载药纳米微粒的临床应用研究进展

载药纳米微粒是纳米技术与现代医药学结合的产物 ,是一种新型的药物输送载体。它缓释药物、延长药物作用时间 ,透过生物屏障靶向输送药物 ,建立新的给药途径等等 ,在药物控释方面显示出其他输送体系无法比拟的优势。近年来载药纳米微粒在临床各个领域的应用基础研究势头强劲 ,并取得了可喜的成绩。本文综述了载药纳米微粒在临床各领域应用的研究成果 ,并对其发展应用前景进行展望     

壳聚糖纳米粒子基因载体的研究现状

背景：壳聚糖纳米粒子因其独有特性作为基因载体的研究日益增多。 目的：综述了壳聚糖纳米粒子作为基因载体的研究进展,进一步促进基因治疗的效果。 方法：应用计算机检索web of science数据库和中国学术期刊数据库中2000-01/2011-04关于壳聚糖及其衍生物作为基因载体研究的文章,在标题和摘要中以“chitosan,gene”或 “壳聚糖;基因”为检索词进行检索。选择内容与基因载体和壳聚糖相关的文章,初检得到120篇文献,根据纳入标准选择31篇文章进行综述。 结果与结论：壳聚糖基因纳米粒子作为非病毒基因述文章的数量、主要结载体将在基因治疗领域中发挥举足轻重的作用,今后壳聚糖转基因体系的研究将更为深入。如何标记、可视跟踪壳聚糖DNA复合物进入不同细胞的过程,明确其基因转染机制,进一步提高基因转染效率,使其尽快进入基因治疗临床应用是今后研究的主要方向。     

载药纳米微粒的临床应用研究进展

载药纳米微粒是纳米技术与现代医药学结合的产物，是一种新型的药物输送载体。它缓释药物、延长药物作用时间，透过生物屏障靶向输送药物，建立新的给药途径等等，在药物控释方面显示出其他输送体系无法比拟的优势。近年来载药纳米微粒在临床各个领域的应用基础研究势头强劲，并取得了可喜的成绩。本综述了载药纳米微粒在临床各领域应用的研究成果，并对其发展应用前景进行展望。     

纳米羟基磷灰石在基因药物载体中的应用

目的讨论HAP纳米粒子作为药物或基因载体的进展。方法本文主要对HAP纳米粒子作为药物或基因载体的研究现状及他的生物相容性评价作了综述。结果指出了HAP纳米粒子作为药物或基因载体的主要发展趋势及存在的问题。结论药物或基因载体的研究较多,但是尚未找到一种理想的载体材料。作为一种新的药物基因载体,HAP纳米粒子有高的药物吸附量及良好的生物相容性,他有望作为一种新的基因药物载体。     

转化生长因子β1基因缓释的壳聚糖纳米粒制备及体外检测***☆

背景：壳聚糖作为一种非病毒载体,具有低毒性、低免疫原性、良好的生物相容性以及带可高正电荷密度的特性,易与带负电荷的DNA通过静电作用形成相互作用体避免核酸酶的降解。 目的：构建负载重组人转化生长因子β1基因的壳聚糖纳米粒,检测其体外缓释转化生长因子β1基因及对软骨细胞基因转染等性能。 方法：将壳聚糖与负载增强型绿色荧光蛋白基因和转化生长因子β1基因的质粒DNA(pDNA)以复凝聚法制成壳聚糖/ pEGFP-TGF-β1纳米粒。 结果与结论：制备的壳聚糖/pEGFP-TGF-β1纳米粒呈球形,粒径、表面电位与pH值相关,随着pH值升高,粒径增大,表面电位减少。纳米粒可有效保护pDNA免受核酸酶的降解。纳米粒的pDNA包封率为(87.5±2.3)%;pDNA可从纳米粒中缓慢释放。体外转染实验证实壳聚糖/pEGFP-TGF-β1纳米粒能转染软骨细胞并在细胞内表达绿色荧光蛋白。提示壳聚糖/ pEGFP-TGF-β1纳米粒能有效保护pDNA免受核酸酶降解,具有良好的缓释转化生长因子β1基因的能力,并能介导基因转染软骨细胞。 关键词：转化生长因子β1;壳聚糖;软骨细胞;组织工程;基因载体 doi:10.3969/j.issn.1673-8225.2012.12.007     

载药纳米粒子在组织工程领域的应用

载药纳米粒子作为一种新型药物和生物大分子输送载体,具有靶向性、通透性、控释性以及促细胞分化等优点.结合蛋白多肽的纳米粒子通过与生物专一性配基接合来输送靶向性药物;结合生长因子的纳米粒子可使生长因子更持久地维持其活性从而达到更好的疗效;结合基因序列的纳米粒子可有效运载目的基因为组织缺损区域提供"种子"细胞;在细胞培养中应用载药纳米技术可以构建三维纳米纤维结构促进细胞生长;表面偶联有特定基团或基因片段的磁性载药纳米粒子可用于物质分离及靶向定位.载药纳米粒子正日益广泛地应用于组织工程,发展潜力巨大,综述其在组织工程领域的应用进展.     

基于壳聚糖的纳米材料在骨组织工程与再生医学中的研究进展

壳聚糖是目前发现的唯一与细胞外基质糖胺聚糖的化学结构相似的天然阳离子多聚糖,具有极为优良的生物相容性、生物可降解性和生物学活性.近年来,基于壳聚糖的纳米材料在组织工程中的研究较为广泛.对壳聚糖的纳米材料、壳聚糖复合纳米材料、壳聚糖纳米纤维和壳聚糖纳米粒子等在骨组织工程与再生医学中的研究进展进行回顾和阐述.近年来的研究显示,壳聚糖复合纳米材料生物支架、壳聚糖纳米纤维支架及包载具有骨诱导性的生物活性因子,以及外源基因的壳聚糖纳米粒子及纳米纤维,在骨组织工程与再生医学中具有良好的应用前景.     

壳聚糖-pJME/GM-CSF纳米免疫原肌注BALB/c鼠所致树突状细胞分布与功能变化

壳聚糖是一种来源广泛、价格低廉、具有良好生物相容性及降解性、安全无毒的阳离子天然高分子聚合物,以纳米颗粒或微球形式与DNA结合后形成聚电解质复合体,后者可优化DNA疫苗的免疫效果.研究证实壳聚糖是一种有效介导DNA疫苗进行皮肤及黏膜免疫的载体物质.     

壳聚糖-pJME/GM-CSF纳米免疫原肌注BALB/c鼠所致树突状细胞分布与功能变化

壳聚糖是一种来源广泛、价格低廉、具有良好生物相容性及降解性、安全无毒的阳离子天然高分子聚合物,以纳米颗粒或微球形式与DNA结合后形成聚电解质复合体,后者可优化DNA疫苗的免疫效果.研究证实壳聚糖是一种有效介导DNA疫苗进行皮肤及黏膜免疫的载体物质.     

壳聚糖-pJME/GM-CSF纳米免疫原肌注BALB/c鼠所致树突状细胞分布与功能变化

壳聚糖是一种来源广泛、价格低廉、具有良好生物相容性及降解性、安全无毒的阳离子天然高分子聚合物,以纳米颗粒或微球形式与DNA结合后形成聚电解质复合体,后者可优化DNA疫苗的免疫效果.研究证实壳聚糖是一种有效介导DNA疫苗进行皮肤及黏膜免疫的载体物质.     

Formulation and in vitro characterization of PEGylated chitosan and polyethylene imine polymers with thrombospondin-I gene bearing pDNA

An ideal gene carrier is required both in safety and efficiency for transfection. We examined the use of water soluble chitosan and polyethyleneimine as a carrier for anti-angiogenic protein, TSP-1 coded, in gene delivery. The aim of this study was to synthesize and characterize polyethylene glycol conjugated cationic polymers to increase anti-angiogenic gene transfection and reduce possible cytotoxicity. Gel electrophoresis study showed strong DNA binding ability of modified cationic polymers. Also structural properties of pegylated polymers were confirmed by (1)H-NMR. We investigated in vitro properties of PEG conjugated and coated particles which were observed between 145 and 250 nm with the positive zeta potential value. In addition, the chitosan-based DNA complexes did not induce remarkable cytotoxicity against MCF-7 cells. Due to low cytotoxicity, we observed high transfection efficiency at chitosan-based formulations compared with PEI ones. Although transfection studies carried on in vitro conditions, we measured slight increases at transfection with PEGylation. PEG-conjugated chitosan formulations can be a promising candidate due to its efficiency in condensing and transfection of pDNA, its low cytotoxicty and comparatively high encapsulation degree.     

The influence of polymeric properties on chitosan/siRNA nanoparticle formulation and gene silencing

We have previously introduced the use of the biomaterial chitosan to form chitosan/siRNA nanoparticles for gene silencing protocols. This present study shows that the physicochemical properties (size, zeta potential, morphology and complex stability) and in vitro gene silencing of chitosan/siRNA nanoparticles are strongly dependent on chitosan molecular weight (Mw) and degree of deacetylation (DD). High Mw and DD chitosan resulted in the formation of discrete stable nanoparticles approximately 200 nm in size. Chitosan/siRNA formulations (N:P 50) prepared with low Mw (approximately 10 kDa) showed almost no knockdown of endogenous enhanced green fluorescent protein (EGFP) in H1299 human lung carcinoma cells, whereas those prepared from higher Mw (64.8-170 kDa) and DD (approximately 80%) showed greater gene silencing ranging between 45% and 65%. The highest gene silencing efficiency (80%) was achieved using chitosan/siRNA nanoparticles at N:P 150 using higher Mw (114 and 170 kDa) and DD (84%) that correlated with formation of stable nanoparticles of approximately 200 nm. In conclusion, this work confirms the application of chitosan as a non-viral carrier for siRNA and the importance of polymeric properties for the optimisation of gene silencing using chitosan/siRNA nanoparticles.     

Controlled and extended drug release behavior of chitosan-based nanoparticle carrier

Controlled drug release is presently gaining significant attention. In this regard, we describe here the synthesis (based on the understanding of chemical structure), structural morphology, swelling behavior and drug release response of chitosan intercalated in an expandable layered aluminosilicate. In contrast to pure chitosan, for which there is a continuous increase in drug release with time, the chitosan–aluminosilicate nanocomposite carrier was characterized by controlled and extended release. Drug release from the nanocomposite particle carrier occurred by degradation of the carrier to its individual components or nanostructures with a different composition. In both the layered aluminosilicate-based mineral and chitosan–aluminosilicate nanocomposite carriers the positively charged chemotherapeutic drug strongly bound to the negatively charged aluminosilicate and release of the drug was slow. Furthermore, the pattern of drug release from the chitosan–aluminosilicate nanocomposite carrier was affected by pH and the chitosan/aluminosilicate ratio. The study points to the potential application of this hybrid nanocomposite carrier in biomedical applications, including tissue engineering and controlled drug delivery.     

Synthesis and characterization of chitosan-g-poly(ethylene glycol)-folate as a non-viral carrier for tumor-targeted gene delivery

Poor water solubility and low transfection efficiency of chitosan are major drawbacks for its use as a gene delivery carrier. PEGylation can increase its solubility, and folate conjugation may improve gene transfection efficiency due to promoted uptake of folate receptor-bearing tumor cells. The aim of this study was to synthesize and characterize folate-poly(ethylene glycol)-grafted chitosan (FA-PEG-Chi) for targeted plasmid DNA delivery to tumor cells. Gel electrophoresis study showed strong DNA binding ability of modified chitosan. The pH(50) values, defined as the pH when the transmittance of a polymer solution at 600 nm has reached 50% of the original value, suggested that the water solubility of PEGylated chitosan had improved significantly. Regression analysis of pH(50) value as a function of substitution degree of PEG yielded an almost linear correlation for PEG-Chi and FA-PEG-Chi. The solubility of PEGylated chitosan decreased slightly by further conjugation of folic acid due to the relatively more hydrophobic nature of folic acid when compared to PEG. In addition, the chitosan-based DNA complexes did not induce remarkable cytotoxicity against HEK 293 cells. FA-PEG-Chi can be a promising gene carrier due to its solubility in physiological pH, efficiency in condensing DNA, low cytotoxicity and targeting ability.     

A hybrid thermo-sensitive chitosan gel for sustained release of Meloxicam

The purpose of this work was to develop a multi-phase gel system for sustained release drug delivery. A thermo-sensitive hydrogel composed of chitosan and glycerol was prepared, and then an o/w emulsion was introduced to the thermo-sensitive gel in order to modulate the gelation behavior. Meloxicam was chosen as a model drug in this study and its release profile was investigated. This study revealed that the factors such as pH, chitosan molecular mass and glycerol concentration could significantly influence the gel formation. Chitosan with a molecular mass of 950 kDa and glycerol proportion ranging from 30 to 60% can form a pH-dependent thermo-sensitive gel system. Both the chitosan–glycerol gel and chitosan–glycerol-emulsion gel systems were applied in delivering drugs. The drug release from the two gels was both in Higuchi mode. Higuchi moduli were 3.04 × 10^?3 mg · h^½ in the chitosan–glycerol-emulsion gel and 1.28 mg · h^½ in the chitosan– glycerol gel. The former was significantly slower in sustained release. The in vivo investigation on the chitosan–glycerol gel indicated that the gel may be useful in sustained drug release in situ. Thermosensitive hydrogels composed of chitosan and glycerol were well formed and could act as a sustained release drug carrier in the work, it showed that this hybrid thermo-sensitive hydrogel system may be a promising sustained release drug carrier.     

壳聚糖基聚电解质的生物医用前景

背景：利用壳聚糖阳离子聚合物特性,以不使用化学交联剂为前提在温和条件下制得的壳聚糖基聚电解质复合物,具有良好的生物相容性。 目的：综述近年来壳聚糖基聚电解质在药物载体、组织工程、伤口敷料、生物传感器、基因载体等方面的应用情况。 方法：由第一作者检索2004至2011年 ACS数据库和Elsevier Science电子期刊有关壳聚糖聚电解质在生物医用领域中的应用,尤其在药物载体、组织工程、伤口敷料、生物传感器及基因载体中的研究情况。 结果与结论：壳聚糖本身由于生物相容性好,可应用于生物体中作为良好的载体材料、支架材料、伤口敷料及生物传感器,经过与其他阴离子物质复合后可以保护壳聚糖本身良好性质,并且避免了使用化学交联剂所带来的生物毒性。壳聚糖的阳离子聚电解质本性使其能与黏液、阴离子表面和其他大分子如DNA产生强静电作用可有效应用于药物传送、基因治疗、固定生物酶等;壳聚糖聚电解质凝胶独特的性质如pH值、离子强度、电场敏感性,可使其通过对外界环境的改变作出不同响应,实现对生物组织的模拟、刺激响应药物控释,并且壳聚糖具备优异的抗菌性、止血性、亲水性和透气性,能够有效促进伤口愈合。     

Chitosan hydrogel as a drug delivery carrier to control angiogenesis

An aqueous solution of photocrosslinkable chitosan containing azide groups and lactose moieties (Az-CH-LA) incorporating paclitaxel formed an insoluble hydrogel within 30 s of ultraviolet light (UV) irradiation. The chitosan hydrogel showed strong potential for use as a new tissue adhesive in surgical applications and wound dressing. The fibroblast growth factor (FGF)-2 molecules retained in the chitosan hydrogel and in an injectable chitosan/IO₄-heparin hydrogel remain biologically active, and were gradually released from the hydrogels as they biodegraded in vivo. The controlled release of biologically active FGF-2 molecules from the hydrogels caused induction of angiogenesis and collateral circulation occurred in healing-impaired diabetic (db/db) mice and in the ischemic limbs of rats. Paclitaxel, which is an antitumor reagent, was also retained in the chitosan hydrogel and remained biologically active as it was released on degradation of the hydrogel in vivo. The chitosan hydrogels incorporating paclitaxel effectively inhibited tumor growth and angiogenesis in mice. The purpose of this review is to describe the effectiveness of chitosan hydrogel as a local drug delivery carrier for agents (e.g., FGF-2 and paclitaxel) to control angiogenesis. It is thus proposed that chitosan hydrogel may be a promising new local carrier for drugs such as FGF-2 and paclitaxel to control vascularization.     

Application of chitosan gel in the treatment of chronic periodontitis

Local administration of antibiotics in periodontal therapy can be provided with an appropriate delivery system. The purpose of this study was to evaluate the clinical effectiveness of chitosan, both as a carrier in gel form and as an active agent in the treatment of chronic periodontitis (CP). The chitosan gel (1% w/w) incorporated with or without 15% metronidazole was prepared and applied adjunctive to scaling and root planing (SRP) in comparison to SRP alone (control group-C), in CP patients. The clinical parameters such as probing depth (PD), clinical attachment level, the amount of gingival recession, plaque index, gingival index, and gingival bleeding time index were recorded at baseline and at weeks 6, 12, and 24. In all groups, significant improvements were observed in clinical parameters between baseline and week 24 (p < 0.05). The reductions in PD values were 1.21 mm for Ch, 1.48 mm for Ch + M, and 0.94 mm for C groups. No complications related to the chitosan were observed in patients throughout the study period. It is suggested that chitosan itself is effective as well as its combination with metronidazole in CP treatment due to its antimicrobial properties.     

Synergistic effects of conjugating cell penetrating peptides and thiomers on non-viral transfection efficiency

Nanoparticles generated by complex coacervation of plasmid DNA (pDNA) and modified chitosans namely chitosan-thioglycolic acid (TGA) conjugate and chitosan-HIV-1 Tat peptide conjugate were evaluated as gene delivery systems. In order to optimize transfection efficiency, chitosan-HIV-1 Tat peptide conjugate was combined with chitosan-TGA before its complexation with pDNA. Particle size and zeta potential measurements were performed to characterize the generated nanoparticles. The nanoparticles transfection efficiencies were assessed by exploitation of the green fluorescent protein (GFP) reporter gene. HEK293 cells were incubated for 24 h with the nanoparticles and the GFP positive cells were observed by fluorescence microscopy. The nanoparticles in the size range of 200-300 nm could transfect HEK293 cells as a model cell line with different transfection efficiencies. Unlike chitosan-TGA, chitosan-HIV-1 Tat peptide led to increased zeta potential of nanoparticles as compared to unmodified chitosan. The transfection efficiency of the nanoparticles generated by combination of chitosan-HIV-1 Tat peptide with chitosan-TGA was comparatively higher than that of the nanoparticles generated by either chitosan-TGA or the combination of chitosan-HIV-1 Tat peptide with unmodified chitosan. After 72 h of incubation, the combination of chitosan-HIV-1 Tat peptide with chitosan-TGA was found to be 7.12- and 67.37 times more efficient than unmodified chitosan and pDNA alone, respectively and showed a synergistic effect in transfection of pDNA into the cells. Moreover, none of the nanoparticles showed any severe cytotoxicity. Accordingly, this strategy might result in a potent carrier for gene delivery.