HRMAS-NMR and simulation study of the self-assembly of surfactants on carbon nanotubes.

Polyethoxylated surfactants, such as those of the Tween and Pluronic series, are commonly used to disperse carbon nanotubes (CNTs) and other nanoparticles. However, the current understanding of the nature of interactions between these surfactants and CNTs is limited. The nature of the interactions between surfactants (Tween-80 [T80] and Pluronic F68 [PF68]) and CNTs was investigated using high-resolution magic angle spinning nuclear magnetic resonance (HRMAS-NMR) and coarse-grained molecular dynamics (MD) simulations.

Stabilization of Carbon Nanotubes and Graphene by Tween-80: Mechanistic Insights from Spectroscopic and Simulation Studies.

Polyoxyethylene sorbitan monooleate is commonly used to obtain stable dispersions of nanoparticles (NPs) such as carbon nanotubes (CNTs) and graphene. However, the mechanism underlying dispersion is poorly understood. The present study aimed at investigating the mechanism of stabilization of carbon NPs (CNPs), namely, single-walled CNTs (SWCNTs), multi-walled CNTs (MWCNTs), and graphene, by Tween-80 using attenuated total internal reflection-Fourier transform infrared and nuclear magnetic resonance (NMR) spectroscopy.

Nanoparticles Incorporating a Fluorescence Turn-on Reporter for Real-Time Drug Release Monitoring, a Chemoenhancer and a Stealth Agent: Poseidon's Trident against Cancer?

The rate and extent of drug release under physiological conditions is a key factor influencing the therapeutic activity of a formulation. Real-time detection of drug release by conventional pharmacokinetics approaches is confounded by low sensitivity, particularly in the case of tissue-targeted novel drug delivery systems, where low concentrations of the drug reach systemic circulation. We present a novel fluorescence turn-on platform for real-time monitoring of drug release from nanoparticles based on reversible fluorescence quenching in fluorescein esters.

Carbon Nanotubes Modulate Activity of Cytotoxic Compounds via a Trojan Horse Mechanism.

Carbon nanotubes (CNTs) are an emerging drug delivery system, but their success is thwarted by potential toxicity concerns. and studies imply toxic potential of CNTs, but their potential to influence toxicity of coadministered compounds still remains elusive. Therefore, the present study was conducted to determine the effect of multiwalled CNTs (MWCNTs) on the toxicity of cytotoxic compounds in macrophage (RAW 264.

Accumulated polymer degradation products as effector molecules in cytotoxicity of polymeric nanoparticles.

Polymeric nanoparticles (PNPs) are a promising platform for drug, gene, and vaccine delivery. Although generally regarded as safe, the toxicity of PNPs is not well documented. The present study investigated in vitro toxicity of poly-ε-caprolactone, poly(DL-lactic acid), poly(lactide-cocaprolactone), and poly(lactide-co-glycide) NPs and possible mechanism of toxicity.

Intranuclear drug delivery and effective in vivo cancer therapy via estradiol-PEG-appended multiwalled carbon nanotubes.

Cancer cell-selective, nuclear targeting is expected to enhance the therapeutic efficacy of a myriad of antineoplastic drugs, particularly those whose pharmacodynamic site of action is the nucleus. In this study, a steroid-macromolecular bioconjugate based on PEG-linked 17β-Estradiol (E2) was appended to intrinsically cell-penetrable multiwalled carbon nanotubes (MWCNTs) for intranuclear drug delivery and effective breast cancer treatment, both in vitro and in vivo. Taking Doxorubicin (DOX) as a model anticancer agent, we tried to elucidate how E2 appendage influences the cell internalization, intracellular trafficking, and antitumor efficacy of the supramolecularly complexed drug.

Augmented anticancer activity of a targeted, intracellularly activatable, theranostic nanomedicine based on fluorescent and radiolabeled, methotrexate-folic Acid-multiwalled carbon nanotube conjugate.

The present study reports the design, synthesis, and biological evaluation of a novel, intravenously injectable, theranostic prodrug based on multiwalled carbon nanotubes (MWCNTs) concomitantly decorated with a fluorochrome (Alexa-fluor, AF488/647), radionucleide (Technitium-99m), tumor-targeting module (folic acid, FA), and anticancer agent (methotrexate, MTX). Specifically, MTX was conjugated to MWCNTs via a serum-stable yet intracellularly hydrolyzable ester linkage to ensure minimum drug loss in circulation. Cell uptake studies corroborated the selective internalization of AF-FA-MTX-MWCNTs (1) by folate receptor (FR) positive human lung (A549) and breast (MCF 7) cancer cells through FR mediated endocytosis.

Surface chemistry dependent "switch" regulates the trafficking and therapeutic performance of drug-loaded carbon nanotubes.

The present study explores the possibility of exploiting surface functionality as one of the key regulators for modulating the intracellular trafficking and therapeutic performance of drug loaded carbon nanotubes (CNTs). In line with that approach, a series of biofunctionalized multiwalled carbon nanotubes (f-CNTs 1-6) decorated with various functional molecules including antifouling polymer (PEG), tumor recognition modules (folic acid/hyaluronic acid/estradiol), and fluorophores (rhodamine B isothiocyanate/Alexa Fluor) were synthesized. By loading different anticancer agents (methotrexate (MTX), doxorubicin (DOX), and paclitaxel (PTX)) onto each functionalized CNT preparation, we tried to elucidate how the surface functional molecules associated with each f-CNT influence their therapeutic potential.

Hyaluronate tethered, "smart" multiwalled carbon nanotubes for tumor-targeted delivery of doxorubicin.

The present study reports the optimized synthesis, physicochemical characterization, and biological evaluation of a novel, multiwalled carbon nanotube-hyaluronic acid (MWCNT-HA) conjugate, complexed with an anticancer agent, Doxorubicin (DOX) via π-π stacking interaction. The therapeutic conjugate was concomitantly labeled with a near-infrared fluorescent dye, Alexa-Flour-647 (AF-647), and radiotracer Technetium-99m ((99m)Tc) to track its whereabouts both in vitro and in vivo via optical and scintigraphic imaging techniques. Covalent functionalization of MWCNTs with HA facilitated their internalization into human lung adenocarcinoma, A549 cells via hyaluronan receptors (HR) mediated endocytosis.

Functionalization density dependent toxicity of oxidized multiwalled carbon nanotubes in a murine macrophage cell line.

The present study investigates the effect of functionalization density on the toxicity and cellular uptake of oxidized multiwalled carbon nanotubes (f-MWCNTs) in vitro. The toxicity of f-MWCNTs at varying degrees of carboxylation was assessed in a murine macrophage RAW 264.7 cell line, a model for liver Kupffer cells.

Cellular uptake, intracellular trafficking and cytotoxicity of silver nanoparticles.

Silver nanoparticles (Ag NPs) are used in consumer products and wound dressings due to their antimicrobial properties. However, in addition to toxic effects on microbes, Ag NPs can also induce stress responses as well as cytotoxicity in mammalian cells. We observed that Ag NPs are efficiently internalized via scavenger receptor-mediated phagocytosis in murine macrophages.

Augmented anticancer efficacy of doxorubicin-loaded polymeric nanoparticles after oral administration in a breast cancer induced animal model.

The present investigation reports an extensive evaluation of in vitro and in vivo anticancer efficacy of orally administered doxorubicin-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (Dox-NPs) in a breast cancer induced animal model. Spherically shaped Dox-NPs were prepared with an entrapment efficiency and particle size of 55.40 ± 2.

A method for screening of volatile antimicrobial compounds.

Presently available methods for determining antimicrobial activity include broth dilution and disc diffusion. However, these methods can not be employed for study of vapor phase antimicrobial activity. The present study describes a new method and a new apparatus for determination of vapor phase antimicrobial activity of volatile substances against bacteria.

Effect of morphine on Mycobacterium smegmatis infection in mice and macrophages.

The immunomodulatory effects of opioids are known in various infections. However, little is known about the effects of opioids in tuberculosis (TB). In the present study, we report the effects of morphine in Mycobacterium smegmatis infection in mice and macrophages.

A comparison of conventional and radiometric methods for the assessment of anti-tubercular activity of drugs against Mycobacterium tuberculosis in mice and macrophage models.

Background: Presently, in vitro and in vivo screening of anti-tubercular drugs is a time-consuming exercise. Therefore, it is important to develop faster methods.

Material And Methods: Towards this end, conventional plating and radiometric BACTEC methods of anti-tubercular screening were compared to determine the efficacy of anti-tubercular drugs (isoniazid and rifampicin) and morphine in Mycobacterium tuberculosis H37Rv-infected mice and macrophages.

Antibacterial and membrane damaging activity of Livistona chinensis fruit extract.

Livistona chinensis is used in traditional Chinese medicine as an anticancer agent. Experimental studies have shown the antiproliferative and antiangiogenic properties of extracts of L. chinensis fruits and seeds.

Effects of morphine during Mycobacterium tuberculosis H37Rv infection in mice.

The effects of opiates in various infections are well known; however, very little is known about tuberculosis infection. Therefore, in the present study, we report for the first time, the effects of morphine during murine tuberculosis. Mice were infected intravenously with Mycobacterium tuberculosis H37Rv, administered morphine (0.