Facile water-assisted permanent shape reconfiguration of zwitterionic polyurethanes

Biomimicry-inspired zwitterionic polyurethane used for vascular implants showing water-induced stiffening and preventing intimal hyperplasia in stent

Polymeric vascular implants with ideal mechanical properties and biocompatibility are essential for dilating blood vessels and reducing the risk of secondary implant diseases. However, traditional polymer materials are still limited for vascular stents by diminished radial support post-expansion and inadequate surface modification techniques. Herein, we synthesized zwitterionic polyurethanes (ZPUs) featuring hydrophilic side chains derived from betaine sulfonate and full-hard main chains. These ZPUs demonstrate a remarkable increase in modulus during shape recovery in 37 °C warm water, ensuring that the stent remains soft during implantation for easy delivery, but becomes stiff once positioned at the lesion site to provide adequate radial support. The distinctive architecture promotes the migration of hydrophilic side chains to the surface upon hydration, establishing a "core-shell structure" with a hard interior and a highly hydrophilic surface that enhances antithrombotic properties, mitigates inflammation, and curbs intimal hyperplasia. Consequently, ZPUE20 stent showed significantly better blood flow patency than traditional PLA stent in carotid artery implantation for at least 3 months, ensuring the long-term biological safety of implantation. Compared to surface modification of bare stents, ZPU stents avoid the complex and unstable surface modifications. All in all, ZPUs represent a promising material for vascular implants, markedly improving both mechanical performance and biocompatibility.

Functional Zwitterionic Polyurethanes: State-of-the-Art Review

Recent advancements in bioengineering and medical devices have been greatly influenced and dominated by synthetic polymers, particularly polyurethanes (PUs). PUs offer customizable mechanical properties and long-term stability, but their inherent hydrophobic nature poses challenges in practically biological application processes, such as interface high friction, strong protein adsorption, and thrombosis. To address these issues, surface modifications of PUs for generating functionally hydrophilic layers have received widespread attention, but the durability of generated surface functionality is poor due to irreversible mechanical wear or biodegradation. As a result, numerous researchers have investigated bulk modification techniques to incorporate zwitterionic polymers or groups onto the main or side chains of PUs, thereby improving their hydrophilicity and biocompatibility. This comprehensive review presents an extensive overview of notable zwitterionic PUs (ZPUs), including those based on phosphorylcholine, sulfobetaine, and carboxybetaine. The review explores their wide range of biomedical applications, from blood-contacting devices to antibacterial coatings, fouling-resistant marine coatings, separation membranes, lubricated surfaces, and shape memory and self-healing materials. Lastly, the review summarizes the challenges and future prospects of ZPUs in biological applications.

Recent Advances in Stimuli-Responsive Commodity Polymers

Known for their adaptability to surroundings, capability of transport control of molecules, or the ability of converting one type of energy to another as a result of external or internal stimuli, responsive polymers play a significant role in advancing scientific discoveries that may lead to an array of diverge applications. This review outlines recent advances in the developments of selected commodity polymers equipped with stimuli-responsiveness to temperature, pH, ionic strength, enzyme or glucose levels, carbon dioxide, water, redox agents, electromagnetic radiation, or electric and magnetic fields. Utilized diverse applications ranging from drug delivery to biosensing, dynamic structural components to color-changing coatings, this review focuses on commodity acrylics, epoxies, esters, carbonates, urethanes, and siloxane-based polymers containing responsive elements built into their architecture. In the context of stimuli-responsive chemistries, current technological advances as well as a critical outline of future opportunities and applications are also tackled.

The synthesis of polyurethane with mechanical properties that are responsive to water retention states

Water-retention-state-responsive polyurethane was designed and synthesized via introducing zwitterionic sulfobetaine onto its polymer chains.

A comprehensive review of the structures and properties of ionic polymeric materials

This review focuses on the mechanistic approach, the structure–property relationship and applications of ionic polymeric materials.