Refine
Document Type
- Journal article (3)
Language
- English (3)
Is part of the Bibliography
- yes (3)
Institute
- Life Sciences (3)
A systematic study using a central composite design of experiments (DoE) was performed on the oxygen plasma surface modifications of two different polymers—Pellethane 2363-55DE, which is a polyurethane, and vinyltrimethoxysilane-grafted ethylene-propylene (EPR-g-VTMS), a cross-linked ethylene-propylene rubber. The impacts of four parameters—gas pressure, generator power, treatment duration, and process temperature—were assessed, with static contact angles and calculated surface free energies (SFEs) as the main responses in the DoE. The plasma effects on the surface roughness and chemistry were determined using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Through the sufficiently accurate DoE model evaluation, oxygen gas pressure was established as the most impactful factor, with the surface energy and polarity rising with falling oxygen pressure. Both polymers, though different in composition, exhibited similar modification trends in surface energy rise in the studied system. The SEM images showed a rougher surface topography after low pressure plasma treatments. XPS and subsequent multivariate data analysis of the spectra established that higher oxidized species were formed with plasma treatments at low oxygen pressures of 0.2 mbar.
For medical polymers, their surface condition is an important factor for their biocompatibility in potential applications. The occurrence of antioxidant separation, in form of additive blooming onto the material surface causes changes in the chemical composition, topography, stability and could influence the bioactivity of the medical devices. In this study, the separation of Irganox antioxidant occurring after the spin coating of polyurethane into thin films under 1 µm thickness was examined. The phenomenon was observed with different polymers from the Pellethane series. The extent of the blooming and its aftereffects were evaluated using scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS) and Raman microscopy. The compatibility of Irganox with the polymers was compared on the basis of the Hansen solubility parameter (HSP) concept. Additionally, Raman imaging in combination with basis analysis was established as a viable and fast method for polymer-additive distinction. The surface coverage of the bloomed areas increased with film thickness, and with it, its impact onto the surface chemistry and topography of the thin films. Simple protein coating tests indicated that the bloomed areas slightly impact the ability of fibronectin to form protein netting structures on the surface.
Due to its availability and minimal invasive harvesting human adipose tissue-derived extracellular matrix (dECM) is often used as a biomaterial in various tissue engineering and healthcare applications. Next to dECM, cell-derived ECM (cdECM) can be generated by and isolated from in vitro cultured cells. So far both types of ECM were investigated extensively toward their application as (bio)material in tissue engineering and healthcare. However, a systematic characterization and comparison of soft tissue dECM and cdECM is still missing. In this study, we characterized dECM from human adipose tissue, as well as cdECM from human adipose-derived stem cells, toward their molecular composition, structural characteristics, and biological purity. The dECM was found to exhibit higher levels of collagens and lower levels of sulfated glycosaminoglycans compared with cdECMs. Structural characteristics revealed an immature state of the fibrous part of cdECM samples. By the identified differences, we aim to support researchers in the selection of a suitable ECM-based biomaterial for their specific application and the interpretation of obtained results.
