Polyurethane Membranes Modified with Isopropyl Myristate as a Potential Candidate for Encapsulating Electronic Implants: A Study of Biocompatibility and Water Permeability

Abstract

Abstract:Medical polyurethanes have shown good bio-stability and mechanical properties and have been used as coating for implantable medical devices. However, despite their excellent properties, they are relatively permeable to liquid water and water vapour which is a drawback for electronic implant encapsulation. In this study polyether polyurethanes with different soft segment molecular weights were modified by incorporating isopropyl myristate (IPM), as a hydrophobic modifying agent, and the effect of IPM on water resistant and biocompatibility of membranes were investigated. IPM changed the surface properties of the polyurethane film and reduced its surface energy. Polyurethane films were found to be stable with IPM concentrations of 1-5 wt% based upon their chemistry; however it leached out in BSA at higher concentrations. Though, low concentrations of IPM reduced both liquid water and water vapour permeability; at higher IPM content liquid OPEN ACCESSPolymers 2010, 2 103 permeability did not improved significantly. In general, the polyurethane materials showed much lower water permeability compared with currently used silicone packaging material for electronic implants. In addition, cytotoxicity assessment of IPM containing polyurethanes showed no evidence of cytotoxcity up to 5 wt% IPM.

Biopolymer Coatings for Biomedical Applications

“…This material can be used for developing medical device coatings and associated applications. In another study, the water resistance and bioactivity of PU were improved by the addition of isopropyl myristate, which modified the hydrophobicity of PU [ 77 ]. The surface properties of PU changed and its surface energy was reduced.…”

Preparation, Physicochemical Properties, and Hemocompatibility of the Composites Based on Biodegradable Poly(Ether-Ester-Urethane) and Phosphorylcholine-Containing Copolymer

“…Protein adsorption: The Bradford protein determining method was used to determine the amount of adsorbed protein onto the film surface when using bovine serum albumin (BSA, Shanghai Aladdin Reagent Co., Ltd., Shanghai, China) [38,39] and human plasma fibrinogen (HPF, Shanghai Macklin Biochemical Co., Ltd., Shanghai, China) [40,41] as model proteins. The film discs (~10 mm diameter) were equilibrated with PBS (pH = 7.4) for ~12 h to achieve complete hydration, and then immersed in a solution of 1.0 mL protein solution (BSA: 45 µg/mL; HPF: 30 µg/mL) for 3 h at the temperature of 37 ± 0.5 °C.…”

A Mild Method for Surface-Grafting PEG Onto Segmented Poly(Ester-Urethane) Film with High Grafting Density for Biomedical Purpose

“…Protein adsorption: Bradford’s protein determining method was used to assay the albumin adsorbed on the film surface with bovine serum albumin (BSA) as the model protein [26,27]. Before measurement, all the film discs (~10 mm in diameter) were aged in phosphate buffer saline (PBS, pH = 7.4) for one day to remove the physically adsorbed impurities and to achieve complete hydration.…”