Chitosan nanopolymers: An overview of drug delivery against cancer.

Cancer is becoming a major reason for death troll worldwide due to the difficulty in finding an efficient, cost effective and target specific method of treatment or diagnosis. The variety of cancer therapy used in the present scenario have painful side effects, low effectiveness and high cost, which are some major drawbacks of the available therapies. Apart from the conventional cancer therapy, nanotechnology has grown extremely towards treating cancer. Nanotechnology is a promising area of science focusing on developing target specific drug delivery system for carrying small or large active molecules to diagnose and treat cancer cells. In the field of nanoscience, Chitosan nanopolymers (ChNPs) are been emerging as a potential carrier due to their biodegradability and biocompatibility. The easy modification and versatility in administration route of ChNPs has attracted attention of researchers towards loading chemicals, proteins and gene drugs for target specific therapy of cancer cells. Therefore, the present review deals with the growing concern towards cancer therapy, introduction of ChNPs, mode of action and other strategies employed by researchers till date towards cancer treatment and diagnosis ChNPs.

Biological and catalytic applications of green synthesized fluorescent N-doped carbon dots using Hylocereus undatus.

In this work, a simple hydrothermal route for the synthesis of fluorescent nitrogen doped carbon dots (N-CDs) is reported. The Hylocereus undatus (H. undatus) extract and aqueous ammonia are used as carbon and nitrogen source, respectively. The optical properties of synthesized N-CDs are analyzed using UV-Visible (UV-Vis) and fluorescence spectroscopy. The surface morphology, elemental composition, crystallinity and functional groups present in the N-CDs are examined using high resolution transmission electron microscopy (HR-TEM) with energy dispersive spectroscopy (EDS), selected area electron diffraction (SAED), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy, respectively. The synthesized N-CDs emit strong blue fluorescence at 400nm under the excitation of 320nm. Further, the excitation dependent emission properties are also observed from the fluorescence of synthesized N-CDs. The HR-TEM results reveal that synthesized N-CDs are in spherical shape with average diameter of 2.5nm. The XRD pattern exhibits, the graphitic nature of synthesized N-CDs. The doping of nitrogen is confirmed from the EDS and FT-IR studies. The cytotoxicity and biocompatibility of N-CDs are evaluated through MTT assay on L-929 (Lymphoblastoid-929) and MCF-7 (Michigan Cancer Foundation-7) cells. The results indicate that the fluorescent N-CDs show less cytotoxicity and good biocompatibility on both L-929 and MCF-7 cells. Moreover, the N-CDs show excellent catalytic activity towards the reduction of methylene blue by sodium borohydride.

Reductive-degradation of carcinogenic azo dyes using Anacardium occidentale testa derived silver nanoparticles.

In the present work, reductive-degradation of azo dyes such as congo red (CR) and methyl orange (MO) was manifested using Anacardium occidentale testa derived silver nanoparticles (AgNPs) as a catalyst. The formation of highly stable AgNPs were visually confirmed by the appearance of yellow color and further substantiated by the existence of surface plasmon resonance (SPR) peak around 425nm. The effect of A. occidentale concentration, reaction time and pH in the formations of AgNPs was corroborated by UV-visible (UV-Vis) spectroscopy. The Fourier transform infrared (FT-IR) spectroscopic results proved that phytoconstituents of A. occidentale testa acts as a capping agent and thereby protects the AgNPs from aggregation. The crystalline nature of the AgNPs was validated from the XRD patterns. The average size of synthesized AgNPs was 25nm, with distorted spherical shape was ascribed from the high resolution transmission electron microscopic (HR-TEM) images. Due to the high stability of the as-synthesized AgNPs, they were utilized for the degradation of carcinogenic azo dyes such as CR and MO using NaBH4 and its catalytic activity was studied via UV-Vis spectroscopy. The results proved that extraordinary catalytic activity of synthesized AgNPs towards the reductive-degradation of both CR and MO.

Nitrogen-doped carbon dots originating from unripe peach for fluorescent bioimaging and electrocatalytic oxygen reduction reaction.

This paper reports the robust hydrothermal synthesis of nitrogen doped carbon dots (N-CDs) using the unripe fruit of Prunus persica (peach) as the carbon precursor and aqueous ammonia as the nitrogen source. The optical properties of synthesized N-CDs were characterized by ultraviolet visible (UV-Vis) and fluorescence spectroscopy techniques. The synthesized N-CDs were emitted blue light when excitated with a portable UV lamp. The materials with the optical properties were characterized further by high resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), Raman, Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). The mean size of the N-CDs was approximately 8nm, as calculated from the HRTEM image. The d-spacing of N-CDs, calculated using Bragg law, was approximately 0.21nm, which was consistent with the interlayer distance calculated from the HRTEM image. FT-IR spectroscopy and XPS revealed the presence of the phytoconstituents functionalities of peach fruit over the N-CDs surface and a high level of nitrogen doping on carbon dots (CDs) was confirmed by XPS studies. These results suggest that the unripe fruit extract of peach is an ideal candidate for the preparation of N-CDs. The resulting N-CDs showed excellent optical properties in water. The synthesized N-CDs exhibited a high fluorescence quantum yield and low cytotoxicity, and can be used as fluorescence imaging probes. In addition, the N-CDs were catalytically activite towards the oxygen reduction reaction (ORR). The N-CDs exhibited good catalytic activity in an alkaline medium (0.1M KOH) with a remarkable ORR of approximately 0.72V vs reversible hydrogen electrode (RHE), and O2 reduction follows mainly a 2 electron pathway by being reduced to hydrogen peroxide. The 2-electron reduction pathway is used in industry for H2O2 production.

Green synthesis of silver nanoparticles using Terminalia cuneata and its catalytic action in reduction of direct yellow-12 dye.

Facile green synthesis of silver nanoparticles (AgNPs) using aqueous bark extract of Terminalia cuneata has been reported in this article. The effects of concentration of the extract, reaction time and pH were studied by UV-Vis spectroscopy. Appearance of yellow color with λmax around ~420 nm suggested the formation of AgNPs. The stable AgNPs were further characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS) with zeta potential and high resolution transmission electron microscopy (HR-TEM) with energy dispersive X-ray spectroscopy (EDS) analysis. The synthesized AgNPs were in the size range of 25-50 nm with a distorted spherical shape identified from HR-TEM analysis. The catalytic activity of AgNPs on the reduction of direct yellow-12 using NaBH4 was analyzed using a UV-Vis spectrophotometer. This study showed the efficacy of biogenic AgNPs in catalyzing the reduction of direct yellow-12.