Sustainable Coating Based on Zwitterionic Functionalized Polyurushiol with Antifouling and Antibacterial Properties

Zwitterionic polymer coatings facilitate the formation of hydration layers via electrostatic interactions on their surfaces and have demonstrated efficacy in preventing biofouling. They have emerged as a promising class of marine antifouling materials. However, designing multifunctional, environmentally friendly, and natural products-derived zwitterionic polymer coatings that simultaneously resist biofouling, inhibit protein adhesion, exhibit strong antibacterial properties, and reduce algal adhesion is a significant challenge. This study employed two diisocyanates as crosslinkers and natural urushiol and ethanolamine as raw materials. The coupling reaction of diisocyanates with hydroxyl groups was employed to synthesize urushiol-based precursors. Subsequently, sulfobetaine moieties were introduced into the urushiol-based precursors, developing two environmentally friendly and high-performance zwitterionic-functionalized polyurushiol antifouling coatings, denoted as HUDM-SB and IPUDM-SB. The sulfobetaine-functionalized polyurushiol coating exhibited significantly enhanced hydrophilicity, with the static water contact angle reduced to less than 60°, and demonstrated excellent resistance to protein adhesion. IPUDM-SB exhibited antibacterial efficacy up to 99.9% against common Gram-negative bacteria (E. coli and V. alginolyticus) and Gram-positive bacteria (S. aureus and Bacillus. sp.). HUDM-SB achieved antibacterial efficacy exceeding 95.0% against four bacterial species. Furthermore, the sulfobetaine moieties on the surfaces of the IPUDM-SB and HUDM-SB coatings effectively inhibited the growth and reproduction of algal cells by preventing microalgae adhesion. This zwitterionic-functionalized polyurushiol coating does not contain antifouling agents, making it a green, environmentally friendly, and high-performance biomaterial-based solution for marine antifouling.

Ultrasensitive Ratiometric Electrochemiluminescence Sensor with an Efficient Antifouling and Antibacterial Interface of PSBMA@SiO2-MXene for Oxytetracycline Trace Detection in the Marine Environment

The sensitivity and accuracy of electrochemiluminescence (ECL) sensors for detecting small-molecule pollutants in environmental water are affected not only by nonspecific adsorption of proteins and other molecules but also by bacterial interference. Therefore, there is an urgent need to develop an ECL sensor with antifouling and antibacterial functions for water environment monitoring. Herein, a highly efficient antifouling sensing interface (PSBMA@SiO2-MXene) based on zwitterionic sulfobetaine methacrylate (SBMA) antifouling nanospheres (NPs) and two-dimensional MXene nanosheets was designed for the sensitive detection of oxytetracycline (OTC), an antibiotic small-molecule pollutant. Specifically, SBMA with good hydrophilicity and electrical neutrality was connected to SiO2 NPs, thus effectively reducing protein and bacterial adsorption and improving stability. Second, MXene with a high specific surface area was selected as the carrier to load more antifouling NPs, which greatly improves the antifouling performance. Meanwhile, the introduction of MXene also enhances the conductivity of the antifouling interface. In addition, a ratio-based sensing strategy was designed to further improve the detection accuracy and sensitivity of the sensor by utilizing Au@luminol as an internal standard factor. Based on antifouling and antibacterial interfaces, as well as internal standard and ratiometric sensing strategies, the detection range of the proposed sensor was 0.1 ng/mL to 100 μg/mL, with a detection limit of 0.023 ng/mL, achieving trace dynamic monitoring of antibiotics in complex aqueous media.

Bioinspired antifouling Fe-based amorphous coating via killing-resisting dual surface modifications

Fe-based amorphous coatings with outstanding corrosion resistance are promise for marine applications. However, these coatings encounter a great challenge of biofouling in marine environments. Inspired by the unique micro-nano hierarchical structure of shark skin with excellent antifouling properties, in this paper, we construct a bioinspired Fe-based amorphous coating with killing-resisting dual-effect via proper surface modifications, i.e., the modification with micro-patterned nanostructured Cu₂O fibers (killing effect), followed by the modification with superhydrophobic surface (resisting effect). As a result, the modified amorphous coating exhibits impressive antifouling properties, achieving 98.6% resistance to Nitzschia closterium f. minutissima, 87% resistance to Bovine serum albumin protein and 99.8% resistance to Pseudomonas aeruginosa, respectively. The remarkable antifouling performance is attributed to a synergistic antifouling mechanism from both resisting effect and killing effect, wherein the superhydrophobic surface provides a barrier to resist protein adsorption, while the patterned nanostructured Cu₂O fibers supply Cu⁺ ions to kill bacterial cells. In addition, the modified amorphous coating also exhibits excellent mechanical robustness, which ensures the durability of the Fe-based amorphous coating in practical services. This work may promote the development of new durable metal-based coatings integrated with anti-fouling and anti-corrosion properties.

Synthesis and performance evaluation of 5-fluorouracil-loaded zwitterionic poly(4-vinylpyridine) nanoparticles

After polymerizing 4-vinylpyridine, the obtained polymer was converted into zwitterionic nanoparticles containing 5-fluorouracil. Their potential for long-term blood circulation was investigated by in vitro and in vivo experiments.

One pot synthesis of zwitteronic 99mTc doped ultrasmall iron oxide nanoparticles for SPECT/T1-weighted MR dual-modality tumor imaging

In this study, we have synthesized ^99mTc intrinsically labeled ultrasmall magnetic iron oxide nanoparticles with zwitterionic surface coating (^99mTc-ZW-USIONPs) via one pot synthesis using sulfobetains functionalized poly (acrylic acid) as stabilizer and Na^99mTcO₄ and SnCl₂ as additives. The commercialization of single photon emission computed tomography (SPECT)/magnetic resonance imaging (MRI) scanner made the combination use of ^99mTc and iron oxide nanoparticles attracting much attention. Direct doping radioisotope into nanoparticles has the advantages of excellent radiochemical stability and no restriction on the surface functionalization. The complex Technetium chemistry made it challenging to direct dope ^99mTc into IONPs, especially those ultrasmall ones without precipitation. We proved that it is possible to prepare ^99mTc doped USIONPs with excellent water solubility and favorable T1 signal by controlling the radioactivity and reducing agent amount. With no need of chelator, the zwitterionic surface resists the protein corona formation, resulting in a reduced RES uptake and higher tumor contrast. The ^99mTc-ZW-USIONPs demonstrated excellent performance of tumor SPECT and T1-weighted MR imaging capability in 4T1 tumor bearing mice. Together with their ease of preparation and superior biocompatibility, we believe these ^99mTc-ZW-USIONPs represent a type of promising dual contrast agent for SPECT/T1 MRI.

Hydrophilic polymer-based anti-biofouling coatings: Preparation, mechanism, and durability

Anti-biofouling materials that combat microorganism attachment have been intensively studied due to the ever-growing demand on smart and durable coatings. Although various hydrophilic polymer surfaces demonstrated superior anti-biofouling properties, their practical application was hampered by the undesired mechanical vulnerability and complicated fabrication process. In this review, we summarized the mechanically and chemically robust anti-biofouling coatings into six strategies namely (i) 3D-grafted coatings, (ii) hierarchical spheres-based coatings, (iii) inorganic nanomaterials-reinforced coatings, (iv) hydrolysis-based coating, (v) semi-interpenetrating structure-based coatings, and (vi) layer-by-layer (LbL) assembled coatings. The anti-biofouling efficacy and durability of these coatings over a series of challenges were also comprehensively presented. The purpose of this review is to inspire researchers to develop novel anti-biofouling coatings for future practical applications.