Formulation of gold nanoparticles with hibiscus and curcumin extracts induced anti-cancer activity

Gold nanoparticles (AuNPs) have shown a potential for biological applications due to their biocompatibility and high efficiency in drug delivery. Most of the times, the chemical routs are being used to synthesize the AuNPs products. In this paper, eco-friendly non-chemical rout was used to prepare AuNPs by utilizing hibiscus and curcumin extracts as reducing and stabilizing agents, and subsequently their anticancer activities were investigated. The synthesized AuNPs were characterized by using ultraviolet–visible spectroscopy (UV–Vis spectroscopy), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). UV–Vis spectroscopy analysis confirmed the characteristics absorption peak of gold, and FTIR findings were highlighted the characteristics boding. SEM and TEM analyses showed that the particles were predominantly spherical in shape. The particles were well dispersed when they were prepared under Hibiscus extracts with average size ～ 13 nm. An interesting morphology was observed when AuNPs were prepared with curcumin, where particles displayed an interconnected morphology (average size ～ 18 nm). The anticancer cell activity of AuNPs was studied against human colorectal carcinoma cells (HCT-116) and breast cancer cells (Michigan Cancer Foundation-7 (MCF-7)). The results of anticancer study showed that the treatment of cancer cells with AuNPs decreased the number of cells significantly as compared to control cells. The AuNPs -Hibiscus specimen showed a better inhibiting property than AuNPs -Curcumin, which is attributed to their uniform dispersion and small size.     

Magnetically polymeric nanocarriers for targeting delivery of curcumin and hyperthermia treatments toward cancer cells

Magnetically polymeric nanocarriers, Cur‐FA‐SAMN, were designed and synthesized for targeting, therapeutic treatments to cancer cells. Amine‐group immobilized iron oxides, Fe₃O₄‐NH₂, were attached on the surface of self‐assembled tri‐block copolymer, poly[(acrylic acid)‐block‐(N‐isopropylacrylamide)‐block‐(acrylic acid)] synthesized via reversible addition‐fragmentation chain‐transfer polymerization. For the purpose of targeting effect, folic acid was grafted on the surface of Fe₃O₄‐NH₂ attached nanoparticles. The nanocarriers were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometer, and UV‐Vis spectral analysis. Therefore, a hydrophobic anti‐cancer drug, curcumin, gained water dispersity, and stable storage via encapsulating into and on the magnetically polymeric nanocarriers, and the release behaviors were studied in vitro, with and without high frequency magnetic field. Biocompatibility and cytotoxicity of inherent and curcumin‐loaded nanocarriers were investigated by MTT assay. Results displayed that our nanocarriers have no cytotoxicity while curcumin‐loaded nanocarriers offered significant death to MCF‐7, human breast camcer cells. Intracellular‐uptake experiments demonstrated tremendous uptake and the destroying effect to MCF‐7 cells, most of the cancer cells were killed and the surviving ones were surrounded by the curcumin‐loaded nanocarriers. According to the aforementioned characteristics, these magnetically polymeric nanocarriers will be able to apply as a potential device for practical therapy. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2706–2713     

Core–Shell Hollow Microspheres of Magnetic Iron Oxide@Amorphous Calcium Phosphate: Synthesis Using Adenosine 5′‐Triphosphate and Application in pH‐Responsive Drug Delivery

Drug nanocarriers with magnetic targeting and pH‐responsive drug‐release behavior are promising for applications in controlled drug delivery. Magnetic iron oxides show excellent magnetism, but their application in drug delivery is limited by low drug‐loading capacity and poor control over drug release. Herein, core–shell hollow microspheres of magnetic iron oxide@amorphous calcium phosphate (MIO@ACP) were prepared and investigated as magnetic, pH‐responsive drug nanocarriers. Hollow microspheres of magnetic iron oxide (HMIOs) were prepared by etching solid MIO microspheres in hydrochloric acid/ethanol solution. After loading a drug into the HMIOs, the drug‐loaded HMIOs were coated with a protective layer of ACP by using adenosine 5′‐triphosphate (ATP) disodium salt (Na₂ATP) as stabilizer, and drug‐loaded core–shell hollow microspheres of MIO@ACP (HMIOs/drug/ACP) were obtained. The as‐prepared HMIOs/drug/ACP drug‐delivery system exhibits superparamagnetism and pH‐responsive drug‐release behavior. In a medium with pH 7.4, drug release was slow, but it was significantly accelerated at pH 4.5 due to dissolution of the ACP shell. Docetaxel‐loaded core–shell hollow microspheres of MIO@ACP exhibited high anticancer activity.     

Novel Polyhedral Silsesquioxanes [POSS(OH)32] as Anthracycline Nanocarriers—Potential Anticancer Prodrugs

Anthracyclines belong to the anticancer drugs that are widely used in chemotherapy. However, due to their systemic toxicity they also exert dangerous side effects associated mainly with cardiovascular risks. The pathway that is currently often developed is their chemical and physical modification via formation of conjugated or complexed prodrug systems with a variety of nanocarriers that can selectively release the active species in cancer cells. In this study, six new nanoconjugates were synthesized with the use of polyhedral oligosilsesquioxanes [POSS(OH)₃₂] as nanocarriers of the anticancer drugs anthracyclines—doxorubicin (DOX) and daunorubicin (DAU). These prodrug conjugates are also equipped with poly(ethylene glycol) (PEG) moieties of different structure and molecular weight. Water-soluble POSS, succinic anhydride modified (SAMDOX and SAMDAU) with carboxylic function, and PEGs (PEG1, PEG2 and PEGB3) were used for the synthesis. New nanoconjugates were formed via ester bonds and their structure was confirmed by NMR spectroscopy (¹H-NMR, ¹³C-NMR, ¹H-¹³C HSQC, DOSY and ¹H-¹H COSY), FTIR and DLS. Drug release rate was evaluated using UV-Vis spectroscopy at pH of 5.5. Release profiles of anthracyclines from conjugates 4–9 point to a range of 10 to 75% (after 42 h). Additionally, model NMR tests as well as diffusion ordered spectroscopy (DOSY) confirmed formation of the relevant prodrugs. The POSS-anthracycline conjugates exhibited prolonged active drug release time that can lead to the possibility of lowering administered doses and thus giving them high potential in chemotherapy. Drug release from conjugate 7 after 42 h was approx. 10%, 33% for conjugate 4, 47% for conjugate 5, 6, 8 and 75% for conjugate 9.     

Dual drug delivery system with flexible and controllable drug ratios for synergistic chemotherapy

Determination of whether multidrug nanocarriers can deliver and release loaded drugs at a predefined synergistic ratio to target cancer cells is crucial. Although there are many successful applications for delivery of multiple drugs, most current carriers are unable to achieve coordinated loading and release, leading to a drug release ratio that disagrees with the predefined loading ratio.In this work, a simple dual-drug delivery system with a flexible and controllable drug release ratio was constructed to deliver two anticancer drugs, doxorubicin(DOX) and curcumin(CUR). The drug ratio of DOX and CUR can be easily tuned for an enhanced synergistic effect, and the drugs can be released at predesigned ratios due to synchronous drug activation and nanoparticle collapse. Drug release at predefined ratios for synergistic anticancer therapy was demonstrated via in vitro and in vivo experiments. Therefore, the dual drug delivery system developed here provides a simple and efficient strategy for combination chemotherapy.     

pH-Responsive Hydrogel Beads Based on Alginate, κ-Carrageenan and Poloxamer for Enhanced Curcumin,Natural Bioactive Compound,Encapsulation and Controlled Release Efficiency

Polyphenolic compounds are used for treating various diseases due to their antioxidant and anticancer properties. However, utilization of hydrophobic compounds is limited due to their low bioavailability. In order to achieve a greater application of hydrophobic bioactive compounds, hydrogel beads based on biopolymers can be used as carriers for their enhanced incorporation and controlled delivery. In this study, beads based on the biopolymers-κ-carrageenan, sodium alginate and poloxamer 407 were prepared for encapsulation of curcumin. The prepared beads were characterized using IR, SEM, TGA and DSC. The curcumin encapsulation efficiency in the developed beads was 95.74 ± 2.24%. The release kinetics of the curcumin was monitored in systems that simulate the oral delivery (pH 1.2 and 7.4) of curcumin. The drug release profiles of the prepared beads with curcumin indicated that the curcumin release was significantly increased compared with the dissolution of curcumin itself. The cumulative release of curcumin from the beads was achieved within 24 h, with a final release rate of 12.07% (gastric fluid) as well as 81.93% (intestinal fluid). Both the in vitro and in vivo studies showed that new hydrogel beads based on carbohydrates and poloxamer improved curcumin’s bioavailability, and they can be used as powerful carriers for the oral delivery of different hydrophobic nutraceuticals.     

Fabrication and characterization of gold nanospheres‐cored pH‐sensitive thiol‐ended triblock copolymer: A smart drug delivery system for cancer therapy

Conventional chemotherapy suffers lack of multidrug resistance (MDR), lack of bioavailability, and selectivity. Nano‐sized drug delivery systems (DDS) are developing aimed to solve several limitations of conventional DDS. These systems have been offered for targeting tumor tissue owing to enhanced long circulation time, drug solubility, their retention effect, and improved permeability. As a result, the aim of this project was the design and development of DDS for biomedical applications. For this purpose, gold nanospheres (GNSs) covered by pH‐sensitive thiol‐ended triblock copolymer [poly(methacrylic acid) ‐b‐poly(acrylamide) ‐b‐poly(ε‐caprolactone)‐SH; PMAA‐b‐PAM‐b‐PCL‐SH] for delivery of anticancer drug doxorubicin (DOX). The chemical structures of triblock copolymer were investigated by proton nuclear magnetic resonance (¹H NMR) and Fourier transform infrared (FTIR) spectroscopies. ¹H NMR spectroscopy and gel permeation chromatography (GPC) were used for calculating the molecular weights of each part in the nanocarrier. The success of coating, GNSs with triblock copolymer was considered by means of dynamic light scattering (DLS), FTIR, ultraviolet‐visible (UV‐Vis), and transmission electron microscopy (TEM) measurement. The pH‐responsive drug release ability, (DOX)‐loading capacity, biocompatibility, and in vitro cytotoxicity effects of the nanocarriers were also studied. As a result, it is expected that the synthesized GNSs@polymer‐DOX considered as a potential application in nanomedicine demand like smart drug delivery, imaging, and chemo‐photothermal therapy.     

Synthesis and self‐assembly of thermoresponsive poly(N‐isopropylacrylamide)‐b‐poly(oligo ethylene glycol methyl ether acrylate) double hydrophilic block copolymers

We report on the synthesis of novel poly(N‐isopropylacrylamide)‐b‐poly(oligo ethylene glycol methyl ether acrylate) (PNIPAM‐b‐POEGA) thermoresponsive block copolymers using reversible addition–fragmentation chain transfer polymerization methodologies. The synthesized block copolymers are characterized by gel permeation chromatography, nuclear magnetic resonance, Fourier transform infrared (FTIR) techniques in terms of molecular weight and composition. Their thermoresponsive self‐assembly in aqueous media is investigated using dynamic and static light scattering. The PNIPAM‐b‐POEGA thermoresponsive block copolymers formed aggregates in water by increasing the temperature above the lower critical solution temperature value of PNIPAM block. Solution pH seems to affect the self‐assembly behavior in some cases due to the presence of ? COOH end groups. Therefore, the copolymers were utilized as “smart” nanocarries for the hydrophobic drug indomethacin, implementing a novel encapsulation protocol taking advantage of the thermoresponsive character of the PNIPAM block. The empty and loaded self‐assembled nanocarriers systems were studied by light scattering techniques, ultraviolet–visible, and FTIR spectroscopy, which gave information on the size and structure of the nanocarriers, the drug loading content and the interactions between the drug and the components of the block copolymers. Drug loaded nanostructures show stability at room temperature, due to active drug/block copolymer interactions. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1467–1477     

Silk Fibroin-Coated Liposomes as Biomimetic Nanocarrier for Long-Term Release Delivery System in Cancer Therapy

Despite much progress in cancer therapy, conventional chemotherapy can cause poor biodistribution and adverse side-effects on healthy cells. Currently, various strategies are being developed for an effective chemotherapy delivery system. Silk fibroin (SF) is a natural protein used in a wide range of biomedical applications including cancer therapy due to its biocompatibility, biodegradability, and unique mechanical properties. In this study, SF-coated liposomes (SF-LPs) were prepared as a biomimetic drug carrier. Physicochemical properties of SF-LPs were characterized by Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering, zeta potential measurement, and transmission electron microscopy (TEM). In vitro release of SF-LPs loaded with doxorubicin (DOX-SF-LPs) was evaluated over 21 days. Anticancer activity of DOX-SF-LPs was determined against MCF-7 and MDA-MB231 cells using the MTT assay. SF-LPs containing 1% SF exhibited favorable characteristics as a drug carrier. SF coating modified the kinetics of drug release and reduced the cytotoxic effect against L929 fibroblasts as compared to the uncoated liposomes containing cationic lipid. DOX-SF-LPs showed anticancer activity against breast cancer cells after 48 h or 72 h at 20 μM of DOX. This approach provides a potential platform of long-term release that combines biocompatible SF and phospholipids for cancer therapy, achieving efficient drug delivery and reducing side-effects.     

Preparation and characterization of N-succinyl-N'-octyl chitosan micelles as doxorubicin carriers for effective anti-tumor activity

N-Succinyl-N′-octyl chitosan (SOC) was prepared and characterized by elemental analysis, FTIR, ¹H NMR, WAXD and TG. An anticancer drug, doxorubicin (DOX), was incorporated into polymeric micelles forming by SOC in aqueous solutions. Critical micelle concentrations (CMC) of SOC were determined by fluorescence spectroscopy. The DOX-loaded SOC micelles were characterized by measurement of size and drug loading. The loading content of DOX increased with increasing drug-to-carrier ratio, and the more amount of the octyl chain, the higher the drug loading content. The average size, which was affected by the amount of octyl chain and drug loading content, was in the range of 100–200 nm. The polymeric micelles containing doxorubicin in the core region exhibited a sustained release and more cytotoxic activity against HepG2, A549, BGC and K562 than doxorubicin alone, this can be attributed to an endocytosis mechanism rather than passive diffusion.     

卡铂@葡聚糖纳米载体的自组装/聚合一步法制备及生物应用

在接枝共聚辅助自组装(GISA)制备葡聚糖纳米载体的过程中, 利用丙烯酸单体与卡铂之间的非共价键作用, 使得卡铂参与到葡聚糖纳米载体的形成中, 从而一步实现了卡铂@葡聚糖纳米载体的制备, 并使用肿瘤还原性环境敏感的二硫键来交联纳米载体, 得到了对肿瘤还原环境响应的纳米药物载体. 对纳米药物载体的结构、 粒径及形貌进行表征, 结果显示, 纳米药物载体粒径为(92±0.2) nm, Zeta电位为(-8±0.3) eV. 通过体外药物释放研究发现, 在还原性环境中, 载体可持续72 h释放药物, 最大释放量达80%. 细胞摄取实验表明负载卡铂的纳米药物载体可在4 h内高效地进入细胞核; 其半抑制浓度(IC₅₀)为25.32 μg/mL, 达到和相同浓度游离卡铂相仿的促肿瘤细胞凋亡效果. 此一步法所制备的卡铂@葡聚糖纳米载体具有良好的生物应用前景.     

荧光介孔二氧化硅纳米粒子的合成及药物运输

合成了荧光介孔二氧化硅纳米粒子（MSNs-FITC）,并研究了其在持续药物释放和生物示踪成像方面的应用。首先,采用一步法合成出MSNs-FITC,结合SEM、TEM、FT-IR、XRD和氮气吸附脱附等表征技术进行表征。其次,将抗癌药物阿霉素（DOX）负载到MSNs-FITC中。载药粒子的药物释放行为具有明显的pH依赖性,酸性环境加速释放速率。同时,体外细胞毒性测试表明MSNs-FITC具有良好的生物相容性。激光共聚焦扫描显微镜（CLSM）图像表明,MSNs-FITC可以进入细胞并具有剂量依赖性,流式细胞术分析（FCM）进一步证明了这一结果。     

Curcumin-loaded layer-by-layer folic acid and casein coated carboxymethyl cellulose/casein nanogels for treatment of skin cancer

Targeted drug delivery systems using natural polysaccharide/protein biopolymer for tumor cells are an attractive platform for enriching the therapeutic effects and reducing the side effects of the drug. Carboxymethyl cellulose (CMC) and casein (CA) nanogels (NGs) loaded with curcumin (CUR) were prepared by self-assembly method and fabricated with folic acid (FA) and casein using layer-by-layer (LbL) technique for skin cancer drug delivery. The prepared samples were characterized by techniques like zeta potential, FTIR, XRD, TGA and Cryo-SEM. Both the swelling and in vitro drug release was performed in acidic pH (4.5 and 6.8) and physiological pH 7.4. Hemolysis assays demonstrated that the drug carriers are hemocompatible. Confocal microscope studies indicate facilitated uptake of 2-FA/CA/CUR@CMC-CA NGs in MEL-39 melanoma cancer cell line, which in turn result in a higher potential for apoptosis. Compared to pure CUR and CUR@CMC-CA NGs, the 2-FA/CA/CUR@CMC-CA NGs has lower IC50 value and superior cytotoxicity in MEL-39 cells because of folate-receptor mediated endocytosis evaluated by the cellular viability quantification using MTT assay and optical microscope images. Finally from in vitro skin permeation experiments, 2-FA/CA/CUR@CMC-CA NGs showed 3.47 ± 0.03 to 4.15 ± 0.25 μg/ml CUR concentrations at the stratum corneum, epidermal and dermal layers. Overall, our results put forth 2-FA/CA/CUR@CMC-CA NGs as an aspiring candidate to achieve enhanced anticancer effects against melanoma skin cancer.     

pH响应型纳米药物载体的释药机制及性能研究进展

pH响应型纳米载体因具有智能的酸敏或碱敏释药性能,已成为当前一类重要的多功能纳米载体,并得到了研究人员的广泛关注。特别是酸敏性纳米载体,可用于肿瘤弱酸微环境的药物控释,因而对药物的定点释放和癌症的靶向治疗等生物医学应用发挥了积极作用。本文综述了近年来各类pH响应型纳米载体的典型合成方法,系统地介绍了共价键、分子间作用力以及物理结构变化3种方式引发的pH响应释药机制。深入阐述了pH响应型纳米载体的载药性能、体外释药性能、体外细胞毒性、体内抗癌性能及体内分布性能,并详细列举了近年来pH响应型纳米载体的各类实验参数,进而为pH响应型纳米载体的深入研究提供了方法学的借鉴和性能参考。     

Cyclodextrin-based nanosponges of curcumin: formulation and physicochemical characterization

Curcumin is the source of the spice turmeric having potential application in tumor treatment but has limited therapeutic utility because of its poor aqueous solubility. Curcumin suppresses the onset of tumors as well as their growth and metastasis. Cyclodextrin-based nanosponges (NS) have been used to increase the solubility of curcumin and to control its release. The aim of the study was to formulate the complex of curcumin with β-cyclodextrin nanosponge obtained with dimethyl carbonate as a cross linker. The particle size of loaded nanosponge was found to be 487.3 nm with minimum polydispersibility index (0.476). The loaded NS have shown more solubilization efficiency (20.89 μg/ml) in comparison with plain curcumin (0.4 μg/ml) and β-CD complex (5.88 μg/ml). The zeta potential was sufficiently high (?27 mV) which indicates formation of a stable colloidal nanosuspension. The curcumin nanosponge complex (CrNS) was characterized for FTIR, XRD and DSC studies and it confirmed the interactions of curcumin with NS. The in vitro drug release of curcumin was controlled over a prolonged period of time. The in vitro hemolysis study showed that the complex was non-hemolytic. CrNS sample showed only a slight reduction in cytotoxicity against MCF-7 cells, which concludes that there is no change in molecular structure of curcumin in CrNS formulation.     

Hydrogel Films Based on Chitosan and Oxidized Carboxymethylcellulose Optimized for the Controlled Release of Curcumin with Applications in Treating Dermatological Conditions

Cross-linked chitosan (CS) films with aldehyde groups obtained by oxidation of carboxymethyl cellulose (CMC) with NaIO₄ were prepared using different molar ratios between the CHO groups from oxidized carboxymethyl cellulose (CMCOx) and NH₂ groups from CS (from 0.25:1 to 2:1). Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy demonstrated the aldehyde groups’ presence in the CMCOx. The maximum oxidation degree was 22.9%. In the hydrogel, the amino groups’ conversion index value increased when the -CHO/-NH₂ molar ratio, cross-linking temperature, and time increased, while the swelling degree values decreased. The hydrogel films were characterized by scanning electron microscopy (SEM) and FTIR analysis. The curcumin encapsulation efficiency decreases from 56.74% to 16.88% when the cross-linking degree increases. The immobilized curcumin release efficiency (R_Ef%) and skin membrane permeability were evaluated in vitro in two different pH solutions using a Franz diffusion cell, and it was found to decrease when the molar ratio -CH=O/NH₂ increases. The curcumin R_Ef% in the receptor compartment was higher at pH = 7.4 (18%- for the sample with a molar ratio of 0.25:1) than at pH = 5.5 (16.5%). The curcumin absorption in the skin membrane at pH = 5.5 (47%) was more intense than at pH = 7.4 (8.6%). The curcumin-loaded films’ antioxidant activity was improved due to the CS presence.     

Formulation and Evaluation of 5-FU Loaded Eudragit Microspheres: Effect of Various Eudragit on Micromeretic Properties of Microspheres

The aim of the present study was to prepare and evaluate microspheres of Eudragit (RS, RL and RSPO) containing an anticancer drug 5-FU. Microspheres were prepared by O/O solvent evaporation method using a acetone/liquid paraffin system. Magnesium stearate was used as the droplet stabilizer and n-hexane was added to harden the microspheres. The prepared microspheres were characterized for their micromeretic properties and entrapment efficiency; as well by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray powder diffractometry (XRPD), thin layer chromatography (TLC) and scanning electron microscopy (SEM) revealed the crystalline nature of drug in a final state. The in vitro release studies were performed in a Phosphate Buffer Solution (PBS) pH 7.4. The best fit release kinetics was achieved with a Higuchi plot. The yields of preparation and entrapment efficiencies were very high with a larger particle size for all the formulations. Mean particle size, entrapment efficiency and production yield were highly influenced by the type of polymer and polymer concentration. It is concluded from the present investigation that various Eudragit are promising controlled release carriers for 5-FU.     

Studies on anticancerious and photocatalytic activity of carboxymethyl cellulose-cl-poly(lactic acid-co-itaconic acid)/ZnO-Ag nanocomposite

In this paper, the microwave-assisted synthesis of carboxymethyl cellulose-cl-poly(lactic acid–co-itaconic acid)/ZnO-Ag nanocomposite [CMC-cl-p(LA-co-IA)/ZnO-Ag] has been discussed. Lactic acid (LA) and itaconic acid (IA) monomers were grafted onto carboxymethyl cellulose (CMC) using potassium persulphate and N, N^'-methylene-bis-acrylamide (MBA) as initiator and crosslinker, respectively at optimized conditions of temperature and pressure. The nanocomposite was characterized using different techniques such as Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and energy dispersive X-ray (EDX). XRD, TEM and FTIR spectral analysis confirmed the formation of the nanocomposite. The release of amoxicillin drug-using nanocomposite as a function of pH and time has been investigated. The maximum drug release of 94.64% was pragmatic at pH 2.2 after 6 h. The degradation of congo red using nanocomposite followed the pseudo-first-order reaction model with the regression coefficient (R²) values of 0.99312. The nanocomposite was also explored for anticancer behavior against yeast cells.     

基于透明质酸的刺激响应纳米给药系统的研究进展

透明质酸(Hyaluronic acid, HA)是一种天然多糖,具有良好的生物相容性和生物降解性,利用 HA 构建的纳米载体自身就具有肿瘤靶向功能,可以作为抗癌药物载体将药物传递到肿瘤细胞内从而实现精准到达病患处。近年来透明质酸在应用于肿瘤靶向给药系统中的关注越来越多,成为了靶向治疗肿瘤的一大研究热点。基于透明质酸的基本特性和肿瘤靶向的生理学基础,在不同的刺激响应下,透明质酸型纳米给药系统能将药物集中释放于肿瘤的微环境内,更好地杀死肿瘤细胞,同时避免其他正常的组织受到药物损害。本文主要综述了透明质酸型纳米药物输送系统在各种刺激响应下释放药物的最新研究进展。     

Conjugation of pectin biopolymer with Au-nanoparticles as a drug delivery system: Experimental and DFT studies

In the present study, pectin-coated gold nanoparticles (GNPs) were used as a candidate for curcumin drug delivery. The effect of the size of synthesized GNPs was examined, as an important factor on the yield of drug delivery. For this purpose, three different sizes of GNPs were first synthesized using a chemical method. The synthesized nanoparticles were then coated with pectin biopolymer. Finally, curcumin drug was loaded in a pectin@GNPs complex. Various methods such as UV–vis spectrophotometry, dynamic light scattering, scanning electron microscopy and Fourier-transform infrared spectroscopy were used to characterize the synthesized GNPs and pectin@GNPs. The encapsulation efficiency and the release percentage of the drug were calculated for two different pH values. Further, an antibacterial study was conducted. The results revealed that 100 nm GNPs had the highest encapsulation efficiency. An investigation of the release rate of curcumin drug at 37°C for 48 h indicated that the amount of drug released was higher in acidic pH than at pH 7.4 with a slow release rate. The electronic structure and the adsorption properties of pectin–GNPs complex were examined using the density functional theory method.