Selective Targeting of Nanocarriers to Neutrophils and Monocytes

We previously identified and characterized cell-type selective binding peptides from random peptide phage display libraries. Here, we used one of these peptides (GGP) to target liposomal nanocarriers to leukocyte subsets. To profile the binding selectivity of GGP-coated liposomes to human blood cells, we performed flow cytometric analysis with whole anti-coagulated blood. It is shown that when liposomal nanocarriers present these peptides on their surface, they facilitated cell-type specific targeting of liposomes to neutrophils and monocytes in contrast to nontargeted liposomes. Our data suggest that engineering the appropriate number of targeting peptide ligands on the nanocarrier surface is a factor in cell-binding selectivity, as is dose. Increasing the peptide density on the surface of the liposomes from 250 to 500 molecules resulted in more binding to neutrophils and monocytes. Fluorescence confocal microscopy corroborated the flow cytometry data revealing that liposomes coated with targeting GGP peptides decorated the surface of targeting cells and facilitate cell uptake of payload as evidenced by nuclear localization of tracer. These data suggest that small peptides identified by phage display techniques can be used to target nanocarriers that potentially carry therapeutic or imaging agents to leukocyte subsets. This ability has important implications for diseases where neutrophils and monocytes play a major role such as arthritis, inflammatory bowel disease, chronic obstructive pulmonary disease, and glomerulonephritis.     

Liposomes coated with chemically modified dextran interact with human endothelial cells.

Some liposomal formulations are now in clinical use. New applications in biology and medicine using targeted liposomes remain an intensive research area. In this context, liposomes constituted of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and cholesterol (70/10/20 mol %) were prepared by detergent dialysis and coated with dextran (Dx) or functionalized dextran (FDx), both hydrophobized by a cholesterol anchor which penetrates the lipid bilayer during the vesicle formation. The coating of liposomes with these polysaccharides was performed because chemically modified dextran but not native Dx interacted with vascular cells. The liposome uptake by human endothelial cells was followed using uncoated and coated liposomes radiolabeled with a neutral lipid (3H-cholesterol) and a polar phospholipid (14C-PC). The results indicated for both radiolabels a preferential uptake by endothelial cells of FDx-coated liposomes compared to uncoated or Dx-coated liposomes. Addition to the culture medium of calcium up to 10 mM further enhanced the level and rate of incorporation of FDx-coated liposomes, whereas interaction of endothelial cells with uncoated liposomes or liposomes coated with Dx was poorly affected. Liposome membranes were then labeled with N-(lissamine rhodamine B sulfonyl)diacyl-PE and liposome uptake by endothelial cells was observed by fluorescence microscopy. The punctate intracellular fluorescence of cells incubated at 37 degrees C with fluorolabeled liposomes is indicative of the liposome localization within the endocytotic pathway of the cells. Altogether, these data demonstrate that coating of liposomes with FDx enable specific interactions with human endothelial cells in culture. Consequently, these liposomes coated with bioactive polymers represent an attractive approach as materials for use as drug delivery vehicles targeting vascular cells.     

Synthesis of nanocarriers with remote magnetic drug release control and enhanced drug delivery for intracellular targeting of cancer cells

Nanotherapeutic strategy is well recognized as the therapeutic approach of the future. Numerous reports have demonstrated the use of nanoparticulate drug carriers for the development of targeted nanotherapeutics by, for instance, incorporation of a moiety that specifically targets certain diseased cells. However, systematic investigation of this aspect has been inadequate, especially with regard to nanosystems with remotely controlled drug delivery. The authors previously designed a magnetic-responsive core-shell drug delivery nanosystem which proved to be technically feasible in vitro. In the present study, this nanosystem is modified for targeted delivery of an anticancer agent (encapsulated camptothecin (CPT)) to cancer cells overexpressing epithelial growth factor receptor (EGFR) with accurate intracellular drug release. The endocytosis of the nanocarriers by cancer cells, the pathway of cellular uptake and the subsequent intracellular controlled drug delivery were systematically investigated. It was found that the modified nanocarriers showed reasonably high drug load efficiency for CPT and a high uptake rate by cancer cells overexpressing EGFR through clathrin-mediated endocytosis. The intracellular release of the CPT molecules via an external magnetic stimulus proved to be technically successful and ensured much higher therapeutic efficacy than that obtained with the free drug. This study employs multiple functions for nanotherapeutic treatment of specific target cells, i.e. cell-specific targeting, controlled cellular endocytosis and magnetic-responsive intracellular drug release.     

Hyaluronic acid controls the uptake pathway and intracellular trafficking of an octaarginine-modified gene vector in CD44 positive- and CD44 negative-cells

The cellular uptake pathway for a gene vector is an important factor in transgene expression. We previously constructed an original gene vector, multifunctional envelope-type nano device (MEND). The use of octaarginine (R8), a cell-penetrating peptide dramatically enhanced the transfection activity of the MEND since efficient cellular uptake via macropinocytosis, while the R8 should overcome its poor cell selectivity. Here we prepared an R8-MEND equipped with GALA (a peptide for endosomal escape) (R8/GALA-MEND) coated with hyaluronic acid (HA) (HA-R8/GALA-MEND), a natural ligand for cancer cells overexpressing CD44. We investigated the cellular uptake pathway of the HA-R8/GALA-MEND and the R8/GALA-MEND using HCT116 cells overexpressing CD44. Both carriers were taken up by cells mainly via macropinocytosis, whereas only the HA-R8/GALA-MEND was partially internalized into cells via a CD44-mediated pathway. Investigation of transgene expression showed that the HA-R8/GALA-MEND had a high transfection activity in HCT116 cells via both macropinocytotic and CD44-mediated pathways. On the other hand, the value for the HA-R8/GALA-MEND was significantly decreased compared with the value for the R8/GALA-MEND in NIH3T3 cells (CD44-negative cells). These findings indicate that the HA-coating controls the intracellular pathway for R8-modified nanocarriers, and that a CD44-mediated pathway is an important route for transgene expression.     

Pentapeptide YIGSR-mediated HT-1080 fibrosarcoma cells targeting of adriamycin encapsulated in sterically stabilized liposomes

In the peptide-targeted therapy for cancer, peptides are used to reach a selective and specific target in cancer cells. Peptides are used free or coupled to chemotherapeutic drugs, phagues, proteins, polymers, liposomes, and polymer-grafted liposomes. Using this latter approach, the pentapeptide YIGSR was coupled to the distal end from carboxyl groups of liposome-grafted polyethyleneglycol (PEG) chains (YIGSR-PEG-liposome). As a control, the peptide PEAGD coupled to PEG-liposome was used. The biological activity of YIGSR-PEG-liposome was tested using HT-1080 human fibrosarcoma cells. In adhesion assays, the YIGSR-PEG-liposome coated to plastic plates promoted 30% of the specific cell attachment. In competition assays, YIGSR-PEG-liposome inhibited the specific attachment of cells to laminin-1-coated plates by 25%. Following this, we prepared peptide-PEG-liposomes encapsulating adriamycin (ADR). In vitro cytotoxicity assays against HT-1080 cells gave IC(50) values 2.1 times lower for YIGSR-PEG-liposomal ADR in comparison to PEAGD-PEG-liposomal ADR. The free peptide added in excess increased the IC(50) value of YIGSR-PEG-liposomal ADR by 72%, while the IC(50) value of control liposomal ADR was unaffected, supporting a receptor-mediated mechanism of targeting. In addition, the lower IC(50) value is correlated with a higher total of ADR accumulation in the cells.     

Study on Tat Mediated Magnetic Nanoparticles Having Composite Targeting Function

INTRODUCTION Therehasbeengreatinterestoverthepasttwodecadesindevelopingandtest-ingironoxidenanoparticlesfortumordetectionandtherapy.Inbrainresearch,nan-odispersedironoxideshavebeenusedforthemappingofblood-brainbarrier(BBB)disruption,ascarriersofdiagnosticandtherapeuticagentstoimprovetumordetec-tionandtherapy〔1～4〕.TheHIV-1Tatpeptideisan86aminoacidpolypeptideandisessentialforviral replication.Ithasbeenshowntofreelytravelthroughcellularandnucleicmem-branes.Itsmembranetranslocationalpro…     

Intracellular trafficking mechanism, from intracellular uptake to extracellular efflux, for phospholipid/cholesterol liposomes

Liposomes are widely used as drug delivery vehicles to transfer chemotherapeutic agents, proteins, and nucleic acids into target cells. To improve therapeutic effects and reduce unexpected toxic side-effects, it is necessary to understand the mechanism of liposomal uptake into cells, and the intracellular fate of internalized liposomes. The intracellular fate of synthesized components used in the construction of liposomes remains unclear. In the work presented here, we investigated the trafficking processes from?intracellular uptake to extracellular efflux using conventional liposomes constructed with phospholipids (DOPC) and cholesterols (Chol). Following intracellular transport of liposomes via endocytosis, DOPC was localized in the endoplasmic reticulum (ER) and Golgi apparatus after escape from the endosome/lysosome, whereas Chol was only localized in the ER. Moreover, proteins involved in the intracellular trafficking of liposomal components were identified. Additionally, we showed that DOPC was partly effluxed via ABCG1, while Chol was partly effluxed via ABCA1 or ABCB1; suggesting that each liposomal component examined in this study was effluxed through different transporters. Our findings offer valuable information regarding targeted delivery to specific intracellular organelles, and how to possibly avoid unexpected toxic effects following multiple applications of liposome formulations.     

Design and application of multifunctional DNA nanocarriers for therapeutic delivery

The unique programmability of nucleic acids offers versatility and flexibility in the creation of self-assembled DNA nanostructures. To date, many three-dimensional DNA architectures of varying sizes and shapes have been precisely formed. Their biocompatibility, biodegradability and high intrinsic stability in physiological environments emphasize their emerging use as carriers for drug and gene delivery. Furthermore, DNA nanocarriers have been shown to enter cells efficiently and without the aid of transfection reagents. A key strength of DNA nanocarriers over other delivery systems is their modularity and their ability to control the spatial distribution of cargoes and ligands. Optimizing DNA nanocarrier properties to dictate their localization, uptake and intracellular trafficking is also possible. This review presents design considerations for DNA nanocarriers and examples of their use in the context of therapeutic delivery applications. The assembly of DNA nanocarriers and approaches for loading and releasing cargo are described. The stability and safety of DNA nanocarriers are also discussed, with particular attention to the in vivo physiological environment. Mechanisms of cellular uptake and intracellular trafficking are examined, and the paper concludes with strategies to enhance the delivery efficiency of DNA nanocarriers.     

Micelles based on amphiphilic PCL-PEO triblock and star-shaped diblock copolymers: Potential in drug delivery applications

In this work, the potential in drug nanodelivery of micelles made from poly(epsilon-caprolactone) (PCL) and poly (ethyleneoxide) (PEO) copolymers with triblock and star-diblock architectures was explored. Linear and 4-arm star-shaped PCL macromers with two or four --OH end groups were prepared by ring-opening polymerization of CL and condensed with alpha-methoxy-omega-carboxy-PEO. The resulting amphiphilic copolymers were characterized by (1)H NMR, size exclusion chromatography, and differential scanning calorimetry. Separate PCL and PEO crystalline phases were observed for both copolymers. Copolymers self-assembled in water giving critical association concentrations in the range 0.010-0.023 mg/mL. Micelles with a size of 32-45 nm were prepared by dialysis and characterized for hydrodynamic diameter and surface charge. Their potential as nanocarriers in drug delivery applications was evaluated too. Micelles were nontoxic to both Red blood cells and HeLa cells. Complement activation experiments indicated that micelles can escape the reticuloendothelial system once intravenously injected. Finally, a different uptake on HeLa cells was found for micelles obtained from triblock and star-shaped copolymers.     

Incorporation of LPS in liposomes diminishes its ability to induce tumoricidal activity and tumor necrosis factor secretion in murine macrophages

We investigated the effect of lipopolysaccharide (LPS) incorporated into phospholipid vesicles (liposomes) on the induction of macrophage-mediated tumor cytotoxicity and tumor necrosis factor (TNF) secretion. The incorporation of Salmonella minnesota rough (Re)-LPS into multilamellar or small unilamellar vesicles (liposomes) resulted in an 100- to 1,000-fold reduction in its potency to activate both the macrophage cell line RAW 264.7 and murine thioglycolate elicited peritoneal macrophages to become cytotoxic for L929 and P815 tumor cells. Liposomal LPS was also a 100- to 1,000-fold less potent inducer of TNF secretion from RAW 264.7 cells. Cytokines secreted by the activated macrophages contributed to the cytotoxic effect on the L929 cells but not the P815 cell line. Human recombinant TNF was not cytotoxic for either cell line but was cytostatic for the L929 cell line. Morphological examination of the cells after uptake of fluorescent, free, and liposomal LPS revealed that both forms were internalized by the endocytic pathway. This, together with the considerably reduced potency of liposomal LPS to induce tumor cytotoxicity and TNF secretion, suggests that the interaction of the hydrophobic part of the lipid A moiety of LPS with the macrophage plasma membrane is needed to optimally activate these cells. Incorporation of LPS into liposomes effectively abrogates this interaction.     

Treatment of calcium channel blocker-induced cardiovascular toxicity with drug scavenging liposomes

Calcium channel blocker (CCB) overdose is potentially lethal. Verapamil and diltiazem are particularly prone to acute toxicity due to their dual effect on cardiac and vascular tissues. Unfortunately, conventional decontamination measures are ineffective in accelerating blood clearance and, to date, few efforts have been made to develop antidotes. To address the issue, injectable long-circulating liposomes bearing a transmembrane pH-gradient are proposed as efficient detoxifying agents of CCB poisoning. By scavenging the drug in situ, these circulating nanocarriers can restrict its distribution in tissues and hinder its pharmacological effect. In vitro, we showed that liposomes stability in serum and their ability to sequester CCBs could be finely-tuned by modulating their internal pH, surface charge, and lipid bilayer structure. Subsequently, we verified their efficacy in reversing the cardiovascular effects of verapamil in rats implanted with telemetric pressure/biopotential transmitters. In animals orally intoxicated to verapamil, an intravenous injection of the liposomal antidote rapidly attenuated the reduction in blood pressure. Areas under diastolic, systolic, and mean pressures curves were significantly reduced by up to 60% and the time to hemodynamic recovery was shortened from 19 to only 11 h. These findings confirm the protective effect of pH-gradient liposomes against cardiovascular failure after CBB intoxication, and endorse their potential as efficient, versatile antidotes.     

cRGD-functionalized, DOX-conjugated, and ⁶⁴Cu-labeled superparamagnetic iron oxide nanoparticles for targeted anticancer drug delivery and PET/MR imaging

Multifunctional and water-soluble superparamagnetic iron oxide (SPIO) nanocarriers were developed for targeted drug delivery and positron emission tomography/magnetic resonance imaging (PET/MRI) dual-modality imaging of tumors with integrin α(v)β? expression. An anticancer drug was conjugated onto the PEGylated SPIO nanocarriers via pH-sensitive bonds. Tumor-targeting ligands, cyclo(Arg-Gly-Asp-d-Phe-Cys) (c(RGDfC)) peptides, and PET ??Cu chelators, macrocyclic 1,4,7-triazacyclononane-N, N', N″-triacetic acid (NOTA), were conjugated onto the distal ends of the PEG arms. The effectiveness of the SPIO nanocarriers as an MRI contrast agent was evaluated via an in vitro r? MRI relaxivity measurement. cRGD-conjugated SPIO nanocarriers exhibited a higher level of cellular uptake than cRGD-free ones in vitro. Moreover, cRGD-conjugated SPIO nanocarriers showed a much higher level of tumor accumulation than cRGD-free ones according to non-invasive and quantitative PET imaging, and ex vivo biodistribution studies. Thus, these SPIO nanocarriers demonstrated promising properties for combined targeted anticancer drug delivery and PET/MRI dual-modality imaging of tumors.     

谷胱甘肽保护的金纳米团簇对HeLa细胞毒性研究

目的 探究由谷胱甘肽作为表面保护剂的金纳米团簇(GSH-Au NCs)对宫颈癌HeLa细胞株的毒性影响.方法 利用荧光分光光度计测定用含有GSH-Au NCs的培养基处理HeLa细胞后不同时间点的荧光强度,观察HeLa细胞对GSH-Au NCs在1、2、6、12、24 h内的摄取情况.同时采用BALB/c荷瘤小鼠进行体内实验,分别腹腔注射0.2 ml浓度为3 mmol/L的GSH-Au NCs和等体积的蒸馏水(对照组)后24 h取出肿瘤组织,通过电感耦合等离子体质谱(ICP-MS)检测组织中的金元素含量以探究纳米团簇在肿瘤处随时间的摄取情况.最后用噻唑蓝(MTT)比色法研究不同浓度(0.003～0.3 mmol/L)的GSH-Au NCs处理HeLa细胞24、48 h的细胞毒性.结果 HeLa细胞对GSH-Au NCs的摄取率在24 h内不断升高,24h时达峰值73.13％.荷瘤小鼠实验表明,腹腔注射GSH-Au NCs 24 h后,肿瘤组织对GSH-Au NCs的摄取量(320±15) ng/g较对照组(腹腔注射蒸馏水)高,差异具有统计学意义(P＜0.05).用不同浓度的GSH-Au NCs处理HeLa细胞24 h,对细胞存活率有轻微影响,随浓度升高对细胞的抑制作用更为明显,GSH-Au NCs浓度为0.3 mmol/L时的HeLa细胞存活率降为对照组(GSH-Au NCs浓度为0)的86％(P＜0.05);处理48 h时,各浓度组的细胞存活率与对照组间差异均无统计学意义(P＞0.05).结论 虽然GSH-Au NCs在体外和体内均易被细胞和肿瘤组织摄取,但其本身对HeLa细胞并无明显细胞毒性,可安全应用于影像、载药及靶向给药等生物医药领域.     

The use of a tumor metastasis targeting peptide to deliver doxorubicin-containing liposomes to highly metastatic cancer

Tumor metastasis is responsible for 90% of cancer-associated deaths and highly metastatic cancers are more prone to form metastasis foci and acquire the drug resistance. Here, a nanocarrier system (TMT-LS) has been constructed by modification of stealth liposomes with a metastatic cancer specific peptide, using the unmodified stealth liposomes (LS) as the control. The active targeted nanocarriers presented satisfactory particle size (about 100?nm) and drug release characteristics in?vitro. Highly metastatic cancer cells (MDA-MB-435S and MDA-MB-231) and non-metastatic cancer cells (MCF-7) were applied as?tumor cell models. The highly metastatic cancer cells were found to endocytose more TMT-LS in a faster?way than TS, through a receptor-mediated pathway proved by specific receptor inhibition. Co-localization technique indicated the integrity of nanocarriers in cytoplasm. The significant targeting of TMT-LS to highly metastatic tumors was demonstrated in?vivo and ex?vivo in an orthotopic model as well as in a double tumor-bearing animal model with both metastatic and non-metastatic tumors in the same mouse. Importantly, the active targeted drug delivery system was found to penetrate deeper into tumor mass and have a longer retention within the malignant tissue. Further, TMT-LS greatly facilitated the efficacy of doxorubicin loaded in terms of inhibiting xenograft tumor growth and inducing cancer cell apoptosis, with only minor side effects. Together, the specific nanocarriers hold great potential in the development of nanomedicine for diagnosis and therapy of metastatic tumor.     

The application of Fe3O4 nanoparticles in cancer research: a new strategy to inhibit drug resistance

Although much effort has been extended to the efficient cancer therapies, the drug resistance is still a major obstacle in cancer chemotherapeutic treatments. Almost 90% of the cancer therapy failure is caused by the relative problems. Recently, the application of drug coated polymer nanospheres and nanoparticles to inhibit the related drug resistance has attracted much attention. In this report, we have explored a novel strategy to inhibit the multidrug resistance of the targeted tumor cells by combining the unique properties of tetraheptylammonium capped Fe(3)O(4) magnetic nanoparticles with the drug accumulation of anticancer drug daunorubicin. Our results of confocal fluorescence and atomic force microscopy (AFM) as well as electrochemical studies demonstrate the remarkable synergistic effect of Fe(3)O(4) nanoparticles on drug uptake of daunorubicin in leukemia K562 cells. These observations indicate that the interaction between the magnetic nanoparticles Fe(3)O(4) and biologically active molecules on the membrane of leukemia cell lines may contribute to their beneficial effect on cellular uptake so that the synergistic enhanced effect of magnetic nanoparticles Fe(3)O(4) on drug uptake of drug resistance leukemia K562 cells could be observed upon application of the Fe(3)O(4) nanoparticles.     

Cellular uptake of polyurethane nanocarriers mediated by gemini quaternary ammonium

The effective passage of drug formulations into tumor cells is a key factor in the development of nanoscale delivery systems. However, rapid cellular uptake with reduced toxicity remains a great challenge for efficient and safe delivery. In this study, we first use gemini quaternary ammonium (GQA) as a cell internalization promoter to enhance the cellular uptake of drug nanocarriers. It is found that a twenty times faster cell internalization could be achieved by introducing GQA into biodegradable multiblock polyurethane nanomicelles, as confirmed by flow cytometry and confocal laser scanning microscopy (CLSM) studies. Meanwhile, an added methoxyl-poly(ethylene glycol) (mPEG) outer corona could protect these cationic micelles from cytotoxicity at high concentrations, as verified by methyl tetrazolium (MTT) assay. Moreover, GQA not only acts as an enhancer for rapid cellular entry, but also plays an important role in controlled self-assembly and high drug loading capacity. Our work offers a new understanding on the role of cationic surfactants; and provides a facile and economical approach for the design of versatile drug nanocarriers to achieve efficient delivery and good biocompatibility.     

Clathrin‐Mediated Endocytosis of Gold Nanoparticles In Vitro

Gold nanoparticles (AuNPs) have potential biomedical and scientific applications. In this study, we evaluated the uptake and internalization of FBS‐coated 20 nm AuNPs into lung fibroblasts and liver cells by different microscopy techniques. AuNP aggregates were observed inside MRC5 lung fibroblasts and Chang liver cells under light microscopy, especially after enhancement with automegallography. Clusters of AuNPs were observed to be adsorbed on the cell surface by scanning electron microscopy. Ultrathin sections showed that AuNPs were mainly enclosed within cytoplasmic vesicles when viewed under transmission electron microscopy. We also investigated the mechanism of uptake for AuNPs, using endocytosis inhibitors and quantification of Au with inductively coupled plasma mass spectrometry. Cells treated with concanavalin A and chlorpromazine showed significant decrease of Au uptake in MRC5 lung fibroblasts and Chang liver cells, respectively, implying that the uptake of AuNPs was facilitated by clathrin‐mediated endocytosis. It would therefore appear that uptake of 20 nm AuNPs in both cell types with different tissues of origin, was dependent upon clathrin‐mediated endocytosis. Anat Rec, 298:418–427, 2015. © 2014 Wiley Periodicals, Inc.     

Vitamin E TPGS as a molecular biomaterial for drug delivery

D-α-tocopheryl polyethylene glycol succinate (Vitamin E TPGS, or simply TPGS) is a water-soluble derivative of natural Vitamin E, which is formed by esterification of Vitamin E succinate with polyethylene glycol (PEG). As such, it has advantages of PEG and Vitamin E in application of various nanocarriers for drug delivery, including extending the half-life of the drug in plasma and enhancing the cellular uptake of the drug. TPGS has an amphiphilic structure of lipophilic alkyl tail and hydrophilic polar head with a hydrophile/lipophile balance (HLB) value of 13.2 and a relatively low critical micelle concentration (CMC) of 0.02% w/w, which make it to be an ideal molecular biomaterial in developing various drug delivery systems, including prodrugs, micelles, liposomes and nanoparticles, which would be able to realize sustained, controlled and targeted drug delivery as well as to overcome multidrug resistance (MDR) and to promote oral drug delivery as an inhibitor of P-glycoprotein (P-gp). In this review, we briefly discuss its physicochemical and pharmaceutical properties and its wide applications in composition of the various nanocarriers for drug delivery, which we call TPGS-based drug delivery systems.     

Enhanced anti-tumor efficacy by co-delivery of doxorubicin and paclitaxel with amphiphilic methoxy PEG-PLGA copolymer nanoparticles

The use of single chemotherapeutic drug has shown some limitations in anti-tumor treatment, such as development of drug resistance, high toxicity and limited regime of clinical uses. The combination of two or more therapeutic drugs is feasible means to overcome the limitations. Co-delivery strategy has been proposed to minimize the amount of each drug and to achieve the synergistic effect for cancer therapies. Attempts have been made to deliver chemotherapeutic drugs simultaneously using drug carriers, such as micelles, liposomes, and inorganic nanoparticles (NPs). Here we reported core-shell NPs that were doubly emulsified from an amphiphilic copolymer methoxy poly(ethylene glycol)-poly(lactide-co-glycolide) (mPEG-PLGA). These NPs offered advantages over other nanocarriers, as they were easy to fabricate by improved double emulsion method, biocompatible, and showed high loading efficacy. More importantly, these NPs could co-deliver hydrophilic doxorubicin (DOX) and hydrophobic paclitaxel (TAX). The drug-loaded NPs possessed a better polydispersity, indicating that they are more readily subject to controlled size distribution. Studies on drug release and cellular uptake of the co-delivery system demonstrated that both drugs were effectively taken up by the cells and released simultaneously. Furthermore, the co-delivery nanocarrier suppressed tumor cells growth more efficiently than the delivery of either DOX or TAX at the same concentrations, indicating a synergistic effect. Moreover, the NPs loading drugs with a DOX/TAX concentration ratio of 2:1 showed the highest anti-tumor activity to three different types of tumor cells. This nanocarrier might have important potential in clinical implications for co-delivery of multiple anti-tumor drugs with different properties.     

The influence of different adjuvants on the immune response to a synthetic peptide comprising amino acid residues 9-21 of herpes simplex virus type 1 glycoprotein D

The immuno-modulating properties of different adjuvant systems on the murine humoral and cellular immune response to a synthetic peptide comprising amino acid residues 9-21 of glycoprotein D of herpes simplex virus type 1 (HSV-1) were investigated. For immunization, the peptide was conjugated to ovalbumin or bovine serum albumin by glutaraldehyde and the adjuvants used in this study were Freund's complete adjuvant (FCA), aluminium hydroxide, the Ribi adjuvant system (RAS) and two non-ionic block polymer surfactants, viz. L101 and 31R1, in oil in water emulsions. High anti-peptide antibody titers were obtained after immunization with FCA, aluminium hydroxide, RAS and L101. All adjuvants, except RAS, stimulated the induction of delayed type hypersensitivity obtained after immunization with peptide 9-21 coupled to ovalbumin and elicited by injection of purified HSV-1 virions in the footpad. Challenge with a lethal dose of HSV-1 showed that mice immunized with peptide 9-21 coupled to ovalbumin in combination with FCA, RAS and L101, respectively, were significantly protected. Although immunization with peptide 9-21 coupled to ovalbumin combined with aluminium hydroxide stimulated induction of delayed type hypersensitivity, no significant protective immunity against the challenge was generated.