超临界CO_2中pH-响应型壳聚糖膜的制备及性能

以壳聚糖为膜基材,制备壳聚糖基多孔膜,并在超临界二氧化碳中,以丙烯酸(AA)和4-乙烯基吡啶(4-VP)为接枝共聚单体,对壳聚糖多孔膜进行接枝,制备了p H-响应型壳聚糖多孔膜。采用傅里叶变换红外光谱和X射线衍射等对接枝膜的结构进行表征,考察了2种接枝单体的摩尔比及反应压力对壳聚糖膜接枝率的影响,以及接枝膜对蛋白质的吸附。红外结果表明聚丙烯酸与聚4-乙烯基吡啶均接枝到壳聚糖膜上。当AA/4-VP单体摩尔比由3∶1增加至6∶1时,接枝率由7.12%逐渐增大至13.36%,此后呈下降趋势。且随着反应压力的提高,壳聚糖膜接枝率先增长后降低,当反应压力在19 MPa时,得到较高的接枝率(13.36%)。当溶液p H=2~10时,壳聚糖接枝膜的水通量随着p H值的增大而降低。蛋白质吸附实验显示,在p H为4.8时接枝膜获得最大比表面积吸附量5.76 mg/cm2。     

接枝层厚度对聚(N-异丙基丙烯酰胺)改性表面与蛋白质相互作用的影响

采用表面引发原子转移自由基聚合(ATRP)的方法制备了聚(N-异丙基丙烯酰胺)(PNIPAAm)改性表面,通过改变聚合时间进而调控表面接枝层厚度.水接触角和蛋白质吸附测试发现PNIPAAm改性表面的浸润性和对蛋白质吸附都具有一定的温度响应性,且随着PNIPAAm接枝层厚度的增加,该温度响应性有一定程度的增强.同时,纤维蛋白原和溶菌酶的吸附测试表明PNIPAAm改性表面对尺寸不同的蛋白质具有不同的温度响应性.     

羟基磷灰石接枝壳聚糖表面改性及其复合水凝胶的生物相容性

用壳聚糖修饰HA表面制备HA-接枝-壳聚糖纳米羟基磷灰石(HA-g-CS),然后将其与壳聚糖共混制成CS/HA-g-CS复合水凝胶。FTIR、TGA、XRD的测试结果表明,CS已经成功地接枝到HA的表面,接枝率为15.8%;SEM结果表明,HA-g-CS在CS基体的分散性相对于HA得到明显的改善,且CS/HA-g-CS比CS/HA复合水凝胶的抗压强度提高了43%。CS/HA-gCS生物相容性评价的结果表明,材料的细胞毒性和植入安全性均达到了国家标准要求。这表明,CS/HA-g-CS复合水凝胶可作为一种优良的支架材料应用于组织工程领域。     

SBA-15介孔硅片胺基修饰及其CO_2吸附

以3-氨基丙基三乙氧基硅烷(APTS)和N-[3-(二甲氧基甲硅烷基)丙基]乙二胺(TPED)为表面胺基修饰剂,通过化学接枝法制备了胺基修饰的SBA-15介孔硅片(SBA-15-EHP)吸附剂。采用SEM、全自动气体吸附仪、XRD、TGA等测试手段对胺基修饰的SBA-15-EHP进行表征,研究了胺基修饰的SBA-15-EHP的表面形貌,孔隙结构,晶体结构,SBA-15-EHP表面胺基的接枝量及CO_2的吸附特性。结果表明,在常压、35℃下,TPED修饰的SBA-15-EHP的CO_2吸附能力优于APTS修饰的SBA-15-EHP,最大的CO_2吸附容量为53.0mg/g,这是由于胺基与CO_2发生酸碱反应形成盐类的可逆化学吸附过程所致。     

壳聚糖与羧甲基壳聚糖蛋白质印迹聚合物的制备及吸附性能

首先制备了壳聚糖的衍生物——羧甲基壳聚糖,再以壳聚糖与羧甲基壳聚糖的共混物为功能单体,牛血清白蛋白(BSA)为模板蛋白质,制备了一种壳聚糖与羧甲基壳聚糖共混物的蛋白质印迹聚合物。模板蛋白质吸附测试结果表明,该蛋白质印迹聚合物对BSA的吸附量是非印迹聚合物的30.8倍;对不同蛋白质的吸附测试结果表明,相比于其它对比蛋白质,该蛋白质印迹聚合物具有良好的选择性吸附模板蛋白质BSA的效果;并且该蛋白质印迹聚合物具有良好的可重复使用性能。     

壳聚糖异相接枝L-谷氨酸甲酯的合成研究

在乙酸乙酯溶剂的异相条件下,以壳聚糖的氨基引发N-羧酸酐(NCA)开环聚合,制备了接枝L-谷氨酸甲酯壳聚糖产物.异相接枝反应中,增加NCA的用量和适当延长反应时间,可提高谷氨酸甲酯接枝侧链聚合度.IR、CP/MAS-13CNMR结果表明,谷氨酸甲酯侧链通过酰胺键与壳聚糖结合,形成梳状接枝产物.XRD和DSC、TG/DTG测试发现,接入谷氨酸甲酯侧链引起的异相接枝物的结构谱图和热稳定性较原料有明显改变,反映了壳聚糖接枝产物结构和接枝量的差异性.反应体系有利于壳聚糖材料的表面接枝改性氨基酸,赋予材料独特的生物活性.     

聚偏氟乙烯膜表面丙烯酸接枝改性研究

采用自由基接枝聚合反应制备了丙烯酸改性的聚偏氟乙烯膜,研究了单体浓度对接枝率的影响,测定了改性后样品的红外光谱、表面接触角、水通量、蛋白吸附等.结果表明,通过自由基接枝聚合,丙烯酸接枝到膜的表面,明显提高膜的亲水性.接枝后膜的水通量也非常明显下降,特别是在高丙烯酸浓度下.改性的膜的通量对溶液的pH值有明确的响应关系,表明接枝链在水中的溶胀对膜的性能有显著的影响.蛋白吸附实验表明,改性后的膜相比未改性膜有较高的吸附量,而且在酸性情况下,膜的吸附量较大,这主要与丙烯酸和蛋白质之间的相互作用有关.     

壳聚糖接枝聚合物的制备及其性能研究

以壳聚糖与丙烯酰胺和丁烯二酸为原料,采用过硫酸钾引发接枝聚合反应,探究了引发剂用量、反应温度、单体的用量以及反应时间对接枝反应的影响。并用红外光谱仪对产物进行了表征,探究了接枝产物对铅离子的吸附以及解吸附性能。实验结果如下,接枝聚合物的最佳反应条件为:引发剂用量为6mmol/L,反应温度为50℃,接枝单体与壳聚糖质量比为3∶1,反应时间为4h;红外光谱显示两个单体已经成功地接枝到了壳聚糖分子上;接枝聚合物相比壳聚糖对铅离子的吸附性能有了很大的提高;以去离子水、HNO3和HCl为解吸附溶液,接枝聚合物在HNO3和HCl中的解吸附效果较好,分别达到了93.5%和65%。     

漆酶催化原儿茶酸与壳聚糖接枝反应机理的初步探究

在非均相条件下,利用漆酶催化氧化原儿茶酸使其接枝到壳聚糖进行改性,初步探究改性过程中,反应体系各组分相对浓度的变化、改性壳聚糖上原儿茶酸的接枝反应历程以及改性壳聚糖抗氧化性能的提升效果。通过React IR(反应红外)分析表明壳聚糖先将原儿茶酸吸附到固相之后才发生进一步反应,通过Py-GC/MS(裂解气相色谱质谱联用)分析表明接枝反应后原儿茶酸是通过化学键连接到了壳聚糖,利用Solid-state 13C NMR(固体核磁共振)和FT-IR(红外光谱)检测到接枝前后新的化学键生成,进一步表明原儿茶酸通过化学键接枝到了壳聚糖,通过ABTS法测定接枝反应前后壳聚糖的抗氧化性能,发现接枝后壳聚糖抗氧化性能的提高显著。     

膜表面纳米TiO_2修饰层的构建及其抗蛋白质污染性能研究

采用纳米二氧化钛胶体和多巴胺作为修饰剂,通过多巴胺的氧化自聚将纳米二氧化钛颗粒沉积到聚丙烯微孔膜(MPPM)的表面.采用FTIR和SEM对膜进行了表征,发现修饰后膜表面多孔形态未发生变化,仅在膜表面均匀地负载着大量的纳米TiO_2颗粒.静态水接触角及纯水通量测试结果显示,修饰膜具有优异的润湿性,在0.10MPa下,MPPM的纯水通量为0,而经纳米TiO_2修饰后的膜纯水通量可稳定在4 625L/(m2·h)左右.蛋白质静态吸附与蛋白质溶液过滤研究结果表明,修饰膜具有良好的抗蛋白质污染性能,蛋白质溶液通量下降率仅为35%,且膜表面的蛋白质可用水清洗除去,通量恢复率达83%.     

壳聚糖修饰银纳米颗粒的制备及抗菌性能研究

采用液相化学还原法,以壳聚糖为修饰剂,硼氢化钠为还原剂,制备了壳聚糖修饰银纳米颗粒(chitosan-Ag NPs)。通过X射线粉末衍射仪、透射电子显微镜、傅立叶变换红外光谱仪等对所制备样品的结构和形貌进行了表征。结果表明,所制备纳米颗粒具有面心立方Ag的晶型结构,壳聚糖通过氨基和羟基中的N、O原子与Ag+的化学键合作用修饰在纳米颗粒表面,起到了限制颗粒粒径长大和防止其团聚的作用。采用肉汤连续稀释法检测了样品对大肠杆菌和金黄色葡萄球菌的抑菌杀菌性能,结果表明chitosan-Ag NPs具有优异的抗菌性,抗菌性能受到粒径大小的影响。     

C6位选择性氧化竹浆纤维的壳聚糖改性处理

采用H_3PO_4/HNO_3-NaNO_2氧化体系对竹浆纤维C6位进行选择性氧化,然后与壳聚糖溶液交联反应制备生态的抗菌壳聚糖改性竹浆纤维。固相CP/MAS 13 C核磁共振分析显示,H_3PO_4/HNO_3-NaNO_2已将竹浆纤维C6位上的伯羟基选择性氧化成羧基,且红外光谱和扫描电镜测试表明,壳聚糖的氨基与氧化竹浆纤维分子上的羧基发生酰胺化反应,壳聚糖分子通过C-N化学键共价交联在竹浆纤维上,并在竹浆纤维表面形成壳聚糖薄膜。通过分析H_3PO_4/HNO_3-NaNO_2氧化和壳聚糖处理过程中竹浆纤维羧基含量、机械强力、壳聚糖含量等指标,得出最佳工艺参数。Kjeldahl定氮分析得出壳聚糖在氧化竹浆纤维上的最大含量为3.92%。壳聚糖接枝竹浆纤维的断裂强度变化不明显,但其断裂伸长率降低。抗菌试验结果显示,与壳聚糖处理的原竹浆纤维抗菌性相比,壳聚糖改性竹浆纤维对大肠杆菌和金黄色葡萄球菌的抗菌效果明显提高,抑菌率均在96%以上,且壳聚糖改性竹浆纤维具有良好的抗菌耐洗涤性能。     

Synthesis, characterization, and antibacterial activity of silver-doped silica nanocomposite particles

Silver nanoparticles were adsorbed preferentially on silica surface to form composite particles using a reverse micelle process that stabilizes the silver particles by an anionic sodium bis(2-ethylhexyl) sulfosuccinate (AOT) surfactant in isooctane solvent together with the silica particles in which their surface being mediated by a cationic poly(allylamine hydrochloride) (PAH) polyelectrolyte. The heterogeneous adsorption was rendered by both electrostatic attraction and hydrophilic/hydrophobic interaction, and was carried out in multiple deposition cycles. The resulting nanocomposite particles were characterized by zeta-potential measurement, electron microscopy, X-ray diffractometry, field-emission electron spectroscopy for chemical analysis (ESCA), and inductively coupled plasma analysis, respectively. In addition, antibacterial activity of the composite particles was examined against Escherichia coli (E. coli) in aqueous environment.     

壳聚糖脱乙酰度对海藻酸钠/壳聚糖微胶囊的表面性质及蛋白吸附的影响

采用流动电势技术、 接触角技术及表面轮廓技术分别考察了由不同脱乙酰度壳聚糖制备的海藻酸钠/壳聚糖(ACA)膜的表面电荷分布、 表面亲疏水性、 表面粗糙度, 并以纤维蛋白原为模型, 采用静态吸附实验技术考察了表面性质对蛋白在ACA微胶囊表面的吸附量及吸附构象的影响。结果表明, ACA微胶囊表面净电荷为负, 表面正电荷随脱乙酰度的降低而减少。由脱乙酰度60%~90%壳聚糖制备的ACA膜的表面接触角均为70°左右, 且无显著性差异。ACA微胶囊表面呈颗粒状结构, 表面粗糙度随壳聚糖脱乙酰度的降低而减小。蛋白吸附分析表明, "棒状"的纤维蛋白原分子以"侧向"和"直立" 2种形式吸附于ACA微胶囊表面。当壳聚糖脱乙酰度较低时, 蛋白吸附量较小, 且此时蛋白多以"直立"形式吸附。以上结果表明, 由壳聚糖脱乙酰度带来的ACA微胶囊表面性质差异不仅影响了蛋白吸附量, 而且影响了蛋白吸附方式。      

Hemocompatibility investigation of the NiTi alloy implanted with tantalum

A composite TiO₂/Ta₂O₅ nano-film has been formed on the NiTi shape memory alloy by Ta implantation. The wettability, protein adsorption, platelets adhesion and hemolysis tests are conducted to evaluate the hemocompatibility. The contact angle measurements showed that the surface of the NiTi alloy kept hydrophilic before and after Ta implantation, although the water contact angle increased with the increasing of implantation current. Both of the surface energy and the interfacial tension decreased after Ta implantation. The protein adsorption behavior was investigated by ¹²⁵I isotope labeling. The fibrinogen adsorption was enhanced by a high surface roughness or a large interfacial tension, while the albumin adsorption was insensitive to the surface modification. Platelet adhesion and activation were weakened and the hemolysis rate was reduced at least 46% after Ta implantation due to the decreased surface energy and improved corrosion resistance ability, respectively.     

Synthesis and characterization of waterborne polyurethane/Cu(II)-loaded hydroxyapatite nanocomposites with antibacterial activity

A novel kind of environmentally friendly nanocomposites, waterborne polyurethane (WBPU)/Cu(II)-loaded hydroxyapatite (CuHAp), with improved physical properties and antibacterial activity have been prepared via in-situ polymerization from functionalized CuHAp nanoparticles (CuHAp NPs). The interaction of the CuHAp NPs with isophorone diisocyanate to form the functionalized CuHAp NPs containing isocyanate groups (CuHAp-g-NCO) has been studied. The microstructure and particle distribution of the nanocomposites were observed using scanning electron microscopy. The improvements of mechanical properties, thermal stability and water resistance of the nanocomposites have also been evaluated. Finally, the antibacterial activity was tested against G(-) Escherichia coli and G(+) Staphylococcus aureus by the zone of inhibition test and the direct contact test. The long-lasting antibacterial activity was studied by measuring antibacterial ability of the nanocomposites after being immersed in water. The results indicate that WBPU incorporation with CuHAp NPs shows strong antibacterial activity upon contact, and long-lasting antibacterial property.     

氧等离子体注入对PET亲水性及抗菌性能影响

利用氧等离子体浸没离子注入技术对聚合物材料(PET)进行表面改性后接枝有机抗菌剂赋予PET薄膜抗菌性能.试验结果表明:PET薄膜表面接枝上的抗菌剂在改性表面呈针状分布.经氧等离子体处理后的PET薄膜表面水接触角从78°降低到33°.红外光谱显示PET薄膜表面的分子结构被破坏,苯环的对位氢发生取代反应,分子链中形成了C-O亲水基团.氧等离子体的注入时间和注入电压均对抗菌持久性有重要的影响,较高的注入电压能够使PET薄膜表面获得较深的改性层,利于改性表面亲水性的保持.注入时间超过10min,电压超过-10kV的样品在空气中放置40天后的抗菌率仍能达到90%以上.     

Antibacterial Performance of a Cu-bearing Stainless Steel against Microorganisms in Tap Water

Tap water is one of the most commonly used water resources in our daily life. However, the increasing water contamination and the health risk caused by pathogenic bacteria, such as Staphylococcus aureus and Escherichia coli have attracted more attention. The mutualism of different pathogenic bacteria may diminish antibacterial effect of antibacterial agents. It was found that materials used for making pipe and tap played one of the most important roles in promoting bacterial growth. This paper is to report the performance of an innovative type 304 Cu-bearing stainless steel(304Cu SS) against microbes in tap water. The investigation methodologies involved were means of heterotrophic plate count, contact angle measurements, scanning electron microscopy for observing the cell and subtract surface morphology,atomic absorption spectrometry for copper ions release study, and confocal laser scanning microscopy used for examining live/dead bacteria on normal 304 stainless steel and 304 Cu SS. It was found that the surface free energy varied after being immersed in tap water with polar component and Cu ions release.The results showed 304 Cu SS could effectively kill most of the planktonic bacteria(max 95.9% antibacterial rate), and consequently inhibit bacterial biofilms formation on the surface, contributing to the reduction of pathogenic risk to the surrounding environments.