光热敏感型羧甲基壳聚糖纳米微球的制备及光热性能

羧甲基壳聚糖因其具有良好的水溶性和生物相容性,被广泛应用于生物医学领域。以天然可降解高分子羧甲基壳聚糖为载体,在引发剂过硫酸钾的作用下,通过自由基组合法将N-异丙基丙烯酰胺接枝到羧甲基壳聚糖上,然后在香草醛的交联作用下,采用乳化交联法制备一种负载光敏剂吲哚菁绿(ICG)的新型光热敏感型羧甲基壳聚糖微球,通过傅里叶红外(FT-IR)、核磁(1H-NMR)及扫描电镜(SEM)对共聚物结构及微球形貌进行表征,考察了油水比、转速、香草醛、乳化时间对该纳米微球包载阿霉素载药量的影响,并研究了其光热性能。结果表明,FT-IR和1H-NMR分析证明,N-异丙基丙烯酰胺成功接枝到羧甲基壳聚糖上;SEM分析可知,纳米微球外观呈球状,分布均匀,平均粒径为143 nm。油水比为20∶1,转速为600 r/min,香草醛量为1 mL,乳化时间3 h的微球载药量最高为19.32%。同时,通过改变外界环境条件,纳米微球能缓慢靶向释放药物,具有良好的光热敏感性,该纳米微球在药物控释及药物载体等领域有广泛的应用前景。     

多功能壳聚糖水凝胶医用材料的功能性研究

作为一类兼具应用价值和经济效益的新型功能高分子材料,水凝胶越来越受关注。以天然可降解的壳聚糖为载体,通过自由基接枝共聚法制备了壳聚糖水凝胶,重点研究了其吸附性及药物控释性能。结果表明:该水凝胶20d左右可以完全降解,降解性能良好。在25℃条件下,铜离子浓度为1200mg/L时,壳聚糖水凝胶对铜离子的平衡吸附量可达225.8mg/g。以亚甲基蓝为药物模型的控释实验结果表明,温度以及初始药物投加量对控释性能影响较大,48h累积释放率达70%左右,可在一定程度上实现缓释控释效果。     

果胶@壳聚糖复合凝胶微球的制备及释药性能EI

文中以天然多糖果胶和壳聚糖为原料,采用乳化交联的方法制备了果胶酸锌微球,再通过自组装壳聚糖层并用柠檬酸钠固化,得到了核壳结构的凝胶微球,将药物奥沙拉嗪封装在凝胶微球中,考察了其药物缓释性能。通过红外光谱、扫描电镜、能谱分析和荧光显微镜对微球形貌和核壳结构进行了表征。通过单因素变量法对凝胶微球的制备进行了优化,并对微球的药物负载性能及在模拟结肠环境中的释药行为进行了研究。结果表明,果胶@壳聚糖载药微球的最高载药量和包封率分别为29.4%和37.3%,果胶@壳聚糖复合载药微球在pH=7.4的模拟结肠液中,前12 h内的释放量仅为35.29%,72 h后奥沙拉嗪的释放量达到了89.90%,而纯果胶载药微球前12 h的释放量就已经高达78.65%,体现了壳聚糖包封层在药物缓释中的重要性。锌离子在果胶@壳聚糖复合微球和果胶微球中的释放趋势与奥沙拉嗪一致,相比于果胶微球,果胶@壳聚糖复合微球具备良好的缓释性能,可用于治疗结肠炎症疾病。     

果胶@壳聚糖复合凝胶微球的制备及释药性能EI北大核心CSCD

文中以天然多糖果胶和壳聚糖为原料,采用乳化交联的方法制备了果胶酸锌微球,再通过自组装壳聚糖层并用柠檬酸钠固化,得到了核壳结构的凝胶微球,将药物奥沙拉嗪封装在凝胶微球中,考察了其药物缓释性能。通过红外光谱、扫描电镜、能谱分析和荧光显微镜对微球形貌和核壳结构进行了表征。通过单因素变量法对凝胶微球的制备进行了优化,并对微球的药物负载性能及在模拟结肠环境中的释药行为进行了研究。结果表明,果胶@壳聚糖载药微球的最高载药量和包封率分别为29.4%和37.3%,果胶@壳聚糖复合载药微球在pH=7.4的模拟结肠液中,前12 h内的释放量仅为35.29%,72 h后奥沙拉嗪的释放量达到了89.90%,而纯果胶载药微球前12 h的释放量就已经高达78.65%,体现了壳聚糖包封层在药物缓释中的重要性。锌离子在果胶@壳聚糖复合微球和果胶微球中的释放趋势与奥沙拉嗪一致,相比于果胶微球,果胶@壳聚糖复合微球具备良好的缓释性能,可用于治疗结肠炎症疾病。     

抗菌活性微球与PVA静电纺复合纤维膜的构建与其长效缓释性能研究

姜科药物姜黄素具有消毒杀菌、抗炎抗癌等多重医药作用，是理想的天然药物材料，但是其稳定性较差，吸收率较低，在人体中代谢较快，导致其生物利用度较低。通过反向乳液聚合制备了壳聚糖/姜黄素微球，并利用静电纺丝技术将其与聚乙烯醇(PVA)混纺制备成壳聚糖/姜黄素微球与PVA共混纤维膜。通过红外光谱和扫描电镜(SEM)对得到的纳米纤维膜进行性能表征，并通过调控微球与PVA比例提高纳米纤维膜的力学性能、缓释性能以及抑菌率。结果表明：当微球与PVA质量比为1∶5时，共混纤维膜机械性能最佳；药物累计释放测试结果表明，体外释放时长可达54h,缓释曲线符合Ritger-Peppas模型；抗菌测试结果表明，对于金黄色葡萄球菌，载药纤维膜的抑菌率可达99.9%。     

光热/pH响应B-CuS-DOX纳米药物用于化疗-光热协同治疗肿瘤

基于纳米材料的化疗-光热协同治疗是一种高效的肿瘤治疗方式, 但如何构建具有高载药量与良好光热转换性能的纳米药物依然面临挑战。本研究通过超声剥离法制备二维硼(boron, B)纳米片, 进一步在其表面原位负载超小粒径硫化铜(CuS)纳米颗粒和化疗药阿霉素(DOX), 形成B-CuS-DOX纳米药物。B-CuS具有高的DOX药物装载能力(864 mg/g)和优异的光热转化性能(在808 nm处的光热转换效率为55.8%), 同时可实现pH及近红外激光双重刺激响应而释放药物。细胞实验表明在808 nm近红外光的照射下, B-CuS-DOX展示了良好的化疗-光热协同治疗效果。本研究构建的纳米药物有望为体内肿瘤治疗提供一种有效的化疗-光热协同治疗策略。     

含磷酰胆碱壳聚糖水凝胶的控释性能研究

将聚阳离子壳聚糖(CS)与聚阴离子甲基丙烯酰氧乙基磷酰胆碱-甲基丙烯酸二元共聚物[poly(MPC-coMA),PMA30]通过聚电解质静电复合制备CS/PMA30水凝胶。然后,分别以中性红为模型药物,对CS/PMA30水凝胶的控释性能进行研究。结果表明:该CS/PMA30体系可以有效地控制中性红的释放速率,具有pH响应性及生物相容性,有望在药物控释、组织工程等领域具有巨大的应用前景。     

1,2-苯并异噻唑啉-3-酮-壳聚糖缓释微球的制备及其性能研究

利用乳化交联法制备了1,2-苯并异噻唑啉-3-酮-壳聚糖缓释微球,通过扫描电子显微镜(SEM)、动态光散射(DLS)、傅里叶变换红外光谱(FT-IR)、X射线衍射和热重-差热分析等检测手段考察分析了微球的性能,并通过体外模拟释放探讨了其控释性能。结果表明:所制备的微球表面光滑,成球性好,分散性能优异,微球粒径主要集中在3~8μm范围内,BIT分子以物理包埋的方式与壳聚糖分子之间相结合,并被壳聚糖分子完全包裹;模拟释放实验表明,BIT-CSM可实现BIT的长期稳定释放,具有一定的控释效果。     

聚苯乙烯/纳米金刚石复合微球的制备及性能测定

以纳米金刚石为乳化剂,BPO为引发剂,利用Pickering效应成功合成得到了聚苯乙烯/纳米金刚石复合微球.XRD、TDA-DTA、TEM、BET以及FT-IR分别进行了结构表征.研究结果表明,在聚苯乙烯/纳米金刚石复合微球中,纳米金刚石晶体为立方相,聚苯乙烯为无定形态,颗粒径粒大约为40～70nm,分散较好,比较面积达到230m2/g,该复合材料具有良好热稳定性.进一步的力学系性能测定表明,随着聚苯乙烯/纳米金刚石复合微球添加应用,聚苯乙烯的拉伸强度、断裂伸长率性能得到了明显地改善,但弯曲强度性能有所下降.     

壳聚糖/羟基磷灰石复合微球的原位合成及体外释药性能

采用原位合成法在乳液体系中制备了壳聚糖/羟基磷灰石(HA)复合微球,并探讨了实验条件对复合微球制备的影响。结果表明,当壳聚糖/HA质量比为4/1时,可以获得球形规则,分散性好,平均粒径为9μm的复合微球。此外,NaOH溶液(1mol/L)的加入量应不少于3mL;交联剂(1mL)的最佳加入浓度为8%;向油相中先加入钙盐比先加入磷酸盐时的成球效果好。以盐酸四环素为模型药物,对复合微球的体外载药和释药性能进行了研究。结果显示,HA的引入大大提高了药物的包封率和载药量,而且使得复合微球比纯壳聚糖微球具有更显著的药物缓释效果。     

Properties of copper-detonation nanodiamond composites obtained by spray drying

Nanostructural copper-detonation nanodiamond (DND) composites have been obtained by the method of spray drying. The technological process consists in spraying and drying a mixture of an aqueous copper salt solution and DND suspension, followed by thermal treatment in a reductive atmosphere. The DND content in copper powder was varied from 0.5 to 5.0 mass %. The average DND particle size in suspension was 4–6 nm. Copper-DND nanocomposite powders consist of nearly spherical particles with average size within 20–30 μm. Composition and structure of obtained materials have been studied.     

两种核-壳结构复合微球对聚丙烯的改性研究

以吸附自组装和共缩聚法制备的PS/MCM-41-g-MPS和P(St-MPS)/MCM-41两种具有不同界面作用的"核-壳"结构复合微球为填料,对聚丙烯(Polypropylene, PP)进行改性,研究了复合微球种类及用量对PP力学与结晶性能的影响.结果表明:两种复合微球的添加均可以显著提高PP的力学性能,在复合微球...     

5-Fluorouracil encapsulated HA/PLGA composite microspheres for cancer therapy

5-Fluorouracil (5FU) was successfully entrapped within poly(lactide-co-glycolide) (PLGA) and hydroyapatite (HA) composite microspheres using the emulsification/solvent extraction technique. The effects of HA to PLGA ratio, solvent ratio as well as polymer inherent viscosity (IV) on encapsulation efficiency were investigated. The degradation and drug release rates of the microspheres were studied for 5?weeks in vitro in phosphate buffered solution of pH 7.4 at 37?°C. The drug release profile followed a biphasic pattern with a small initial burst followed by a zero-order release for up to 35?days. The initial burst release decreased with increasing HA content. The potential of HA in limiting the initial burst release makes the incorporation of HA into PLGA microspheres advantageous since it reduces the risk of drug overdose from high initial bursts. The linear sustained drug release profile over the course of 5?weeks makes these 5-FU-loaded HA/PLGA composite microparticles a promising delivery system for the controlled release of chemotherapy drugs in the treatment of cancer.     

负载淫羊藿苷的丝蛋白/β-磷酸三钙复合骨修复材料制备及性能

在多孔β-Ca_3(PO_4)_2(β-TCP)表面沉积含有淫羊藿苷(ICA)的丝蛋白(SF)层,制备可缓释ICA的SFICA/β-TCP骨修复复合材料,研究SF-ICA/β-TCP复合材料的相关性能。结果表明,SF-ICA/β-TCP复合材料中ICA的引入并未改变基体材料的微观形貌与孔隙率;体外释放实验表明,通过负载量的调控,可以实现SF-ICA/β-TCP复合材料中ICA的高浓度释放(2.80×10~(-4) mg/mL至7.00×10~(-4) mg/mL)和低浓度释放(5×10~(-6) mg/mL至1.0×10~(-5) mg/mL),累计释放量分别达到约5.2×10~(-3) mg和7.0×10~(-5) mg;细胞增殖实验与电镜观察表明,SF-ICA/β-TCP复合材料中ICA的负载对小鼠颅顶前骨细胞的增殖无显著性影响;但碱性磷酸酶活性检测实验表明,负载高含量ICA的SF-ICA/β-TCP复合材料中的细胞具有较高的碱性磷酸酶表达。所制备的负载ICA的SFICA/β-TCP复合材料在体内骨修复领域具有潜在的应用前景。     

In vitro release kinetics and physical, chemical and mechanical characterization of a POVIAC ? /CaCO 3 /HAP-200 composite

Coralline calcium-hydroxyapatite and calcium carbonate from Porites Porites coral were added to a polymeric matrix based on polyvinyl acetate (POVIAC^?), to obtain a novel bone substitute composite as well as a system for the controlled drug (cephalexin) release. Composite samples with different compositions were characterized by physical–chemical and mechanical methods. Furthermore, the in vitro release profile of cephalexin and the kinetic behavior of its release from these composites were analyzed by appropriate mathematical models. It was shown that there is no chemical interaction between the inorganic filler and the polymer matrix, each conserving the original properties of the raw materials. The compressive mechanical strength and Young modulus of the composite with 17.5% of POVIAC^?, has better mechanical properties than those of cancellous bone. The variation of POVIAC^? content can affect the cephalexin release kinetic in the composite. The cephalexin release mechanism from the composites can be considered as the result of the joint contribution of a prevailing Fickian diffusion and of polymer chain relaxation. It was also demonstrated that cephalexin is occluded inside the composites and not on their surface.     

Surface functionalization and structure characterizations of nanodiamond and its epoxy based nanocomposites

The aim of this study is the potential use of nanodiamond to make the lightweight and strong nanocomposites. Here, effects of size and surface modification of detonation nanodiamond (DND) on mechanical performance of epoxy based nanocomposites is presented. Our characterizations reveal that the process of functionalization not only removes the non-diamond content and impurities by significantly reducing DND's size but also introduces oxygen containing functional groups on its surface. The average size of functionalized DND aggregations could be decreased from 300 to 100 nm in contrast to pristine DND, which greatly benefits its homogeneous dispersion in epoxy matrix. In addition, strong chemical bonding among functionalized DND and epoxy resin due to functional groups leads to the formation of efficient interface. These interfaces overlap at high concentrations making a network which in turn significantly enhances the tensile properties. The enhancement in Young's modulus can reach up to 2.5 times higher than that of neat epoxy whereas the enhancement in tensile strength is about 1.5 times in functionalized DND/epoxy nanocomposites.     

Screening of elemental impurities in commercial detonation nanodiamond using sector field inductively coupled plasma-mass spectrometry

The quantitation of 55 elemental impurities in 15 commercial samples of detonation nanodiamond (DND), micron-sized diamond of high pressure/high temperature synthesis and detonation synthesis soot (DS) was achieved using a direct sector field ICP-MS analytical method. A set of 23 elements contributing more than 99.8 mass % of all impurities was selected and used as markers for the evaluation of DND purity. Obtained data were evaluated to identify important information on possible sources of nanodiamond contamination during purification, disaggregation, solubilisation or stabilisation of suspensions. Distinctive groups of elements (including Cr, Mn and S; Mo, W, V and Ti; Na, B and Si; Ca and Mg) occurring at elevated levels in DND can be readily visualised using radar plots, and can be related to the detonation synthesis (construction materials of explosion chamber, admixture in coolant, detonator type) and/or purification processes (type of oxidation process and reagents). The contaminant profile for each respective DND can be also considered as a fingerprint, characteristic for every producer and technology used. Results obtained also highlight how DND can be considered as effective collectors of various inorganic impurities from chemical reagents, glassware, sonotrode and other materials used during processing, including disaggregation and stabilisation of suspensions.     

Fabrication,characterization and long-term in vitro release of hydrophilic drug using PHBV/HA composite microspheres

In this paper, we fabricated polyhydroxybutyrate-co-hydroxyvalerate (PHBV)/Hydroxyapatite (HA) composite microspheres as a long-term drug delivery system. The characterization and in vitro release properties of the system were investigated. It was observed that the PHBV/HA composite microspheres showed very low initial burst that could be neglected, owing to the high affinity and absorbability of nano-HA particles, and the sustained release lasted more than 10 weeks. The in vitro release rate was controlled by diffusion rate of drugs from polymer matrices, and the release profile can be expressed by the Higuchi equation. From our work, it indicated that PHBV/HA composite microsphere could be a promising long-term drug release system.     

Alginate microsphere-collagen composite hydrogel for ocular drug delivery and implantation

A composite collagen hydrogel containing protein encapsulated alginate microspheres was developed for ocular applications. Bovine serum albumin (BSA) served as a drug model. The composite hydrogel retained optical clarity and mechanical robustness of control hydrogels without microspheres. A sustained release of BSA was achieved during an 11-day period in neutral phosphate buffer. The composite hydrogel supported human corneal epithelial cell growth and had adequate mechanical strength and excellent optical clarity for possible use as therapeutic lens for drug delivery and/or use as corneal substitute for transplantation into patients who have corneal diseases.