Biofouling is a great challenge for engineering material in medical-, marine-, and pharmaceutical-related applications. In this study, a novel trimethylamine N-oxide (TMAO)-analog monomer, 3-(2-methylacrylamido)-N,N-dimethylpropylamine N-oxide (MADMPAO), was synthesized and applied for the grafting of poly(MADMPAO) (pMPAO) brushes on quartz crystal microbalance (QCM) chips by the combination of bio-inspired poly-dopamine (pDA) and surface-initiated atom transfer radical polymerization technology. The result of ion adsorption exhibited that a sequential pDA and pMPAO arrangement from the chip surface had different characteristics from a simple pDA layer. Ion adsorption on pMPAO-grafted chips was greatly inhibited at low salt concentrations of 1 and 10 mmol/L due to strong surface hydration in the presence of charged N+ and O- of zwitterionic pMPAO brushes on the outer layer on the chip surface, well known as the \"anti-polyelectrolyte\" effect. During BSA adsorption, pMPAO grafting also led to a marked decrease in frequency shift, indicating great inhibition of protein adsorption. It was attributed to weaker BSA-pMPAO interaction. In this study, the Au@pDA-4-pMPAO chip with the highest coating concentration of DA kept stable dissipation in BSA adsorption, signifying that the chip had a good antifouling property. The research provided a novel monomer for zwitterionic polymer and demonstrated the potential of pMPAO brushes in the development and modification of antifouling materials.

Alginate (Alg) coatings have attracted attention as protective layers on solid surfaces for marine antifouling applications due to their strong water binding capability and environmentally friendly characteristics. However, the effectiveness of Alg coatings in preventing marine fouling diminishes upon interaction with divalent cations present in seawater. To address this issue, post-modification of the Alg coating is conducted. The carboxyl groups of Alg, which are susceptible sites for interaction with divalent cations, are conjugated with polymerization initiators through metal-mediated coordination bond formation. Subsequently, poly(sulfobetaine methacrylate) (poly(SBMA)) brushes are grown from the initiator-immobilized Alg coatings, resulting in the formation of multilayered Alg/poly(SBMA) coatings. In marine diatom adhesion assays using Amphora Coffeaeformis, multilayered Alg/poly(SBMA) coatings exhibited superior antifouling performance compared to single-layered Alg or poly(SBMA) coating controls.

OBJECTIVE: To evaluate the mechanical and biological properties of three-dimensionally (3D) printable resins filled with 2-methacryloyloxyethyl phosphorylcholine (MPC) and silicate-based composites and compare with those of a commercially available 3D-printable resin for definitive restorations.
METHODS: A group of 3D-printable hybrid resins (HRs) filled with 6 wt% MPC and three different compositions of silicate-based composites (barium silicate to zirconium silicate ratios: 1.50:1 for HR1, 0.67:1 for HR2, and 0.25:1 for HR3) were prepared. The HR groups were compared with the commercially available unfilled 3D-printable resin (CR) marketed for definitive restorations in terms of flexural strength and modulus, fracture toughness, surface roughness, Vickers hardness, light transmittance (all, n = 15), cytotoxicity, and protein adsorption (both, n = 3). All data were analyzed by using non-parametric Kruskal-Wallis and Dunn\'s tests (α=0.05).
RESULTS: The HR groups had significantly higher flexural strength, modulus, fracture toughness, and hardness values than the CR (P < 0.001). HR3 had the highest surface roughness and light transmittance among the groups (P ≤ 0.006). None of tested resins showed cytotoxicity. Both HR2 and HR3 showed significantly lower protein adsorption than the CR, with a difference of approximately 60% (P ≤ 0.026).
CONCLUSIONS: Both HR2 and HR3 exhibited superior mechanical properties (flexural strength, flexural modulus, fracture toughness, and Vickers hardness), light transmittance, and protein-repellent activity than the CR, with no impact on cytotoxicity.
CONCLUSIONS: The MPC/silicate-based composite-filled resins may be a suitable alternative for definitive restorations, given their higher mechanical properties and promising biological properties to prevent microbial adhesion and subsequent biofilm formation, as well as their non-cytotoxic properties.

Thermoresponsive sol-gel transition polymers are of significant interest because of their fascinating biomedical applications, including as drug reservoirs for drug delivery systems and scaffolds for tissue engineering. Although extensive research has been conducted on lower critical solution temperature (LCST)-type sol-gel transition polymers, there have been few reports on upper critical solution temperature (UCST)-type sol-gel transition polymers. In this study, we designed an ABA-type triblock copolymer composed of a poly(ethylene glycol) (PEG) block and zwitterionic polymer blocks that exhibit UCST-type thermoresponsive phase transitions. A sulfobetaine (SB) monomer with both ammonium and sulfonate (-SO3) groups in its side chain or a sulfabetaine (SaB) monomer with both ammonium and sulfate (-OSO3) groups in its side chain was polymerized from both ends of the PEG block via reversible addition-fragmentation chain-transfer (RAFT) polymerization to obtain PSB-PEG-PSB and PSaB-PEG-PSaB triblock copolymers, respectively. Although an aqueous solution containing the PSB-PEG-PSB triblock copolymer showed an increase in viscosity upon cooling, it did not undergo a sol-to-gel transition. In contrast, a sol-to-gel transition was observed when a phosphate-buffered saline containing PSaB-PEG-PSaB was cooled from 80 °C to 25 °C. The PSaB blocks with -OSO3 groups exhibited a stronger dipole-dipole interaction than conventional SB with -SO3 groups, leading to intermolecular association and the formation of a gel network composed of PSaB assemblies bridged with PEG. The fascinating UCST-type thermoresponsive sol-gel transition properties of the PSaB-PEG-PSaB triblock copolymer suggest that it can provide a useful platform for designing smart biomaterials, such as drug delivery reservoirs and cell culture scaffolds.

Biofouling is a serious issue affecting the marine industry because the attached micro- and macrocontaminants can increase fuel consumption and damage ship hulls. A hydrophilic hydrogel-based coating is considered a promising antifouling material because it is environmentally friendly and the dense hydration layer can protect the substrate from microbial attachment. However, sediment adsorption can be an issue for hydrogel-based coatings. Their natural soft and porous structures can trap sediment from the marine environment and weaken the antifouling capability. There is still little research on the antisediment properties of hydrogels, and none of them deal with this problem. Here, we report on optimizing zwitterionic hydrogel-based coatings to improve their antisediment properties and achieve comparable performance to commercial biocidal coatings, which are the gold standard in the antifouling coating area. After 1 week of sediment contamination and 2 weeks of diatom coculturing, this optimized zwitterionic hydrogel coating maintained its antifouling properties with a few diatoms on the surface. Its large-scale samples also achieved antifouling performance similar to that of biocidal coatings in the Atlantic Ocean for 1.5 months. More importantly, our research provides a universal strategy to improve the antisediment properties of soft hydrogel-based coatings. For the first time, we report that the introduction of interfacial electrostatic interactions enhanced the antisediment properties of hydrogels.

Zwitterionic polymers possess equal total positive and negative charges in the repeating units, making them electrically neutral overall. This unique property results in superhydrophilicity, which makes the zwitterionic polymers highly effective in resisting protein adsorption, thus endowing the drug carriers with long blood circulation time, inhibiting thrombus formation on biomedical devices in contact with blood, and ensuring the good sensitivity of sensors in biomedical application. Moreover, zwitterionic polymers have tumor-targeting ability and pH-responsiveness, rendering them ideal candidates for antitumor drug delivery. Additionally, the high ionic conductivity of zwitterionic polymers makes them an important raw material for ionic skin. Zwitterionic polymers exhibit remarkable resistance to bacterial adsorption and growth, proving their suitability in a wide range of biomedical applications such as ophthalmic applications, and wound dressings. In this paper, we provide an in-depth analysis of the different structures and characteristics of zwitterionic polymers and highlight their unique qualities and suitability for biomedical applications. Furthermore, we discuss the limitations and challenges that must be overcome to realize the full potential of zwitterionic polymers and present an optimistic perspective for zwitterionic polymers in the biomedical fields. STATEMENT OF SIGNIFICANCE: Zwitterionic polymers have a series of excellent properties such as super hydrophilicity, anti-protein adsorption, antibacterial ability and good ionic conductivity. However, biomedical applications of multifunctional zwitterionic polymers are still a major field to be explored. This review focuses on the design and application of zwitterionic polymers-based nanosystems for targeted and responsive delivery of antitumor drugs and cancer diagnostic agents. Moreover, the use of zwitterionic polymers in various biomedical applications such as biomedical devices in contact with blood, biosensors, ionic skin, ophthalmic applications and wound dressings is comprehensively described. We discuss current results and future challenges for a better understanding of multifunctional zwitterionic polymers for biomedical applications.

Constructing antifouling surfaces is a crucial technique for optimizing the performance of devices such as water treatment membranes and medical devices in practical environments. These surfaces are achieved by modification with hydrophilic polymers. Notably, zwitterionic (ZI) polymers have attracted considerable interest because of their ability to form a robust hydration layer and inhibit the adsorption of foulants. However, the importance of the molecular weight and density of the ZI polymer on the antifouling property is partially understood, and the surface design still retains an empirical flavor. Herein, we individually assessed the influence of the molecular weight and density of the ZI polymer on protein adsorption through machine learning. The results corroborated that protein adsorption is more strongly influenced by density than by molecular weight. Furthermore, the distribution of predicted protein adsorption against molecular weight and polymer density enabled us to determine conditions that enhanced (or weaken) antifouling. The relevance of this prediction method was also demonstrated by estimating the protein adsorption over a wide range of ionic strengths. Overall, this machine-learning-based approach is expected to contribute as a tool for the optimized functionalization of materials, extending beyond the applications of ZI polymer brushes.

Ferroptosis inhibits tumor growth by iron-dependently accumulating lipid peroxides (LPO) to a lethal extent, which can result from iron overload and glutathione peroxidase 4 (GPX4) inactivation. In this study, we developed biodegradable zwitterionic polymer-cloaked atorvastatin (ATV)-loaded ferric metal-organic frameworks (Fe-MOFs) for cancer treatment. Fe-MOFs served as nanoplatforms to co-deliver ferrous ions and ATV to cancer cells; the zwitterionic polymer membrane extended the circulation time of the nanoparticles and increased their accumulation at tumor sites. In cancer cells, the structure of the Fe-MOFs collapsed in the presence of glutathione (GSH), leading to the depletion of GSH and the release of ATV and Fe2+. The released ATV decreased mevalonate biosynthesis and GSH, resulting in GPX4 attenuation. A large number of reactive oxygen species were generated by the Fe2+-triggered Fenton reaction. This synergistic effect ultimately contributed to a lethal accumulation of LPO, causing cancer cell death. The findings both in vitro and in vivo suggested that this ferroptosis-inducing nanoplatform exhibited enhanced anticancer efficacy and preferable biocompatibility, which could provide a feasible strategy for anticancer therapy.

The fouling of separation membranes has consistently been a primary factor contributing to the decline in membrane performance. Enhancing the surface hydrophilicity of the membrane proves to be an effective strategy in mitigating membrane fouling in water treatment processes. Zwitterionic polymers (containing an equimolar number of homogeneously distributed anionic and cationic groups on the polymer chains) have been used extensively as one of the best antifouling materials for surface modification. The conventional application of zwitterionic compounds as surface modifiers is intricate and inefficient, adding complexity and length to the membrane preparation process, particularly on an industrial scale. To overcome these limitations, zwitterionic polymer, directly used as a main material, is an effective method. In this work, a novel zwitterionic polymer (TB)-zwitterionic Tröger\'s base (ZTB)-was synthesized by quaternizing Tröger\'s base (TB) with 1,3-propane sultone. The obtained ZTB is blended with TB to fabricate microfiltration (MF) membranes via the vapor-induced phase separation (VIPS) process, offering a strategic solution for separating emulsified oily wastewater. Atomic force microscopy (AFM), scanning electron microscopy (SEM), water contact angle, and zeta potential measurements were employed to characterize the surface of ZTB/TB blended membranes, assessing surface morphology, charge, and hydrophilic/hydrophobic properties. The impact of varying ZTB levels on membrane surface morphology, hydrophilicity, water flux, and rejection were investigated. The results showed that an increase in ZTB content improved hydrophilicity and surface roughness, consequently enhancing water permeability. Due to the attraction of water vapor, the enrichment of zwitterionic segments was enriched, and a stable hydration layer was formed on the membrane surface. The hydration layer formed by zwitterions endowed the membrane with good antifouling properties. The proposed mechanism elucidates the membrane\'s proficiency in demulsification and the reduction in irreversible fouling through the synergistic regulation of surface charge and hydrophilicity, facilitated by electrostatic repulsion and the formation of a hydration layer. The ZTB/TB blended membranes demonstrated superior efficiency in oil-water separation, achieving a maximum flux of 1897.63 LMH bar-1 and an oil rejection rate as high as 99% in the oil-water emulsion separation process. This study reveals the migration behavior of the zwitterionic polymer in the membrane during the VIPS process. It enhances our comprehension of the antifouling mechanism of zwitterionic membranes and provides guidance for designing novel materials for antifouling membranes.

Amid growing interest in using body heat for electricity in wearables, creating stretchable devices poses a major challenge. Herein, a hydrogel composed of two core constituents, namely the negatively-charged 2-acrylamido-2-methylpropanesulfonic acid and the zwitterionic (ZI) sulfobetaine acrylamide, is engineered into a double-network hydrogel. This results in a significant enhancement in mechanical properties, with tensile stress and strain of up to 470.3 kPa and 106.6%, respectively. Moreover, the ZI nature of the polymer enables the fabrication of a device with polar thermoelectric properties by modulating the pH. Thus, the ionic Seebeck coefficient (Si) of the ZI hydrogel ranges from -32.6 to 31.7 mV K-1 as the pH is varied from 1 to 14, giving substantial figure of merit (ZTi) values of 3.8 and 3.6, respectively. Moreover, a prototype stretchable ionic thermoelectric supercapacitor incorporating the ZI hydrogel exhibits notable power densities of 1.8 and 0.9 mW m-2 at pH 1 and 14, respectively. Thus, the present work paves the way for the utilization of pH-sensitive, stretchable ZI hydrogels for thermoelectric applications, with a specific focus on harvesting low-grade waste heat within the temperature range of 25-40 °C.