阳离子抗菌聚合物

阳离子抗菌聚合物, 作为一种新型抗菌材料, 具有独特的抗菌机理和高效的抗菌活性, 并且能有效解决细菌耐药性问题, 引起了人们的广泛关注。阳离子抗菌聚合物具有有效的抗菌活性, 其抗菌活性受到亲疏水平衡、分子质量、烷基链长度和阴离子等因素的影响。抗菌活性是评价抗菌剂优劣的重要因素之一, 了解和掌握影响抗菌活性的因素, 对于优化或开发更安全、更高效的阳离子抗菌聚合物具有重大意义。本文总结了通过不同作用方式作用于细菌的多种抗菌策略, 依据影响阳离子抗菌聚合物抗菌活性的因素, 总结包括天然阳离子抗菌聚合物、季铵盐类聚合物、N-卤代胺类聚合物、膦盐和锍盐类聚合物、胍盐类聚合物和抗菌水凝胶的研究进展。最后, 对阳离子抗菌聚合物面临的挑战和未来发展方向进行了讨论。     

Self‐Propagating Association of Zwitterionic Polymers Initiated by Ionene Polymers

A self‐propagating association of zwitterionic polymers is observed when a small amount of x,y‐ionene bromide (x = 3 or 6; y = 3, 4, 6, 10 or 12) polymer is added to aqueous solutions of zwitterionic polymer, poly[3‐dimethyl(methacryloyloxyethyl)ammoniumpropanesulfonate] (PDMAPS), to give large amount of PDMAPS precipitate. The self‐propagating association initiated by ionene polymers is explained in terms of the electrostatic interaction between the ionene polymers and the zwitterionic polymers whereupon the geometry of the charges on the polymer chains plays an important role.     

Internal Architecture of Zwitterionic Polymer Brushes Regulates Nonfouling Properties

In this work, we study how film thickness and chain packing density affect the protein‐resistant properties of polymer brushes in complex media. Polymer brushes based on dual‐functional poly(carboxybetaine acrylamide) (pCB) were prepared via surface‐initiated photoiniferter‐mediated polymerization. By adjusting UV radiation time and solvent polarity, pCB films with different thicknesses can be achieved and characterized using an ellipsometer. The packing density of pCB polymer chains is directly related to the swelling ratio of swollen to collapsed film thicknesses. Results showed that the dry film thickness alone, used often in the literature, is not sufficient to correlate with nonfouling properties and the chain packing density must be considered for the design of nonfouling surface coatings.     

两性离子聚合物的生物应用

两性离子聚合物具有亲水的阴、阳离子基团,能够高度水化从而具有独特的抗生物污染性能,即能够阻抗非特异性蛋白质的吸附、细菌黏附和生物膜的形成,这种特性使得此类材料在生物医学等相关领域得到越来越多的应用。本文概略介绍了现有两性离子聚合物的抗生物污染机理——空间排斥效应和水化理论。基于抗生物污染性质,两性离子聚合物可用于防污涂层、抗菌涂层、抗凝血材料、生物医学诊断、药物传输、基因传递载体、分离膜以及船体涂料中。本文综述了两性离子聚合物的应用进展,分析了当前研究中需要解决的问题以及发展趋势,并展望了其应用前景。     

Restraint of the Differentiation of Mesenchymal Stem Cells by a Nonfouling Zwitterionic Hydrogel

The success of human mesenchymal stem cell (hMSC) therapies is largely dependent on the ability to maintain the multipotency of cells and control their differentiation. External biochemical and biophysical cues can readily trigger hMSCs to spontaneously differentiate, thus resulting in a rapid decrease in the multipotent cell population and compromising their regenerative capacity. Herein, we demonstrate that nonfouling hydrogels composed of pure poly(carboxybetaine) (PCB) enable hMSCs to retain their stem‐cell phenotype and multipotency, independent of differentiation‐promoting media, cytoskeletal‐manipulation agents, and the stiffness of the hydrogel matrix. Moreover, encapsulated hMSCs can be specifically induced to differentiate down osteogenic or adipogenic pathways by controlling the content of fouling moieties in the PCB hydrogel. This study examines the critical role of nonspecific interactions in stem‐cell differentiation and highlights the importance of materials chemistry in maintaining stem‐cell multipotency and controlling differentiation.     

Towards Sequence‐Controlled Antimicrobial Polymers: Effect of Polymer Block Order on Antimicrobial Activity

Synthetic polymers have shown promise in combating multidrug‐resistant bacteria. However, the biological effects of sequence control in synthetic antimicrobial polymers are currently not well understood. As such, we investigate the antimicrobial effects of monomer distribution within linear high‐order quasi‐block copolymers consisting of aminoethyl, phenylethyl, and hydroxyethyl acrylamides made in a one‐pot synthesis approach via photoinduced electron transfer–reversible addition–fragmentation chain transfer polymerisation (PET‐RAFT). Through different combinations of monomer/polymer block order, antimicrobial and haemolytic activities are tuneable in a manner comparable to antimicrobial peptides.     

Applications of Zwitterions and Zwitterionic Polymers for Li-Ion Batteries

A zwitterion is a neutral compound that has both a cation and an anion in the same molecule. Quaternary ammonium cations are frequently used for zwitterions. Zwitterions with quaternary ammonium cations are also common in biological molecules, such as phospholipids, which are the main components of cell membranes. Chemically, they have broad applicability because they are dielectric, non-volatile, and highly polar compounds with a large dipole moment. In addition, after salt addition, ion exchange does not occur in the presence of zwitterions. Owing to these characteristics, zwitterions have been applied as novel electrolyte materials targeting high ionic conductivity. In this review, application of zwitterions and their polymers for Li-ion batteries is addressed.     

Functional Zwitterionic Polymers on Surface: Structures and Applications

Zwitterionic polymers are important in a wide range of industrial, biological and medical fields. Their chemical structures include an equal amount of anion and cation groups, and such structures give rise to many unique functionalities, such as temperature response, anti‐polyelectrolyte effect, and strong hydration properties. In this review, we focus on the structures and applications of functional zwitterionic polymers on surfaces. We review three areas of applications according to the architecture of the polymeric systems: surface coating, complex solutions, and hydrogel. We review the simulation and theory work and highlight some outlooks for further development.     

基于双苯并咪唑及二羧酸配体配合物的合成、结构及抗菌活性

利用双苯并咪唑基配体4,4′-二(苯并咪唑-1-甲基)联苯(bbmb)与V形二羧酸配体4,4′-二羧苯基醚(H2dcpe)合成了配合物{[Ni(bbmb)(dcpe)(H_2O)]·2H_2O}_n(1)和{[Mn_2(bbmb)(dcpe)_2(H_2O)]·1.5H_2O}_n(2)。通过红外、元素分析、X射线单晶衍射、热重分析等检测手段对配合物结构进行了表征。配合物1是具有sql拓扑构型的二维层状化合物。配合物2呈现出含有四核锰构型的二维层状结构。体外抗菌实验证明2个配合物都表现出良好的抗菌活性。     

Antimicrobial Polymers Prepared by Ring‐Opening Metathesis Polymerization: Manipulating Antimicrobial Properties by Organic Counterion and Charge Density Variation

The synthesis and characterization of a series of poly(oxanorbornene)‐based synthetic mimics of antimicrobial peptides (SMAMPs) is presented. In the first part, the effect of different organic counterions on the antimicrobial properties of the SMAMPs was investigated. Unexpectedly, adding hydrophobicity by complete anion exchange did not increase the SMAMPs’ antimicrobial activity. It was found by dye‐leakage studies that this was due to the loss of membrane activity of these polymers caused by the formation of tight ion pairs between the organic counterions and the polymer backbone. In the second part, the effect of molecular charge density on the biological properties of a SMAMP was investigated. The results suggest that, above a certain charge threshold, neither minimum inhibitory concentration (MIC₉₀) nor hemolytic activity (HC₅₀) is greatly affected by adding more cationic groups to the molecule. A SMAMP with an MIC₉₀ of 4 μg mL^?1 against Staphylococcus aureus and a selectivity (=HC₅₀/MIC₉₀) of 650 was discovered, the most selective SMAMP to date.     

两性离子聚合物的抗蛋白质吸附机理及其应用

两性离子聚合物是一类同时带有阴、阳离子基团的聚合物。依据分子结构,它主要包括磷酰胆碱型、磺基甜菜碱型、羧基甜菜碱型以及混合型两性离子聚合物等。两性离子聚合物溶液性质可以通过调节溶液的pH值来实现近似阳离子或阴离子聚电解质。两性离子聚合物又具有特殊的“反聚电解质效应”。另外,两性离子聚合物还具有极强的亲水性、优良的热和化学稳定性、优异的生物相容性以及良好的抗污染性能等特性。本文着重介绍了两性离子聚合在抗蛋白质吸附机理的研究进展,同时针对近年来两性离子聚合物在抗污染材料、药物及基因的运输载体、物质检测与分离材料等领域的应用进行了简要的概述。并且,就两性离子聚合物在这几个应用领域的发展前景进行了展望。     

Polymer‐Based Surfaces Designed to Reduce Biofilm Formation: From Antimicrobial Polymers to Strategies for Long‐Term Applications

Contact‐active antimicrobial polymer surfaces bear cationic charges and kill or deactivate bacteria by interaction with the negatively charged parts of their cell envelope (lipopolysaccharides, peptidoglycan, and membrane lipids). The exact mechanism of this interaction is still under debate. While cationic antimicrobial polymer surfaces can be very useful for short‐term applications, they lose their activity once they are contaminated by a sufficiently thick layer of adhering biomolecules or bacterial cell debris. This layer shields incoming bacteria from the antimicrobially active cationic surface moieties. Besides discussing antimicrobial surfaces, this feature article focuses on recent strategies that were developed to overcome the contamination problem. This includes bifunctional materials with simultaneously presented antimicrobial and protein‐repellent moieties; polymer surfaces that can be switched from an antimicrobial, cell‐attractive to a cell‐repellent state; polymer surfaces that can be regenerated by enzyme action; degradable antimicrobial polymers; and antimicrobial polymer surfaces with removable top layers.     

Pulsed Plasma Polymerization of Cyclic Ethers: Production of Biologically Nonfouling Surfaces

Polymerization of low molecular weight cyclic ethers was investigated under pulsed plasma conditions. Film formation conditions were adjusted to optimize retention of ethylene oxide (EO) content of the monomers in the resultant plasma generated polymers. To a large extent this goal was achieved with the 12-crown-4 and 15-crown-5 monomers, but not with dioxane. Films obtained from the 12-crown-4 monomer under ultra low power inputs are shown to be highly resistant to protein adsorption, while exhibiting good chemical compositional stability and adhesion during prolonged immersion in aqueous solutions. The dramatic differences observed in contrasting polymer film compositions from 12-crown-4 and dioxane are believed to arise from distinctive differences in the low electron impact fragmentation patterns of these two compounds, as discussed in this report.     

Antimicrobial Food Packaging with Biodegradable Polymers and Bacteriocins

Innovations in food and drink packaging result mainly from the needs and requirements of consumers, which are influenced by changing global trends. Antimicrobial and active packaging are at the forefront of current research and development for food packaging. One of the few natural polymers on the market with antimicrobial properties is biodegradable and biocompatible chitosan. It is formed as a result of chitin deacetylation. Due to these properties, the production of chitosan alone or a composite film based on chitosan is of great interest to scientists and industrialists from various fields. Chitosan films have the potential to be used as a packaging material to maintain the quality and microbiological safety of food. In addition, chitosan is widely used in antimicrobial films against a wide range of pathogenic and food spoilage microbes. Polylactic acid (PLA) is considered one of the most promising and environmentally friendly polymers due to its physical and chemical properties, including renewable, biodegradability, biocompatibility, and is considered safe (GRAS). There is great interest among scientists in the study of PLA as an alternative food packaging film with improved properties to increase its usability for food packaging applications. The aim of this review article is to draw attention to the existing possibilities of using various components in combination with chitosan, PLA, or bacteriocins to improve the properties of packaging in new food packaging technologies. Consequently, they can be a promising solution to improve the quality, delay the spoilage of packaged food, as well as increase the safety and shelf life of food.     

Liquid-to-Solid Phase Transitions of Imidazolium-Based Zwitterionic Polymers Induced by Hofmeister Anions

In this study, we compared the responses of two different types of zwitterionic polymers (ZPs), polyvinylimidzole sulfobetaine (poly(SBVI)) and polymethacrylate sulfobetaine (poly(SBMA)) to Hofmeister anions. Although the anions of the two ZPs were the same as the sulfonate anions and only the types of their cations were different from each other, the aggregation behavior of each in the salt aqueous solution was remarkably different. Consequently, poly(SBVI) exhibited both salting-in and salting-out effects depending on the type and concentration of salt, while poly(SBMA) only exhibited the anti-polyelectrolyte effect. The results of this study provide a deeper understanding of the behavior of zwitterionic polymers in salt solutions and will greatly expand their applications.     

Zwitterionic Base‐Stabilized Digermadistannacyclobutadiene and Tetragermacyclobutadiene

The syntheses of a zwitterionic base‐stabilized digermadistannacyclobutadiene and tetragermacyclobutadiene supported by amidinates and low‐valent germanium amidinate substituents are described. The reaction of the amidinate Ge^I dimer, [LGe:]₂ ( 1 , L=PhC(NtBu)₂), with two equivalents of the amidinate tin(II) chloride, [LSnCl] ( 2 ), and KC₈ in tetrahydrofuran (THF) at room temperature afforded a mixture of the zwitterionic base‐stabilized digermadistannacyclobutadiene, [L₂Ge₂Sn₂L′₂] ( 3 ; L′=LGe:), and the bis(amidinate) tin(II) compound, [L₂Sn:] ( 4 ). Compound 3 can also be prepared by the reaction of 1 with [L^ArSnCl] ( 5 , L^Ar=tBuC(NAr)₂, Ar=2,6‐iPr₂C₆H₃) in THF at room temperature. Moreover, the reaction of 1 with the “onio‐substituent transfer” reagent [4‐NMe₂‐C₅H₄NSiMe₃]OTf ( 8 ) in THF and 4‐(N,N‐dimethylamino)pyridine (DMAP) at room temperature afforded a mixture of the zwitterionic base‐stabilized tetragermacyclobutadiene, [L₄Ge₆] ( 9 ), the amidinium triflate, [PhC(NHtBu)₂]OTf ( 10 ), and Me₃SiSiMe₃ ( 11 ). X‐ray structural data and theoretical studies show conclusively that compounds 3 and 9 have a planar and rhombic charge‐separated structure. They are also nonaromatic.     

Biologically Active Polymers, 6

Various copolymers were prepared by the copolymerization of 2‐chloroethyl vinyl ether (CEVE) with methyl methacrylate (MMA), hydroxyethyl methacrylate (HEMA) and vinylbenzyl chloride (VBC). The copolymers were further modified by quaternization with triethylamine, triphenylphosphine, and tributylphosphine. The antimicrobial activities of the prepared, quaternized copolymers were evaluated against Candida albicans, Fusarium oxysporium, Aspergillus flavus, Bacillus subtilis, Escherichia coli, and Staphylococcus aureus. The antimicrobial activity was explored by the cut plug method, viable cell counting (surviving ratio), transmission electron microscopy, and potassium leakage tests. The results indicated that the prepared polymers had a high antimicrobial activity, and control experiments on the main polymer without ammonium, phenyl, or butyl and/or phosphonium groups were carried out. The phosphonium containing polycationic biocides are more effective than the quaternary ammonium salt polymers. Examining the C. albicans and S. aureus polymer‐treated cells by electron microscopy indicated disruption for the cytoplasmic membrane and release of potassium ion as shown by the assay of potassium leakage.

Growth inhibition of different concentrations of polymer (X_b).     

Zwitterionic Cellulose Carbamate with Regioselective Substitution Pattern: A Coating Material Possessing Antimicrobial Activity

A polyzwitterion is synthesized by regioselective functionalization of cellulose possessing a uniform charge distribution. The positively charged ammonium group is present at position 6, while the negative charge of carboxylate is located at positions 2 and 3 of the repeating unit. The molecular structure of the biopolymer derivative is proved by NMR spectroscopy. This cellulose‐based zwitterion is applied to several support materials by spin‐coating and characterized by means of atomic force microscope, contact angle measurements, ellipsometry, and X‐ray photoelectron spectroscopy. The coatings possess antimicrobial activity depending on the support materials (glass, titanium, tissue culture poly(styrene)) as revealed by confocal laser scanning microscopy and live/dead staining.