Prasun Patra

Luminescent S-doped carbon dots: an emergent architecture for multimodal applications

A facile route has been developed to synthesise and isolate sulphur doped fluorescent carbon dots for the first time. Such carbogenic quantum dots exhibit a wide band gap of 4.43 eV with a high open circuit voltage (VOC) of 617 mV along with a fill factor (FF) as high as 37%, using phenyl-C60-butyric acid methyl ester (PCBM) as the electron transporting layer. Besides the wide band gap, which is useful in the fabrication of solar cells, sulphur modified carbon dots also exhibit a high fluorescence quantum yield of 11.8% without any additional surface passivation, producing a unique fluorescent probe for further applications. In addition, the particles have a strong tendency to interact with the surface of gold nanoparticles and produce a thin fluorescent layer over their surfaces. Moreover, as they are completely biocompatible in nature, the highly fluorescent S-doped carbon dots have a strong potential for use in bioimaging applications. Interestingly, owing to the presence of oxygen and sulphur functionality, the highly negatively charged particles can easily bind with positively charged DNA-PEI complexes, simply by mixing them, and after interaction with DNA, bright blue fluorescence has been observed under an excitation wavelength of 405 nm .

Mechanical Downsizing of a Gadolinium(III)-based Metal-Organic Framework for Anticancer Drug Delivery

A Gd(III) -based porous metal-organic framework (MOF), Gd-pDBI, has been synthesized using fluorescent linker pDBI (pDBI=(1,4-bis(5-carboxy-1H-benzimidazole-2-yl)benzene)), resulting in a three-dimensional interpenetrated structure with a one-dimensional open channel (1.9×1.2 nm) filled with hydrogen-bonded water assemblies. Gd-pDBI exhibits high thermal stability, porosity, excellent water stability, along with organic-solvent and mild acid and base stability with retention of crystallinity. Gd-pDBI was transformed to the nanoscale regime (ca. 140 nm) by mechanical grinding to yield MG-Gd-pDBI with excellent water dispersibility (>90 min), maintaining its porosity and crystallinity. In vitro and in vivo studies on MG-Gd-pDBI revealed its low blood toxicity and highest drug loading (12 wt %) of anticancer drug doxorubicin in MOFs reported to date with pH-responsive cancer-cell-specific drug release.

Photochemical Modulation of Biosafe Manganese Nanoparticles on Vigna radiata: A Detailed Molecular, Biochemical, and Biophysical Study

Manganese (Mn) is an essential element for plants which intervenes mainly in photosynthesis. In this study we establish that manganese nanoparticles (MnNP) work as a better micronutrient than commercially available manganese salt, MnSO4 (MS) at recommended doses on leguminous plant mung bean (Vigna radiata) under laboratory condition. At higher doses it does not impart toxicity to the plant unlike MS. MnNP-treated chloroplasts show greater photophosphorylation, oxygen evolution with respect to control and MS-treated chloroplasts as determined by biophysical and biochemical techniques. Water splitting by an oxygen evolving complex is enhanced by MnNP in isolated chloroplast as confirmed by polarographic and spectroscopic techniques. Enhanced activity of the CP43 protein of a photosystem II (PS II) Mn4Ca complex influenced better phosphorylation in the electron transport chain in the case of MnNP-treated chloroplast, which is evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and corresponding Western blot analysis. To the best of our knowledge this is the first report to augment photosynthesis using MnNP and its detailed correlation with different molecular, biochemical and biophysical parameters of photosynthetic pathways. At effective dosage, MnNP is found to be biosafe both in plant and animal model systems. Therefore MnNP would be a novel potential nanomodulator of photochemistry in the agricultural sector.

Porous ZnO nanorod for targeted delivery of doxorubicin: in vitro and in vivo response for therapeutic applications

Cancer cell specific targeted delivery (TDD) by porous nanocarrier is on a high role. Here in a simple route for the synthesis of porous ZnO nanorods (ZnO) has been demonstrated. ZnO expressed very high surface area of 305.14 m2 g−1 (SBET) and uniformly distributed pores of 5 nm. In continuation ZnO has been fabricated with 3-aminophosphonic acid followed by folic acid to yield folate conjugated porous ZnO nanorod (ZnO-FA). High surface area, uniformly distributed pores on its surface make the nanocarrier suitable for high drug loading (88%) of the anticancer drug doxorubicin (DOX). A pH triggered drug release was observed with minimum release in pathophysical conditions. In vitro efficacy of DOX loaded ZnO-FA (ZnO-FA-DOX) has been evaluated against breast cancer cells MDA-MB-231, which is not possible alone by DOX or ZnO-FA. Targeted scaffold with pendant –NH2 group has been covalently bonded with fluorescent dye (RITC) for cellular uptake and imaging studies in MDA-MB-231 cells; the possible pathway for cancer regression has also been evaluated. Even in vivo acute and intravenous toxicological evaluation on murine model system complemented biocompatibility of ZnO-FA in TDD. All together we have collaged a template free synthesis of porous ZnO nanorod, successful targeting on to cancer cells, high drug loading, pH triggered drug release, in vitro efficacy of ZnO-FA-DOX against MDA-MB-231 cells and in vivo compatibility as well. We envisioned the future prospect of porous ZnO nanostructures in TDD.

Biochemical-, biophysical-, and microarray-based antifungal evaluation of the buffer-mediated synthesized nano zinc oxide: an in vivo and in vitro toxicity study.

Here we describe a simple, novel method of zinc oxide nanoparticle (ZNP) synthesis and physicochemical characterization. The dose-dependent antifungal effect of ZNPs, compared to that of micronized zinc oxide (MZnO), was studied on two pathogenic fungi: Aspergillus niger and Fusarium oxysporum. Superoxide dismutase (SOD) activity, ascorbate peroxidase activity, catalase activity, glutathione reductase (GR) activity, thiol content, lipid peroxidation, and proline content in ZNP-treated fungal samples were found to be elevated in comparison to the control, which strongly suggested that the antifungal effect of ZNPs was due to the generation of reactive oxygen species (ROS). Protein carbonylation, another marker of oxidative stress, was also evaluated by the dinitrophenyl hydrazine (DNPH) binding assay and Fourier transform infrared (FTIR) spectral analysis followed by Western blot and microarray analysis of fungal samples to confirm ROS generation by ZNPs. Micrographic studies for the morphological analysis of fungal samples (ZNP-treated and a control) exhibited an alteration in fungal morphology. The bioavailability of ZNPs on fungal cell was confirmed by energy-dispersive X-ray (EDX) analysis followed by high-resolution transmission electron microscopy (HR-TEM) and confocal microscopic analysis of the fungal samples. In vivo acute oral toxicity, acetylcholine esterase activity, and a fertility study using a mice model were also investigated for ZNPs. The long-term toxicity of ZNPs through intravenous injection was evaluated and compared to that of MZnO. The in vitro comparative toxicity of ZNPs and MZnO was evaluated on MRC-5 cells with the help of water-soluble tetrazolium (WST-1) and lactate dehydrogenase (LDH) assays. These results suggested that ZNPs could be used as an effective fungicide in modern medical and agricultural sciences.

Novel fluorescent matrix embedded carbon quantum dots for the production of stable gold and silver hydrosols

A facile one step route has been developed for the synthesis of highly fluorescent matrix embedded carbon quantum dots (MCQDs) by the assistance of microwave irradiation. The material shows a homogeneous distribution of carbon quantum dots throughout the surfaces of the carbon matrices with an average size of 1 to 3 nm. The synthetic MCQDs can be employed as excellent catalysts during the synthesis of gold and silver nanoparticles.

Manganese nanoparticles: impact on non-nodulated plant as a potent enhancer in nitrogen metabolism and toxicity study both in vivo and in vitro.

Mung bean plants were grown under controlled conditions and supplemented with macro- and micronutrients. The objective of this study was to determine the response of manganese nanoparticles (MnNP) in nitrate uptake, assimilation, and metabolism compared with the commercially used manganese salt, manganese sulfate (MS). MnNP was modulated to affect the assimilatory process by enhancing the net flux of nitrogen assimilation through NR-NiR and GS-GOGAT pathways. This study was associated with toxicological investigation on in vitro and in vivo systems to promote MnNP as nanofertilizer and can be used as an alternative to MS. MnNP did not impart any toxicity to the mice brain mitochondria except in the partial inhibition of complex II-III activity in ETC. Therefore, mitochondrial dysfunction and neurotoxicity, which were noted by excess usage of elemental manganese, were prevented. This is the first attempt to highlight the nitrogen uptake, assimilation, and metabolism in a plant system using a nanoparticle to promote a biosafe nanomicronutrient-based crop management.

Copper Nanoparticle (CuNP) Nanochain Arrays with a Reduced Toxicity Response: A Biophysical and Biochemical Outlook on Vigna radiata

Copper deficiency or toxicity in agricultural soil circumscribes a plants growth and physiology, hampering photochemical and biochemical networks within the system. So far, copper sulfate (CS) has been used widely despite its toxic effect. To get around this long-standing problem, copper nanoparticles (CuNPs) have been synthesized, characterized, and tested on mung bean plants along with commercially available salt CS, to observe morphological abnormalities enforced if any. CuNPs enhanced photosynthetic activity by modulating fluorescence emission, photophosphorylation, electron transport chain (ETC), and carbon assimilatory pathway under controlled laboratory conditions, as revealed from biochemical and biophysical studies on treated isolated mung bean chloroplast. CuNPs at the recommended dose worked better than CS in plants in terms of basic morphology, pigment contents, and antioxidative activities. CuNPs showed elevated nitrogen assimilation compared to CS. At higher doses CS was found to be toxic to the plant system, whereas CuNP did not impart any toxicity to the system including morphological and/or physiological alterations. This newly synthesized polymer-encapsulated CuNPs can be utilized as nutritional amendment to balance the nutritional disparity enforced by copper imbalance.

Effect Sulfur and ZnO Nanoparticles on Stress Physiology and Plant (Vignaradiata) Nutrition

Phytotoxic and agro beneficial properties of antimicrobially efficient Sulfur nanoparticles (SNPs) and ZnO nanoparticles (ZNPs) were evaluated on Mung (Vigna radiata). Mung seeds were germinated with an increasing concentration gradient of nanoparticles. The extent of phtotoxicity were assessed depending upon the effect of used nanoparticles on physical factors (relative root and shoot length, dry weight and area of leaves), photosynthetic pigments (chlorophyll, carotene and xanthophyll content) and mitochondrial stress indicator level (thiol), A simultaneous study was undertaken to understand the effect of SNPs and ZNPs on overall plant growth and nutrition. The nutritive values of nanoparticles were determined in terms of total lipid and protein content. All the aforementioned biochemical assays were performed in triplicate for statistical viability.

Ciprofloxacin conjugated zinc oxide nanoparticle: A camouflage towards multidrug resistant bacteria

Gradual development of antibiotic resistant bacteria is producing severe global threat. Newer strategies are now being employed in order to control the microbial infections and to reduce the mortality as well as infection rates. Herein we describe successful synthesis of ZnO nanoparticles (ZNP) under microwave assisted condition followed by functionalization with ciprofloxacin, an antibiotic, using EDC/NHS chemistry. Successful conjugation of ciprofloxacin was confirmed by FTIR spectra. Ciprofloxacin-conjugated ZnO nanoparticles (ZN-CIP) exhibited excellent antibacterial activity against clinically isolated multidrug resistant bacterial strains of Escherichia coli, Staphylococcus aureus and Klebsiella sp. ZNP were small in size with particle size distribution 18–20 nm as obtained from transmission electron microscope (TEM). Surface topology was obtained from atomic force microscopic (AFM) image and x-ray diffraction confirmed that ZNP possessed hexagonal crystal structure. A concentration of 10 µg/mL of ZN-CIP was a benchmark concentration. During evaluation of minimum inhibitory concentration (MIC) values, similar concentration of antibiotic was incapable of producing antibacterial activity.