Surface functionalization of poly(ε-caprolactone) and poly(3-hydroxybutyrate) with VEGF

Abstract

Abstract:In this study, surface modifications for the biodegradable polymers poly(ε-caprolactone) (PCL) and poly(3-hydroxybutyrate) [P(3HB)] were developed in order to improve their suitability as scaffold material for bioartificial vessel prostheses. The challenge of wet-chemical surface modifications is to avoid bulk adjustments resulting in undesired changes in mechanical properties of these polymers. Nevertheless subsequent immobilization and controlled release of potent angiogenic biomolecules like vascular endothelial growth factor (VEGF) from the polymer surface is required. In order to improve the biocompatibility of PCL and P(3HB), terminal hydroxyl groups on the surface of these polymers were generated via oxygen (O 2 ) and carbon dioxide (CO 2 ) plasma. Then, the immobilization of VEGF was achieved through hydrolysable ester bonds using the crosslinker N,N′-disuccinimidyl carbonate (DSC). Our studies demonstrated that the plasma surface activations have no negative influence on the viability of L929 mouse fibroblasts and hemocompatibility. The immobilization of VEGF on the modified polymers via DSC is improved compared to the untreated reference. For the CO 2 plasma-chemical activated surfaces we observed the highest VEGF surface immobilization. Our release studies also reveal the highest cumulative release using CO 2 plasma-chemical activated samples.

Accelerated Endothelialization of Nanofibrous Scaffolds for Biomimetic Cardiovascular Implants

“…Plasma-chemical surface modification was conducted by plasma etching (PE) of nonwoven samples in an ammonia (NH 3 ) plasma, generating radical species and amino groups. The short plasma activation process was performed for 1 min and 60% generator output in an ammonia radio frequency (RF) plasma generator (frequency 13.56 MHz, power 100 W, Diener electronic GmbH and Co. KG, Ebhausen, Germany) at a low pressure of 0.3 mbar based on previously studies [ 42 , 49 , 51 ]. The screening data were not presented because the energy density of the plasma in the chamber depends on a wide range of factors such as chamber material, design, sample positioning and mounting, electrode spacing, size, shape and material, and the method of excitation.…”

“…In this context, plasma treatment has been extensively studied and applied to thin films and bulk polymer scaffolds but has not yet been sufficiently investigated for electrospun hydrophobic fiber scaffolds [ 50 ]. We selected ammonia plasma based on previous studies of the materials in the field of cardiovascular application [ 42 , 49 , 51 ]. Thus, this study examined the potential of NH 3 -plasma functionalization of electrospun fibrous biomaterials for promoting cell attachment and physiological growth patterns of human endothelial cells in vitro for the development of biocompatible and biomimetic cardiac scaffolds.…”

Biofunctionalization

“…In this context, Spatz et al [2] discuss the impact of spacer integration between biomaterial surface and the integrin-recognition motif cyclic RGD on the formation of integrin-based cellular adhesion. Furthermore, the immobilization strategy defines the short-term or long-term localization of the biomolecule on the biomaterials surface, which is explored using the example of the immobilization of the potent angiogenic vascular endothelial growth factor (VEGF) in order to improve the hemocompatibility and endothelialization of biodegradable polymer surfaces [3].…”

“…In this context, Spatz et al [2] discuss the impact of spacer integration between biomaterial surface and the integrin-recognition motif cyclic RGD on the formation of integrin-based cellular adhesion. Furthermore, the immobilization strategy defines the short-term or long-term localization of the biomolecule on the biomaterials surface, which is explored using the example of the immobilization of the potent angiogenic vascular endothelial growth factor (VEGF) in order to improve the hemocompatibility and endothelialization of biodegradable polymer surfaces [3].One more important field is the biofunctionalization of nanostructured materials and nanoparticles with possible biomedical application for imaging and quantifying of target molecules such as proteins in assays, cells and tissues. In this context, Walter et al [4] give general insights into the principles and factors controlling the binding affinity of aptamers, as promising alternative binders that can substitute antibodies in various applications immobilized to nanostructured materials.…”

Influence of bulk incorporation of FDAc and PTX on polymer properties

“…The Contact Angle System (OCA 20, Dataphysics Instruments GmbH, Filderstadt, Germany) was used to determine the influence of drug incorporation on the surface hydrophilicity via sessile drop method with ultra-pure water [6]. Presented mean values and standard deviations were calculated from n = 5 samples.…”