Luminal Plasma Treatment for Small Diameter Polyvinyl Alcohol Tubular Scaffolds

Abstract

Plasma-based surface modification is recognized as an effective way to activate biomaterial surfaces, and modulate their interactions with cells, extracellular matrix proteins, and other materials. However, treatment of a luminal surface of a tubular scaffold remains non-trivial to perform in small diameter tubes. Polyvinyl alcohol (PVA) hydrogel, which has been widely used for medical applications, lacks functional groups to mediate cell attachment. This poses an issue for vascular applications, as endothelialization in a vascular graft lumen is crucial to maintain long term graft patency. In this study, a Radio Frequency Glow Discharges (RFGD) treatment in the presence of NH 3 was used to modify the luminal surface of 3-mm diameter dehydrated PVA vascular grafts. The grafted nitrogen containing functional groups demonstrated stability, and in vitro endothelialization was successfully maintained for at least 30 days. The plasma-modified PVA displayed a higher percentage of carbonyl groups over the untreated PVA control. Plasma treatment on PVA patterned with microtopographies was also studied, with only the concave microlenses topography demonstrating a significant increase in platelet adhesion. Thus, the study has shown the possibility of modifying a small diameter hydrogel tubular scaffold with the RFGD plasma treatment technique and demonstrated stability in ambient storage conditions for up to 30 days.

Physical modification approaches to enhance cell supporting potential of poly (vinyl alcohol)‐based hydrogels

“…Plasma treatment, 17 ion implantation, 29 electron beam irradiation, 30 and flame‐treatment 31 are the several types of these techniques. Among them, plasma treatment is a well‐known invasive technique to activate or functionalize upper layer (about few nanometers) of a polymer surface without employing chemicals or creating undesirable wastes 32 . The most unique merit of plasma treatment is that it allows the reactive moieties to incorporate onto the surface and changes its energy for subsequent functionalization without altering bulk properties 33 .…”

Quantifying Physical Thrombus Characteristics on Cardiovascular Biomaterials Using MicroCT

“…Samples, which were modified by the integration of GFPGER, a peptide subsequence of type I collagen, had GFPGER mixed with the STMP in the PVA manufacturing process [ 17 ]. The luminal surfaces of plasma modification samples were subjected to NH 3 plasma modification using a variation of the radio frequency glow discharge treatment in the presence of NH 3 , as described previously [ 16 , 22 ]. The PVA for the gelatin-modified samples were activated using CDI with the goal of conjugating a gelatin protein, as described previously [ 18 ].…”

“…The luminal surfaces were then modified using a variety of techniques, including biochemical and topographical modifications, and assessed for thrombogenesis and hemocompatibility in the ex vivo shunt whole blood test. Specific modifications included integration of the peptide sequence Gly-Phe-Pro-Gly-Glu-Arg (GFPGER), plasma modification, addition of gelatin with a carbonyldiimidazole (CDI) covalent linker, and sterilization, and their preparation methods are described in greater detail in previous publications [16][17][18][19]. Samples, which were modified by the integration of GFPGER, a peptide subsequence of type I collagen, had GFPGER mixed with the STMP in the PVA manufacturing process [17].…”

“…Specifically, ePTFE served as a clinical control; collagen-coated ePTFE acted as a positive, thrombogenic control; and poly(vinyl alcohol) (PVA) served as a preclinical, non-thrombogenic, hydrogel material. Several surface modifications of the PVA, which were previously evaluated for their hemocompatibility and endothelialization potential [16][17][18][19], were used in this work to assess and validate the measurement of the physical properties of the thrombus. Advanced image software analysis was then used to quantify the luminal volume (the inverse of thrombus volume) and the intra-thrombus variability.…”

Optimization of a Novel Preferential Covered Stent through Bench Experiments and in Vitro Platelet Activation Studies

“…Each well was loaded with 200 μL of PRP and incubated at 37 °C for 1 h on a plate shaker at 200 rpm. Collagen I-coated coverslip (rat tail, C3867, Sigma-Aldrich) served as a positive control. − The negative controls were: (1) resting PRP in the absence of biomaterials membrane without shaking and (2) resting PRP with heparin added before experiment.…”