Shell cross-linked stearic acid grafted chitosan oligosaccharide self-aggregated micelles for controlled release of paclitaxel

Stearic acid grafted chitosan oligosaccharide (CSO-SA) with different degree of amino substitution (SD) was synthesized by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling reaction. The critical micelle concentration (CMC) of CSO-SA with different SD was about 0.06, 0.04, 0.01 mg/ml, respectively. With the increase of micelle concentration, the micelle size decreased, and the zeta potential increased. On the other hand, with the increase of SD of CSO-SA, the micelle size and zeta potential decreased due to the increased hydrophobic interaction of SA and the reduced free amino groups. To increase the stability of the micelle in vivo and controll drug release, the shells of micelles were cross-linked by glutaraldehyde. By controlling the molar ratio of CSO-SA to glutaraldehyde, the cross-linking of intra-micelle could be reached, and the nanoparticle with smaller size than that of its initial micelle was obtained. Paclitaxel was then used as model drug to incorporate into the micelles, and the surfaces of the micelles were further cross-linked by glutaraldehyde to form drug loaded and shell cross-linked nanoparticles. The effects of drug loading, SD of CSO-SA and cross-link degree on the size, zeta potential, drug entrapment efficiency and in vitro drug release behavior of micelles and its cross-linked nanoparticles were investigated. The higher drug entrapment efficiencies (above 94%) were observed in all case. The charged amounts of drug did not affect the drug release behavior. The drug release rate decreased with the increase of SD of CSO-SA and cross-link degree.     

两亲嵌段共聚物胶束用作医用材料

两亲嵌段共聚物可以在水溶液中自组装形成亲水性链段为外壳、疏水性链段为内核的胶束,这种胶束能够用作药物载体而引起人们极大的关注。本文综述了两亲嵌段共聚物胶束用作医用材料的研究进展,主要内容包括医用两亲嵌段共聚物的种类,胶束化,以及用作诊断试剂载体、药物缓释载体、靶向载体等。两亲嵌段共聚物胶束用作磁共振造影剂载体有利于肿瘤的诊断,用作药物缓释载体可以有效增溶难溶性抗肿瘤药物,延长药物在体内的血液循环时间。此外,通过对胶束表面进行修饰或者施加外场,还可以实现靶向功能。因此,两亲嵌段共聚物胶束在医用材料领域有着广阔的发展前景。     

Preparation of electrospun luminescent polyimide/europium nanofibers by simultaneous in situ sol-gel and imidization processes

Comicellization of a star block copolymer poly(ε-caprolactone)-block-poly(diethylamino)ethyl methacrylate (S(PCL-b-PDEAEMA)) and a linear block copolymer methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) (mPEG-b-PCL) was developed to enhance the stability and lower the cytotoxicity of the micelles. The two copolymers self-assembled into the mixed micelles with a common PCL core surrounded by a mixed PDEAEMA/mPEG shell in aqueous solution. This core-shell structure was transformed to the core-shell-corona structure at high pH due to the collapse of the PDEAEMA segment. The properties of the polymeric micelles were greatly dependent on the weight ratio of the two copolymers and the external pH. As increasing the mPEG-b-PCL content, the size and the zeta potential of the mixed micelles were lowered while the pH-dependent stability and the biocompatibility were improved. Moreover, an increase in pH accelerated the release of indomethacin (IND) from the mixed micelles in vitro. These results augured that the mixed micelles could be applied as a stable pH-sensitive release system.     

Complex micelles formed from two diblock copolymers for applications in controlled drug release

Double‐responsive core‐shell‐corona complex micelles for applications in drug release were formed from self‐assembly of two diblock copolymers PtBA‐b‐ PNIPAM and PtBA‐b‐P4VP. The two diblock copolymers coaggregated into core‐shell complex micelles in acidic water with the hydrophobic PtBA blocks as the common core and soluble PNIPAM/P4VP blocks as the mixed shell. Increasing temperature or pH value, the micelles converted into core‐shell‐corona micelles because of the collapse of PNIPAM or P4VP blocks as the inner shell and soluble P4VP or PNIPAM chains stretching outside as the outer corona. The anti‐inflammation drug naproxen (NAP) was loaded as the model drug in micelles in acidic water and released because of the ionization of NAP in alkaline solutions. Compared with pure core‐shell micelles, release of NAP from core‐shell‐corona complex micelles avoided the burst diffusion and the release rate is more easily controlled by tuning the composition of the mixtures or by adjusting the pH of the medium. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1804–1810, 2009     

两亲性壳聚糖衍生物的制备及其包覆量子点

以天然壳聚糖为功能性高分子的骨架,通过西弗碱还原法,以正辛醛和端醛基聚乙二醇单甲基醚(mPEG aldehyde,mPEG-ald)修饰壳聚糖,制备了具有亲疏水性质的N-辛基化-N-mPEG化壳聚糖衍生物(N-octyl-N-mPEG-chitosan,OPEGC),并且以此两亲性壳聚糖衍生物包覆量子点制备了水溶性聚合物量子点纳米粒子.用FTIR、1H-NMR对壳聚糖衍生物进行了结构表征.制备的水溶性胶束,用动态光散射(DLS)测试其流体力学直径与分布,研究了烷基链接枝比率对粒径大小的影响,研究结果表明:烷基链接枝率越高,聚合物胶束粒径越小.以芘为分子探针,通过荧光光谱法测定了壳聚糖衍生物的临界胶束浓度(CMC)为2.032×10-2mg/mL,并对水溶性聚合物量子点纳米粒子进行了紫外、荧光及形貌表征,结果表明得到了荧光发射产率高的聚合物量子点纳米粒子,且尺寸均一、水溶性好.     

Fusiform micelles from nonlinear poly(ethylene glycol)/polylactide copolymers as biodegradable drug carriers

PEG-PLA copolymers with dumbbell- and Y-shaped structures are prepared. They can self-assemble from nanoparticles to micro-sized fusiform micellar particles in aqueous solution. In particular the micelles formed by the (PLA)2-PEG-(PLA)2 particles show a better drug loading capacity and encapsulation efficiency than those formed by linear MPEG-PLA. In vitro studies show that the particles formed by Y-shaped copolymers show a particularly quick drug release. The copolymers have good biocompatibility with low cytotoxicity. These unique self-assembled systems thus have many possible biomedical applications, such as a sustained delivery of high-dosed water insoluble drugs, quick effective drugs for trauma, controlled delivery of the oral-administration drugs, and so forth.     

Synthesis and characterization of core–shell‐type polymeric micelles from diblock copolymers via reversible addition–fragmentation chain transfer

A method was developed to enable the formation of nanoparticles by reversible addition–fragmentation chain transfer polymerization. The thermoresponsive behavior of polymeric micelles was modified by means of micellar inner cores and an outer shell. Polymeric micelles comprising AB block copolymers of poly(N‐isopropylacrylamide) (PIPAAm) and poly(2‐hydroxyethylacrylate) (PHEA) or polystyrene (PSt) were prepared. PIPAAm‐b‐PHEA and PIPAAm‐b‐PSt block copolymers formed a core–shell micellar structure after the dialysis of the block copolymer solutions in organic solvents against water at 20 °C. Upon heating above the lower critical solution temperature (LCST), PIPAAm‐b‐PHEA micelles exhibited an abrupt increase in polarity and an abrupt decrease in rigidity sensed by pyrene. In contrast, PIPAAm‐b‐PSt micelles maintained constant values with lower polarity and higher rigidity than those of PIPAAm‐b‐PHEA micelles over the temperature range of 20–40 °C. Structural deformations produced by the change in the outer polymer shell with temperature cycles through the LCST were proposed for the PHEA core, which possessed a lower glass‐transition temperature (ca. 20 °C) than the LCST of the PIPAAm outer shell (ca. 32.5 °C), whereas the PSt core with a much higher glass‐transition temperature (ca. 100 °C) retained its structure. The nature of the hydrophobic segments composing the micelle inner core offered an important control point for thermoresponsive drug release and the drug activity of the thermoresponsive polymeric micelles. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3312–3320, 2006     

Polymeric micelle systems of hydroxycamptothecin based on amphiphilic N-alkyl-N-trimethyl chitosan derivatives

This research investigated the possible utilization of amphiphilic N-octyl-N-trimethyl chitosan (OTMCS) derivatives in solublization and controlled release of 10-hydroxycamptothecin (10-HCPT), a hydrophobic anticancer drug. The release behavior of the 10-HCPT-OTMCS micelles was measured and compared to that of a commercial 10-HCPT lyophilized powder in vitro and in vivo. This research also examined the effects of chemical structure of the chitosan derivatives and the micellar preparation conditions on the encapsulation efficiency, drug loading content, and particle size of the polymeric micelles. The results showed that these chitosan derivatives were able to self-assemble and form spherical shape polymeric micelles with an average particle size range of 24–280 nm and a drug loading content of 4.1–32.5%, depending on the modified structures and loading procedures. The solubility of 10-HCPT in aqueous fluid was increased about 80,000-fold from 2 ng/ml in water to 1.9 mg/ml in OTMCS micellar (degree of octyl and trimethyl substitution is 8% and 54%, respectively) solution. In addition, OTMCS was able to modulate the in vitro release of 10-HCPT and improve its pharmacokinetic properties and lactone ring stability in vivo. These data suggested the possible utilization of the amphiphilic micellar chitosan derivatives as carriers for hydrophobic drugs for improving their delivery and release properties.     

Syntheses of amphiphilic biodegradable copolymers of poly(ethyl ethylene phosphate) and poly(3-hydroxybutyrate) for drug delivery

Biodegradable and amphiphilic triblock copolymers poly(ethyl ethylene phosphate)-poly(3-hydroxy-butyrate)-poly(ethyl ethylene phosphate) (PEEP-b-PHB-b-PEEP) have been successfully synthesized through ring-opening polymerization. The structures are confirmed by gel permeation chromatography and NMR analyses. Crystallization investigated by X-ray diffraction reveals that the block copolymer with higher content of poly(ethyl ethylene phosphate) (PEEP) is more amorphous, showing decreased crystallizability. The obtained copolymers self-assemble into biodegradable nanoparticles with a core-shell micellar structure in aqueous solution, verified by the probe-based fluorescence measurements and transmission electronic microscopy (TEM) observation. The hydrophobic poly(3-hydroxybutyrate) (PHB) block serves as the core of the micelles and the micelles are stabilized by the hydrophilic PEEP block. The size and size distribution are related to the compositions of the copolymers. Paclitaxel (PTX) has been encapsulated into the micelles as a model drug and a sustained drug release from the micelles is observed. MTT assay also demonstrates that the block copolymers are biocompatible, rendering these copolymers attractive for drug delivery. Supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No.20060358036)     

Thermosensitive t‐PLA‐b‐PNIPAAm tri‐armed star block copolymer nanoscale micelles for camptothecin drug release

Thermosensitive polylactide‐block‐poly(N‐isopropylacrylamide) (t‐PLA‐b‐PNIPAAm) tri‐armed star block copolymers were synthesized by atom transfer radical polymerization (ATRP) of monomer NIPAAm using t‐PLA‐Cl as macroinitiator. The synthesis of t‐PLA‐Cl was accomplished by esterification of star polylactides (t‐PLA) with 2‐chloropropionyl chloride using trimethylolpropane as a center molecule. FT‐IR, ¹H NMR, and GPC analyses confirmed that the t‐PLA‐b‐PNIPAAm star block copolymers had well‐defined structure and controlled molecular weights. The block copolymers could form core‐shell micelle nanoparticles due to their hydrophilic‐hydrophobic trait in aqueous media, and the critical micelle concentrations (CMC) were from 6.7 to 32.9 mg L^?1, depending on the system composition. The as‐prepared micelle nanoparticles showed reversible phase changes in transmittance with temperature: transparent below low critical solution temperature (LCST) and opaque above the LCST. Transmission electron microscopy (TEM) observations revealed that the micelle nanoparticles were spherical in shape with core‐shell structure. The hydrodynamic diameters of the micelle nanoparticles depended on copolymer compositions, micelle concentrations and media. MTT assays were conducted to evaluate cytotoxicity of the camptothecin‐loaded copolymer micelles. Camptothecin drug release studies showed that the copolymer micelles exhibited thermo‐triggered targeting drug release behavior, and thus had potential application values in drug controlled delivery. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4429–4439     

Comparison of drug delivery properties of PEG-<Emphasis Type="Italic">b</Emphasis>-pdhpc micelles with different compositions

An anti-tumor drug doxorubicin was encapsulated in micelles of poly（ethylene glycol）-b-poly（2,2-dihydroxyl-methyl propylene carbonate）（PEG-b-PDHPC） diblock copolymers.The morphology of both blank micelles and drug loaded micelles was characterized by TEM.The in vitro drug release profiles of micelles were investigated.The cytotoxicity of the micelles was evaluated by incubating with Hela tumor cells and 3T3 fibroblasts.The drug loaded micelles were co-cultured with HepG2 cells to evaluate the in vitro anti-tumor efficacies.The results showed that the mean sizes of both micelles with different copolymer compositions increased after being loaded with drugs.The drug release rate of PEG₄₅-b-PDHPC₃₄ micelles was faster than that of mPEG₁₁₄-b-PDHPC₂₆,micelles.Both of the two block copolymers were non-toxic.The confocal laser scanning microscopy and flow cytometry results showed that both the drug loaded micelles could be internalized efficiently in HepG2 cells.The PEG₄₅-b-PDHPC₃₄ micelles exhibited higher anti-tumor activity comparing to mPEG₁₁₄-b-PDHPC₂₆ micelles.     

Bioreducible and core‐crosslinked hybrid micelles from trimethoxysilyl‐ended poly(ε‐caprolactone)‐S‐S‐poly(ethylene oxide) block copolymers: Thiol‐ene click synthesis and properties

Bioreducible and core‐crosslinked hybrid micelles were for the first time fabricated from biodegradable and biocompatible trimethoxysilyl‐terminated and disulfide‐bond‐linked block copolymers poly(ε‐caprolactone)‐S‐S‐poly(ethylene oxide), which were prepared by combining thiol‐ene coupling reaction and ring‐opening polymerization. The molecular structures, physicochemical, self‐assembly, and bioreducible properties of these copolymers were thoroughly characterized by means of FTIR, ¹H NMR, gel permeation chromatography, differential scanning calorimetry, wide‐angle X‐ray diffraction, dynamic light scattering (DLS), and transmission electron microscopy. The core‐crosslinking sol‐gel reaction was confirmed by ¹H NMR, and the core‐crosslinked hybrid micelles contained about 3 wt % of silica. The bioreducible property of both uncrosslinked and core‐crosslinked micelles in 10 mM 1,4‐dithiothreitol (DTT) solution was monitored by DLS, which demonstrated that the PEO corona gradually shedded from the PCL core. The anticancer doxorubicin drug‐loaded micelles showed nearly spherical morphology compared with blank micelles, presenting a DTT reduction‐triggered drug‐release profile at 37 °C. Notably, the core‐crosslinked hybrid micelles showed about twofold drug loading capacities and a half drug‐release rate compared with the uncross‐liked counterparts. This work provides a useful platform for the fabrication of bioreducible and core‐crosslinked hybrid micelles potential for anticancer drug delivery system. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Nanoparticle carriers based on copolymers of poly(ε-caprolactone) and hyperbranched polymers for drug delivery

Novel amphiphilic copolymers based on poly(ε-caprolactone) (PCL) and hyperbranched poly (amine-ester) (HPAE) with various compositions were synthesized. The amphiphilic copolymers can self-assemble into nanoscopic micelles and their hydrophobic cores can encapsulate doxorubicin (DOX) in aqueous solutions. The DOX-loaded HPAE-co-PCL nanoparticles diameter increased from 121 to 184 nm with the increasing PCL segment in the copolymer composition. An in vitro study at 37°C demonstrated that DOX-release from nanoparticles at pH 5.0 was much faster than that at pH 7.4. The cytotoxicity for HeLa cells study demonstrated that DOX-loaded HPAE-co-PCL nanoparticles exhibited the anti-tumor effect was enhanced significantly, suggesting that the DOX-loaded HPAE-co-PCL nanoparticles have great potential as a tumor drug carrier.     

Preparation and properties of ionically cross‐linked chitosan nanoparticles

Chitosan nanoparticles were fabricated by a method of tripolyphosphate (TPP) cross‐linking. The influence of fabrication conditions on the physical properties and drug loading and release properties was investigated by transmission electron microscopy (TEM), dynamic light scattering (DLS), and UV–vis spectroscopy. The nanoparticles could be prepared only within a zone of appropriate chitosan and TPP concentrations. The particle size and surface zeta potential can be manipulated by variation of the fabrication conditions such as chitosan/TPP ratio and concentration, solution pH and salt addition. TEM observation revealed a core–shell structure for the as‐prepared nanoparticles, but a filled structure for the ciprofloxacin (CH) loaded particles. Results show that the chitosan nanoparticles were rather stable and no cytotoxicity of the chitosan nanoparticles was found in an in vitro cell culture experiment. Loading and release of CH can be modulated by the environmental factors such as solution pH and medium quality. Copyright © 2008 John Wiley & Sons, Ltd.     

pH敏感型mPEG-Hz-PLA聚合物纳米载药胶束的制备

以合成的含有腙键的聚乙二醇大分子(mPEG-Hz-OH)为引发剂,以丙交酯为单体引发开环聚合反应,并通过调整投料比,制备出3种不同分子量的含腙键的生物可降解嵌段聚合物(mPEG-Hz-PLA).将腙键引入到聚合物的骨架中,以此构建聚合物胶束并作为pH敏感型纳米药物载体.制备的pH敏感型胶束的CMC值等于或低于5.46×10-4 mg/m L,DLS和TEM显示粒径均小于100 nm,且粒径分布均匀.非pH敏感型胶束在不同pH下的粒径变化不明显,而pH敏感型胶束在酸性环境下(pH=4.0和pH=5.0)胶束粒径出现了明显变化.以阿霉素为模型药物制备了pH敏感型载药胶束,其粒径比空白胶束大(100~200 nm),且粒径分布均匀.药物释放实验表明pH敏感型载药胶束随着释放介质pH降低累积释药量增高.MTT实验表明空白胶束对HeLa细胞和RAW264.7细胞几乎没有抑制作用,而载阿霉素的胶束对2种细胞的抑制作用都随着剂量的增大和时间的延长而增强.     

Self-assembled polypeptide-block-poly(vinylpyrrolidone) as prospective drug-delivery systems

Poly(β-benzyl-l-aspartate)-block-poly(vinylpyrrolidone) diblock copolymers (PAsp(OBzl)-b-PVP) having both hydrophobic and hydrophilic segments of various lengths were synthesized by a combination of ATRP and ROP. These amphiphilic diblock copolymers formed polymeric micelles consisting of a hydrophobic PAsp(OBzl) core and a hydrophilic PVP shell in aqueous solution. The block copolymer was characterized using ¹H NMR and gel permeation chromatography (GPC) analysis. Due to its core–shell structure, this block polymer forms unimolecular micelles in aqueous solutions. The micelle properties of PAsp(OBzl)-b-PVP diblock copolymer were extensively studied by dynamic light scattering (DLS), fluorescence spectroscopy, and transmission electron microscopy (TEM). PAsp(OBzl)-b-PVP copolymers displayed the lowest CMC and demonstrated little cytotoxicity when exposed to SW-1990 pancreatic cancer cells. In order to assess its application in biomedical area, the anti-inflammation drug prednisone acetate was loaded as the model drug in the polymeric nanoparticles. In vitro release behavior of prednisone acetate was investigated, which showed a dramatic responsive fast/slow switching behavior according to the pH-responsive structural changes of a micelle core structure. All of theses features are quite feasible for utilizing it as a novel intelligent drug-delivery system.     

Synthesis and applications of shell cross-linked thermoresponsive hybrid micelles based on poly(N-isopropylacrylamide-co-3-(trimethoxysilyl)propyl methacrylate)-b-poly(methyl methacrylate)

Shell cross-linked (SCL) thermoresponsive hybrid micelles consisting of a cross-linked thermoresponsive hybrid hydrophilic shell and a hydrophobic core domain were synthesized from poly(N-isopropylacrylamide-co-3- (trimethoxysilyl)propyl methacrylate)-b-polymethyl methacrylate (P(NIPAAm-co-MPMA)-b-PMMA) amphiphilic block copolymers. Transmission electron microscopy (TEM) images showed that the SCL micelles formed regularly globular nanoparticles. The SCL micelles showed reversible dispersion/aggregation in response to temperature cycles through an outer polymer shell lower critical solution temperature (LCST) for PNIPAAm at around 33 degrees C, observed by turbidity measurements and dynamic light scattering (DLS). The drug loading and in vitro drug release properties of the SCL micelles bearing a silica-reinforced PNIPAAm shell were further studied, which showed that the SCL micelles exhibited a much improved entrapment efficiency (EE) as well as a slower release rate which allowed the entrapped molecules to be slowly released over a much longer period of time as compared with pure PNIPAAm-b-PMMA micelles.     

Preparation of pH- and thermo-sensitive chitosan-PNIPAAm core–shell nanoparticles and evaluation as drug carriers

Environmentally sensitive polysaccharide nanoparticles (NPs) were prepared by in situ polymerization of N-isopropylacrylamide (NIPAAm) monomer in the presence of chitosan (CS) micelles. First, CS was found to develop a cationic micelle-like structure in the acetic acid solution when its concentration was increased to above the critical micelle concentration, as evidenced by fluorescence and TEM. When the NIPAAm was polymerized in the CS micelle solution by using potassium persulfate as initiator, the produced PNIPAAm with anionic chain end(s) became hydrophobic, as long as the reaction temperature was above its phase transition temperature; and therefore it would diffuse into the hydrophobic core of the CS micelles, producing CS-PNIPAAm core–shell NPs. Increasing the feeding amount of NIPAAm increased the monomer conversion and therefore the particle size; yet it decreased the surface zeta potential. Moreover, the CS-PNIPAAm NPs were sensitive to both pH value and temperature. For the study of drug release properties, doxycycline hyclate was used as a model drug and loaded into the NPs at pH 4.5 and 25 °C. The result illustrated that these NPs had a continuous drug release behavior up to 1 week, depending on the pH value and temperature. In addition, enzyme or hydrogen peroxide capable of degrading CS shell was added in the solution to facilitate the drug release.     

温度/pH响应性MPEG-b-PCL/PNVCL-b-PCL共聚物复合胶束的制备及载药性质

以基于亚胺键的嵌段共聚物为构筑单元的温度/pH响应性共聚物复合胶束(CMs), 由于具有亚胺键和核-壳-冠结构, 表现出较高的灵敏度和稳定性. 以聚乙二醇单甲醚(MPEG)、 N-乙烯基己内酰胺(NVCL)和ε-己内酯(ε-CL)为原料, 分别制备了端醛基聚乙二醇单甲醚(MPEG-CHO)、 端醛基聚N-乙烯基己内酰胺(PNVCL-CHO)和端氨基聚己内酯(H₂N-PCL), 利用希夫碱反应, 进一步制备了基于亚胺键的聚乙二醇单甲醚-b-聚己内酯(MPEG-b-PCL)和聚N-乙烯基己内酰胺-b-聚己内酯(PNVCL-b-PCL)嵌段共聚物, 对共聚物结构进行了确认. 以MPEG-b-PCL和PNVCL-b-PCL为构筑单元, 制备了共聚物复合胶束, 研究了复合胶束对阿霉素的包载、 释放性质和细胞毒性等. 研究结果表明, 室温下MPEG-b-PCL和PNVCL-b-PCL能够在水中自组装形成以PCL为核、 MPEG和PNVCL为混合壳的共聚物复合胶束, 在生理温度下, 温敏性PNVCL链段发生相变塌缩在PCL核表面, 能够防止药物扩散释放, 亲水性MPEG链段形成可控通道. 药物体外释放结果表明, 在弱酸性环境中, 亚胺键能够断裂, 胶束被破坏, 促进药物的释放, 噻唑蓝(MTT)实验表明, 复合胶束的细胞毒性较低.     

肽类树枝状大分子:自组装胶束及药物释放研究

本文以三代聚谷氨酸肽类树枝状分子(G3-Glu)为大分子引发剂,引发N-羧基-L-苯丙氨酸-环内酸酐(NCA-Phe)的开环聚合反应,制备聚谷氨酸树枝状大分子-聚苯丙氨酸嵌段共聚物.嵌段共聚物通过自组装形成以聚苯丙氨酸链段为核,聚谷氨酸树枝状大分子为壳的胶束.将抗肿瘤药物阿霉素负载到高分子胶束中,研究其药物释放性能及体外抗肿瘤效果.结果表明,共聚物胶束具有良好的生物相容性.载药胶束具有药物缓释效果,药物持续释放时间可达60h.载药胶束的体外抗肿瘤实验表明其对肝癌细胞HepG2具有很好的杀灭效果,共培养48h后对癌细胞的杀死率可高达75%.