve the albumin attachment leading to a higher cell adhesion. 41 The cell adhesion rate of the SF/PLLA composite scaffolds ( Figure 5B) was higher than the PLLA scaffolds at which SF/PLLA with the optimum weight ratio of 2:8 resulted in the highest cell adhesion rate (89%). The addition of SF nanoparticles altered the surface properties and roughness of PLLA scaffolds and, therefore, improved the protein adsorption and cell adhesion.…”

Surface modification of PdlLGA microspheres with gelatine methacrylate: Evaluation of adsorption, entrapment, and oxygen plasma treatment approaches

“…On the collapse of the swollen layer, the modifying molecule is trapped as a penetrating network at the surface of the polymer structure [26], [27], [28]. Electron beam irradiation and plasma induced polymerisation were reported to functionalise the surface with a minor effect on surface topography [29], [30], [31], [32], [33], [34], [35], [36], [37].…”