[en] Zwitterionic materials as a new class of emerging materials have recently been developed and applied to a broad range of biomedical and engineering applications. Zwitterionic materials possess a unique molecular structure combining both cationic and anionic groups with overall charge neutrality and high hydrophilicity. In this review, we first provide the structure-property relationship of the zwitterionic materials at molecular level, from a molecular simulation viewpoint. Then, we discuss the recent experimental developments in the preparation, properties, and applications of zwitterionic materials, with a particular focus on their antifouling properties on coating surfaces and with additional functionality and applications. Finally, we offer our personal viewpoint of current challenges and future directions in this emerging area. Our goal is to introduce the current status of this type of new zwitterionic materials to researchers from different areas and motivate them to explore all the potentials. (topical review)

[en] In this study, a charge-conversion mechanism was introduced into the design of a bacteria-responsive antibacterial surface. The antibacterial surface was facilely constructed via surface tethering of antimicrobial peptides (AMPs) to solid supports and subsequently integrating charge-conversion moieties into the peptide structure. The resulting zwitterionic structure of the AMPs rendered the antibacterial surface biocompatible under normal physiological conditions. Importantly, the surface exhibited self-defense properties specifically against pathogenic bacteria; the toxicity of AMPs was activated in bacterially induced acidic environments. Unlike previously described self-defense systems that utilize an antimicrobial release mechanism, this antibacterial surface exerts its bactericidal effects by diminishing the nonbactericidal masking moieties and activating the surface-tethered AMPs to avoid the undesirable toxic effects caused by planktonic AMPs. In contrast to the prevailing passive switchable antibacterial surfaces, our surface uses a unique self-adaptive zwitterionic-to-cationic transition mechanism to inhibit the development of bacterial infections.

[en] Two zwitterionic stationary phases with largely corroborated capacities were obtained by attachment sulfobetaine monomers (H/sub 2/C=CHC/sub 6/H/sub 4/CH/sub 2/N+(CH/sub 3/)2-CH/sub 2/-SO/sub 3/- and H/sub 2/C=CHC/sub 6/H/sub 4/CH/sub 2/N+(CH/sub 3/)2-(CH/sub 2/)5-SO/sub 3/-) onto a PS/DVB particles were investigated for chromatographic separation of ranitidine hydrochloride. The different chain lengths are used as an investigative tool for the retention behavior of pharmaceutical ranitidine hydrochloride. The retention behavior of ranitidine hydrochloride was examined with eluent at various ACN contain, buffer concentrations and pH. The separation mechanism is based on partitioning in reversed phase and ZIC ion exchange resulting in a mixed mode for the ranitidine hydrochloride. A direct calibration graph was constructed for ZIC1 and ZIC5 columns and it was found that the linear range (10-1000 ng.ml-1), RSD% (0.41-1.55), LOD (1.55 and 2.56 ng.ml-1), LOQ (5.17 and 8.53 ng.ml/sup -1/), Recovery% (101.06 ± 1.15 and 100.47 ± 0.12) and E/sub rel/% (1.666 ± 0.78 and 0.47 ± 0.12), respectively. (author)

[en] Highlights: • First evaluation of genotoxicity of strong bases and zwitterions in effluents. • Ion-exchange cartridge could divide the acid-base properties of genotoxicants. • Strong bases and zwitterions contributed to 46.9% of the total genotoxicity. • The contribution ratio of weak acids was 50.7% of the total genotoxicity. Various genotoxic substances in household effluents have not been sufficiently studied. The purpose of this study is to evaluate them using the umu test after dividing them based on the acid-base properties of their functional groups by solid-phase extraction cartridges. The results of the samples concentrated with reverse-phase cartridges showed that the substances with acid functional groups had stronger genotoxicity as 4.1–12.1 ng-4-NQO/mL without S9 enzyme and 17.4–51.8 ng-2-AA/mL with S9 enzyme, while the basic substances also showed a certain degree of toxicity. The results of dividing the effluents by acid-base properties using ion-exchange cartridges showed that chemical substances with strong acid functional groups did not demonstrate genotoxicity. It was found that the genotoxicity of chemicals with functional groups of weak acids was half of that of the total amount. The genotoxicity of the neutral substance was not strong, and the genotoxicity of the weak basic substances was negligible. The zwitterions and substances with strong basic functional groups showed about half the total genotoxicity. This is the first report that has investigated the genotoxicity of zwitterions in effluents.

[en] Highlights: • Response surface method is applied to trace the fading path of photochromic film. • The effects on the decoloration rate of photochromic film are explored. • Quantum chemical calculation offers quantitative insight into the photochromism. Response surface method is applied here to trace the photochromic path and explore the substituent and β-cyclodextrin effects on the decoloration of the spiropyran/β-cyclodextrin polymer (SP/CDP) complex. Calculations support the ultraviolet/visible experimental results, suggesting that introducing an electron-withdrawing group to the benzopyryl moiety of SPs favors an enhancement in their decoloration, whereas replacing the benzopyryl with a naphthopyryl moiety obstructs their decoloration. CDP complexation weakens the C₁O bond of the closed SP form and enhances the polar zwitterionic structure in the open photomerocynine form. However, the electron-withdrawing group strengthens the interaction of benzopyryl SPs with CDP, thereby hindering their decoloration.

[en] 5-Bromo-3-methoxysalicylidene-2-furfurylamine (HL⁵) and 3-nitrosalicylidene-2-furfurylamine (HL⁶) were synthesized and studied by X-ray diffraction. Both structures are stabilized by strong intramolecular N1–H1···O2 hydrogen bonds. Both molecules exist as zwitterions. The structure of the HL⁶ molecule has a contribution of the tautomeric quinoid form.

[en] Zwitterionic materials have been attracting significant attentions due to their excellent non-fouling and biocompatible properties and thus have been widely used in many biomedical applications. However, differences among different types of zwitterionic materials have rarely been investigated and compared. In this work, four types of zwitterionic monomers were systematically studied and compared by testing the properties of the hydrogels. Their hydration, diffusion coefficient of water and mechanical properties were evaluated and analyzed. It was found that poly(carboxybetaine methacrylate) (PCBMA) hydrogel possessed the strongest compressive modulus, while poly(carboxybetaine acrylamide) (PCBAA) hydrogel showed the highest diffusion coefficient of water and highest hydration of water. Compared with other hydrogels, the mesh size of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) hydrogel was the largest. Furthermore, poly(sulfobetaine methacrylate) (PSBMA) hydrogel with disulfide crosslinker degraded faster than the others. Findings in this work provided insights and guidance for the selection of different zwitterionic polymers to suit different applications.

[en] Thermodynamics and kinetics of sorption with the participation of nicotinic and isonicotinic acids on the strongly basic anion exchanger АВ-17-8 were studied. According to calorimetric measurements, partial (differential) heat of sorption was estimated for anions and zwitterions of pyridinecarboxylic acids upon sorption by the OH-form of the anion exchanger AB-17-8 at 298K. Sorption of zwitterions of pyridinecarboxylic acids by the OH-form of the strongly basic anion exchanger can be presented as the process that involves independent reactions of ion exchange, dissociation of pyridinecarboxylic acid, and neutralization. The kinetics of sorption on the strongly basic anion exchanger with the participation of nicotinic and isonicotinic acids is shown to be controlled by the slow diffusion of the components in the polymer phase. For the organic anion in the phase of the anion exchanger АВ-17-8, the diffusion coefficient is equal to (1.3±0.4)•10^–12 m² s^–1.

[en] A facile approach is established to prepare zwitterionic nanocapsules (ZN_Cs) with controlled diameters and core/shell structures based on an inverse reversible addition-fragmentation transfer (RAFT) miniemulsion interfacial polymerization method. The diameters and core volume fractions of ZN_Cs can be tuned finely from 61 to 220 nm and from 0.22 to 0.61, respectively. Furthermore, the thermal-responsive property of the prepared zwitterionic nanocapsules was systematically studied relating to core/shell ratios and cross-linking degrees. These ZN_Cs could be particularly useful in constructing polymeric materials with well-defined nanoporous structures for nano-void membranes, drug delivery devices and catalytic carriers. (paper)

[en] We investigate two imidazolium zwitterionic salts, 1,3-dimethylimidazolium-2-carboxylate and 1-butyl-3-methylimidazolium-2-carboxylate, together with 1-butyl-3-methylimidazolium acetate using X-ray photoelectron spectroscopy. The electronic environment of each element for the two zwitterionic salts is analyzed. Due to the electron-withdrawing effect of the imidazoliumcation, the binding energies of Ccarboxyl 1s and O 1s for zwitterionic salts are higher than those of 1-butyl-3-methylimidazolium acetate. The impact of the alkyl chain length on the charge distribution is also illustrated. It suggests that the electron-withdrawing effect of the imidazoliumcation decreases along with the increasing of the alkyl chain length.