Pyromellitimide benzoyl thiourea cross-linked carboxymethyl chitosan hydrogels as antimicrobial agents

A series of novel hydrogels based on carboxymethyl chitosan (CMCS) has been synthesized by a cross-linking reaction between CMCS and various amounts of N,N′-bis [4-(isothiocyanate carbonyl)phenyl] pyromellitimide as a cross-linker to produce pyromellitimide benzoyl thiourea–CMCS hydrogels designated as PIBTU–CMCS (1–4). Hydrogel structures were identified by elemental analyses and FTIR and ¹H-NMR spectroscopy. The prepared hydrogels were characterized for their properties to understand the influence exerted by controlled structural variations in these hydrogels. All the hydrogels showed a greater antibacterial activity on Gram-positive than Gram-negative bacteria. They also exhibited higher antifungal activities. Their antimicrobial activity improved by increasing their cross-linking degree.     

季铵化壳聚糖-聚苯乙烯共混膜的制备及表征

以十六烷基三甲基溴化铵(CTAB)为表面活性剂,过硫酸钾为引发剂制备了聚苯乙烯微乳液,用共混法制备了3种不同质量比的季铵化壳聚糖和聚苯乙烯微乳液的共混膜.研究了该膜的温度和pH的敏感性及力学强度.结果表明,共混膜的拉伸强度与纯壳聚糖膜相比有较大提高,而且该膜仍然具有一定的温度敏感性和pH敏感性,有较好的应用价值.     

Synthesis,characterization, and antimicrobial activity of chitosan hydrazide derivative

A series of modified chitosan derivatives 1–4 has been synthesized. Modification process of chitosan was achieved through a sequence of four reactions starting by protection of its amino group with benzaldehyde (derivative 1), followed by reaction with epichlorohydrine (derivative 2), then reaction with benzhydrazide (derivative 3), and finally restoring the free amino groups on the chitosan by removing of benzaldehyde molecules (derivative 4). These four derivatives were characterized by elemental analyses, FTIR, and X-ray. The four chitosan derivatives showed better antibacterial and antifungal activities than that of chitosan. Derivative 4 exhibited the highest antimicrobial activity relative to the other derivatives.     

Preparation of quaternized carboxymethyl chitosan and its capacity to flocculate COD from printing wastewater

A bioflocculant, quaternized carboxymethyl chitosan (QCMC), was developed by the quaternization of N,O‐carboxymethyl chitosan (N,O‐CMC) and characterized by FTIR, ¹H‐NMR, GPC, and potentiometry. The efficiency of the removal of chemical oxygen demand (COD) in printing wastewater by this flocculant was further reported. Results indicated that the capacity of QCMC to remove the COD from tested wastewater was the best one among the investigated flocculants. The pH had great influence on this capacity and the suitable pH for QCMC to treat the tested wastewater was about 5.0. The utilization of aid‐flocculant, especially bentonite, could improve this capacity obviously, and the increase of mass ratio of bentonite to QCMC resulted in the increase of the capacities of complex flocculant to remove the COD from the tested wastewater. When the mass ratio of bentonite to QCMC was 40, pH of wastewater was 5.0 and amount of complex flocculant in the wastewater was from 2500 to 3142 mg L^?1, the removal ratio of COD was more than 80%. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

壳聚糖季铵盐及其复合物的研究进展

壳聚糖季铵盐及其复合物是一种很有应用前景的材料,作者综述了壳聚糖季铵盐及其复合物在载基因、载药、抗菌创伤材料、抗凝血材料、水处理材料等领域的研究进展。     

Preparation,characterization, structure,and dynamics of carboxymethyl chitosan grafted with acrylic acid sodium salt

Graft copolymerization of different vinyl monomers onto chitosan (Cs) and its derivatives can alter their properties and consequently expands their potential applications. In this study, carboxymethyl chitosan (CMCs) was prepared and characterized. Graft copolymerization of acrylic acid sodium salt (AAs) onto CMCs was accomplished by using ammonium persulphate (APS)‐induced free radical polymerization in aqueous medium under nitrogen atmosphere. Occurrence of grafting was confirmed and the effects of [AAs], [APS], reaction time, and temperature on the extent of grafting were studied. The influence of grafting yield on the structure and dynamics was also investigated by using differential scanning calorimetry (DSC), two‐dimensional wide‐angle X‐ray scattering (2D‐WAXS), scanning electron microscopy (SEM), and dielectric spectroscopy. Preliminary study, using dielectric spectroscopy, was carried out to the CMCs‐g‐AAs copolymer with grafting percent ～ 2900%, as an example, in a wide range of temperature (from 299 to 473 K) and frequency (from 1 × 10^?2 to 1 × 10⁵ Hz). One relaxation process with Arrhenius type was detected. This process has the characteristics of a secondary relaxation process related to local chain dynamics with activation energy of 53 ± 3 kJ/mol. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and antibacterial properties of polycaprolactone/quaternized chitosan blends

This article is a preliminary study on antibacterial blends of polycaprolactone, chitosan and quaternized chitosan by melt processing. Blends were characterized, mechanical test and antibacterial evaluation against Escherichia coli and Staphylococcus aureus, were conducted. Results showed that the antibacterial potential of chitosan was limited in blends and polycaprolactone/chitosan did not show significant antibacterial effect compared with neat polycaprolactone (PCL). Inhibition rates of polycaprolactone/quaternized chitosan were 39.2％–99.9％ against Escherichia coli, while inhibition rate was 40.9％–99.9％against Staphylococcus aureus. When quaternized chitosan (QCTS) content was up to 20％, blends exhib-ited 99.9％inhibition rates against both two types of bacteria.     

Antibacterial activity of cationically modified cotton fabric with carboxymethyl chitosan

A water‐soluble carboxymethyl chitosan was prepared with a view to develop a multifunctional finish on cotton. Carboxymethyl chitosan (CMCTS) was synthesized by chemical reaction of chitosan with monochloroacetic acid under alkaline condition. The water soluble CMCTS was applied to cationized cotton with different concentrations. The treated fabrics were characterized through monitoring the textile physical properties and for the antibacterial activity against Escherichia coli DSMZ 498 and Micrococcus luteus ATCC 9341. The results obtained show that the physical properties of the treated fabrics are improved by increasing the CMCTS concentration, as well as the antibacterial activity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

羧甲基壳聚糖基水溶性高分子紫外线吸收剂的合成与表征

以2,4-二羟基二苯甲酮(UV-O)与氯乙酰氯为原料合成了中间体2-羟基-4-氯乙酸酯基二苯甲酮,然后使其与羧甲基壳聚精反应,合成了一系列含有二苯甲酮结构的羧甲基壳聚糖基紫外线吸收剂(CMC-g-HCBP).采用IR,UV,XRD,1HNMR等对产物进行了结构表征.测定结果表明,接枝产物在240～400 nm内均有较强的紫外吸收,并在332 nm处有最大紫外吸收;产物有较好的光稳定性.     

Composite films of N,O‐carboxymethyl chitosan and bamboo fiber

To obtain an antibacterial chitosan derivative, composite films of N,O‐Carboxymethyl Chitosan (N,O‐CMCS) and bamboo fiber were prepared. A water‐soluble chitosan derivative‐N,O‐CMCS was synthesized from chitosan with chloroacetic acid in alkaline solution. Composite films with 1–5 wt % N,O‐CMCS content were prepared in NaOH/urea/thiourea solution. The DS of N,O‐CMCS reached 1.70 and the water solubility increased with the increasing of DS. The carboxymethyl group was introduced into chitosan, which led to the decrease of thermal stability and crystallinity. The structural characterization confirmed that N,O‐CMCS was adsorbed on the surface of bamboo fiber. The antibacterial performance of the composite films were enhanced with the increasing of N,O‐CMCS content. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39851.     

壳聚糖/羧甲基壳聚糖及其衍生物在日化方面的应用

壳聚糖及其衍生物含有大量的氨基和羟基,为壳聚糖的改性或者接枝反应提供了活性基团,壳聚糖/羧甲基壳聚糖因特殊的化学结构而使其具有优异的化学性质,如良好的生物相容性、无毒、生物可降解性以及抗微生物活性等性质,因此受到生物工程、医药、食品、化妆品以及其他一些领域的广泛关注,成为近年来研究开发的热点。对壳聚糖/羧甲基壳聚糖及其衍生物在日用化学中的应用进行了综述,并对其发展趋势进行了展望。     

反相微乳液法制备纳米银/羧甲基壳聚糖复合微粒

采用反相微乳液法,以水合肼为还原剂制备纳米银/羧甲基壳聚糖复合微粒,并用红外光谱、X射线衍射、透射电镜对制备的样品微粒进行表征,讨论了搅拌速度、AgNO_3用量以及乳液体系的组成对纳米银复合粒子形貌与尺寸的影响。结果表明,当搅拌速度为1400r/min,AgNO_3用量为0.52g,吐温-80/液体石蜡体积比为4:5时,可制得粒径在50nm左右的纳米银/羧甲基壳聚糖复合微粒,且粒子具有较好的面心立方晶体结构。     

Preparation of water‐soluble chitosan derivatives and their antibacterial activity

Carboxymethyl chitosan sodium (CMCTS) was synthesized by chitosan and chloroacetic acid under an alkali catalyst. Acrylic acid sodium salt and methylacrylic acid sodium salt were grafted onto CMCTS to obtain copolymers with good water solubility. The graft reaction was carried out at 70°C for 2 h, and ammonium persulfate was used as an initiator. The structure changes of chitosan and its derivatives were investigated by the FTIR. The antibacterial activity of chitosan derivatives against Staphylococcus aureus and Escherichia coli were explored by the viable cell counting method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1357–1361, 2002     

Novel pH,ion sensitive polyampholyte gels based on carboxymethyl chitosan and gelatin

Natural pH and ion sensitive polyampholyte gels were successfully prepared by blending carboxymethyl chitosan (CM‐chitosan) and gelatin using glutaraldehyde as crosslinking agent. Their swelling behaviour under the influence of pH and ionic strength of the solution has been studied, and molecular interaction and, morphology of the gels were investigated by infrared spectroscopy and scanning electron microscopy. At the isoelectric point (IEP) the blend gels shrunk most, and when pH deviated from the IEP they behaved as polycations or polyanions. A decrease in swelling degree (D_s) with rising NaCl concentration up to 0.15 M was observed for all gels, while addition of Ca²⁺ made them shrink due to formation of Ca²⁺ crosslinked bridges. The blended gels showed increasing sensitivity to pH and ionic strength as the weight fraction of CM‐chitosan increased. Two essential components seem to regulate the swelling behaviour of blended gel: the first is related to osmotic pressure difference caused by the redistribution of mobile ions; the second is related to the possible formation of interactions corresponding to hydrogen bonding and hydrophobic interactions. © 2003 Society of Chemical Industry     

Preparation,evaluation, and in vitro release study of O‐carboxymethyl chitosan nanoparticles loaded with gentamicin and salicylic acid

To inhibit the ototoxicity of gentamicin (GM) and overcome the drawback related to chitosan (CS) nanoparticles preparation in acid solution, O‐carboxymethyl chitosan (O‐CMC) nanoparticles loaded with GM and salicylic acid (SA) were prepared by ionic cross‐linking method using calcium chloride as crosslinking agent. The Fourier transform infrared (FTIR) spectroscopy and X‐ray diffraction (XRD) were used to analyze the reaction of O‐CMC and crosslinking agent. The parameters of preparation of the compound nanoparticles including the concentration of O‐CMC, the mass ratio of O‐CMC to calcium chloride, and the feed ratio of SA to GM were investigated. The results showed that the obtained nanoparticles had a high zeta potential and drug‐loading capacity. The nanoparticles were characterized by a spherical morphology, with average size ranging from 148 to 345 nm and a narrow particle size distribution. In vitro release studies in phosphate buffer saline (pH 7.4) evidenced a burst release in the first 1 h, followed by a sustained release in the residual time. The release amount of SA and GM were approximately equal in 24 h, which indicated that the SA‐ and GM‐loaded O‐CMC nanoparticles are a promising carrier system for inhibiting the ototoxicity of GM. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis,characterization, and anticoagulant activity of carboxymethyl starch sulfates

To develop a renewable and compatible anticoagulant as potential heparin alternative, carboxymethyl starch sulfate (CMSS) was prepared by the reaction of carboxymethyl starch (CMS) and sulfating reagent [N(SO₃Na)₃]. The chemical structures of CMS and CMSS were characterized by Fourier transform infrared spectroscopy and ¹³C nuclear magnetic resonance. The influences of reaction parameters, including the pH of sulfating reagent, the molar ratio of sulfating reagent to CMS, reaction time, and temperature on the degree of substitution of sulfate groups (DS) of CMSS were studied. Meantime, the DS of each CMSS was determined by barium sulfate–glutin nephelometery method. Moreover, the anticoagulant activity of CMSS was investigated by the coagulation assays of activated partial thromboplastin time, thrombin time, and prothrombin time. The results revealed that the anticoagulant activity of CMSS was closely related to the DS value and concentration. The anticoagulant activity was promoted with the increasing of the DS and concentration. The molecular weight (M_w) in measured range had little impact on anticoagulant activity in contract to the DS and concentration. In this article, the CMSS with the DS of 1.91, concentration of 75 μg/mL and the M_w of 2.61 × 10⁴ had the best blood anticoagulant activities. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Chelation of chitosan derivatives with zinc ions. I. O,N‐carboxymethyl chitosan

The chelation between O,N‐carboxymethyl chitosan (ONCMCh) and zinc sulfate in aqueous solution was studied by kinetic experiments and characterized by inductively coupled plasma (ICP) and UV spectrophotometry. The experimental data indicated that the chelating processes were greatly controlled by the reaction conditions (i.e., reaction time, temperature, and Zn²⁺ ionic and ligand concentrations). The consequence of chelating Zn²⁺ onto ONCMCh was the formation of complexes with different solubilities. The favorable complexes for ONCMCh‐Zn²⁺ chelate were at the low zinc ionic and ligand concentrations, as well as at the appropriate temperature. The evidence provided by the kinetic parameters and the changes in zinc concentration by ICP analysis further confirmed the plausible complexing mechanisms. While the formation of water‐soluble products was occasioned by the electrostatic attraction mechanism, the water‐insoluble products were predominantly formed by chelation of Zn²⁺ with O,N‐carboxymethyl chitosan. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2246–2253, 2000     

叶酸偶联N-季铵化壳聚糖的制备及其基因载体性能

首先对壳聚糖进行季铵化改性合成N-季铵化壳聚糖（HTCC）,再接枝叶酸基团制备了叶酸偶联N-季铵化壳聚糖（FA-HTCC）,用FTIR和1H NMR等对产物进行表征,并对其作为基因载体进行研究。结果表明,合成产物具有较好的水溶性,N/P为4的FA-HTCC/DNA复合物粒径为188 nm、Zeta电位为15.4 mV。与PEI和阳离子脂质体相比,FA-HTCC具有更低的细胞毒性和更高的转染效率。     

三苯基锡壳聚糖羧酸酯的表征与杀螺活性研究

以羧甲基壳聚糖(CMC-Na)为接枝骨架、三苯基氯化锡(Ph_3SnCl)为接枝单体,用80%的甲醇水溶液作溶剂在20℃反应2 d,合成了三苯基锡壳聚糖羧酸酯(CMC-SnPh_3),借助红外光谱、热重分析、差热分析、X射线衍射等分析手段对CMC-SnPh_3的结构进行了表征,并进行杀钉螺活性实验。结果表明:分析的谱图数据与CMC-SnPh_3的结构相符,证明CMC-SnPh_3接枝共聚物的生成;CMC-SnPh_3的浓度大于10 mg/L时,能抑制钉螺七爬,CMC-SnPh_3的浓度大于1 mg/L,室温浸泡3 d后,钉螺的死亡率达100%,该接枝共聚物具有高效杀钉螺活性。     

Synthesis and antimicrobial activity of Schiff base of chitosan and acylated chitosan

Chitosan, a biocompatible, biodegradable, nontoxic polymer, is prepared from chitin, which is the second most naturally occurring biopolymer after cellulose. Schiff base of chitosan, sorbyl chitosan, and p‐aminobenzoyl chitosan were synthesized working under high‐intensity ultrasound and their antimicrobial properties were analyzed against Escherichia coli, Staphylococcus aureus, and Aspergillus niger. The structures of the derivatives were characterized by FTIR spectroscopy and elemental analysis. The results of antimicrobial activities indicated that the antimicrobial activities of the derivatives increased with increasing the concentration. The antibacterial activity of schiff base of chitosan against E. coli was stronger, while acylated chitosan had better inhiting effect on S. aureus than others. It was also found that the antifungal activities of the derivatives were stronger than that of chitosan, and schiff base of chitosan was obviously superior to acylated chitosan. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012