羧甲基壳聚糖用作防止术后粘连的研究

本研究合成制备了N-羧甲基壳聚糖（N-CMC）、O-羧甲基壳聚糖（O-CMC）和N,O-羧甲基壳聚糖（N,O-CMC）;研究了它们的凝血性、体外酶解、抑菌性、对细胞生长的影响、对胶原合成的作用等生物特性;评价了它们的动物体内防粘连效果.研究结果表明,与N-CMC和N,O-CMC相比,O-CMC具有良好的凝血性,良好的生物降解性,轻微的抑菌活性,适度的抑制成纤维细胞增殖作用,轻微的抑制表皮细胞增殖作用,能抑制成纤维细胞胶原合成的能力,显示较好的防止术后粘连的效果,有希望成为新一代术后防止粘连材料.     

一种新型纳米基因载体的制备及体外实验

本实验以聚乳酸和O-羧甲基壳聚糖为基质材料，采用超声波法制备了聚乳酸-O-羧甲基壳聚糖纳米微球，并用环境扫描电镜和XPS对其进行了表征，将聚乳酸-O-羧甲基壳聚糖纳米微球携带寡核苷酸转染TJ905人脑胶质瘤细胞，并通过RT-PCR方法对细胞的转染情况作了一系列的体外检测，结果表明，携带寡核苷酸的聚乳酸-O-羧甲基壳聚糖纳米微球能有效地转染TJ905人脑胶质瘤细胞，同时也能有效地抑制胶质瘤细胞中端粒酶RNA，端粒酶催化亚基RNA的表达和端粒酶的活性，从而抑制人脑胶质瘤细胞生长，达到基因治疗的目的。     

羟丙基甲基纤维素(HPMC)在医用润滑液中增稠作用的研究

研究了羟丙基甲基纤维素(HPMC)对羧甲基壳聚糖(CMC)水溶液的增稠效果。保持溶液的总质量分数不变,依次改变羧甲基壳聚糖、羟丙基甲基纤维素的比例,分析溶液的动力粘度、特性粘数与溶液质量分数的关系,确定羧甲基壳聚糖和羟丙基甲基纤维素的最佳配比。结果表明,保持溶液的总质量分数不变,当溶液中的羟丙基甲基纤维素用量在0.5%~0.9%范围内时,溶液的动力粘度迅速增大,羟丙基甲基纤维素的增稠效果明显。     

纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的生物相容性与体内降解研究

对制备的纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的生物相容性及体内降解情况进行研究,为临床提供实验依据。参照GB/T16886医疗器械生物学评价标准和要求,对纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥进行急性细胞毒性试验、溶血试验、热源试验、急性全身毒性试验及体内植入试验等系列体内外生物学试验研究,以进行有效的生物相容性和安全性评价。纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的溶血率小于国家规定的5%,在体外不引起溶血反应;浸提液注入动物体内后无死亡,活动进食正常;无细胞毒性反应;热原试验动物体温升高均在0.7℃以下,3只兔体温升高值的总数〈1.5℃,无致热作用;材料植入体内初期有轻度炎症反应,随植入时间延长逐渐减轻,材料也逐渐降解吸收。纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥具有良好的生物相容性和降解性能,具有临床开发应用前景。     

纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的生物相容性与体内降解研究

对制备的纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的生物相容性及体内降解情况进行研究,为临床提供实验依据.参照GB/T16886医疗器械生物学评价标准和要求,对纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥进行急性细胞毒性试验、溶血试验、热源试验、急性全身毒性试验及体内植入试验等系列体内外生物学试验研究,以进行有效的生物相容性和安全性评价.纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的溶血率小于国家规定的5％,在体外不引起溶血反应;浸提液注入动物体内后无死亡,活动进食正常;无细胞毒性反应;热原试验动物体温升高均在0.7℃以下,3只兔体温升高值的总数＜1.5℃,无致热作用;材料植入体内初期有轻度炎症反应,随植入时间延长逐渐减轻,材料也逐渐降解吸收.纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥具有良好的生物相容性和降解性能,具有临床开发应用前景.     

三种水溶性壳聚糖的制备工艺研究

目的 壳聚糖具有优良的生物相容性和生物可降解性,但其亲水性较差难以满足组织工程的需要.为满足组织工程支架材料的需求,对壳聚糖进行羧甲基化改性,以期改善其溶解性能.方法 通过3种不同的方法来摸索3种不同取代位置的羧甲基壳聚糖(CMC)的制备工艺,分别考察了原料比、反应时间、反应温度等影响因素对产物取代度(DS)的影响.结果 摸索得到3种羧甲基壳聚糖的最佳制备工艺条件,以这种工艺条件制备产物水溶性良好.结论 通过羧甲基化反应可以大大改善壳聚糖的水溶解性能,为以后更深一步的研究提供了科研基础和实验依据.     

复合多糖聚合物的止血性能研究

观察复合多糖聚合物对动物的止血作用,并与进口多糖微球、羧甲基壳聚糖微球、淀粉微球进行比较。用新西兰白兔进行耳缘静脉、耳动脉、体表创面和肝脏止血试验,观察复合多糖聚合物及对照品对家兔的止血作用。复合多糖聚合物组与模型对照组相比,能明显缩短出血时间。家兔肝损伤模型,复合多糖聚合物的止血效果明显优于羧甲基壳聚糖微球组以及淀粉微球组;其他创伤模型,复合多糖聚合物与各止血对照组相比,止血效果相当。复合多糖聚合物对家兔耳缘静脉、耳动脉、体表创伤以及肝损伤均呈现明显的止血效果。复合多糖聚合物与羧甲基壳聚糖微球以及淀粉微球相比,有一定的优势;与进口对照品比较,无明显差异。     

三种水溶性壳聚糖的制备工艺研究

目的 壳聚糖具有优良的生物相容性和生物可降解性,但其亲水性较差难以满足组织工程的需要.为满足组织工程支架材料的需求,对壳聚糖进行羧甲基化改性,以期改善其溶解性能.方法 通过3种不同的方法来摸索3种不同取代位置的羧甲基壳聚糖(CMC)的制备工艺,分别考察了原料比、反应时间、反应温度等影响因素对产物取代度(DS)的影响.结...     

纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥与骨髓基质细胞的生物相容性*☆

背景：在前期的试验中,通过共沉淀法合成了纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合粉体,并与柠檬酸衍生物溶液调和制备出可生物降解、适当力学性能以及较好黏合强度的骨水泥。 目的：验证纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥材料对体外兔骨髓基质细胞黏附及增殖的影响,了解材料的生物相容性。 方法：应用共沉淀法制备纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合材料作为骨水泥的固相粉体,将柠檬酸衍生物配制成溶液作为液相调和制备黏合性骨水泥。培养兔骨髓基质细胞,传代扩增后接种到材料上,体外继续培养;以细胞加入无材料的培养皿培养为对照。 结果与结论：体外培养的兔骨髓基质细胞2 d后呈梭形成纤维细胞样,生长良好。有材料实验组细胞数显著多于对照组(P < 0.01)。扫描电镜下骨水泥材料具有良好的多孔网状结构,兔骨髓基质细胞伸出多个伪足样突起,紧密贴附在材料表面。两组细胞均保持持续增殖,2,4,6,和8 d实验组增殖均显著快于对照组(P < 0.01)。提示纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥材料具有良好的生物相容性。      

羧甲基壳聚糖复合纳米银、纳米氧化铜的制备及抑菌性研究

本研究在水热条件下利用羧甲基壳聚糖分别还原硝酸银和硫酸铜,得到稳定的羧甲基壳聚糖复合纳米银和纳米氧化铜,并测试其抑菌能力.表征测试显示,所制的纳米银为20～30 nm的球状结构,纳米氧化铜为80～100 nm的花瓣状结构,二者都均匀稳定地分布于羧甲基壳聚糖中.抑菌试验显示,不同浓度的羧甲基壳聚糖复合纳米银(A组2 mg...     

Superporous hydrogels containing poly(acrylic acid-co-acrylamide)/O-carboxymethyl chitosan interpenetrating polymer networks

Superporous hydrogels containing poly(acrylic acid-co-acrylamide)/O-carboxymethyl chitosan interpenetrating polymer networks (SPH-IPNs) were prepared by cross-linking O-carboxymethyl chitosan (O-CMC) with glutaraldehyde (GA) after superporous hydrogel (SPH) was synthesized. The structures of the SPH-IPNs were characterized with FT-IR, 13C-NMR and DSC. SEM, CLSM and light images revealed that the SPH-IPNs possessed both the IPN network and large numbers of pores and the cross-linked O-CMC molecules were located on the peripheries of these pores. The swelling behavior of SPH-IPNs was dependent on the O-CMC content, GA amount and cross-linking time. Due to the cross-linked O-CMC network, in vitro muco-adhesive force and mechanical properties, including compression and tensile modulus, of the SPH-IPN were greatly improved when compared with the CSPH. An enhanced loading capacity for insulin could be obtained by the SPH-IPNs as compared to non-porous hydrogel and CSPH, and more than 90% of the insulin was released within 1 h. With the improved mechanical properties, in vitro muco-adhesive force and loading capacities, the SPH-IPN may be used as a potential muco-adhesive system for peroral delivery of peptide and protein drugs.     

纳米高分子材料在抗癌药物控释方面的应用

本研究用“等电临界法”制备Ｏ－羧甲基甲壳胺甲氨喋呤毫微粒并在模拟人工胃液、肠液和１％新鲜小鼠血清中进行控释试验，结果表明抗癌药物与载体材料不同的投料比，交联剂用量及释药介质均对毫微粒的释药速度产生影响。本研究还采用ＳＥＭ和光子相关光谱对释药前后毫微粒的形态和粒径进行了定性和定量分析     

Study on Tat Mediated Magnetic Nanoparticles Having Composite Targeting Function

INTRODUCTION Therehasbeengreatinterestoverthepasttwodecadesindevelopingandtest-ingironoxidenanoparticlesfortumordetectionandtherapy.Inbrainresearch,nan-odispersedironoxideshavebeenusedforthemappingofblood-brainbarrier(BBB)disruption,ascarriersofdiagnosticandtherapeuticagentstoimprovetumordetec-tionandtherapy〔1～4〕.TheHIV-1Tatpeptideisan86aminoacidpolypeptideandisessentialforviral replication.Ithasbeenshowntofreelytravelthroughcellularandnucleicmem-branes.Itsmembranetranslocationalpro…     

Carboxymethylation of ulvan and chitosan and their use as polymeric components of bone cements

Ulvan, extracted from the green algae Ulva lactuca, and chitosan, extracted from Loligo forbesis squid-pen, were carboxymethylated, yielding polysaccharides with an average degree of substitution of ～98% (carboxymethyl ulvan, CMU) and ～87% (carboxymethyl chitosan, N,O-CMC). The carboxymethylation was confirmed by Fourier transform infrared spectroscopy and quantified by conductimetric titration and ¹H nuclear magnetic resonance. The average molecular weight increased with the carboxymethylation (chitosan, M_n 145→296 kDa and M_w 227→416 kDa; ulvan, M_n 139→261 kDa and M_w 368→640 kDa), indicating successful chemical modifications. Mixtures of the modified polysaccharides were tested in the formulation of polyacrylic acid-free glass-ionomer bone cements. Mechanical and in vitro bioactivity tests indicate that the inclusion of CMU in the cement formulation, i.e. 0.50:0.50 N,O-CMC:CMU, enhances its mechanical performance (compressive strength 52.4 ± 8.0 MPa and modulus 2.3 ± 0.3 GPa), generates non-cytotoxic cements and induces the diffusion of Ca and/or P-based moieties from the surface to the bulk of the cements.     

聚乳酸载药纳米微粒的表面修饰及体外评价

本研究的目的是用O 羧甲基壳聚糖作乳化剂和表面修饰剂 ,采用超声乳化法制备聚乳酸载药纳米微粒 ,并对聚乳酸载药纳米微粒进行表面修饰 ,然后分别对载药纳米微粒的表面形貌、粒径分布、微粒结构、表面元素、体外释放和肿瘤细胞抑制率等微粒性能进行考察与评价。实验证明 ,O 羧甲基壳聚糖可用于制备纳米药物载体系统 ,对聚乳酸载药纳米微粒的制备起到很好的乳化性能和表面修饰作用。采用复乳法制备包载 5 Fu的PLA/O CMC纳米微粒的平均粒径在 5 0nm ,在PBS缓冲溶液中释放时间可达 12d。在对胃癌、乳腺癌和大肠癌三种肿瘤细胞的抑制率测定实验中 ,PLA/O CMC纳米微粒的肿瘤细胞抑制率分别可以达到 72 .8%、77.3%和 75 .6 % ,接近或等同于游离 5 Fu药物的抑制率。在作用时间上 ,PLA/O CMC载药纳米微粒也显示出良好的缓释效应。     

Immobilization of laminin peptide in molecularly aligned chitosan by covalent bonding

We developed a new biomaterial effective for nerve regeneration consisting of molecularly aligned chitosan with laminin peptides bonded covalently. Molecularly aligned chitosan was prepared from crab (Macrocheira kaempferi) tendons by ethanol treatment and 4 wt%-NaOH aqueous solutions to remove proteins and calcium phosphate, followed by deacetyl treatment using a 50 wt%-NaOH aqueous solution at 100 degrees C. Molecularly aligned tendon chitosan was chemically thiolated by reacting 4-thiobutyrolactone with the chitosan amino group. The introduction of thiol groups and their distribution to tendon chitosan and chitosan cast film were confirmed using ATR FT-IR, (1)H-NMR, and EDS. The 1.24 micromol/g of thiol groups introduced on the surface of tendon chitosan and the chitosan cast film was confirmed using ultraviolet (UV) spectra. Thiol groups of cysteine located at the end of synthetic laminin peptides were then reacted chemically with thiolated chitosan to form chitosan-S-S-laminin peptide. YIGSR estimated at 0.92 micromol/g and IKVAV estimated at 0.28 micromol/g on thiolated tendon chitosan were confirmed using UV spectra. YIGSR was estimated at 0.85 micromol/g and IKVAV was estimated at 0.34 micromol/g on the thiolated chitosan cast film.     

Cell adhesion behavior of chitosan surface modified by bonding 2-methacryloyloxyethyl phosphorylcholine

2-Methacryloyloxyethyl phosphorylcholine (MPC)-bonded chitosan was prepared by Michael addition of MPC to the amino groups of chitosan. The modified surfaces were characterized by static contact angle and electron spectroscopy for chemical analysis (ESCA). The water contact angle of chitosan decreased with the MPC bonding and the rate of decrease depended on the amount of MPC bonding. ESCA analysis results proved that MPC had been bonded on the chitosan surface and the chitosan modified directly by MPC had a much higher concentration of MPC on the surface compared with that of MPC on chitosan modified indirectly by MPC. Cell adhesion tests indicated that a low concentration of MPC bonded chitosan was more favorable to cell adhesion while a high concentration of MPC bonded chitosan inhibited cell attachment.     

Cell adhesion behavior of chitosan surface modified by bonding 2-methacryloyloxyethyl phosphorylcholine

2-Methacryloyloxyethyl phosphorylcholine (MPC)-bonded chitosan was prepared by Michael addition of MPC to the amino groups of chitosan. The modified surfaces were characterized by static contact angle and electron spectroscopy for chemical analysis (ESCA). The water contact angle of chitosan decreased with the MPC bonding and the rate of decrease depended on the amount of MPC bonding. ESCA analysis results proved that MPC had been bonded on the chitosan surface and the chitosan modified directly by MPC had a much higher concentration of MPC on the surface compared with that of MPC on chitosan modified indirectly by MPC. Cell adhesion tests indicated that a low concentration of MPC bonded chitosan was more favorable to cell adhesion while a high concentration of MPC bonded chitosan inhibited cell attachment.     

A novel mucoadhesive polymer prepared by template polymerization of acrylic acid in the presence of chitosan

A novel mucoadhesive polymer was prepared by template polymerization of acrylic acid in the presence of chitosan for transmucosal drug delivery system (TMD). FT-IR results indicated that polymer complex was formed between poly(acrylic acid) (PAA) and chitosan through hydrogen bonding. Glass transition temperature (Tg) of chitosan and PAA in the PAA/chitosan polymer complexes was inner-shifted compared with Tg of chitosan and PAA itself. This may be due to the increased miscibility of PAA with chitosan through the hydrogen bonding. The crystallinity of chitosan in the PAA/chitosan polymer complexes was decreased with polymer complex formation with PAA. The dissolution rate of the PAA/chitosan polymer complex was dependent on pH and ratio of PAA/chitosan. The mucoadhesive force of PAA/chitosan polymer complex was similar to a commericial product, Carbopol 971P NF.     

The interaction of Schwann cells with chitosan membranes and fibers in vitro

The bridging of nerve gaps is still one of the major problems in peripheral nerve regeneration. A promising alternative for the repair of peripheral nerve injuries is the bioartificial nerve graft, comprised of a biomaterial pre-seeded with Schwann cells (SCs), which is an effective substrate for enhancing nerve regeneration. Interaction between cultured SCs and biomaterials is of importance. For the purposes of this study, culture systems of normal SCs were used. The biocompatibility of chitosan, including chitosan membranes and chitosan fibers, was evaluated in vitro. The growth of SCs was observed by light and scanning electron microscopy at regular intervals. SCs were identified by immunocytochemical staining and the viability of SCs was measured by MTT assay. The experimental results indicated that SCs could grow onto chitosan materials with two different shapes: spherical and long olivary. They contacted with the extensions. The long olivary cells inclined to encircle chitosan fibers up. It was also found that the cells on the chitosan fibers migrated faster than those on the chitosan membranes. There was a good biological compatibility between chitosan and SCs. Compared with the chitosan membranes, SCs migrated more easily onto the stereoframe of chitosan fibers. These studies contribute information necessary to enhancing our understanding of biocompatibility of chitosan.