Graphene oxide@gold nanorods for chemo-photothermal treatment and controlled release of doxorubicin in mice Tumor.

Graphene oxide (GO) is a close derivative of graphene has unlocked many pivotal steps in drug delivery due to their inherent biocompatibility, excellent drug loading capacity, and shows antibacterial, antifungal properties etc. We used a novel plant material called Gum arabic (GA) to increase the solubility of GO as well as to chemically reduce it in the solution. GA functionalized GO (fGO) exhibited increased absorption in near infra-red region (NIR) which was exploited in photothermal therapy for cancer. In order to understand the shape and size effect of GO which may affect their rheological properties, we have conjugated them with gold nanorods (GNRs) using in situ synthesis of GO@GNRs via seed mediated method. To the above conjugate, Doxorubicin (DOX) was attached at ambient temperature (28±2°C). The release kinetics of DOX with the effect of NIR exposure was also carefully studied via in vitro photothermal killing of A549 cell lines. The enhancement in NIR induced drug release and photothermal property was observed which indicates that the fGO@GNRs-DOX method is an ideal choice for chemotherapy and photothermal therapy simultaneously.

Folic Acid navigated Silver Selenide nanoparticles for photo-thermal ablation of cancer cells.

Photothermal ablation of the cancer cells is a non-invasive technique for cancer treatment, involving cellular assassination in presence of photothermal agent. We are reporting silver selenide (Ag2Se) nanoparticles for photothermal therapy using folic acid for selective targeting. The material, when exposed to 808nm laser, the temperature got boosted to 54°C in 6.5min, thus proving its potential for photothermal ablation. The material was highly biocompatible (95%) at highest concentration (10µg/mL) against A 549 cells. However, in presence of laser, the cellular killing was 55%. The mode of death was analyzed using MALDI-TOF MS.

Tellurium platinate nanowires for photothermal therapy of cancer cells.

Among the most celebrated modes of cancer treatment, photothermal therapy has been the most promising tool over the past few years. In spite of the introduction of many novel nanomaterials for photothermal therapy, there is still plenty of room for exploration of naïve materials. We have explored the photothermal properties of metal chalcogenides, namely tellurium platinate nanowires (TePt NWrs), in this work. Upon irradiation with a laser (Ti:sapphire laser, 808 nm) the temperature of the aqueous suspension of TePt NWrs was found to increase to ∼62 °C from room temperature at optimum concentrations. This was due to the stability and high photothermal transduction efficiency of nanorods (NRs) i.e.∼47%. The power to ablate tumor cells was studied using A549 cells and tumor grafted experimental mice models. After an initial exposure for 10 min (808 nm laser at 1 W cm-2), the cells were killed mainly by the process of apoptosis as confirmed by a flow cytometry assisted cell sorting system (FACS; PI-FITC-Annexin V staining). Tumor growth was significantly reduced after photothermal therapy via a combination of TePt NRs and laser, thus proving the importance of this new nanomaterial for cancer photothermal therapy. The current approach has introduced a highly potential photothermal therapy method for applications in the medical world in the near future.

Controlled delivery of dopamine hydrochloride using surface modified carbon dots for neuro diseases.

Delivery of therapeutic agents using water-soluble, highly biocompatible Carbon dots (C-dots) is an efficient strategy to control drug release under physiological milieu. Dopamine hydrochloride (DA), the most important inotropic vasopressor agent used in neurological diseases. In our study DA is anchored to water-soluble carbon dots for controlled release under mimicked in vitro physiological conditions. The tenure of the DA release at pH 7.4 was greatly extended to 60 h for C-dots-DA, in comparison with the control DA alone. The statistical calculation was used to comprehend the release pattern of the DA, which exhibited the pattern of Hixson-Crowell model of release. In order to understand the impact of the C-dots-DA conjugate under physiological conditions, Neuro 2A cells were taken under consideration. The conjugate C-dots-DA was found to be biocompatible against Neuro 2A cells. The survival rate was found to be 74% at maximum concentration of 9 µg mL(-1). In vivo toxicity was studied using thin section of tissues after staining with Hematoxyline and Eosin Yellow (H&E). As per microscopic observations, conjugates did not inflict any anatomical distortions or hostile effects on tissues. Body weight of mice was also taken into consideration after injecting 20 µg mL(-1) of nano-conjugates via tail vein. The impact of nano-conjugate on body weight was found to be negligible after 45 days of observation.

Synthesis of highly fluorescent hydrophobic carbon dots by hot injection method using Paraplast as precursor.

We have reported synthesis of bright blue colored hydrophobic carbon dots (hC-dots) using highly pure blend of polymers called Paraplast. We developed a hot injection method for making nearly monodispersed hC-dots with a diameter in a range: 5-30nm as confirmed by high resolution transmission electron microscopy (HRTEM). The involvement of various functional groups was confirmed by Fourier transform infra-red (FTIR) spectroscopy. These hC-dots were incubated with breast cancer stem cells in order to check the entry as well as biological imaging. The cells were analyzed using epifluorescent microscopy. hC-dots showed concentration dependent cytotoxicity (LD50: 50mg/ml) and could be used for bioimaging even at lower concentration (0.5mg/ml). hC-dots were found to be versatile agents for peeping inside the cells which could also be used for delivery of water insoluble chemotherapeutic agents to variety of solid tumors.

Fluorophotometric determination of critical micelle concentration (CMC) of ionic and non-ionic surfactants with carbon dots via Stokes shift.

A new and facile method for the determination of critical micelle concentration (CMC) of ionic and non-ionic surfactants is proposed in this article. Carbon dots exhibited substantial fluorescence and therefore enhanced the sensitivity of this evaluation. Understanding the formation of surfactant micelles is vital for the applications of biomedicine such as drug fabrication and smart molecular vehicles in delivering therapeutic dosage to various molecular sites. The fluorescence property of carbon dots was utilized for the first time to estimate the critical micelle concentration of surfactants. The central concept of the approach is based on the Stokes shift determination of a system composed of constant amount of carbon dots with varying concentrations of ionic and non-ionic surfactants. The synthesized carbon dots were characterized by FTIR, TEM, XRD, Raman, UV, and fluorescence spectroscope. The carbon dots were excited at 280 nm so as to obtain maximum emission for the Stokes shift measurement. The CMC value of cetyltrimethyl ammonium bromide (CTAB), sodium dodecyl sulfate (SDS), Triton X-100, dodecyldimethyl(3-sulfopropyl)ammonium hydroxide (SB-12) evaluated by this approach was found to be 0.98, 7.3, 0.19, and 3.5mM, respectively. The signals of spectra were assigned and explained in terms of both electron transitions between specific molecular orbital and the interaction with solvent.

Facile synthesis of gold nanohexagons on graphene templates in Raman spectroscopy for biosensing cancer and cancer stem cells.

Several surface enhanced Raman spectroscopy (SERS) substrates were prepared based on in situ nucleation of gold nanohexagons (Au) on graphene (G) nanosheets (Au@G), G, Au nanoparticles and Au conjugated G nanomaterials. These were applied to enhance Raman scattering and to differentiate human breast normal, cancer and cancer stem cells. These SERS substrates at concentrations of 100 µg/1 × 10(4) cells led to 5.4 fold increase in detecting breast cancer cells (BCCs) and 4.8 fold of sensitivity for detecting breast cancer stem cells (BCSCs) and they were able to identify and differentiate between normal cells, cancer cells and cancer stem cells. These approaches are rapid, simple and reliable for healthy normal cells, cancer cells and cancer stem cell detection which have a huge potential for cancer research for medical or biomedicine applications.

Growth of different morphologies (quantum dots to nanorod) of Ag-nanoparticles: role of cysteine concentrations.

This work describes an easy chemical method for the preparation of orange-red color silver sol by the cysteine reduction of silver (I) in the presence of cetyltrimethylammonium bromide (CTAB). The obtained sol was found to have very small particles in the order of quantum dots for the first time. Transmission electron microscope (TEM) images show that the silver sol consists of aggregated as well as cross-linking arrangement of spherical silver quantum dots (size in the range ca. or=20.0x10(-4)mol dm(-3)), white precipitate was formed instead of transparent silver sol. Cysteine acts as a reducing, cross-linking, stabilizing and buffering agent during the growth of different shape and size of silver nanoparticles.