Gradient crystallinity and its influence on the poly(vinylidene fluoride)/poly(methyl methacrylate) membrane‐derived by immersion precipitation method

Evaluation of the Mechanical and Physical Properties of Maxillofacial Silicone Type A-2186 Impregnated with a Hybrid Chitosan-TiO2 Nanocomposite Subjected to Different Accelerated Aging Conditions

The effects of incorporating a pioneer chitosan-TiO2 nanocomposite on the mechanical and physical properties of room-temperature vulcanization (RTV) maxillofacial A-2186 silicone under accelerated aging protocols were rigorously examined. This investigation utilized 450 samples distributed across five distinct silicone classifications and assessed their attributes, such as tensile strength, elongation, tear strength, hardness, and surface roughness, before and after various accelerated aging processes. Statistical methodologies, including a one-way ANOVA, Tukey's HSD, and Dunnett's T3, were employed based on the homogeneity of variance, and several key results were obtained. Silicones infused with 1 wt.% chitosan-TiO2 showed enhanced tensile strength across various aging procedures. Moreover, the 1 wt.% TiO2/Chitosan noncombination (TC) and 2 wt.% TiO2 compositions exhibited pronounced improvements in the elongation percentage. A consistent rise was evident across all silicone categories regarding tear strength, with the 1 wt.% chitosan-TiO2 variant being prominent under certain conditions. Variations in hardness were observed, with the 1 wt.% TC and 3 wt.% chitosan samples showing distinctive responses to certain conditions. Although most samples displayed a decreased surface roughness upon aging, the 1 wt.% chitosan-TiO2 variant frequently countered this trend. This investigation provides insights into the potential of the chitosan-TiO2 nanocomposite to influence silicone properties under aging conditions.

Bio-Inspired Proanthocyanidins from Blueberries’ Surface Coating Prevents Red Blood Cell Agglutination on Urinary Silicon-Based Catheters

Thrombosis can cause the occlusion of implantable medical devices, leading to the rejection of the device and subsequent mortality. Thrombosis is primarily induced by red blood aggregation and coagulation. The administration of anticoagulant drugs is generally used as a treatment to avoid these processes. Adverse effects such as bleeding in the event of an anticoagulant overdose, osteoporosis associated with prolonged use, hypersensitivity, and hives have been reported. New strategies such as biomolecule surface functionalization have recently been studied to overcome these problems. In this study, we report a novel coating composed of polydopamine (PDA) and proanthocyanidins (PACs) from blueberry extract to avoid red blood aggregation in short-term use medical devices such as silicone catheters. We showed that PDA formed stable films on silicone surfaces and PACs could be immobilized on PDA layers using laccase as a catalyst. The PDA–PACs films decreased surface hydrophilicity, increased surface roughness, and decreased plasma protein adsorption. The films were stable in phosphate buffer saline (PBS) and cell culture media. Furthermore, red blood cell adsorption and aggregation decreased. These effects are attributed to changes in the membrane fluidity that influences adhesion, the steric hindrance of the layers, and the low adsorption of plasma proteins on the PAC layer.