Preparation and Characterization of Copolymer Micelles Formed by Poly(ethylene glycol)-Polylactide Block Copolymers as Novel Drug Carriers

Diblock copolymer poly(ethylene glycol) methyl ether–polylactide (MePEG–PLA) micelles were prepared by dialysis against water. Indomethacin (IMC) as a model drug was entrapped into the micelles by dialysis method. The critical micelle concentration (CMC) of the prepared micelles in distilled water investigated by fluorescence spectroscopy was 0.0051 mg/mL which is lower than that of common low molecular weight surfactants. The diameters of MePEGPLA micelles and IMC loaded MePEGPLA micelles in a number-averaged scale measured by dynamic light scattering were 52.4 and 53.7 nm respectively. The observation with transmission electron microscope and scanning electron microscope showed that the appearance of MePEGPLA micelles was in a spherical shape. The content of IMC incorporated in the core portion of the micelles was 18% (ω). The effects of the synthesis method of the copolymer on the polydispersity of the micelles and the yield of the micelles formation were discussed.

Preparation of adhesive resveratrol micelles and determination of drug content

Objective:Resveratrol polymer micelles with tissue adhesion were prepared and the content of resveratrol in the micelles was determined by HPLC.Method:The micelle adhesion experiment was carried out by polylysine orifice plate experiment and small animal fluorescence imaging method,and the micelle prescription was optimized to obtain resveratrol micelles with good adhesion.The separation was performed on a Shiseido SPOLAR C18 column(150 mm×4.6 mm,5μm)with methanol-water(42:58)as the mobile phase.The flow rate was 1.0 mL·min^(-1),the detection wavelength was 305 nm,the column temperature was 35℃,and the injection volume was 10μL.Results:Resveratrol micelles prepared with F127 alone had the best adhesion.The peak area and concentration of resveratrol had a good linear relationship in the concentration range of 10~200μg/mL(r=0.9996).The specificity,precision,recovery and stability all met the methodological requirements.Conclusion:In this experiment,resveratrol micelles with tissue adhesion were successfully prepared,and a method for the determination of resveratrol content in micelles was established.The method is accurate,rapid and simple.

ROS-responsive and triple-synergistic mitochondria-targeted polymer micelles for efficient induction of ICD in tumor therapeutics

Immunogenic cell death(ICD)represents a modality of apoptosis distinguished by the emanation of an array of damage-related molecular signals.This mechanism introduces a novel concept in the field of contemporary tumor immunotherapy.The inception of reactive oxygen species(ROS)within tumor cells stands as the essential prerequisite and foundation for ICD induction.The formulation of highly efficacious photodynamic therapy(PDT)nanomedicines for the successful induction of ICD is an area of significant scientific inquiry.In this work,we devised a ROS-responsive and triple-synergistic mitochondria-targeted polymer micelle(CAT/CPT-TPP/PEG-Ce6,CTC)that operates with multistage amplification of ROS to achieve the potent induction of ICD.Utilizing an“all-in-one”strategy,we direct both the PDT and chemotherapeutic units to the mitochondria.Concurrently,a multistage cyclical amplification that caused by triple synergy strategy stimulates continuous,stable,and adequate ROS generation(domino effect)within the mitochondria of cells.Conclusively,influenced by ROS,tumor cell-induced ICD is effectively activated,remodeling immunogenicity,and enhancing the therapeutic impact of PDT when synergized with chemotherapy.Empirical evidence from in vitro study substantiates that CTC micelles can efficiently provoke ICD,catalyzing CRT translocation,the liberation of HMGB1 and ATP.Furthermore,animal trials corroborate that polymer micelles,following tail vein injection,can induce ICD,accumulate effectively within tumor tissues,and markedly inhibit tumor growth subsequent to laser irradiation.Finally,transcriptome analysis was carried out to evaluate the changes in tumor genome induced by CTC micelles.This work demonstrates a novel strategy to improve combination immunotherapy using nanotechnology.

Intelligent self-assembly prodrug micelles loading doxorubicin in response to tumor microenvironment for targeted tumors therapy

Compared with physical drug-loaded nanocarriers,polymeric prodrug micelles have many advantages such as high drug loading and enhanced stability in blood,so they have great potential in cancer therapy.However,these micelles have a big disadvantage,which cannot achieve long-term circulation in vivo and high absorption of tumor cells simultaneously,resulting in low administration efficiency and poor therapeutic effect on cancer.To solve problems of traditional polymeric prodrug micelles,novel polymeric micelles with tumor microenvironment response were designed in this work.The prodrug formed by covalently linking D-α-tocopherol polyethylene glycol succinate(TPGS_(3350)),peptide(Pep),and doxorubicin(DOX)(TPGS_(3350)-Pep-DOX)was self-assembled into micelles by encapsulating DOX physically.When the micelles entered the tumor tissue,the long-chain polyethylene glycol(PEG)was sensitively cut by the matrix metalloproteinase 2/9(MMP2/9)enzyme,exposing the targeting molecule folate,then it entered the cell through the endocytic pathway mediated by the folate receptor.The drug loading content,encapsulation efficiency,critical micelle concentration,and invitro release of the micelles invented in this study were measured to characterize their properties.The particle size and zeta potential of micelles were characterized by dynamic light scattering.Images were scanned by transmission electron microscopes.In vitro cytotoxicity,cellular uptake,and in vivo antitumor effect evaluation experiments were measured to show that smart micelles have made much progress in material chemistry and drug delivery,making it possible to apply a stimulus-response carrier drug delivery system in clinical application.

Nanofabrication in Polymer Solutions

This review covers recent advances in fabrication of nanomaterials in polymer solutions with emphasis on using the self assembled amphiphilic block copolymers in solution to fabricate organic/inorganic composites with nanoscale modifications. The phase behavior of block copolymers in water and the use of templates to form ordered nanostructures are reviewed in detail. Modern physical techniques for nanoscale characterization are also introduced. The authors suggested that this approach should provide new routes to create materials with interesting morphologies for many different applications.

Enhancement of Formation of Polar Microenvironment in Polymer by Compressed CO_(2)

The copolymer (EO)22(PO)52(EO)22 in p-xylene can solubilize much more water in the presence of compressed CO2 than the case without CO2.

Analysis on the Characteristic Properties of PEDOT Nano-particle Based on Reversed Micelle Method

Based on the study of a new type of conducting polymer poly （3,4-ethylenedioxythiophene） （PEDOT）,we focussed on the preparation and characteristics of PEDOT nanoparticles made by reversed micelle method.Moreover,we deeply investigated the optical,electrical and the thermal stability of PEDOT nanoparticles.The main results are as follows： the small-sized PEDOT nanoparticles were prepared and utilized by different methods,such as ultraviolet/visible （UV-Vis） spectroscopy,Fourier-transform infrared （FT- IR） spectrum,scanning electron microscopy（SEM） and so on.The results show that the amount of oxidizer,ultrasonic treatment,polymerizing temperature and doping degree can influent morphology,electrical ability and gas sensitivity of PEDOT nanoparticles.The Bragg peaks of nanoparticles at 6.7°,12.7°,25° were observed by XRD and the better orientation of molecular chain was attributed to the effective doping of toluene-p-sulfonic acid,which also resulted in an enhancement of thermal stability of nanoparticles than conventional PEDOT.

蓝靛果果渣花色苷胶束的制备及其稳定性研究

为增强花色苷的稳定性,拓宽其在食品保健以及医药领域的应用,以羧甲基壳聚糖(CMCS)、L-组氨酸(L-His)和硬脂酸(SA)为载体材料,蓝靛果果渣花色苷为芯材,采用响应面法优化酸响应性蓝靛果果渣花色苷胶束的制备工艺,通过在光照、温度、pH等不同条件下蓝靛果果渣花色苷的稳定性以及其对肝癌细胞杀伤性进行评价。结果表明:经响应面优化的最佳制备工艺为水浴时间10 min,超声时间15 min,超声温度60℃,包封率为85.3%±0.31%。储存稳定性分析表明在各种温度、pH、光照、氧化剂、还原剂的条件下,载花色苷胶束中花色苷的保存率分别是花色苷的1.33、1.26、1.16、1.11、2.41倍;在体外肝癌细胞杀伤实验中,在24 h后,载花色苷胶束对肝癌细胞抑制率是花色苷的1.34倍。本研究合成了一种新型的两亲性羧甲基壳聚糖衍生物,可以显著提高花色苷稳定性,适宜作为花色苷以及其他食品活性成分的潜在纳米胶束载体。

基于聚半乳糖醛酸的聚合物胶束制备及性能

以胱胺(CYS)和脱氧胆酸(DOCA)为原料合成了胱胺修饰的脱氧胆酸(CD),再将CD的氨基(―NH_(2))与聚半乳糖醛酸(PGA)的羧基(―COOH)通过酰胺化反应制得PGA-g-CD聚合物,并自组装为胶束。通过调节n(―NH_(2))∶n(―COOH)对胶束载药性能进行调控。测试了聚合物的结构及聚合物胶束的载药和释药性能。结果表明,最佳投料比为n(―NH_(2))∶n(―COOH)=1.3∶1,在该条件下,CD在聚合物中取代度为31%,临界胶束浓度为0.025 mg/mL,胶束载药量达11.53%,载药胶束粒径和粒径多分散系数分别为(296.1±0.3)nm和0.101±0.053,在还原性环境中36 h的释药量可达78.8%,体现良好的还原响应性。

聚合物胶束体内命运分析技术的研究进展

聚合物胶束(PMs)是研究非常广泛的纳米给药系统。它是由两亲性聚合物组成的自聚集纳米颗粒,这些聚合物在临界胶束浓度(CMC)以下以单分子形式存在于溶液中,在CMC以上则会自组装形成胶束。相对于其他纳米载体,PMs具有独特的性质:相对较小的尺寸,疏水性核对疏水性化合物具有良好溶解性,亲水性壳能延长药物在血液的循环时间。对PMs体内时空命运的未知,使得PMs从实验室设计到临床应用的成功转化仍然面临重大挑战。目前,一系列分析测试技术已经开发出来用于揭示PMs的体内命运,包括放射性示踪,荧光共振能量转移(FRET)、聚集诱导发射(AIE)、聚集荧光猝灭(ACQ)、液质联用(LC-MS),透射电子显微镜(TEM)等。主要叙述了一系列分析技术在PMs体内命运研究中的进展。

低临界胶束浓度PEGMA-b-PCL的制备及其药物缓释性能

以ε-己内酯(ε-CL)为疏水链段、聚乙二醇甲醚甲基丙烯酸酯(PEGMA)为亲水链段、4-氰基-4-[(十二烷基硫烷基硫代羰基)硫烷基]戊醇(CDPA)为可逆加成-断裂链转移(RAFT)试剂、甲苯为溶剂,在N_(2)氛围、80℃、反应24 h的条件下,通过RAFT聚合法制备了两嵌段共聚物(PEGMA-b-PCL)。将其自组装为胶束,作为纳米药物载体用于负载姜黄素(Cur)。采用FTIR、^(1)HNMR、GPC、SEM、DLS对PEGMA-b-PCL进行了表征,测试了胶束载体的载药和释药性能。结果表明,两嵌段共聚物数均相对分子质量范围为1478~7318,其具有较低的临界胶束浓度(在pH=5.0~7.4,范围为0.920~1.600 mg/L)。胶束载体粒径范围为68.34~186.93 nm。当n(CDPA)∶n(ε-CL)=1∶200时,胶束载药率和包封率最高,可达12.05%±0.29%和75.26%±2.41%。在不同pH环境下,药物缓释性能可达15 d,其中pH=5.0时的累积释药率最高,可达38.20%。

Docetaxel-loaded mixed micelles composed of Solutol HS15 and Pluronic F127 or folate-conjugated F127: preparation, optimization and in vitro comparative characterization

In this study, two kinds of docetaxel （DTX）-loaded mixed micelles, composed of Solutol HS15 （HS 15）/Pluronic F127 （F 127） or folate-conjugated F127, （SF-DTX and FSF-DTX）, were prepared by the thin-film hydration method and evaluated in vitro. Both SF-DTX and FSF-DTX were spherical with diameter close to 23 nm. They had high encapsulating efficiency （99.05% and 90.28% for SF-DTX and FSF-DTX, respectively） and sustained-release property. SF and FSF were able to enhance the cellular accumulation of DTX in KBv cells and reduce ATP content in A-549 cells. They also were able to reverse multidrug resistance （MDR）. In vitro cytotoxicity and cellular accumulation of DTX suggested an active targeting of FSF-DTX. It could be concluded from the results that the novel F 127/HS 15 system could serve as a potential nanocarrier with the ability of overcoming MDR, and folate-conjugated F 127/HS 15 might achieve active targeting at the same time.

超声波在聚合物溶液中的衰减特性研究

研究了超声波在不同浓度、结构的5种聚合物溶液(阴、阳离子聚丙烯酰胺(APAM,CPAM)、聚丙烯酸钠(PAAS)、羧甲基纤维素钠(CMC)、海藻酸钠(SA)中的声衰减系数变化,发现聚合物溶液黏度与声衰减并不呈现完全正相关关系,声衰减还与聚合物溶液中的胶束有关:阳离子聚丙烯酰胺(CPAM)溶液黏度仅增加0.83 mPa·s,胶束的存在使得声衰减系数增大124.48%。进一步地,将聚合物溶液加入到不同浓度的NaCl溶液中,改变聚合物溶液中胶束的形态,发现只有当胶束达到一定尺寸时,才会对声衰减造成影响。

磁性聚合物胶束的制备及其药物释放行为研究

癌症是目前世界上最具致命性的疾病之一.为解决疏水性药物在体内无法维持长时间循环、代谢速度较快、生物利用率低的问题,通过β-环糊精(β-CD)与二茂铁(Fc)的主客体识别,采用制备主体分子β-CD覆盖的磁性纳米颗粒(CD-MNPs)和客体分子二茂铁修饰的聚乙二醇单甲醚(mPEG-Fc)以及二茂铁修饰的聚异丙基丙烯酰胺(PNIPAM-Fc),在磁性纳米颗粒表面构建了两种不同亲水性的聚合物链,在水中共组装形成直径约250 nm的规则球形胶束.通过改变温度,可以实现组装体系的形成与解体.研究结果表明,该胶束作为载体负载抗癌药物阿霉素(DOX),实现包封率73%,药物载量17%,并具有良好的缓释效果.所制备的磁性聚合物胶束具有良好稳定性以及较高的药物包封率和药物载量,在药物递送系统和可控释放领域具有潜在的应用前景.

羧甲基纤维素棕榈酸酯的合成及其胶束包载姜黄素研究

以羧甲基纤维素和棕榈酸为原料,合成具有两亲性的羧甲基纤维素棕榈酸酯,以其在水相中自组装形成的胶束作为载体对姜黄素进行包载。通过红外光谱验证了羧甲基纤维素棕榈酸酯的成功合成,激光粒度仪测试则证明载药胶束纳米乳液的形成,采用液相色谱测试并计算了载药胶束的载药量及包封率。本研究以全生物基载体实现了疏水姜黄素在水中的稳定分散。

Bioreducible unimolecular micelles based on amphiphilic multiarm hyperbranched copolymers for triggered drug release

A novel type of bioreducible amphiphilic multiarm hyperbranched copolymer (H40-star-PLA-SS-PEG) based on Boltorn H40 core,poly(L-lactide) (PLA) inner-shell,and poly(ethylene glycol) (PEG) outer-shell with disulfide-linkages between the hydrophobic and hydrophilic moieties was developed as unimolecular micelles for controlled drug release triggered by reduction.The obtained H40-star-PLA-SS-PEG was characterized in detail by nuclear magnetic resonance (NMR),Fourier transform infrared (FTIR),gel permeation chromatography (GPC),differential scanning calorimeter (DSC),and thermal gravimetric analysis (TGA).Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses suggested that H40-star-PLA-SS-PEG formed stable unimolecular micelles in aqueous solution with an average diameter of 19 nm.Interestingly,these micelles aggregated into large particles rapidly in response to 10 mM dithiothreitol (DTT),most likely due to shedding of the hydrophilic PEG outer-shell through reductive cleavage of the disulfide bonds.As a hydrophobic anticancer model drug,doxorubicin (DOX) was encapsulated into these reductive unimolecular micelles.In vitro release studies revealed that under the reduction-stimulus,the detachment of PEG outer-shell in DOX-loaded micelles resulted in a rapid drug release.Flow cytometry and confocal laser scanning microscopy (CLSM) measurements indicated that these DOX-loaded micelles were easily internalized by living cells.Methyl tetrazolium (MTT) assay demonstrated a markedly enhanced drug efficacy of DOX-loaded H40-star-PLA-SS-PEG micelles as compared to free DOX.All of these results show that these bioreducible unimolecular micelles are promising carriers for the triggered intracellular delivery of hydrophobic anticancer drugs.

Cylindrical polymer brushes-anisotropic unimolecular micelle drug delivery system for enhancing the effectiveness of chemotherapy

Polymer systems can be designed into different structures and morphologies according to their physical and chemical performance requirements,and are considered as one of the most promising controlled delivery systems that can effectively improve the cancer therapeutic index.However,the majority of the polymer delivery systems are designed to be simple spherical nanostructures.To explore morphology/size-oriented delivery performance optimization,here,we synthesized three novel cylindrical polymer brushes(CPBs)by atom transfer radical polymerization(ATRP),which were cellulose-g-(CPT-b-OEGMA)(CCO)with different lengths(~86,~40,and~21 nm).The CPBs are composed of bio-degradable cellulose as the carrier,poly(ethylene glycol)methyl ether methacrylate(OEGMA)as hydrophily block,and glutathione(GSH)-responsive hydrophobic camptothecin(CPT)monomer as loaded anticancer drug.By controlling the chain length of the initiator,three kinds of polymeric prodrugs with different lengths(CCO-1,CCO-2,and CCO-3)could be self-organized into unimolecular micelles in water.We carried out comparative studies of three polymers,whose results verified that the shorter CPBs exhibited higher drug release efficiency,more cellular uptake,and enhanced tumor permeability,accompanied by shortened blood circulation time and lower tumor accumulation.As evidenced by in vivo experiments,the shorter CPBs exhibited higher anti-tumor efficiency,revealing that the size advantage has a higher priority than the anisotropic structure advantage.This provided vital information as to design an anisotropic polymer-based drug delivery system for cancer therapy.

Photo-Dimerization Characteristics of Coumarin Pendants within Amphiphilic Random Copolymer Micelles

The photo-dimerization characteristics of coumarin pendants within amphiphilic random copolymer micelles in aqueous solution was comprehensively investigated using various selected wavelength light in the UV-Vis-NIR region. The time-dependent photo-dimerization degree （PD） changes in the photo-dimerization experiments showed saturating behaviors with intensity-independent of PDmax values at 28%, 44%, 92%, 85%, 36%, 35%, 32% and 31% for 254, 288, 320, 360, 400, 500, 650 and 900 nm irradiations, respectively. The irradiation experiments at 254 and 288 nm announced the occurring of an asymmetric equilibrium of photo-dimerization and photo-cleavage at the used conditions. Both the alternative irradiation cycles of 360 and 254 nm, 650 and 254 nm showed a partially, but evidently reversible photo-dimerization tendency.

Dissipative Particle Dynamics Study on Aggregation of MPEG- PAE-PLA Block Polymer Micelles Loading Doxorubicine

To guide the molecular design of the pH-sensitive triblock amphiphilic polymer MPEG-PAE-PLA and the for- mula design of its doxorubicine （DOX）-loaded micelles, dissipative particle dynamics （DPD） simulations are em- ployed to investigate the aggregation behaviors of the DOX-loaded micelles. The simulation results showed that the aggregate morphologies of micelles and DOX distribution are influenced by degree of polymerization of blocks, and the proposed structure of polymer is MPEG44-PAE3-PLA4. With different contents of polymer or DOX, differ- ent aggregate morphologies of the micelles, like microsphere, spindle/column, reticulation or lamella are observed. To prepare the micro-spherical DOX-loaded micelles, the polymer content is proposed as 10%--15%, and the DOX content less than 10%.

Single-Metal-Atom Polymeric Unimolecular Micelles for Switchable Photocatalytic H_(2) Evolution

Developing“green”catalytic systems with desirable performance such as good water solubility,recyclability,and switchability is a great challenge.Here,to address this challenge,we extend the concept of polymeric unimolecular micelles(a typical selfassembled structure)to the construction of a stimuli-responsive and recoverable molecular catalyst with single-metal atoms that exhibits switchable photocatalytic activity for water splitting.