Heparinized Polyurethane Surface Via a One-Step Photografting Method

Research progress of metal biomaterials with potential applications as cardiovascular stents and their surface treatment methods to improve biocompatibility

Facing the growing issue of cardiovascular diseases, metallic materials with higher tensile strength and fatigue resistance play an important role in treating diseases. This review lists the advantages and drawbacks of commonly used medical metallic materials for vascular stents. To avoid post-procedural threats such as thrombosis and in-stent restenosis, surface treatments, and coating methods have been used to further improve the biocompatibility of these materials. Surface treatments including laser, plasma treatment, polishing, oxidization, and fluorination can improve biocompatibility by modifying the surface charges, surface morphology, and surface properties of the material. Coating methods based on polymer coatings, carbon-based coatings, and drug-functional coatings can regulate the surface properties, and also serve as an effective barrier to the interaction of metallic biomaterial surfaces with biomolecules, which can be used to improve corrosion resistance and stability, as well as improve their biocompatibility. Biocompatibility serves as the most fundamental property of cardiovascular stents, and maintaining the excellent and stable biocompatibility of cardiovascular stent surfaces is a current research bottleneck. Few reviews have been published on metallic biomaterials as cardiovascular stents and their surface treatments. For the purpose of advancing research on cardiovascular stents, common metal biomaterials, surface treatment methods, and coating methods to improve biocompatibility and comprehensive properties of the materials are described in this review. Finally, we suggest future directions for stent development, including continuously improving the durability and stability of permanent stents, accelerating the development of biodegradable stents, and strengthening feedback to improve the safety and reliability of cardiovascular stents.

Preparation of phospholipid-based polycarbonate urethanes for potential applications of blood-contacting implants

Polyurethanes are widely used in interventional devices due to the excellent physicochemical property. However, non-specific adhesion and severe inflammatory response of ordinary polyurethanes may lead to severe complications of intravenous devices. Herein, a novel phospholipid-based polycarbonate urethanes (PCUs) were developed via two-step solution polymerization by direct synthesis based on functional raw materials. Furthermore, PCUs were coated on biomedical metal sheets to construct biomimetic anti-fouling surface. The results of stress–strain curves exhibited excellent tensile properties of PCUs films. Differential scanning calorimetry results indicated that the microphase separation of such PCUs polymers could be well regulated by adjusting the formulation of chain extender, leading to different biological response. In vitro blood compatibility tests including bovine serum albumin adsorption, fibrinogen adsorption and denaturation, platelet adhesion and whole-blood experiment showed superior performance in inhibition non-specific adhesion of PCUs samples. Endothelial cells and smooth muscle cells culture tests further revealed a good anti-cell adhesion ability. Finally, animal experiments including ex vivo blood circulation and subcutaneous inflammation animal experiments indicated a strong ability in anti-thrombosis and histocompatibility. These results high light the strong anti-adhesion property of phospholipid-based PCUs films, which may be applied to the blood-contacting implants such as intravenous catheter or antithrombotic surface in the future.

Functional-modified polyurethanes for rendering surfaces antimicrobial: An overview

Antimicrobial surfaces and coatings are rapidly emerging as primary components in functional modification of materials and play an important role in addressing the problems associated with biofouling and microbial infection. Polyurethane (PU) consisting of alternating soft and hard segments has been one of the most important coating materials that have been widely applied in many fields due to its versatile properties. This review attempts to provide insight into the recent advances in antimicrobial polyurethane coatings or surfaces. According to different classes of antimicrobial components along with their antimicrobial mechanism, the synthesis pathways are presented systematically herein to afford polyurethane with antimicrobial properties. Also, the challenges and opportunities of antimicrobial PU coatings and surfaces are also discussed. This review will be beneficial to the exploitation and the further studies of antimicrobial polyurethane materials for a variety of applications.

Recent advances in heparinization of polymeric membranes for enhanced continuous blood purification

Continuous blood purification technology such as hemodiafiltration has been used worldwide for saving patients suffering from severe diseases or organ function failure, especially in the intensive care unit and emergency setting. The filters as core devices are commonly made of polymer materials as hollow fiber membranes. However, the membrane is often inductively blocked by blood clot formation due to its interactions with blood components. Heparin is the anticoagulant often used in clinical practice for anti-coagulation. Recently, heparin is also employed to modify the hollow fiber membranes either chemically or physically to improve the filtration performance. This review summarizes recent advances in methodology for surface heparinization of such hollow fiber membranes, and their filtration performance improvement. The review also provides expert opinions for further research in this rapidly expanding field.