Novel Approach of Nanophotonic Electron Transfer for Augmenting Photosynthesis in Arachis hypogaea: A Biophysical Rationale behind the Plasmonic Enhancement of Chemical Energy Transfer.

Plant photosynthetic machinery is the main source of acquisition and conversion of solar energy to chemical energy with the capacity for autonomous self-repair. However, the major limitation of the chloroplast photosystem is that it can absorb light only within the visible range of the spectrum, which is roughly 50% of the incident solar radiation. Moreover, the photosynthetic apparatus is saturated by less than 10% of available sunlight. If the capacity of solar light absorption and the transmission of resulting photons through the photosynthetic electron transport chain (ETC) can be extended, the overall efficiency of photosynthesis can be improved. The plant nanobionic approach can address this via the introduction of nanoparticles into or in the vicinity of the photosynthetic machinery/chloroplast. We have studied this exceptional nanobionic-mediated capability of two optically active nanostructures and evaluated the impact of their optical properties on plant photosynthesis. Our study revealed that metal (Ag) and core-shell metal nanostructures (AgS) can increase light absorption and improve electron transport through ETC. Both nanostructures were found to have a beneficial effect on the photoluminescence property of the isolated chloroplast. Translocation studies confirmed systemic transportation of the nanomaterial in different plant tissues. The primary growth parameters showed no detrimental effect until 21 days of treatment on Arachis hypogaea. The nano silver/silica core/shell structure (AgS) was found to be more advantageous over nano silver (AgNP) in photon entrapment, light-dependent biochemical reactions, and toxicity parameters. In the future, these nanostructures can enhance photosynthesis by increasing light absorption and resulting in higher assimilatory power generation in the form of ATP and NADPH. This approach may lead to a paradigm shift toward a sustainable method for the configuration of plant chloroplast-based hybrid energy harvesting devices.

Determination of antifungal efficacy and phytotoxicity of a unique silica coated porous zinc oxide nanocomposite medium for slow-release agrochemicals.

AIMS: In this study, the antifungal efficacy and phytotoxicity of silica coated porous zinc oxide nanoparticle (SZNP) were analyzed as this nanocomposite was observed to be a suitable platform for slow release fungicides and has the promise to bring down the dosage of other agrochemicals as well. METHODS AND RESULTS: Loading and release kinetics of tricyclazole, a potent fungicide, were analyzed by measuring surface area (SBET) using Brunauer-Emmett-Teller (BET) isotherm and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. The antifungal efficacy of ZnO nanoparticle (ZNP) and SZNP was investigated on two phytopathogenic fungi (Alternaria solani and Aspergillus niger). The morphological changes to the fungal structure due to ZNP and SZNP treatment were studied by field emission-scanning electron microscopy. Nanoparticle mediated elevation of reactive oxygen species (ROS) in fungal samples was detected by analyzing the levels of superoxide dismutase, catalase, thiol content, lipid peroxidation, and by 2,7-dichlorofluorescin diacetate assay. The phytotoxicity of these two nanostructures was assessed in rice plants by measuring primary plant growth parameters. Further, the translocation of the nanocomposite in the same plant model system was examined by checking the presence of fluorescein isothiocyanate tagged SZNP within the plant tissue. CONCLUSIONS: ZNP had superior antifungal efficacy than SZNP and caused the generation of more ROS in the fungal samples. Even then, SZNP was preferred as an agrochemical delivery vehicle because, unlike ZNP alone, it was not toxic to plant system. Moreover, as silica in nanoform is entomotoxic in nature and nano ZnO has antifungal property, both the cargo (agrochemical) and the carrier system (silica coated porous nano zinc oxide) will have a synergistic effect in crop protection.

Application of Core/Shell Nanoparticles in Smart Farming: A Paradigm Shift for Making the Agriculture Sector More Sustainable.

Modern agriculture has entered an era of technological plateau where intervention of smarter technology like nanotechnology is imminently required for making this sector economically and environmentally sustainable. Throughout the world, researchers are trying to exploit the novel properties of several nanomaterials to make agricultural practices more efficient. Core/shell nanoparticles (CSNs) have attracted much attention because of their multiple attractive novel features like high catalytic, optical, and electronic properties for which they are being widely used in sensing, imaging, and medical applications. Though it also has the promise to solve a number of issues related to agriculture, its full potential still remains mostly unexplored. This review provides a panoramic view on application of CSNs in solving several problems related to crop production and precision farming practices where the wastage of resources can be minimized. This review also summarizes different classes of CSNs and their synthesis techniques. It emphasizes and analyzes the probable potential applications of CSNs in the field of crop improvement and crop protection, detection of plant diseases and agrochemical residues, and augmentation of chloroplast mediated photosynthesis. In a nutshell, there is enormous scope to formulate and design CSN-based smart tools for applications in agriculture, making this sector more sustainable.

Recent trends in nanomaterials applications in environmental monitoring and remediation.

Environmental pollution is one of the greatest problems that the world is facing today, and it is increasing with every passing year and causing grave and irreparable damage to the earth. Nanomaterials, because of their novel physical and chemical characteristics, have great promise to combat environment pollution. Nanotechnology is being used to devise pollution sensor. A variety of materials in their nano form like iron, titanium dioxide, silica, zinc oxide, carbon nanotube, dendrimers, polymers, etc. are increasingly being used to make the air clean, to purify water, and to decontaminate soil. Nanotechnology is also being used to make renewable energy cheaper and more efficient. The use of nanotechnology in agriculture sector will reduce the indiscriminate use of agrochemicals and thus will reduce the load of chemical pollutant. While remediating environment pollution with nanomaterials, it should also be monitored that these materials do not contribute further degradation of the environment. This review will focus broadly on the applications of nanotechnology in the sustainable development with particular emphasis on renewable energy, air-, water-, and soil-remediation. Besides, the review highlights the recent developments in various types of nanomaterials and nanodevices oriented toward pollution monitoring and remediation.

Chitosan, Carbon Quantum Dot, and Silica Nanoparticle Mediated dsRNA Delivery for Gene Silencing in Aedes aegypti: A Comparative Analysis.

In spite of devastating impact of mosquito borne pathogens on humans, widespread resistance to chemical insecticides and environmental concerns from residual toxicity limit mosquito control strategies. We tested three nanoparticles, chitosan, carbon quantum dot (CQD), and silica complexed with dsRNA, to target two mosquito genes (SNF7 and SRC) for controlling Aedes aegypti larvae. Relative mRNA levels were quantified using qRT-PCR to evaluate knockdown efficiency in nanoparticle-dsRNA treated larvae. The knockdown efficiency of target genes correlated with dsRNA mediated larval mortality. Among the three nanoparticles tested, CQD was the most efficient carrier for dsRNA retention, delivery, and thereby causing gene silencing and mortality in Ae. aegypti.

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.

Evolution of nanoparticle-induced distortion on viral polyhedra.

Morphological changes in the polyhedra of the Bombyx mori L. nuclear polyhedrosis virus (BmNPV), a baculovirus causing the deadly grasserie disease in silkworms, brought about by mixing with lipophilically capped amorphous silica nanoparticles (LASN, average size 10 ± 2 nm) were studied with scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. SEM shows that the regular octagonal polyhedra facets are replaced by a larger number of newly formed irregular ones. The average number of facets reveals a nonlinear growth pattern with nanoparticle (NP) concentration, where an initial linear region ends in a plateau. IR bands corresponding to vibration modes of the capping show (a) a saturation of the area under the band with NP concentration, indicating a correlation with attachment to viral polyhedra and (b) a narrowing of the band per NP from the linear to the plateau portions of the distortion curve, suggesting non-equilibrium and equilibrium situations, respectively.

Nanoparticle-induced morphological transition of Bombyx mori nucleopolyhedrovirus: a novel method to treat silkworm grasserie disease.

Grasserie, a polyorganotrophic disease caused by Bombyx mori nucleopolyhedrovirus (BmNPV), accounts for lethal infection to fifth instar silkworm larvae. It was found that nanoparticle (NP)-induced morphological transformation of BmNPV polyhedra could reduce the infectivity of BmNPV both in cell line and in silkworm larvae. Initially, 11 NPs were screened for evaluation of their nature of interaction with polyhedra surface through scanning electron microscopy. Amongst these NPs, lipophilically coated silica nanoparticle (SNPL), alumina nanoparticles in the hexagonal close-packed α structure and aspartate capped gold nanoparticle transformed polyhedra were tested for their infectivity in B. mori cell line using cytopathic effect and plaque reduction assay. SNPL was evaluated for its bio-efficacy in fifth instar silkworm larvae. The study of polyhedra morphology as a function of NP concentration showed severe 'roughening' of the polyhedra with replacement of the regular facets by a large number of irregular ones by SNPL, and this caused transition of highly infectious polyhedra into a nearly spherical, non-infectious structure. A moderate polyhedra roughening was observed for alumina NPs, and no roughening was noticed for gold NPs. The morphological changes could be correlated with reduction of virus-induced cytopathic effect and plaque formation, and increased survival rate of SNPL transformed polyhedra infected silkworm larvae to 70.09±6.61% after 96 h. In this group, 61.04±8.03% larvae formed normal cocoons from which moths eclosed, laid eggs and larvae emerged. This study could lead to open up newer pathways for designing nano pharmaceuticals to combat other viral diseases.

Comparative analysis of stability and toxicity profile of three differently capped gold nanoparticles for biomedical usage.

Nowadays gold nanoparticle (GNP) is increasingly being used in drug delivery and diagnostics. Here we have reported a comparative analysis of detailed stability and toxicity (in vitro and in vivo) profile of three water soluble spherical GNPs, having nearly similar size, but the surfaces of which were modified with three different capping materials aspartic acid (GNPA), trisodium citrate dihydrate (GNPC) or bovine serum albumin (GNPB). Spectral analyses on the stability of these GNPs revealed that depending on the nature of capping agents, GNPs behave differently at different environmental modalities like wide range of pH, high salt concentrations, or in solutions and buffers of biological usage. GNPB was found to be extremely stable, where capped protein molecule successfully maintained its secondary structure and helicity on the nanoparticle, whereas colloidal stability of GNPA was most susceptible to altered conditions. In vitro cytotoxicity of these nanoparticle formulations in vitro were determined by water soluble tetrazolium and lactate dehydrogenase assay in human fibroblast cell line (MRC-5) and acute oral toxicity was performed in murine model system. All the GNPs were non-toxic to MRC-5 cells. GNPC had slight hepatotoxic and nephrotoxic responses. Hepatotoxicity was also evident for GNPA treatment. Present study established that there is a correlation between capping material and stability together with toxicity of nanoparticles. GNPB was found to be most biocompatible among the three GNPs tested.

Nature-inspired novel drug design paradigm using nanosilver: efficacy on multi-drug-resistant clinical isolates of tuberculosis.

Despite discovery of the pathogen more than 100 years ago, tuberculosis (TB) continues to be a major killer disease worldwide. Currently a third of world population is infected and multiple-drug-resistant (mdr) TB registers maximum mortality by a single pathogen. Nanomedicine provides enormous opportunity for developing novel drugs. We have recently demonstrated surface-modified-lipophilic-nanosilica as drug to combat malaria and 100% lethal virus, BmNPV. Nanosilver possesses inherent antibacterial properties, but toxicity is a major concern. We hypothesized that capping with nature-inspired biomolecules, bovine serum albumin (BSA) and Poly-n-vinyl-pyrrolidone (PVP) used as blood volume extender, might insure biosafety. BSA-nano-Ag was found to be more stable than PVP-nano-Ag at physiological pH. In this first ever study on clinical isolates collected from TB endemic areas, we report, BSA-nano-Ag act as potent anti-TB drug. Further study with (human serum albumin)-nano-Ag and core-shell-nano-Ag could increase the biocompatibility of oral TB drug formulations without compromising on the efficacy of the drug.