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Developing a delivery vehicle to protect siRNA from degradation is a significant challenge. To solve this challenge, researchers attempted to use protein-based nanoparticles to deliver siRNA with limited to moderate success. However, a systematic investigation of comparing the ability of different protein-based nanoparticles as vehicles to deliver siRNA stably within cells is still unavailable. Therefore, in this study we synthesized a library of both non-targeted (proteinsiRNA) nanoparticles (NPs) and targeted (antibody conjugated protein-siRNA) NPs and evaluated ability to stably deliver siRNA in to cells to silence the gene of interest. We investigated nanoparticles of casein, bovine serum albumin, and gelatin for the delivery of siRNA. We synthesized and characterized a total of 12 nanoconjugates; in these conjugates, we either encapsulated, electrostatically attached, or covalently conjugated siRNA. We evaluated the efficiency of attaching siRNA to nanoconjugates, stability, and cellular delivery. The ability of siRNA to silence the protein of interest in cancer cells was also investigated. Among non-targeted conjugates, BSA matrix imparted relatively high stability to siRNA when encapsulated. Among targeted nanoconjugates, gelatin nanoparticles rendered high stability to siRNA upon covalent conjugation to the surface. On comparing with both targeted and non-targeted NPs for release of siRNA within cells, antibody-gelatin-siRNA conjugate exhibited high release and functional activity (down-regulation of target protein levels) within the cells as confirmed by both fluorescence imaging and Western blotting. In summary, our investigations show that targeted gelatin nanoparticles and non-targeted BSA nanoparticles possess high stability and excellent gene suppression capabilities and warrants further studies. We can extend the results from this study to develop stable siRNA delivery vehicles to specifically silence the protein of interest.

The gold nanoparticles (AuNPs) have been synthesized by a green chemical approach using the biopolymer pectin which is isolated from the orange peel. The pectin-AuNPs nanoconjugates are attached on the PLA-PEG-PLA triblock copolymer matrix by the ultra-sonication induced water-in-oil (W/O) emulsion method. The pectin-AuNPs-PLA-PEG-PLA nanoconjugates are characterized by UV-Visible absorption spectroscopy, X-Ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive X-Ray spectroscopy (EDS) and X-Ray photo electron spectroscopy (XPS). The XPS results confirm the zero oxidation state of Au, while the TEM images confirm the spherical shape of 7–13 nm of AuNPs. The XRD analysis reveals that the AuNPs exhibit fcc crystal structure with an average crystallite size of 12 nm. The biocompatibility of the pectin-AuNPs-PLA-PEG-PLA nanoconjugates has been investigated by the In Vitro cell line study on South African green monkey’s kidney cells. The anti-inflammatory activity of the nanoconjugates has been established by the membrane stabilization and inhibition of protein denaturation methods. The pectin-AuNPs-PLA-PEG-PLA nanoconjugates exhibit better anti-inflammatory activity than pectin and pectin-AuNPs.

Simulating the modeling of smooth muscle layer in the vascular structure makes a great difference for vascular tissue regeneration. A functional tissue engineered vascular media shall promote the aligned organization and three-dimensional penetration of smooth muscle cells (SMCs) into the scaffold. To this aim, dynamic liquid and conjugated nanoyarns based on poly(L-lactide-co-caprolactone) (P(LLA-CL)) and collagen (COL) with a weight ratio at 3:1 were fabricated by electrospinning methods, with random and aligned nanofibers as control groups. The Fourier transform infrared spectroscopy and X-ray diffraction analyses confirmed the preservation of P(LLA-CL)/COL components and structure. Scanning electron microscope (SEM) results indicated a significant increase of yarn diameters at 19.27 ± 6.16 μm (dynamic liquid) and 10.24 ± 3.09 μm (conjugated), and both of the nanoyarns had improved mechanical tensile properties than the random nanofibers. Compared with random and aligned nanofibers, the nanoyarns presented significant higher porosity and larger pore diameter, leading to a decrease of water contact angle and a promotion of SMCs proliferation and migration. Better SMCs orientation was observed on the conjugated nanoyarns, while superior SMCs penetration was achieved on the dynamic liquid nanoyarns, owing to the differences in yarns microstructure. Herein, this study demonstrated that the aligned and porous P(LLA-CL)/COL nanoyarns fabricated by dynamic liquid and conjugated electrospinning were beneficial to regulating vascular SMCs outgrowth, which had important implications for functional reconstruction of vascular media.

BACKGROUND: The concept of precision medicine to treat cancer shows promise and a co-delivery carrier for chemotherapy drugs and target genes is the key tool for both basic research and clinical application. To address this, we developed a cancer-targeting nanoparticle vector to transfer gemcitabine (Gem) and small interfering RNA (siRNA) to pancreatic cancer. METHODS: Iron oxide nanoparticles (IONPs) resonant at 15 nm were conjugated with the single chain variable fragment (scFv) against CD44v6 (scFvCD44v6), which has proven pancreatic cancer-targeting specificity as reported in our previous study. Gem was then linked through a lysosomally cleavable tetrapeptide linker, resulting in a scFv-targeted nanoparticle construct, which was subsequently conjugated to siRNA targeting the Bmi-1 oncogene (siBmi-1) to obtain the multifunctional nanoparticle scFv-Gem-siBmi-1-NPs. A series of biological experiments were performed to test its biophysical characterization, gene silencing efficacy and anti-tumor effect in vitro and in vivo. RESULTS: The multifunctional nanoparticle not only possesses an ultra-small size of approximately 80 nm, excellent biocompatibility and biodegradability, but also exerts a synergistic anti-tumor effect both in vitro and in vivo, such as inhibition of tumor cell growth, invasion and migration, reduction of cell cycle progression and promotion of tumor apoptosis. Furthermore, this nanoparticle can efficiently target pancreatic cancer in vivo, resulting in the enhanced bioavailability and efficacy of Gem. CONCLUSION: scFv-Gem-siBmi-1-NPs provide an effective and targeted co-delivery of Gem and siBmi-1 to pancreatic cancer, and exert an efficient and corporate anti-tumor therapeutic effect. This prospective vector shows promise for precise treatment of pancreatic cancer.

Visualizing the biodistribution of pesticides inside living cells is great importance for enhancing targeting of pesticides. Here we reported for the first time that gold nanorods (Au NRs) with size of 39.4 nm x 11.3 nm could be used as a fluorescent tracer to examine the distribution of a typical herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), in tobacco bright yellow 2 (BY-2) cells. The nanostructures of hybrid materials were analyzed by using Raman spectra and X-ray photoelectron spectroscopy (XPS), including spectra assignments and electronic property. These data revealed 2,4-D has successfully conjugated MP-Au NRs according to Raman and XPS. The biodistribution of the conjugates inside BY-2 cells was directly examined at 12 and 24 h by the two-photon microscopy. The intensity of two-photon luminescence (TPL) inside cells demonstrated that the conjugates could be localized and excluded by BY-2 cells. Thus, this labeling approach opens up new avenues to the facile and efficient labeling of pesticides.

Gold nanoparticles (GNPs) are synthesized using the medicinal plant Leucas Aspera extract (LAE) and poly lactic acid-co-poly ethylene glycol-co-poly lactic acid (PLA-PEG-PLA) copolymer by water-in-oil (W/O) emulsion method. The proposed method of W/O emulsion technique involves synthesis of GNPs and loading of Leucas Aspera extract on to the PLA-PEG-PLA copolymer matrix simultaneously. The synthesized GNPs are characterized by Fourier transform infra-red (FTIR) spectroscopy, dynamic light scattering (DLS), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The GNPs-LAE loaded polymer NPs are examined for the in vitro cytotoxicity on South African green monkey's kidney cells. The GNPs-LAE loaded polymer nanoconjugates exhibit maximum up to 95% of cell viability with 100 μg concentration of GNPs in the sample. The GNPs-LAE loaded polymer NPs exhibit better anti-inflammatory activity when compared to the pure LAE.

Gold Nanospheres (AuNS) have been widely explored as an emerging system for various biomedical applications including drug delivery, bioimaging and photomedicine. However, method of synthesizing nanoparticles and its toxicity including bioaccumulation has been a problem of concern. In the present study, we explored the appropriateness of 12.0 ±1.99 nm chitosan reduced AuNS in vivo models with respect to its bioavailability and toxicity against various concentrations (2.5-7.5 mg/kg). Administration of AuNS did not show any signs of morbidity. Inductively coupled plasma optical emission spectrometry (ICP-OES) analysis of blood (0.156 ± 0.154), urine (0.084 ± 0.08) and tissues indicates gradual dissipation and obligatory clearance within 24 h time interval. Nevertheless, pres- ence of AuNS in blood after 24 h confirms the bioavailability of AuNS demonstrating the evidence for no immune clearance and efficient tissue uptake. Further, brain shows the lowest quantity of injected AuNS. From this result, we determine this chitosan monolayer protected AuNS could cross the blood brain barrier and enter to the neural tissues. Interestingly there was no evidence of toxicity in any of the organs. In conclusion, our data suggest that AuNS injected though tail vain were easily taken up by tissues and does not produce sub-acute physiological damage even at high concentrations tested, supporting chitosan reduced AuNS as biocompatible, nontoxic nanoconjugates for targeted drug delivery and other biomedical applications.

A novel amphiphilic biodegradable cholesterol and poly(ethylene glycol)-folate grafted poly(α,β-malic acid) (PMA-g-Chol/PEG-FA) was synthesized and characterized as self-assembled nanoparticles for targeted delivery of doxorubicin (DOX). The nanoparticles showed extremely low critical aggregation concentrations (CAC), appropriate zeta potential, narrow size distribution, good stability in serum conditions and negligible toxicity. After encapsulation'of DOX, PMA-g-Chol/PEG-FA nanoparticles showed significantly reduced cell viability (up to 30% for Hela and 27% for 4T1 cells) compared with the non-targeted ones on carcinoma cells with different levels of folate receptor (FR) expression. While no difference was detected on HEK293 cells (FR receptor negative) between the two nanoparticles. Addition of extra free folate obviously decreased the cellular mortality and inhibited the cellular uptake of targeted nanoparticles. In the Hela/HEK293 co-culture model, folate conjugated nanoparticles showed specific affiliation with Hela cells other than HEK293 cells, indicating good targeting property of the delivery system. As detected from ex vivo fluorescent imaging, PMA-g-Chol/PEG-FA nanoparticles could accumulate at tumor site with higher selectivity compared to PMA-g-Chol/PEG nanoparticles and DOX x HCl. In vivo antitumor studies confirmed the significant tumor inhibition efficacy of drug-loaded PMA-g-Chol/PEG-FA nanoparticles with lower toxicity to normal tissues than DOX x HCI at the same dosage.

Spermatozoa are not only essential for animal reproduction they also represent important tools for the manipulation of animal genetics. For instance, the genetic labeling and analysis of spermatozoa could provide a prospective complementation of pre-fertilization diagnosis and could help to prevent the inheritance of defective alleles during artificial insemination or to select beneficial traits in livestock. Spermatozoa feature extremely specialized membrane organization and restricted transport mechanisms making the labeling of genetically interesting DNA-sequences, e.g., with gold nanoparticles, a particular challenge. Here, we present a systematic study on the size-related internalization of ligand-free, monovalent and bivalent polydisperse gold nanoparticles, depending on spermatozoa membrane status. While monovalent conjugates were coupled solely to either negatively-charged oligonucleotides or positively-charged cell-penetrating peptides, bivalent conjugates were functionalized with both molecules simultaneously. The results clearly indicate that the cell membrane of acrosome-intact, bovine spermatozoa was neither permeable to ligand-free or oligonucleotide-conjugated nanoparticles, nor responsive to the mechanisms of cell-penetrating peptides. Interestingly, after acrosome reaction, which comprises major changes in sperm membrane composition, fluidity and charge, high numbers of monovalent and bivalent nanoparticles were found in the postequatorial segment, depicting a close and complex correlation between particle internalization and membrane organization. Additionally, depending on the applied peptide and for nanoparticle sizes < 10 nm even a successive nuclear penetration was observed, making the bivalent conjugates promising for future genetic delivery and sorting issues.

Interleukin-2 (IL-2) possesses a strong stimulatory activity for activated T and NK cells and it is an attractive molecule for immunotherapy. Nevertheless, extremely short half-life and severe toxicities associated with high-dose IL-2 treatment are serious and limiting drawbacks. In order to increase IL-2 half-life in vivo, we covalently conjugated synthetic semitelechelic polymeric carrier based on N-(2-hydroxypropyl)methacrylamide (HPMA) to IL-2. Thus, we synthesized IL-2-poly(HPMA) conjugate containing 2-3 polymer chains per IL-2 molecule in average. Such conjugate has lower biologic activity in comparison to IL-2 in vitro. However, it exerts much higher activity than IL-2 in vivo as shown by expansion of memory CD8+ T, NK, NKT, γδT and Treg cells. Moreover, IL-2-poly(HPMA) extremely effectively potentiates CD8+ T cell peptide-based vaccination. IL-2-poly(HPMA) shows also much longer half-time in circulation than IL-2 (-4 h versus -5 min). Collectively, modification of IL-2 with poly(HPMA) chains dramatically improves its potency and pharmacologic features in vivo, which have implications for immunotherapy. To our knowledge, this is the first proof-of-concept report of the use of polymer/protein modification of IL-2 to obtain more pronounced biological activity.

Generation 5 (G5) poly(amidoamide) (PAMAM) dendrimers are synthetic polymers that have been broadly applied as drug delivery carriers. Methotrexate (MTX), an anti-folate metabolite, has been successfully used as an anti-inflammatory drug to treat rheumatoid arthritis (RA) in the clinic. In this study, we examine the therapeutic efficacy of G5 PAMAM dendrimer methotrexate conjugates (G5-MTX) that also have folic acid (FA) conjugated to the G5-MTX (G5-FA-MTX) to target inflammation-activated folate receptors overexpressing macrophages. These cells are thought to play an important role in the development of RA. With G5 serving as a control, the in vitro binding affinities of G5-FA-MTX and G5-MTX to activated macrophages were assessed in RAW264.7, NR8383 and primary rat peritoneal macrophages. The results indicated that the binding of either conjugate to macrophages was concentration- and temperature-dependent and could be blocked by the presence of 6.25 mM free FA (p < 0.005). The preventive effects of G5-MTX and G5-FA-MTX conjugates on the development of arthritis were explored on an adjuvant-induced inflammatory arthritis model and had similar preventive effects in inflammatory arthritis at a MTX equivalent dose of 4.95 μmol/kg. These studies indicated that when multiples of MTX are conjugated on dendritic polymers, they specifically bind to folate receptor overexpressing macrophages and have comparable anti-inflammatory effects to folate targeted MTX conjugated polymers.

Stealth PLGA/Liposome nanoparticles (NPs) modified with tumor-targeting single-chain antibody fragment (scFV-P/L) for systemic delivery of recombinant methioninase (rMETase) for gastric cancer were prepared. The morphologies and therapeutic effects of rMETase-loaded scFV-P/L (scFV-rMETase-P/L) in vitro were analyzed. Functional scFV-P/L NPs composed of PLGA, DOPC and DSPE-PEG display low cell cytoxicity in SGC-7901 cells, and has more cell uptake ability than P/L NPs. scFV-rMETase-P/L was more effective in inhibiting tumor growth in the subcutaneous gastric carcinoma tumor model than free rMETase in solution (p < 0.05) and rMETase-loaded P/L (rMETase-P/L) (p < 0.05). Our findings collectively support the utility of scFV-targeted P/L NPs as a potentially effective drug delivery system.

To achieve liver-specific delivery of antitumor drug doxorubicin (DOX), PEGylated dendrimer-DOX conjugates were designed and synthesized, whereas DOX was conjugated to dendrimers via hydrazone bonds and the dendrimers were functionalized with galactose moieties. The release rates of DOX from the conjugates at pH 5.0 were much faster than those at pH 7.4 due to the pH-sensitive cleavage of the hydrazone bonds. The conjugates were shown to effectively kill HepG2 cells in vitro. Compared to other conjugates, the PEGylated dendrimer-DOX one with multiple galactose moieties (Dendrimer-DOX-PEG-Gal) demonstrated HepG2 cells specificity, higher efficacy and good biosafety due to the lower IC50 value and higher cellular uptake confirmed by in vitro cytotoxicity assays, confocal laser scanning microscopy and flow cytometric studies. These results suggest that Dendrimer-DOX-PEG-Gal is an efficient and biocompatible candidate for the specific delivery of antitumor drug to HepG2 cells and could be used as liver cancer specific drug delivery system.

A nanodiamond-polyglycerol-gadolinium(ll) conjugate has been designed and prepared as novel nanodiamond-based magnetic resonance (MR) contrast agent dispersible in physiological media. Detonation nanodiamond (dND) was first grafted with polyglycerol (PG) through ring-opening polymerization of glycidol to impart dispersibility to dND in physiological media. Since the hydroxyl group in PG serves as a scaffold for further surface functionalization, diethylenetriaminepentaacetic acid (DTPA) was immobilized on the surface of dND-PG through multistep organic transformations and Gd(III) ion was complexed in the last step. The resulting dND-PG-Gd(III) exhibited good dispersibility (> 4.5 mg/mL) and stability (> 3 months) in phosphate buffered saline (PBS). In vitro MR evaluation indicates that water proton T1 relaxivity or r1 of dND-PG-Gd(III) in aqueous solutions is larger than that of Magnevist® and the difference in the relaxivity becomes larger under weaker magnetic fields. The good dispersibility together with relatively high T1 relaxivity makes dND-PG-Gd(III) a promising contrast agent for in vivo MR imaging.

We report a perfluoroaryl azide-based photoreaction for synthesizing functionalizable and nonbiofouling poly[oligo(ethylene glycol) methacrylate] (pOEGMA) films on a chemically inert COC substrate, and an estimation of a surface coverage of the antibody immobilized onto the surface with the immuno-gold nanoparticles. The processes were confirmed by water contact angle measurement, FT-IR spectroscopy, and FE-SEM. The strategy demonstrated in this work could be applied to functionalizations of other polymeric materials and determination of the binding capacity of analytes in biosensors and microfluidic devices.

Copper ferrocyanide-functionalized magnetite nanoparticles (Cu-FC-MNPs) were successfully synthesized by immobilizing copper and ferrocyanide on the surfaces of [1-(2 amino-ethyl)-3-aminopropyl] trimethoxysilane-modified magnetite nanoparticles. Radioactive cesium (Cs) adsorption tests were conducted to investigate the effectiveness of the Cu-FC-MNPS toward the removal of radioactive Cs. The Cu-FC-MNPs showed excellent separation properties using an external magnet in an aqueous solution.

Multi-walled-carbon nanotubes (MWNTs) are widely explored as carriers for drug delivery due to their facile transport through cellular membranes and are reportedly found to be effective against cancer. In the present study, we have evaluated cellular uptake of Docetaxel (DTX) conjugated MWNTs from human breast cancer cells (MCF-7 and MDA-mb-231) and have provided primary results on cytotoxicity of the same. Efficient internalization of the drug conjugate (DTX-MWNTs) inside the cell was corroborated with the help of confocal microscopy, transmission electron microscopy and flow cytometry. The comparison of cytotoxicity of the conjugate and DTX was done by MTT assay. Results of the study indicated increased efficacy of the conjugates over the drug in terms of their cytotoxicity. It was observed that such conjugation of drug to MWNTs can be explored as a strategy to improve therapeutic index of cytotoxic drugs such as DTX and thereby enriching cancer therapies of coming time.

This work investigates a new type of polyelectrolyte complex nanocarrier composed of hyaluronic acid (HA) and protamine (PROT). Small (approximately 60 nm) and negatively charged nanoparticles (NPs) with a polydispersity index of less than 0.2 were obtained with properties that were dependent on the mixing ratio, concentration of polyelectrolytes and molecular weight of HA. Salmon calcitonin (sCT) was efficiently (up to 100%) associated with the NPs, and the drug loading (9.6-39% w/w) was notably high, possibly due to an interaction between HA and sCT. The NPs released -70-80% of the sCT after 24 hours, with the estimated total amount of released sCT depending on the amount of HA and PROT present in the NPs. The isoelectric point of the NPs was close to pH 2, and the negative surface charge was maintained above this pH. The HA/PROT nanoplexes protected the sCT from enzymatic degradation and showed low toxicity to intestinal epithelial cells, and thus may be a promising oral delivery system for peptides.

In this study we demonstrate for the first time a new approach for highly specific targeting of viable human leukocytes by functionalised gold nanoconjugates made on the basis of citrate-stabilised gold nanoparticles. This immobilisation involves highly specific recognition of the cells of interest by plasma membrane-associated receptor ligands or functional antibodies attached to gold nanoconjugates. Using this technology we managed to deliver pharmacological inhibitors into the target cells. Also we immobilized fully functional human leukocytes utilising both cell lines and rare primary human cells (basophils). This approach demonstrates possibilities of using nanoconjugates for diagnostics, drug delivery and immune therapy.

The ability to specifically silence genes using RNA interference (RNAi) has wide therapeutic applications for the treatment of disease. Numerous studies have demonstrated global gene and protein signatures distinguishing malignant and nonmalignant tissues. This worldwide pursuit of optimal cancer targets has so far provided a wide list of potential targets for each cancer type and for each patient, for which RNAi-based therapies can be applied. Nevertheless, due to poor stability of RNAi molecules in physiological conditions and their inability to cross cellular membranes, the delivery of siRNA and microRNA (miRNA) in vivo holds a great challenge and remains a crucial issue for their therapeutic success. Supramolecular carriers are often used in order to improve the physicochemical and biopharmaceutical properties of RNAi. Nano-sized delivery systems enable the accumulation of drugs and oligonucleotides (ONTs) in angiogenesis-dependent areas due to the enhanced permeability and retention (EPR) effect, and are able to cross cellular membranes and release the siRNA/miRNA only inside the target cell. In addition, a targeting moiety can increase the selectivity and specific uptake in the target tissue. Several vehicles (dendrimers, nanoparticles, liposomes, polyplex, lipoplex, polymeric nanoconjugates) are being developed for siRNA/miRNA delivery. These vehicles provide an important tool for exploiting the full potential of ONTs as therapeutic agents. In this review we will focus on the polymer-based approaches to deliver siRNA to cancer in vivo.

The development of effective polymer-based nanocarriers which are able to target diseased tissues still remains a great challenge in current research. Dendritic polyglycerols have emerged as novel polymeric scaffolds that have demonstrated a great potential for diverse biomedical applications. These architectures have already proven their usefulness in therapeutic approaches related to multivalency, given by the synergy between the nanosized dimensions combined with the high density of functional groups. However, a continuous effort is necessary to modify and tailor polyglycerol architectures to fit the future demands of biomedical applications. The present work deals with the development of a general synthetic strategy that allows the linkage of low molecular weight dendritic polyglycerols to fluorescent dyes and cell targeting ligands. The receptor mediated cellular uptake of the polyglycerol conjugates highlight their potential to acts as new targeted nanocarriers that should be able to decrease non-specific cellular uptake.

Hyaluronan (HA) is biodegradable, highly biocompatible, and contains derivatizable functional groups along its backbone. This relatively simple, non-branched polysaccharide can target specific cell surface receptors making it an attractive polymeric carrier for targeted delivery of therapeutic agents. This article provides an overview of recent developments involving small molecule and bio-macromolecule conjugates of HA as new generation of human therapeutic agents. Several approaches have been developed to prepare conjugates of HA with small molecule drugs, therapeutic peptides, antibodies, and nucleotides. This article discusses such approaches that can modulate the pharmacokinetic and biodistribution of these therapeutic agents so as to appreciate the design criteria for HA based (bio)conjugates or nanoparticles based on their in vitro assay and in vivo pharmacokinetic study.

In recent years, hyaluronic acid (HA) has attracted significant interest in development of drug delivery systems because of its intrinsic physicochemical and biological properties, including water solubility, viscoeleasticity, non-immunogenicity, biocompatibility, and biodegradability. In addition, HA has the ability to selectively bind specific receptors on the disease-related cells such as cancer cells and activated macrophages, followed by receptor-mediated endocytosis. Owing to these unique features, HA has been extensively used for development of the targetable carriers to deliver the therapeutic and imaging agents. In this review, we discuss the recent progress in various HA-based conjugates for cancer therapy and imaging, in which the active agents are covalently conjugated or physically encapsulated.

The purpose of this research is to develop and evaluate Pluronic P123 (P123)-docetaxel (DTX) conjugate that could form core-shell-type micelles in aqueous solution. DTX was covalently conjugated to P123 via ester bond after the activation of DTX by succinic anhydride. The structure of P123-DTX conjugate was confirmed by 1H-NMR. The self-assembly behavior of the P123-DTX conjugate in aqueous solution was characterized by the measurement of critical micelle concentration (CMC). The CMC of P123-DTX conjugate was (1.34 +/- 0.05) x 10(-5) mol/L, which was lower than that of P123 ((1.91 +/- 0.07) x 10(-5) mol/L). The DTX content in the conjugate could reach 13.69% (wt.%). TEM and DLS analysis showed that the conjugate formed approximately spherical micelles with mean particle size of 85.3 +/- 1.59 nm. In vitro release of DTX from the conjugate micelles showed pH dependence, being faster at lower pH value than that at pH 7.4. In vitro cytotoxicity of P123-DTX conjugate micelles was evaluated by MTT method against HepG2, MCF-7 and B16 cell lines and the result indicated that P123-DTX conjugate micelles showed lower cytotoxicity than the DTX injection-Duopafei. Compared with Duopafei, in vivo antitumor activity of P123-DTX conjugate micelles in Kunming mice bearing B16 tumor was more effective and less toxic. These results indicated that the P123-DTX conjugate micelles prepared in this study may be considered as an alternative and promising DTX delivery system.

Gold nanoparticles have been widely explored as cancer therapeutics and diagnostic agents in recent years. With their unique subcellular size and good biocompatibility, gold nanoparticles are a promising drug delivery vehicle. In this study, folic acid-coated gold nanoparticles conjugated with fluorophore FITC through amine terminated poly(ethylene glycol) were prepared and confocal microscopy together with bright-field differential interference contrast imaging data showed that folic acid-coated gold nanoparticles accumulated mainly in cytoplasm of primary human fibroblasts, without causing any observable cytotoxicity upon exposure for 48 hours. Through the further development of a drug delivery system that conjugates doxorubicin onto the surface of gold nanoparticles with a poly(ethylene glycol) spacer via an SMCC linker, we demonstrated that multidrug resistance in cancer cells can be significantly overcome by a combination of highly efficient cellular entry and enhanced cytotoxicity of Au-SMCC-DOX nanoconjugates, as revealed both by confocal microscopy imaging and cytotoxicity assay. The prepared Au-SMCC-DOX nanoconjugates demonstrated enhanced drug accumulation and retention in multidrug resistant hepG2-R cancer cells when it was compared with free doxorubicin, with a cytoplasm accumulation profile. The results indicated that gold nanoparticles are a kind of promising drug delivery vehicle with good biocompatibility and suitable for further applications in drug delivery for improved chemotherapy, especially for overcoming multidrug resistance.

In this work, a novel, biocompatible conjugates of gelatin and oleic acid (GOC) were synthesized by a novel aqueous solvent-based method that overcame challenges of completely contrary solubility between gelatin and oleic acid (OA). The GO nanoparticles (GONs) and Paclitaxel encapsulated nanoparticles (PTX-GON) were prepared by self-assembly in water. These nanoparticles (NPs) were then conjugated with folic acid (FA) for targeting cervical cancer cells (Hela cells) and were characterized for their various physicochemical and pharmaceutical properties. Fourier transform infrared spectroscopy (FT-IR) and 1H NMR studies indicated the successful synthesis of GOC which showed low critical aggregation concentration in water (0.015 mg/ml). All NPs were stable in human blood serum and their mean diameters were below 300 nm suitable for passive targeting. Powder X-ray diffraction (PXRD) diffractograms showed the reduction in drug crystallinity and hence, leading to the solubility enhancement of PTX. The release of PTX from both PTX-GON and FA conjugated PTX-GON (PTX-FA-GON) was controlled for a long time. The cytotoxicity results demonstrated great advantages of PTX-FA-GON and PTX-GON over the conventional dosage form of pacliaxel (Taxol). These results, therefore, indicate that GOC is a promising material to prepare drug encapsulated NP as a controlled delivery system and PTX-FA-GON is a potential targeted delivery system for cancer therapy.

Systemic toxicity following cancer chemotherapy is an important concern. Targeted drug delivery systems could reduce the toxicity of anticancer drugs. Vitamins have been considered as targeting moieties in novel cancer treatment strategies. In this study, biotin was attached to nanoparticles of conjugated methotrexate-human serum albumin. Biotin functionalized methotrexate-human serum albumin with three different amounts of biotin attached to the nanoparticles were prepared. It was shown that the cytotoxicity of biotin functionalized nanoparticles on T47D and HeLa tumor cells was significantly higher than that of free methotrexate and non-functionalized nanoparticles. The cytotoxicity of biotin functionalized nanoparticles further increased when the number of biotin molecules attached on the surface of nanoparticles increased. The uptake of FITC labeled biotin functionalized nanoparticles by T47D and HeLa cells measured by flow cytometry, was also higher than that of non-functionalized nanoparticles. It can be concluded that the biotin functionalized methotrexate-human serum albumin conjugated nanoparticles could be used as a potent drug for specific delivery of methotrexate to tumors.

The separation, reusability and high catalytic activity of bioconjugate remain challenging task in proteins bound gold nanoparticles. A facile synthetic route for the fabrication of gold nanoparticle assembled polyurethane microsphere template and immobilization of trypsin on gold/polyurethane surface to form trypsin-nanogold-polyurethane bioconjugate was developed. The bioconjugate was characterized by X-ray diffraction, Field emission scanning electron microscopy, Transmission electron microscopy, UV-visible, Fourier transform infrared, Fluorescence and Circular dichroism spectroscopy. The catalytic studies confirmed retention of approximately 40% of its original activity even after eight consecutive reaction cycles. The bioconjugate is also very effective for its separation from the reaction medium and exhibited significant enhanced stability over a wide range of pH and temperature compared to free trypsin. These findings clearly demonstrate that trypsin immobilized gold nanoparticle assembled polyurethane microsphere acts as an excellent recyclable biocatalyst with enzyme-specific biocompatibility.

Phospholipid vesicles encapsulating magnetic nanoparticles (liposome complexes) have been prepared for targeting a drug to a specific organ using a magnetic force, as well as for local hyperthermia therapy. Liposome complexes are also an ideal platform for use as contrast agents of magnetic resonance imaging (MRI). We describe the preparation and characterization of liposomes containing magnetite. These liposomes were obtained by thin film hydration method and Fe3O4 nanoparticles were synthesized by coprecipitation method. They were characterized by an electrophoretic light scattering spectrophotometer, the liposome complexes were subsequently coated using chitosan. We have further investigated the ability of the above formulation for drug delivery and MRI applications. We are specifically interested in evaluating our liposome complexes for drug therapy; hence, we selected paclitaxel for the combination study. The amount of paclitaxel was measured at 227 nm using a UV-Vis spectrophotometer. Cytotoxicity of liposome complexes was treated with the various concentrations of paclitaxel in PC3 cell lines. The structure and properties of liposome complexes were analyzed by FT-IR, XRD and VSM. The particle size was analyzed by TEM and DLS.

A sensitive and effective amperometric glucose biosensor based on gold nanotubes electrode (GNTE) was investigated. Gold nanotubes (GNTs), which were prepared by electroless plating of the metal within the pores of nanoporous polycarbonate (PC) track-etched membranes, were filled into a hollow teflon cylinder to construct a GNTE. Glucose oxidase (GOD) was immobilized on the electrode via glutaraldehyde cross-linkage method. The electrochemical properties were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The km value of the immobilized glucose oxidase on GNTE was 0.47 mM. The biosensor showed a linear range from 0.4 to 11 mM with excellent sensitivity of 8.77 microA cm(-2) mM(-1) and fast response time within 5 s.

A method for fast delivery of proteins conjugated to superparamagnetic iron oxide nanoparticles (SPION) into mammalian cells by applying a strong magnetic field in pulses was proposed. Firstly, SPION were prepared from an alkaline solution of divalent and trivalent iron ions and covalently bound with protein through the activation of N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC). After fluorescently labelling, the protein-nanoparticle conjugate was mixed with mammalian cell line and exposed to a pulsed magnetic field for short durations of few milliseconds. Results suggested that superparamagnetic nanoparticles were able to carry proteins into living cells immediately. Cellular internalization of the fluorescently labelled protein-nanoparticle conjugate was proved by the observation of cell fluorescence in a fluorescent microscopy, as well as cell analysis by a flow cytometer. We found that the cellular uptake was accomplished dominantly by the process of bombardment of magnetic nanoparticles.

Angiogenesis is essential for the development of malignant tumors and provides important targets for tumor diagnosis and therapy. Quantum dots have been broadly investigated for their potential application in cancer molecular imaging. In present work, CdSe quantum dots were synthesized, polyamidoamine dendrimers were used to modify surface of quantum dots and improve their solubility in water solution. Then, dendrimer-modified CdSe quantum dots were conjugated with arginine-glycine-aspartic acid (RGD) peptides. These prepared nanoprobes were injected into nude mice loaded with melanoma (A375) tumor xenografts via tail vessels, IVIS imaging system was used to image the targeting and bio-distribution of as-prepared nanoprobes. The dendrimer-modified quantum dots exhibit water-soluble, high quantum yield, and good biocompatibility. RGD-conjugated quantum dots can specifically target human umbilical vein endothelial cells (HUVEC) and A375 melanoma cells, as well as nude mice loaded with A735 melanoma cells. High-performance RGD-conjugated dendrimers modified quantum dot-based nanoprobes have great potential in application such as tumor diagnosis and therapy.

Molecular imaging techniques now allow recognition of early biochemical, physiological, and anatomical changes before manifestation of gross pathological changes. Photoacoustic imaging represents a novel non-ionizing detection technique that combines the advantages of optical and ultrasound imaging. Noninvasive photoacoustic tomography (PAT) imaging in combination with nanoparticle-based contrast agents show promise in improved detection and diagnosis of cardiovascular and cancer related diseases. In this report, a novel strategy is introduced to achieve self-assembled colloidal gold nanorods, which are constrained to the vasculature. Gold nanorods (2-4 nm) were incorporated into the core of self-assembled lipid-encapsulated nanoparticles (sGNR) (approximately 130 nm), providing more than hundreds of gold atoms per nanoparticle of 20% colloid suspension. The physico-chemical characterization in solution and anhydrous state with analytical techniques demonstrated that the particles were spherical and highly mono dispersed. In addition to the synthesis and characterization, sensitive near-infrared photoacoustic detection was impressively demonstrated in vitro.