Zwitterionic Copolymer Research Articles

Fabrication of novel zwitterionic copolymer high performance membrane applied for oil/water mixtures and emulsions separation

The separation of oily wastewater is important for the ecological environment. Due to all kinds of defects in traditional methods, membrane technology shows outstanding merit for separating oil contaminants from water. In this work, a novel zwitterionic monomer 2-(3-carboxyacryloyloxy)-N-(Carboxyethyl)-N, N-dimethyl ethanaminium (DMAAA) was synthesized and characterized. Then, a novel zwitterionic copolymer, poly(2-(3-carboxyacryloyloxy)-N-(Carboxyethyl)-N, N-dimethyl ethanaminium-co-2-hydroxyethyl acrylate) (P(DMAAA-co-HEA)) was prepared by free radical polymerization. The superhydrophilic and underwater-superoleophobic membranes were prepared using stainless steel mesh (SSM) with different pore sizes as substrate, P(DMAAA-co-HEA) as superhydrophilic component, nano-silica (SiO2) as micro-nano porous structure, and tetraethyl orthosilicate (TEOS) as cross-linking agent by the one-step dip-coating method. P(DMAAA-co-HEA)-TEOS-SiO2 coated 400 mesh SSM(PTS-SSM400) exhibits ultra-high separation flux (243,600 L·m−2·h−1) and separation efficiency (>99.88%) in separating oil/water mixtures. And the coated 2000 mesh SSM (PTS-SSM2000) can separate various surfactant-stabilized emulsions with high water flux and efficiency only under gravity. Moreover, the membranes have excellent chemical stability and wear resistance. Even having been successively immersed for seven days in acidic, alkaline, and saline environments, respectively, and after 50 wear resistance cycle tests, the coated membranes can still effectively separate oil/water mixtures. The simple and facile preparation method is especially suitable for large-scale practical industrial applications.

Phase Behavior of Double Zwitterionic Block Copolymers in Water: Morphology Transition through Concentration Dependent Selectivity of Water Partitioning

AbstractPhase behavior of double zwitterionic diblock copolymers composed of a poly(carboxybetaine methacrylate) (PCB2) and a poly(sulfobetaine methacrylate) (PSB4) (PCB2n‐b‐PSB4m) has been mapped out in aqueous solutions. Phase diagrams are constructed with polymer concentration, ϕ, ranging from 0.08 to 0.80 and PSB4 volume fraction in the PCB2n‐b‐PSB4ms, fPSB4, ranging from 0.23 to 0.93 at 25 °C. PCB2n‐b‐PSB4m aqueous solutions show symmetric phase diagram above ϕ = 0.55, indicating that water is nearly neutral with respect to PCB2 and PSB4. The morphology transforms from columnar with PCB2 cylinders to lamellar to columnar with PSB4 cylinders with decreasing ϕ, and the phase boundaries exhibit a negative slope below ϕ = 0.45. The morphology transition is rationalized in terms of interfacial curvature modulation through the volume expansion of the PCB2 phase due to the selective water partitioning. The lyotropic mesophase of double hydrophilic block copolymers is a unique molecular compartment for hydrophilic molecules with low interfacial tension.

Surface modification of commercial intraocular lens by zwitterionic and antibiotic-loaded coating for preventing postoperative endophthalmitis

After cataract surgery, to prevent possible postoperative endophthalmitis (POE) caused by attached pathogenic bacteria onto the surface of implanted intraocular lens (IOL), various antibiotic-loaded IOLs have been proposed and widely studied to inhibit bacterial infection. However, most of these developed antibiotic-loaded IOLs still suffer from shortcomings such as insufficient drug loading, short release time, poor biocompatibility, and risk of secondary infection. Herein, we propose a zwitterionic and high-drug loading coating for surface modification of commercial hydrophobic IOL with both antifouling and antibacterial properties to effectively prevent POE. In this strategy, zwitterionic poly(carboxylbetaine-co-dopamine methacrylamide) copolymers (pCBDA) and dopamine (DA) were first robustly co-deposited onto IOL surface via facile mussel-inspired chemistry, resulting in a hydrophilic coating (defined as PCB) without sacrificing the high light transmittance of the native IOL. Subsequently, amikacin (AMK), an amine-rich antibiotic was reversibly conjugated onto the coating through the acid-sensitive Schiff base bonds formed by the reaction between amino and catechol groups, with high-drug payload over ∼35.5 μg per IOL and 30 days of sustained drug release under weak acid environment. Benefiting from the antifouling property of zwitterionic pCBDA copolymers, the intraocularly implanted PCB/AMK-coated IOL could effectively resist the adhesion and proliferation of residual LECs to inhibit the development of posterior capsule opacification (PCO) without affecting the normal ocular tissues, demonstrating excellent in vivo biocompatibility. Moreover, the synergy of zwitterionic pCBDA and conjugated AMK with acidic-dependent release behavior endowed this PCB/AMK-coated IOL strong antibacterial activity against both in vitro biofilm formation and in vivo postoperative Staphylococcus aureus infection, suggesting its promising application in preventing POE.

A zwitterionic copolymer as fluid loss reducer for water-based drilling fluids in high temperature and high salinity conditions

With the exploration and development of deep and ultra-deep oil/gas resources, higher challenges have been placed on the performance of water-based drilling fluids (WBDFs). Integrating synergistic characteristics such as excellent high temperature- and salt-resistance, rheology, and fluid loss control capabilities is still a massive challenge for water-based drilling fluid loss reducers. Herein, an innovative temperature- and salt-resistant zwitterionic copolymer filtration reducer was synthesized using N, N-dimethyl acrylamide, 1-(2-carboxyethyl)-3-vinyl imidazolium chloride, sulfobetaine vinyl imidazole through free radical copolymerization. Due to the excellent rigid cationic imidazole ring and salt-resistant hydration groups in the copolymer, the copolymer can be efficiently adsorbed on the surface of bentonite particles through strong electrostatic force and hydrogen bonds, thus maintaining the excellent hydration and dispersibility of bentonite particles. Even after aging at high temperatures (up to 200 °C) and high salinity (saturated salt) conditions, the DCS-based drilling fluids still exhibit excellent rheological and filtration properties (FLAPI < 10 mL), showing the potential for application in deep and ultra-deep drilling operations.

Synthesis and thermomechanical characteristics of zwitterionic poly(arylene ether sulfone) copolymers

Charge-containing polymeric materials have been widely studied for a range of applications. The fundamental relationships between the charge species, charge density, and the microscale morphology of charge-containing polymers are critical for defining the application in which they may be used. In this work, a series of thermoplastic poly(arylene ether sulfone) (PAES) copolymers with controllable sulfobetaine charge contents (0–100 mol%) and high molecular weights (Mw ∼ 65 kDa) were prepared. All the zwitterionic PAESs synthesized showed thermal stability up to 250 °C. DSC and tensile tests showed a decreased Tg and mechanical strength with the incorporation of increasing charge density, which suggests a plasticization effect by the charged group. Electron microscopy and X-ray scattering data confirmed the absence of microphase separation in the ion-containing random copolymer system, which corroborated with the observation of a single Tg for all zwitterionic copolymers studied. Furthermore, the relative hydrophilicity of the samples was evaluated by water uptake measurements, which revealed that the water uptake of the zwitterionic PAESs can reach up to 64% for the 72 mol% zwitterion copolymer while the free-standing film in the wet state still maintains a Young's modulus of 185 MPa. The thermoplastic charge-containing copolymers in this work demonstrated potential for applications such as coatings or water purification membranes, in which balancing hydrophilicity, processibility, and thermomechanical performance are important.

On the assembly of zwitterionic block copolymers with phospholipids

Materials containing zwitterionic polymers are interesting candidates for diverse applications due to their versatile properties. The assembly of the amphiphilic block copolymer poly(cholesteryl methacrylate)-block-poly(2-methacryloyloxyethyl phosphorylcholine) with three different phospholipids (1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE)) into small and giant vesicles is reported focusing on their morphology, size, and membrane properties. Giant hybrid vesicles were obtained for all types of lipids, but DOPC was more suitable to assemble small hybrid vesicles without a large fraction of hybrid micelles present. Further, the permeability of the small vesicle membranes towards 5(6)-carboxyfluorescein is very similar to comparable sized liposomes. In contrast, the permeability of the giant hybrid vesicle membranes towards 5(6)-carboxy-X-rhodamine is higher compared to only cholesterol-containing lipid giant vesicles. DOPS-containing vesicles showed pH-dependent morphology changes. Hybrid vesicles containing DOPS and DOPE in addition to the block copolymer have the highest association with HepG2 cells. In contrast, only DOPC-containing hybrid vesicles can be incorporated into alginate beads. Taken together, using these block copolymer with a zwitterionic hydrophilic extension of the chosen architecture offers fundamental insight into the possibility to assemble hybrid vesicles and their potential in bottom-up synthetic biology.

Synthesis of zwitterionic copolymer containing sulfobetaine and catechol for antibacterial application

• A catechol zwitterionic copolymer was handily prepared by PET-RAFT polymerization. • Polymer grafted surfaces were readily fabricated via solution deposition method. • Incorporation of catechol rendered copolymer excellent antibacterial potency. Catechol-modified zwitterionic polymers have been successfully applied for functional modification of surfaces. However, catechol derivatives synthesized by atom transfer radical polymerization (ATRP) involve complicated procedures and harsh conditions. In this study, a random copolymer P(SBMA- co -DA) (PSD) was prepared from sulfobetaine methacrylate (SBMA) and N-3,4-dihydroxybenzenethyl methacrylamide (DA) by photo-induced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization technique. Staphylococcus aureus adhesion assay showed that PSD possessed similarly powerful antibacterial performance at high concentration as compared to dopamine-modified poloxamer 407, while PSBMA (PSB) exhibited no obvious antibacterial potency. We believe that the facile method will be beneficial to synthesis of catechol-containing polymers for different applications.

ZwitterCo raises cash for water membranes

ZwitterCo has raised $33 million to continue development and production of membranes that clean wastewater. The company says its membranes are built with zwitterionic copolymers—molecules that have both negatively and positively charged groups—and that they maintain their performance even after repeated cleanings. The copolymers form channels that let water pass through but that repel oils, greases, and proteins. ZwitterCo has pilot projects treating wastewater from farms and food makers.

Zwitterionic Polymers toward the Development of Orientation-Sensitive Bioprobes

Dynamics with an orientational degree of freedom are fundamental in biological events. Probes with polarized luminescence enable a determination of the orientation. Lanthanide-doped nanocrystals can provide more precise analysis than quantum dots due to the nonphotoblinking/bleaching nature and the multiple line-shaped emission. However, the intrinsic polarization property of the original nanocrystals often deteriorates in complex physiological environments because the colloidal stability easily breaks and the probes aggregate in the media with abundant salts and macromolecules. Engineering the surface chemistry of the probes is thus essential to be compatible with biosystems, which has remained a challenging task that should be exclusively addressed for each specific probe. Here, we demonstrate a facile and efficient surface functionalization of lanthanide-doped nanorods by zwitterionic block copolymers. Due to the steric interaction and the intrinsic zwitterionic nature of the polymers, high colloidal stability of the zwitterionic nanorod suspension is achieved over wide ranges of pH and concentration of salts, even giving rise to the lyotropic liquid crystalline behavior of the nanorods in physiological media. The shear-aligned ability is shown to be unaltered by the coated polymers, and thus, the strongly polarized emission of Eu3+ is preserved. Besides, biological experiments reveal good biocompatibility of the zwitterionic nanorods with negligible nonspecific binding. This study is a stepping stone for the use of the nanorods as orientation probes in biofluids and validates the strategy of coupling zwitterions to lanthanide-doped nanocrystals for various bioapplications.

Synthesis of a new high temperature and salt resistant zwitterionic filtrate reducer and its application in water-based drilling fluid

To overcome the negative effects of high temperature and salt pollution on the performance of drilling fluid in deep and ultra-deep wells, it is imperative to develop a high- temperature-and salt-resistant filtrate reducer. A zwitterionic quaternary copolymer (DADN) of N, N-dimethylacrylamide (DMAA), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), diallyl dimethyl ammonium chloride (DMDAAC), and N-vinylcaprolactam (NVCL) was synthesized in an aqueous solution by free radical copolymerization reaction. The composition, structure, and thermal stability of the copolymers were characterized by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), Gel Permeation Chromatography (GPC), elemental analysis and thermogravimetric analysis (TGA), respectively. Furthermore, the filtration loss reduction performance of DADN was evaluated according to the American Petroleum Institute (API) standard. The mechanisms of filtrate loss reduction and salt resistance were revealed based on the transmission electron microscopy (TEM) analysis, adsorption isotherm and zeta potential analysis for the water-based drilling fluid (WBDF) containing DADN, and the scanning electron microscopy (SEM) analysis, energy-dispersive spectrometry (EDS) analysis and Brunner–Emmet–Teller (BET) analysis for the corresponding filter cake. The results showed that the thermal decomposition of DADN mainly happened over 298 ℃. Meanwhile, DADN exhibited the most outstanding filtration loss reduction ability compared to three commercially filtrate reducers (Driscal D, CMC and PAC-Lv). Specifically, the filtration losses of Driscal D/WBDF, CMC/WBDF and PAC-Lv/WBDF were 18.2, 31.2 and 24.8 mL after hot rolling at 220 °C for 16 h, respectively, while the filtration loss of DADN was only 6.5 mL. It was found that 2% DADN showed excellent filtration loss reduction ability at 220 °C and 15% NaCl. As confirmed by the SEM, EDS and adsorption isotherm results, strong adsorption of DADN on bentonite was obtained even under a high temperature and high-salinity environment. In particular, in the high-salinity environment, a firm “star network” structure formed by bentonite/DADN was observed by TEM, significantly improving the colloidal stability and filter cake compactness of WBDF.

Engineering sterilization-resistant and fouling-resistant porous membranes by the vapor-induced phase separation process using a sulfobetaine methacrylamide amphiphilic derivative

The in-situ modification of polyvinylidene fluoride (PVDF)-based membranes with zwitterionic copolymers for environmental applications remains challenging because of the large polarity difference between PVDF and zwitterionic materials. Besides, common zwitterionic units such as sulfobetaine methacrylate fail when exposed to elevated temperatures, limiting their range of applications in biomedical engineering. We designed an amphiphilic copolymer containing sulfobetaine methacrylamide (SBAA), styrene and ethylene glycol methyl ether methacrylate (EGMA) groups. Once the appropriate composition determined, membranes were prepared by vapor-induced phase separation (VIPS), a process permitting fine control over formation mechanisms, hence over the matrix structure. Sorption, mapping FT-IR and DSC tests indicated that even a low proportion of SBAA (< 10 mol%) in the P(S-r-EGMA-r-SBAA) copolymer significantly increases the proportion of non-freezable water and enhances the strength of the hydration layer, compared to a system containing styrene and EGMA groups only, P(S-r-EGMA). The modification also resulted in a large increase in membrane hydration capacity (> 550 mg/cm3 vs. < 25 mg/cm3 for the virgin membrane). Consequently, the zwitterionic copolymer could efficiently mitigate biofouling by fibrinogen (76% drop), Escherichia coli (99% decrease) or whole blood (82% reduction), even after a steam sterilization process, while the control zwitterionic sulfobetaine methacrylate material failed at maintaining its performances. Separation tests carried out with bacterial solutions revealed the ability of the zwitterionic copolymer to significantly decrease irreversible fouling (27%), compared to a commercial membrane (47%). All in all, their porous structure, hydration capacity and their ability to withstand steam sterilization make these novel porous zwitterionic membranes ideal candidates for biomedical (blood filtration) or environmental applications (water treatment).

In Situ Chemical Modification with Zwitterionic Copolymers of Nanofiltration Membranes: Cure for the Trade-Off between Filtration and Antifouling Performance.

Breaking the trade-off between filtration performance and antifouling property is critical to enabling a thin-film nanocomposite (TFC) nanofiltration (NF) membrane for a wide range of feed streams. We proposed a novel design route for TFC NF membranes by grafting well-defined zwitterionic copolymers of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA) and 2-aminoethyl methacrylate hydrochloride (AEMA) on the polyamide surfaces via an in situ surface chemical modification process. The successful grafting of a zwitterionic copolymer imparted the modified NF membranes with better surface hydrophilicity, a larger actual surface area (i.e., nodular structures), and a thinner polyamide layer. As a result, the water permeability of the modified membrane (i.e., TFC-10) was triple that of the pristine TFC membrane while maintaining high Na2SO4 rejection. We further demonstrated that the TFC-10 membrane possessed exceptional antifouling properties in both static adsorption tests and three cycles of dynamic protein and humic acid fouling tests. To recap, this work provides valuable insights and strategies for the fabrication of TFC NF membranes with simultaneously enhanced filtration performance and antifouling property.

A zwitterionic copolymer-interlayered ultrathin nanofilm with ridge-shaped structure for ultrapermeable nanofiltration

Interlayered thin-film composite (TFC) membranes have a great potential for enhancing salt separation in wastewater reclamation, because of the highly permeable and selective properties. However, mechanistic insights regarding the structural features of the surface nanofilms and their corresponding interlayers, which lead to enhanced separation efficiency, remain poorly understood. Herein, we report a zwitterionic copolymer 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-amino-ethyl methacrylate hydrochloride (AEMA) (P[MPC-co-AEMA]) interlayered TFC membrane that exhibits an ultrahigh water permeance of 20.4 L m−2 h−1 bar−1 (almost three folds higher water permeance than that of the pristine PA membrane), together with a simultaneously enhanced rejection of inorganic salts (96.8% against Na2SO4). Detailed mechanistic investigations revealed that the promoted membrane separation property was mainly explained as the enriched amine monomer diffusion-driven instability induced by the P[MPC-co-AEMA] interlayer. This triggers membrane sealing and inhibits its growth, leading to the formation of an ultrathin PA nanofilm with a thickness of 12 nm, a ridge-shaped surface structure with enhanced specific surface area, and enhanced crosslinking. The fundamental mechanism revealed in this study lays a solid foundation for the engineering of the high-performance TFC membrane, which is appealing for the energy-efficient water remediation industry.

Electrospraying Zwitterionic Copolymers as an Effective Biofouling Control for Accurate and Continuous Monitoring of Wastewater Dynamics in a Real-Time and Long-Term Manner.

Long-term continuous monitoring (LTCM) of water quality can provide high-fidelity datasets essential for executing swift control and enhancing system efficiency. One roadblock for LTCM using solid-state ion-selective electrode (S-ISE) sensors is biofouling on the sensor surface, which perturbs analyte mass transfer and deteriorates the sensor reading accuracy. This study advanced the anti-biofouling property of S-ISE sensors through precisely coating a self-assembled channel-type zwitterionic copolymer poly(trifluoroethyl methacrylate-random-sulfobetaine methacrylate) (PTFEMA-r-SBMA) on the sensor surface using electrospray. The PTFEMA-r-SBMA membrane exhibits exceptional permeability and selectivity to primary ions in water solutions. NH4+ S-ISE sensors with this anti-fouling zwitterionic layer were examined in real wastewater for 55 days consecutively, exhibiting sensitivity close to the theoretical value (59.18 mV/dec) and long-term stability (error <4 mg/L). Furthermore, a denoising data processing algorithm (DDPA) was developed to further improve the sensor accuracy, reducing the S-ISE sensor error to only 1.2 mg/L after 50 days of real wastewater analysis. Based on the dynamic energy cost function and carbon footprint models, LTCM is expected to save 44.9% NH4+ discharge, 12.8% energy consumption, and 26.7% greenhouse emission under normal operational conditions. This study unveils an innovative LTCM methodology by integrating advanced materials (anti-fouling layer coating) with sensor data processing (DDPA).

Construction of Enzyme-Responsive Micelles Based on Theranostic Zwitterionic Conjugated Bottlebrush Copolymers with Brush-on-Brush Architecture for Cell Imaging and Anticancer Drug Delivery.

Bottlebrush copolymers with different chemical structures and compositions as well as diverse architectures represent an important kind of material for various applications, such as biomedical devices. To our knowledge, zwitterionic conjugated bottlebrush copolymers integrating fluorescence imaging and tumor microenvironment-specific responsiveness for efficient intracellular drug release have been rarely reported, likely because of the lack of an efficient synthetic approach. For this purpose, in this study, we reported the successful preparation of well-defined theranostic zwitterionic bottlebrush copolymers with unique brush-on-brush architecture. Specifically, the bottlebrush copolymers were composed of a fluorescent backbone of polyfluorene derivate (PFONPN) possessing the fluorescence resonance energy transfer with doxorubicin (DOX), primary brushes of poly(2-hydroxyethyl methacrylate) (PHEMA), and secondary graft brushes of an enzyme-degradable polytyrosine (PTyr) block as well as a zwitterionic poly(oligo (ethylene glycol) monomethyl ether methacrylate-co-sulfobetaine methacrylate) (P(OEGMA-co-SBMA)) chain with super hydrophilicity and highly antifouling ability via elegant integration of Suzuki coupling, NCA ROP and ATRP techniques. Notably, the resulting bottlebrush copolymer, PFONPN9-g-(PHEMA15-g-(PTyr16-b-P(OEGMA6-co-SBMA6)2)) (P2) with a lower MW ratio of the hydrophobic side chains of PTyr and hydrophilic side chains of P(OEGMA-co-SBMA) could self-assemble into stabilized unimolecular micelles in an aqueous phase. The resulting unimolecular micelles showed a fluorescence quantum yield of 3.9% that is mainly affected by the pendant phenol groups of PTyr side chains and a drug-loading content (DLC) of approximately 15.4% and entrapment efficiency (EE) of 90.6% for DOX, higher than the other micelle analogs, because of the efficient supramolecular interactions of π–π stacking between the PTyr blocks and drug molecules, as well as the moderate hydrophilic chain length. The fluorescence of the PFONPN backbone enables fluorescence resonance energy transfer (FRET) with DOX and visualization of intracellular trafficking of the theranostic micelles. Most importantly, the drug-loaded micelles showed accelerated drug release in the presence of proteinase K because of the enzyme-triggered degradation of PTyr blocks and subsequent deshielding of P(OEGMA-co-SBMA) corona for micelle destruction. Taken together, we developed an efficient approach for the synthesis of enzyme-responsive theranostic zwitterionic conjugated bottlebrush copolymers with a brush-on-brush architecture, and the resulting theranostic micelles with high DLC and tumor microenvironment-specific responsiveness represent a novel nanoplatform for simultaneous cell image and drug delivery.

A novel method to immobilize zwitterionic copolymers onto PVDF hollow fiber membrane surface to obtain antifouling membranes

Zwitterionic materials are considered to be a promising new-generation non- or low-fouling materials. However, stable, and straightforward introduction of zwitterions into membranes for commercial production remains as a big challenge yet. Herein for the first time we propose a simple approach to immobilize zwitterionic copolymers on poly(vinylidene fluoride) (PVDF) hollow fiber membrane (HFM) surfaces with considerably high stability via surface entrapment and subsequent simple reactions. First, a commercial amphiphilic copolymer, viz. styrene–maleic anhydride (PSMA), was entrapped on the outer surface of PVDF membranes using co-extrusion by a triple orifice spinneret. PSMA exhibited excellent stability on the PVDF membrane, and its reactive anhydride (MA) group was stabilized on the outer membrane surface. Next, the commercially available zwitterionic copolymer poly(2-methacryloyloxyethyl phosphorylcholine-co-2-aminoethyl methacrylate hydrochloride) (P(MPC-AEMA)) was immobilized on the PVDF/PSMA membrane surface by a simple reaction between the MA groups of PSMA and the amine groups of P(MPC-AEMA). The P(MPC-AEMA) reacted membrane exhibited noticeable bovine serum albumin (BSA) antifouling and antibacterial properties during both static adsorption and dynamic filtration. The flux recovery ratio (FRR) of the membrane exceeded 80% after seven cycles of BSA filtration. The modified membrane showed an even higher FRR (∼95%) during bacterial filtration, and such excellent performance was attributed to its super hydrophilicity. Our novel, advanced and straightforward modification method lights on a spotlight for a new pathway to make immobilization of zwitterions on polymeric membrane without needing complicated reactions or procedures.

Bioinspired Polysaccharide-Derived Zwitterionic Brush-like Copolymer as an Injectable Biolubricant for Arthritis Treatment.

Developing highly efficient and biocompatible biolubricants for arthritis treatment is extraordinarily demanded. Herein, inspired by the efficient lubrication of synovial joints, a paradigm that combines natural polysaccharide (chitosan) with zwitterionic poly[2-(methacryloyloxy) ethyl phosphorylcholine] (PMPC), to design a series of brush-like Chitosan-g-PMPC copolymers with highly efficient biological lubrication and good biocompatibility is presented. The Chitosan-g-PMPC copolymers are prepared via facile one-step graft polymerization in aqueous medium without using any toxic catalysts and organic solvents. The as-prepared Chitosan-g-PMPC copolymers exhibit very low coefficient of friction (μ < 0.01) on Ti6 Al4 V alloy substrate in both pure water and biological fluids. The superior lubrication is attributed primarily to the hydrated feature of PMPC side chains, interface adsorption of copolymer as well as to the hydrodynamic effect. In vivo experiments confirm that Chitosan-g-PMPC can alleviate the swelling symptom of arthritis and protect the bone and cartilage from destruction. Due to their facile preparation, distinctive lubrication properties, and good biocompatibility, Chitosan-g-PMPC copolymers represent a new type of biomimetic lubricants derived from natural biopolymer for promising arthritis treatment and artificial joint lubrication.

Zwitterionic Block Copolymers for the Synthesis and Stabilization of Perovskite Nanocrystals.

Traditional hot injection methods for the preparation of cesium lead halide perovskite nanocrystals (CsPbX3 PNCs, where X=Cl, Br, or I) rely on small molecule surfactants to produce PNCs with cube, plate, or rod-like morphologies. Here, we describe a new method whereby zwitterionic block copolymers are employed as macromolecular ligands in PNC synthesis, affording PNCs with excellent colloidal stability, high photoluminescence quantum yield, and in some cases distinctly non-cubic shapes. The block copolymers used in this study - composed of a poly(n-butyl methacrylate) hydrophobic block and zwitterionic methacrylate hydrophilic blocks - dissolve in useful solvents for PNC growth despite containing large mole percentages of zwitterionic groups. PNCs prepared with block copolymer ligands were found to disperse and retain their fluorescence in a range of polar organic solvents and were amenable to direct integration into optically transparent nanocomposite thin films with high PNC content.

Surface Hydration and Antifouling Activity of Zwitterionic Polymers.

It is believed that the strong surface hydration of zwitterionic polymers leads to excellent antifouling properties. This Perspective presents the recent developments in studies on such surface hydration in situ using sum frequency generation (SFG) vibrational spectroscopy. SFG research provides direct molecular level evidence that zwitterionic polymers have strong surface hydration, which prevents protein adsorption and marine animal attachment. The salt effect and protein interaction on surface hydration of zwitterionic polymers have also been examined using SFG. Possible future research directions on surface hydration of new zwitterionic polymers including zwitterionic hydrogels, copolymers, and mixed charged polymers are discussed. It is also important to combine experimental SFG studies with computer simulations to further elucidate the surface hydration to understand antifouling mechanisms.

Facile zwitterionization of polyvinylidene fluoride microfiltration membranes for biofouling mitigation

Styrene maleic anhydride (SM) is a commercially available copolymer able to react with diamines. The ring-opening reaction results in the formation of a zwitterionic compound of prime interest to the development of fouling-resistant membranes. To this end, we designed microfiltration antifouling polyvinylidene fluoride (PVDF) membranes by blending PVDF with a copolymer obtained from the reaction of SM with N,N-dimethylamino-1,3-propanediamine, and then by inducing phase inversion of the casting solution from the vapor phase. The resulting membranes possess excellent surface and bulk hydrophilicity, compared to the pristine membrane. Besides, as adding copolymer shifts the zeta potential closer to electroneutrality, biofouling is alleviated, as tested in static conditions with Escherichia coli , blood cells or bovine serum albumin. Filtration of a bacterial solution also demonstrated the superior performances of the as-prepared membrane to those of a commercial hydrophilic PVDF membrane, with a higher flux recovery ratio (90% vs. 65%) and lower irreversible flux decline ratio (10% vs. 32%). Given also the stability of the design and the low costs involved in the making of the membranes (all materials are commercially available and inexpensive), the present membranes are suitable alternatives to commercial hydrophilic PVDF membranes, but with better fouling mitigation. • The facile zwitterionization of a commercial copolymer is introduced. • The zwitterionic copolymer is solubilized with polyvinylidene fluoride. • Stable zwitterionic bi-continuous are fabricated. • Effective anti-biofouling property is demonstrated with various biofoulants.