Mussel-inspired polymeric coatings with the antifouling efficacy controlled by topologies

Construction of Loop Polyzwitterion Brushes on PET Sheets via the Chain-End Closure Strategy To Improve Antifouling and Hemocompatible Properties

Steric stabilization and lubrication give loop polymer brushes enhanced antifouling properties. In the study, linear zwitterionic poly(NMASMCMS) brushes were first constructed on a poly(ethylene terephthalate) (PET) surface through surface-initiated reversible addition-fragmentation chain-transfer (SI-RAFT) polymerization. The tethered linear brushes on sheets were then thiolated with ethanolamine, followed by oxidation to form loop brushes. The chain-end closure strategy to form loop brushes is facile, with a high transformation rate. The physical and chemical structures were characterized by the water contact angle (WCA), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Loop brush grafted sheets (PET-L) exhibited better lubricity than linear brush grafted sheets (PET-B) due to the rigidity of loop brush structures. The two brushes exhibited good antifouling and hemocompatible properties on low protein adsorption, bacteria adhesion, platelet adhesion, and hemolysis. In comparison, loop brushes performed with antifouling properties superior to those of linear brushes.

Comparative Study on the Lubrication Mechanism and Performance of Two Representative Ionic and Nonionic Self-Adhesive Polymer Coatings

Surface modification of lubricating coatings on biomedical devices is a pivotal strategy to improve the overall performance and clinical efficacy, significantly reducing friction between devices and human tissues and mitigating tissue damage during intervention and long-term implantation. Recently, various hydrophilic polymeric materials have been used for achieving surface functionalization, endowing the biomedical device with excellent superlubrication performance. N-Vinylpyrrolidone (NVP) and 2-methacryloyloxyethyl phosphorylcholine (MPC) are two typical representatives of nonionic and zwitterionic materials. However, there is still a research gap in a comparative study of the lubrication mechanisms and properties between them. In this study, a bioinspired and dopamine-assisted codeposition technique was used to fabricate biomimetic hydrophilic coatings, including P(DMA-NVP) and P(DMA-MPC), on polyurethane. To achieve a thorough comparative analysis of the self-adhesive coating performance, 3 M ratios of the copolymers were synthesized and comprehensive material evaluations were conducted. Additionally, surface morphology, hydrophilicity, and lubrication at both the microscale and macroscale were performed. It was found that both hydrophilic coatings exhibited good stability. The P(DMA-MPC) coating, due to the ability to attract and bind a large number of water molecules, demonstrated superior lubrication effects compared to the P(DMA-NVP) coating. The study provides an in-depth understanding of the lubrication behavior of the self-adhesive coatings to enhance the functionality and application in biomedical engineering.

The antifouling mechanism and application of bio-inspired superwetting surfaces with effective antifouling performance

With the rapid development of industries, the issue of pollution on Earth has become increasingly severe. This has led to the deterioration of various surfaces, rendering them ineffective for their intended purposes. Examples of such surfaces include oil rigs, seawater intakes, and more. A variety of functional surface techniques have been created to address these issues, including superwetting surfaces, antifouling coatings, nano-polymer composite materials, etc. They primarily exploit the membrane's surface properties and hydration layer to improve the antifouling property. In recent years, biomimetic superwetting surfaces with non-toxic and environmental characteristics have garnered massive attention, greatly aiding in solving the problem of pollution. In this work, a detailed presentation of antifouling superwetting materials was made, including superhydrophobic surface, superhydrophilic surface, and superhydrophilic/underwater superoleophobic surface, along with the antifouling mechanisms. Then, the applications of the superwetting antifouling materials in antifouling domain were addressed in depth.

Research on topological effect of natural small molecule and high-performance antibacterial air filtration application by electrospinning

The application of natural small molecule (NSM) in electrospun fibers is the key to achieving powerful functionality and sustainable development. However, the lack of understanding regarding the mechanism for loading NSM hinders the advancement of high-performance functional fibers. This work clarified the loading mechanism of NSM in polymer solution by comparing the different behaviors of curcumin (Cur), phloretin (PL), and tea polyphenols (TP) blended ethyl cellulose (EC) solutions. We found that TP may lead to the folding of polymer chains due to its strongest hydrogen bond, which in turn promoted the dispersion of TP along the polymer chain. Therefore, TP could achieve good electrospinnability at the highest loading capacity (16 times the Cur and 4 times the PL). Finally, chitosan was introduced into EC/TP to prepare tree-like nanofibers, achieving high-performance antibacterial air filtration. The filtration efficiency for 0.3 μm NaCl particles, pressure drop, and quality factor were 99.991 %, 85.5 Pa, and 0.1089 Pa-1, respectively. The bacteriostatic rates against Escherichia coli and Staphylococcus aureus were all 99.99 %. This work will promote the application of NSM and the developments of multifunctional electrospun fibers and high-performance air filters.

Glycocalyx-inspired dynamic antifouling surfaces for temporary intravascular devices

Protein and cell adhesion on temporary intravascular devices can lead to thrombosis and tissue embedment, significantly increasing complications and device retrieval difficulties. Here, we propose an endothelial glycocalyx-inspired dynamic antifouling surface strategy for indwelling catheters and retrievable vascular filters to prevent thrombosis and suppress intimal embedment. This strategy is realized on the surfaces of substrates by the intensely dense grafting of hydrolyzable endothelial polysaccharide hyaluronic acid (HA), assisted by an amine-rich phenol-polyamine universal platform. The resultant super-hydrophilic surface exhibits potent antifouling property against proteins and cells. Additionally, the HA hydrolysis induces continuous degradation of the coating, enabling removal of inevitable biofouling on the surface. Moreover, the dense grafting of HA also ensures the medium-term effectiveness of this dynamic antifouling surface. The coated catheters maintain a superior anti-thrombosis capacity in ex vivo blood circulation after 30 days immersion. In the abdominal veins of rats, the coated implants show inhibitory effects on intimal embedment up to 2 months. Overall, we envision that this glycocalyx-inspired dynamic antifouling surface strategy could be a promising surface engineering technology for temporary intravascular devices.

Antifouling polymers for nanomedicine and surfaces: recent advances

Antifouling polymers are materials that can resist nonspecific interactions with cells, proteins, and other biomolecules. Typically, they are hydrophilic polymers with polar or charged moieties that are capable of strong nonbonding interactions with water molecules. This propensity to bind water generates a surface hydration layer that reduces nonspecific interactions with other molecules and is paramount to the antifouling behavior. This property is especially useful for nanoscale applications such as nanomedicine and surface modifications at the molecular level. In nanomedicine, antifouling polymers such as poly(ethylene glycol) and its alternatives play a key role in shielding drug molecules and therapeutic proteins/genes from the immune system within nanoassemblies, thereby enabling effective delivery to target tissues. For coatings, antifouling polymers help to prevent adhesion of cells and molecules to surfaces and are thus valued in marine and biomedical device applications. In this Review, we survey recent advances in antifouling polymers in the context of nanomedicine and coatings, while shining the spotlight on the major polymer classes such as PEG, polyzwitterions, poly(oxazoline)s, and other nonionic hydrophilic polymers.

Anchoring of Polymer Loops on Enzyme-Immobilized Mesoporous ZIF-8 Enhances the Recognition Selectivity of Angiotensin-Converting Enzyme Inhibitory Peptides

Immobilized angiotensin-converting enzyme (ACE) is a promising material for the rapid screening of antihypertensive drugs, but the nonspecific adsorption is a serious problem in separation processes involving complex biological products. In this study, triblock copolymers with dopamine (DA) block as anchors and PEG block as the main body (DA-PEGx-DA) were attached to an immobilized ACE (ACE@mZIF-8/PDA, AmZP) surface via the “grafting to” strategy which endowed them with anti-nonspecific adsorption. The influence of DA-PEGx-DA chain length on nonspecific adsorption was confirmed. The excellent specificity and reusability of the obtained ACE@mZIF-8/PDA/DA-PEG5000-DA (AmZPP5000) was validated by screening two known ACE inhibitory peptides Val-Pro-Pro (VPP, competitive inhibitory peptides of ACE) and Gly-Met-Lys-Cys-Ala-Phe (GF-6, noncompetitive inhibitory peptides of ACE) from a mixture containing active and inactive compounds. These results demonstrate that anchored polymer loops are effective for high-recognition selectivity and AmZPP5000 is a promising compound for the efficient separation of ACE inhibitors in biological samples.