Effect of degree of substitution and molecular weight of carboxymethyl chitosan nanoparticles on doxorubicin delivery

The aim of this study was to evaluate the potential of carboxymethyl chitosan (CM‐chitosan) nanoparticles as carriers for the anticancer drug, doxorubicin (DOX). Different kinds of CM‐chitosan with various molecular weight (MW) and degree of substitution (DS) were employed to prepare nanoparticles through ionical gelification with calcium ions. Factors affecting nanoparticles formation in relation to MW and DS of CM‐chitosan were discussed. By the way of dynamic light scattering (DLS), TEM, and atomic force microscopy (AFM), nanoparticles were shown to be around 200–300 nm and in a narrow distribution. FTIR revealed strong electrostatic interactions between carboxyl groups of CM‐chitosan and calcium ions. DOX delivery was affected by the molecular structure of CM‐chitosan. Increasing MWs of CM‐chitosan from 4.50 to 38.9 kDa, DOX entrapment efficiency was enhanced from 10 to 40% and higher DS slightly improved the load of DOX. In vitro release studies showed an initial burst followed by an extended slow release. The DOX release rate was hindered by CM‐chitosan with high MW and DS. These preliminary studies showed the feasibility of CM‐chitosan nanoparticles to entrap DOX and the potential to deliver it as controlled release nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4689–4696, 2006     

Mesoporous silica nanoparticles loading doxorubicin reverse multidrug resistance: performance and mechanism

Multidrug resistance (MDR) is one of the major obstacles for successful chemotherapy in cancer. One of the effective approaches to overcome MDR is to use nanoparticle-mediated drug delivery to increase drug accumulation in drug resistant cancer cells. In this work, we first report that the performance and mechanism of an inorganic engineered delivery system based on mesoporous silica nanoparticles (MSNs) loading doxorubicin (DMNs) to overcome the MDR of MCF-7/ADR (a DOX-resistant and P-glycoprotein (P-gp) over-expression cancer cell line). The experimental results showed that DMNs could enhance the cellular uptake of doxorubicin (DOX) and increase the cell proliferation suppression effect of DOX against MCF-7/ADR cells. The IC(50) of DMNs against MCF-7/ADR cells was 8-fold lower than that of free DOX. However, an improved effect of DOX in DMNs against MCF-7 cells (a DOX-sensitive cancer cell line) was not found. The increased cellular uptake and nuclear accumulation of DOX delivered by DMNs in MCF-7/ADR cells was confirmed by confocal laser scanning microscopy, and could result from the down-regulation of P-gp and bypassing the efflux action by MSNs themselves. The cellular uptake mechanism of DMNs indicated that the macropinocytosis was one of the pathways for the uptake of DMNs by MCF-7/ADR cells. The in vivo biodistribution showed that DMNs induced a higher accumulation of DOX in drug resistant tumors than free DOX. These results suggested that MSNs could be an effective delivery system to overcome multidrug resistance.     

Polyurethane/doxorubicin nanoparticles based on electrostatic interactions as pH‐sensitive drug delivery carriers

In order to obtain a pH‐sensitive delivery carrier for doxorubicin (DOX), DOX‐loaded polyurethane (PU·DOX) nanoparticles were readily prepared in water by electrostatic interactions between amphiphilic polyurethane with carboxyl pendent groups (PU‐COOH) and doxorubicin hydrochloride (DOX·HCl). The structures of the products obtained were characterized by Fourier transform infrared spectroscopy, ¹H NMR spectroscopy, gel permeation chromatography, UV–visible spectroscopy, dynamic light scattering and transmission electron microscopy. The average hydrodynamic size of the PU·DOX nanoparticles was around 182 nm with negative surface charge (?1.1 mV) and a spherical or rodlike shape. PU·DOX nanoparticles had a higher drug‐loading content of 14.1 wt%. The in vitro drug release properties of PU·DOX nanoparticles were investigated at pH 4.0, 5.0 and 7.4, respectively. PU·DOX nanoparticles exhibited a good pH‐sensitive drug release property, but there was almost no release of DOX from PU·DOX nanoparticles at pH 7.4. The in vitro cellular uptake assay and the Cell Counting Kit‐8 assay demonstrated that PU·DOX nanoparticles had a higher level of cellular internalization and higher inhibitory effects on the proliferation of human breast cancer (MCF‐7) cells than pure DOX. The enhancement of the inhibition effects resulted from increasing apoptosis‐inducing effects on MCF‐7 cells, which was related to the enhancement of Bax expression and the reduction of Bcl‐2 expression confirmed by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay, real‐time polymerase chain reaction (PCR) assay and western blot assay. © 2018 Society of Chemical Industry     

PEGylated hollow pH‐responsive polymeric nanocapsules for controlled drug delivery

Novel pH‐responsive PEGylated hollow nanocapsules (HNCaps) were fabricated through a combination of distillation–precipitation copolymerization and surface thiol–ene ‘click’ grafting reaction. For this purpose, SiO₂ nanoparticles were synthesized using the Stöber approach, and then modified using 3‐(trimethoxysilyl)propyl methacrylate (MPS). Afterward, a mixture of triethyleneglycol dimethacrylate (as crosslinker), acrylic acid (AA; as pH‐responsive monomer) and MPS‐modified SiO₂ nanoparticles (as sacrificial template) was copolymerized using the distillation–precipitation approach to afford SiO₂@PAA core–shell nanoparticles. The SiO₂ core was etched from SiO₂@PAA using HF solution, and the obtained PAA HNCaps were grafted with a thiol‐end‐capped poly(ethylene glycol) (PEG) through a thiol–ene ‘click’ reaction to produce PAA‐g‐PEG HNCaps. The fabricated HNCaps were loaded with doxorubicin hydrochloride (DOX) as a model anticancer drug, and their drug loading and encapsulation efficiencies as well as pH‐dependent drug release behavior were investigated. The anticancer activity of the drug‐loaded HNCaps was extensively evaluated using MTT assay against human breast cancer cells (MCF7). The cytotoxicity assay results as well as superior physicochemical and biological features of the fabricated HNCaps mean that the developed DOX‐loaded HNCaps have excellent potential for cancer chemotherapy. © 2020 Society of Chemical Industry     

Chitosan/OA nanoparticle as delivery system for celecoxib: Parameters affecting the particle size,encapsulation, and release

Self‐assembled nanoparticles prepared from amphiphilic chitosan/oleic acid (Ch/OA) have shown antibacterial activity and potential application as a carrier for hydrophobic anticancer drugs. In this study, a low molecular weight chitosan was modified with oleic acid obtaining a degree of substitution (DS) of 12%. The critical aggregation concentration (CAC) of the Ch/OA polymer obtained (0.025 mg mL^?1) is lower in comparison with some systems of chitosan‐fatty acids. The self‐assembled Ch/OA nanoparticle size was optimized by changing polymer concentration, solvent, method, and time of homogenization to obtain particles with sizes around 300 nm and positive zeta potential. The drug loading about 7 μg mL^?1 and encapsulation efficiency of 75.8 ± 3.6% for Celecoxib was affected by the drug concentration. In vitro release behavior performed in (PBS, pH 7.4) and MES buffer (pH 6) indicated a pH‐dependent drug release behavior. The self‐assembled systems show stability during 4 weeks after the encapsulation of the hydrophobic drug. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44472.     

Acid and light dual- stimuli-cleavable polymeric micelles

In this study, acid and light dual- stimuli-responsive amphiphilic AB-type methoxy poly(ethylene glycol)-acetal-ONB-poly(4-substituted-ε-caprolactone) (MPEG-a-ONB-PXCL) diblock copolymers were synthesized using ring-opening polymerization and nucleophilic substitution reactions. The prepared copolymer features an acid-cleavable acetal group and photocleavable o-nitrobenzyl linkage between the hydrophilic MPEG and hydrophobic PXCL blocks. The design enables the diblock copolymers to respond to both acid and ultraviolet (UV) light while ensuring the minimum number of stimuli-reactive moieties in the copolymer structure. The disruption of the copolymeric micelles in aqueous solution was examined under the action of pH or UV light alone or under the combined stimulation pH and UV light. Under the combined stimulation of UV irradiation and pH, the micellar nanoparticles could dissociate; therefore, the loaded molecules could be released from the assemblies more efficiently than under either stimulus alone. The nanoparticles exhibited nonsignificant toxicity against human cervical cancer (HeLa) cells at concentrations ≤300 μg mL^?1. Doxorubicin (DOX)-loaded micelles facilitated the uptake of DOX by the HeLa cells at the initial stage. The dual stimuli-cleavable polymeric micelles show promising potential as new nanocarrier for precisely controlled release of encapsulated drug.     

Surface modified cellulose nanocrystalline hybrids actualizing efficient and precise delivery of doxorubicin into nucleus with: In vitro and in vivo evaluation

Rod-like-shape nanomedicines with the ability of lysosomal pH-controlled drug release can precisely deliver doxorubicin (DOX) into its target, nucleus, and can fully exert its anticancer effect. Taking advantage of their large specific surface area, cellulose nanocrystals (CNCs) were used to fabricate pH-responsive DOX-loaded rod-like shaped hybrids nanomedicines: cis-aconityl-doxorubicin (CAD)@polyethylenimine (PEI)@CNCs (CAD@PEI@CNCs) via layer-by-layer (LbL) assembly. In vitro, CAD@PEI@CNCs hybrids displayed rod-like shape, high drug loading content, lysosomal pH-controlled drug release, efficient and precise doxorubicin (DOX) delivering into the nucleus. Moreover, the cellular uptake of CAD@PEI@CNCs hybrids was 20.9 folds higher than that of DOX·HCl against A549 cells. The cytotoxicity of CAD@PEI@CNCs hybrids was much higher than that of DOX·HCl and the pH-irresponsive hybrids against A549 cell. In vivo, CAD@PEI@CNCs hybrids exhibited good antitumor effect: (42.0 ± 6)% inhibition rate and few harms to the nude mice. Altogether, rod-like shaped pH-responsive CAD@PEI@CNCs hybrids nanomedicines could efficiently overcome the vascular and tumor barriers, and precisely deliver DOX to nucleus to convert DOX antitumor effects. These results indicate that CAD@PEI@CNCs have great potential to act as advanced nanomedicines with enhanced delivery efficiency and therapeutic efficiency.     

分子模拟研究壳聚糖-氮化硼纳米管封装及输运阿霉素

壳聚糖-BNNTs复合载体在药物输运领域存在潜在的应用前景。通过分子动力学方法，以抗癌药物阿霉素DOX为药物模型，研究利用壳聚糖-BNNTs复合载体材料封装及跨膜输运抗癌药物的过程。结果表明，非质子化壳聚糖能吸附且调整DOX以合适的构象进入管中。细胞膜磷脂分子能自发嵌入到BNNT (14,14)管中，将管中壳聚糖挤出并使DOX在管中快速上升。该研究可以为实验提高药物封装效率，并提高癌细胞表面药物浓度提供设计思路。     

一种新型靶向壳聚糖纳米载体的制备及性质

制备了不同乳糖取代度的乳糖化油酰壳聚糖(Lac-OCH)。通过粘度法检测了Lac-OCH的流变学特性;通过荧光法研究了Lac-OCH在溶液中的自聚集行为,随着乳糖取代度升高,临界聚集浓度(CAC)值升高;采用超声法制备Lac-OCS纳米体系;采用透射电镜观察Lac-OCH纳米球呈现椭球棒状,粒径约为200 nm;研究了Lac-OCH负载药物阿霉素后的包封率和体外释放情况。     

pH-响应型K5多糖药物传递系统的构建及应用

化学疗法是目前癌症治疗的主要方法,但目前常用的化疗药物却普遍存在水溶性不佳、缺乏选择性、毒副作用大等不足,而限制了其应用。本研究基于肝素前体K5多糖为模板,利用具有pH响应性的硼酸酯键,构建了K5-脱氧胆酸（K5AD）两亲性药物传递系统,用于阿霉素（doxorubicin,DOX）的靶向传递释放。考察了该体系的体外药物释放行为,并在体外评价其对肿瘤细胞的抑制作用。结果表明,K5AD的临界胶束浓度值为23.5mg/L,在水溶液中能自组装形成平均粒径为196.7nm的胶束;K5AD-DOX体外药物释放实验显示其具有pH-响应的释药行为,在pH 5.0的酸性环境下药物释放速率较pH 7.4下更快。细胞实验表明,K5AD-DOX对肿瘤细胞的毒性远大于对正常细胞的毒性,表现出治疗的选择性。     

透明质酸自组装聚合物胶束的制备及表征

为了增强抗肿瘤药物的靶向性与抗肿瘤活性,本文制备了透明质酸-十八烷聚合物,用其对阿霉素进行包载,考察其理化性质及体外细胞毒性。合成两亲性透明质酸-十八烷聚合物,利用核磁对其结构进行确证。选择超声法制备载阿霉素的聚合物胶束,考察胶束的粒径、电位、包封率、载药量以及体外释放行为。选择乳腺癌细胞MCF-7为肿瘤细胞模型,考察载药胶束的体外抗肿瘤活性。成功合成了透明质酸-十八烷聚合物。制备的空白胶束和载药的胶束的粒径分别为（180.7±1.25）nm和（178.3±2.24）nm,Zeta电位分别为（-21.3±0.25）mV和（-18.1±0.31）mV。载阿霉素聚合物胶束的包封率为（96.1%±0.72%）,载药量为16.1%±1.18%,体外释放行为表明在72h的累计药物释放率仅为40%左右,具有明显的缓释行为。体外细胞毒性结果表明,空白聚合物胶束对肿瘤细胞几乎没有毒性,而载阿霉素的聚合物胶束具有较好的抗肿瘤活性。结论：透明质酸-十八烷聚合物胶束可以有效地包载抗肿瘤药物阿霉素,具有良好的缓释特性和抗肿瘤活性。     

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 (TPGS₃₃₅₀), peptide (Pep), and doxorubicin (DOX) (TPGS₃₃₅₀-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.     

Self‐assembled nanoparticles from folate‐decorated maleilated pullulan–doxorubicin conjugate for improved drug delivery to cancer cells

The goal of this study was to develop doxorubicin conjugate nanoparticles with increased antitumor effects, reduced side effects and the ability to overcome multidrug resistance (MDR). In this regard, folate‐decorated maleilated pullulan–doxorubicin conjugate nanoparticles were developed as carriers for co‐delivery of pyrrolidinedithiocarbamate and doxorubicin (FA‐MP‐DOX/PDTC + DOX NPs). The resultant nanoparticles showed spherical geometry, with an average diameter of 152 nm. The two drugs were released from the nanoparticles in a slow, pH‐dependent sustained release. To test the efficacy of these nanoparticles, in vitro tests including cell viability and folate receptor‐mediated endocytosis were conducted against both A2780 cells and A2780/DOX^R cells. Compared to free DOX, the FA‐MP‐DOX/PDTC + DOX NPs showed effective but less potent cytotoxicity against A2780 cells. For A2780/DOX^R cells, they showed enhanced cellular uptake, increased targeting capacity and cytotoxicity. These results suggest that co‐delivery of PDTC and DOX may further overcome MDR by transporting an increased amount of DOX within cells in addition to the folate receptor‐mediated endocytosis process. © 2012 Society of Chemical Industry     

Simple Fabrication of Glutathione-Responsive PEGylated Micellar Nanocarriers for Dual Drugs Delivery

The authors report a feasible simple method to fabricate two kinds of micellar nanocarriers (MPEG-SS-CPT/DOX) with polyethylene glycol (PEG) based on the self-assembly of glutathione (GSH)-responsive amphiphilic PEGylated polymers (MPEG-SS-CPT) in free doxorubicin (DOX) solution, which could carry two anticancer drugs of camptothecin (CPT) and DOX toward cancer cells together. In in vitro release studies, the micelles of MPEG-SS-CPT/DOX could undergo the triggered disassembly to release CPT and DOX under GSH stimulus much faster than without GSH. Furthermore, the MPEG-SS-CPT nanocarriers could release CPT with no change of its original structure after degradation. From the experiments of loading and release of drugs, the cell viability assay, cellular uptake, and flow cytometry studies, it was found that the fibrous micelles modified by PEG with a molecular weight of 350 had greater potential in the field of drug delivery than the other with a molecular weight of 1900.     

Preparation,Characterization, and Drug-Release Behaviors of a pH-Sensitive Composite Hydrogel Bead Based on Guar Gum,Attapulgite, and Sodium Alginate

A novel guar gum-g-poly (acrylic acid)/attapulgite/sodium alginate (GG-g-PAA/APT/SA) composite hydrogel bead with excellent pH sensitivity was prepared via a facile ionic gelation approach and characterized by FTIR and SEM techniques. The effect of APT content on the encapsulation efficiency (EE), swelling ratio, and drug release behaviors of the beads was investigated and the in-vitro release kinetics were also evaluated using diclofenac sodium (DS) as the model drug. The results indicate that the burst release effect of DS drug was eliminated due to the incorporation of APT, and the DS cumulative release was clearly decreased with increasing the APT content.     

Temperature,pH, and reduction triple‐stimuli‐responsive inner‐layer crosslinked micelles as nanocarriers for controlled release

Temperature, pH, and reduction triple‐stimuli‐responsive inner‐layer crosslinked micelles as nanocarriers for drug delivery and release are designed. The well‐defined tetrablock copolymer poly(polyethylene glycol methacrylate)–poly[2‐(dimethylamino) ethyl methacrylate]–poly(N‐isopropylacrylamide)–poly(methylacrylic acid) (PPEGMA‐PDMAEMA‐PNIPAM‐PMAA) is synthesized via atom transfer radical polymerization, click chemistry, and esterolysis reaction. The tetrablock copolymer self‐assembles into noncrosslinked micelles in acidic aqueous solution. The core‐crosslinked micelles, shell‐crosslinked micelles, and shell–core dilayer‐crosslinked micelles are prepared via quaternization reaction or carbodiimide chemistry reaction. The crosslinked micelles are used as drug carriers to load doxorubicin (DOX), and the drug encapsulation efficiency with 20% feed ratio reached 59.2%, 73.1%, and 86.1%, respectively. The cumulative release rate of DOX is accelerated by single or combined stimulations. The MTT (3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay verifies that the inner‐layer crosslinked micelles show excellent cytocompatibility, and DOX‐loaded micelles exhibit significantly higher inhibition for HepG2 cell proliferation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46714.     

疏水修饰磁性壳聚糖载药纳米粒子的制备与表征

利用O-羧甲基壳聚糖(O-CMC)的表面多种官能团(如-NH_2,-OH,-COOH等)与胆酸(CA)进行化学修饰得到两亲性共聚物,再以反溶剂法将Fe_3O_4和阿霉素(DOX)包埋在两亲性共聚物疏水的核中,制备两亲性的磁性壳聚糖载药纳米粒子,并对磁性载药纳米粒子的形貌、粒径大小、磁性、药物控释等进行了研究。结果表明:磁性壳聚糖纳米粒子有较高的药物包埋效率(92.3%),与自由阿霉素相比,磁性复合物具有明显的缓释作用和pH响应性;同时,有较好的超顺磁性。这些说明制备的疏水修饰磁性壳聚糖载药纳米粒子具有双重响应性,有望作为药物输送载体对肿瘤进行实时跟踪、诊断和治疗。     

PEG化羟基磷灰石纳米体系的制备及双通道荧光成像

PEG化的药物递送系统（DDSs）可以通过增强药物的渗透性和滞留性（EPR）效应克服传统化疗的副作用。利用共沉淀法和水热法制备纳米粒子DOX@HAP，进一步通过偶联反应修饰菁染料（Cy），通过铜（I）催化的炔-叠氮化物环加成反应修饰PEG链，构建了纳米制剂DOX@HAP-Cy-PEG。通过透射电子显微镜（TEM）、扫描电子显微镜（SEM）、粒度分析仪、傅里叶红外光谱仪（FTIR）、X射线光电子能谱仪（XPS）和X射线衍射仪（XRD）对该纳米载药体系的形貌、粒径、物相组成进行表征分析。利用紫外-可见（UV-Vis）分光光度法测定了该纳米材料的药物负载量以及体外药物释放曲线。进一步，利用DOX和Cy双通道荧光成像，监测DDSs在Hela和HepG2细胞中的摄取行为。表明DOX@HAP-Cy-PEG纳米载药体系有望作为一种新型的治疗与示踪一体化的抗癌纳米制剂。     

Synthesis of PEGylation hydroxyapatite drug delivery system and its dual channels fluorescence imaging

PEGylated drug delivery systems (DDSs) can overcome the side effects of traditional chemotherapy by enhancing drug permeability and retention (EPR) effects. In this work, DOX@HAP (hydroxyapatite) was initially fabricated via the coprecipitation and hydrothermal method, further functionalized with Cy (cyanine) by coupling reaction of APTES and then introduced hydrophilic PEG chains by using copper(I)-catalyzed alkyne–azide cycloaddition reaction. Physicochemical properties including the morphology, particle size and phase composition, were characterized by TEM, SEM, particle size analyzer, FTIR, XPS and XRD. The encapsulation efficiency and drug release profile of DOX@HAP-Cy-PEG were analyzed by UV-Vis spectrophotometry. Furthermore, the cellular uptake of DOX@HAP-Cy-PEG nanoparticles in Hela and HepG2 cells was monitored by the dual channels fluorescence imaging of DOX and Cy. The results showed that DOX@HAP-Cy-PEG nanoparticles could be used to real-time monitor the dynamic distribution of DDSs in Hela and HepG2 cells by dual channels.     

Efficient pH Dependent Drug Delivery to Target Cancer Cells by Gold Nanoparticles Capped with Carboxymethyl Chitosan

Doxorubicin (DOX) was immobilized on gold nanoparticles (AuNPs) capped with carboxymethyl chitosan (CMC) for effective delivery to cancer cells. The carboxylic group of carboxymethyl chitosan interacts with the amino group of the doxorubicin (DOX) forming stable, non-covalent interactions on the surface of AuNPs. The carboxylic group ionizes at acidic pH, thereby releasing the drug effectively at acidic pH suitable to target cancer cells. The DOX loaded gold nanoparticles were effectively absorbed by cervical cancer cells compared to free DOX and their uptake was further increased at acidic conditions induced by nigericin, an ionophore that causes intracellular acidification. These results suggest that DOX loaded AuNPs with pH-triggered drug releasing properties is a novel nanotheraputic approach to overcome drug resistance in cancer.