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Gold nanoparticles have found their application as optical probes, antibacterial agents, catalyst and sensors. Here, we report the synthesis of gold nanoparticles (GNPs) using leaf extract (LE) of three different plants viz., Populus alba (PA), Lantana camara (LC) and Hibiscus arboreus (HA). The effect of reaction temperature and concentration of leaf extracts (LEs) were studied in detail on the synthesis and size of GNPs. The prepared GNPs were chemically characterized by UV–Vis and FTIR whereas the morphological analysis was done using DLS, TEM and SEM. When 5% PA LE was used at 65 °C, almost uniform shaped GNPs were obtained of size ~ 16.3 ± 0.7 nm. The as prepared GNPs showed antibacterial activity against both Staphylococcus aureus and Escherichia coli with MIC value of ~ 100 µg/ml. Further, these GNPs were also used for the degradation of toxic dyes viz., methylene blue (MB) and congo red (CR). Overall, present studies suggested the use of green synthesized GNPs in both biomedical and analytical field.

Successful and effective treatment of different types of infections depends upon fast and selective identification of the microorganisms. Pseudomonas aeruginosa is a Gram-negative bacterium which is involved in a number of human infections and may become life-threatening for immunocompromised persons. Pyocyanin is a unique exotoxin which is exclusively secreted as a virulence factor by P. aeruginosa. In this respect, a nano-assembly, composed of a carbon dot conjugated gold nanocomposite (Au@OPCDPEG) having a size of ∼11.5 ± 1.6 nm, was synthesized and used as both a fluorescence resonance energy transfer (FRET) and a colorimetric sensor for pyocyanin detection. When titrated with increasing concentrations of pyocyanin, Au@OPCDPEG NPs showed ∼1.76 ± 0.12 times increase in fluorescence intensity (at ∼505 nm), whereas three distinct isosbestic points were observed in absorption studies. The limit of detection for pyocyanin was found to be ∼3.04 ± 0.27 μM. It was found that Au@OPCDPEG NPs can selectively recognize pyocyanin even in the presence of other toxins under different biological interference. Real-time P. aeruginosa detection studies suggested the minimum detection limit to be ∼1.5 × 106 cfu ml−1 even in the presence of Staphylococcus aureus contamination in the sample. Confocal studies suggested that Au@OPCDPEG NPs can effectively penetrate P. aeruginosa biofilm under laser irradiation. Overall, the present engineered nanoprobe provides an easy, fast and selective method for the detection of P. aeruginosa in biological samples.

Inhibition of hen egg white lysozyme (HEWL) and Aβ42 fibrillation have been established as the main models for the treatment of systemic lysozyme amyloidosis and Alzheimer's disease (AD), respectively. Several antiamyloidogenic nanomaterials have been developed over the period; however, their intracellular mechanism of action is still not well understood. In this context, plant-based, gold-conjugated, injectable, hydrophilic cellulose nanoonions (CNOs), viz., DH-CNO (∼60 ± 5 nm) and LC-CNO (∼55 ± 12 nm), were developed from their respective hydrophobic cellulose nanocrystals (DH-CNC and LC-CNC) using a single-step chemical template-mediated process. This unique nanocellulose architecture was chemically and morphologically characterized by various spectroscopic and microscopic techniques. Further, the different biophysical studies documented marked the inhibition/disintegration potential of gold-conjugated LC-CNO against HEWL and Aβ42 peptide aggregation. It was further observed that inhibition of protein fibrillation could be achieved within ∼10 min when the same materials were used under photoirradiation conditions. In vitro protein aggregation studies using HEK293 cells suggested that gold-conjugated LC-CNO could effectively reduce the cellular toxicity via regulation of oxidative stress and ion homeostasis. The outcome of the present study will help in designing cellulose-based novel functional nanochaperones against various neurodegenerative diseases.

Tissue engineering (TE) is an emerging field where alternate/artificial tissues or organ substitutes are implanted to mimic the functionality of damaged or injured tissues. Earlier efforts were made to develop natural, synthetic, or semisynthetic materials for skin equivalents to treat burns or skin wounds. Nowadays, many more tissues like bone, cardiac, cartilage, heart, liver, cornea, blood vessels, and so forth are being engineered using 3-D biomaterial constructs or scaffolds that could deliver active molecules such as peptides or growth factors. Nanomaterials (NMs) due to their unique mechanical, electrical, and optical properties possess significant opportunities in TE applications. Traditional TE scaffolds were based on hydrolytically degradable macroporous materials, whereas current approaches emphasize on controlling cell behaviors and tissue formation by nano-scale topography that closely mimics the natural extracellular matrix. This review article gives a comprehensive outlook of different organ specific NMs which are being used for diversified TE applications. Varieties of NMs are known to serve as biological alternatives to repair or replace a portion or whole of the nonfunctional or damaged tissue. NMs may promote greater amounts of specific interactions stimulated at the cellular level, ultimately leading to more efficient new tissue formation. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2433-2449, 2019.

Fluorescent silicon NPs (Si-NPs) and 3-mercaptopropionic acid-coated CdS NPs (MPA-NPs) were prepared and conjugated with two different albumin proteins, viz., BSA (B) and HSA (H). The absorption, fluorescence, FTIR, circular dichroism, and gel electrophoresis studies confirmed the conjugation of proteins to NPs. DPPH assay confirmed that the conjugated proteins retained their functional activity even after chemical modifications. The sizes of Si-NPs by TEM were found to be ∼8.7 ± 2 nm, whereas MPA-NPs showed individual particle sizes of ∼4.6 ± 1 nm. The in vitro studies suggested that these NPs were highly biocompatible. The potential of these protein-conjugated NPs in cholesterol effluxing and fluorescence imaging was studied using two different macrophage cell lines, viz., human coronary artery endothelial cells (HCAEC) and human umbilical vein endothelial cells (HUVEC). Results suggested that HSA-conjugated NPs showed better cholesterol effluxing ability and superior penetration toward these treated ce...

Multifunctional hybrid nanocomposite material, consists of chitosan encapsulated iron oxide (as MRI contrasting agent), CdS (as fluorescent probe) nanoparticles and podophyllotoxin (as anticancer drug) was synthesized and characterized. The TEM studies suggested the size of the NPs to be in the range of 80-100 nm. These nanocomposites were treated with different cancer cell lines viz., KB, C6 and A549 cells. Fluorescence imaging and Perl's Prussian blue staining confirmed the presence of these nanocomposites inside both KB and C6 cells but not in A549 cells. Cytotoxicity experiments revealed that these biopolymer coated nanocomposites showed minimal toxicity towards cancerous cells. Further the intraperitoneal administration of one of the nanoformulations to Wistar rats suggested deposition of these nanocomposites in the lungs. The hematological, biochemical and histopathological analysis confirmed that these nanocomposites are safe to use as a novel dual mode imaging material.

Amongst many projected applications, nanotechnology has the ability to revolutionize agro-food sector. With the current global population reaching close to 7 billion, many developing countries are facing the problem of food shortages. Agriculture nanotechnology, with its possible applications in providing ranging from better food quality to minimization of agriculture inputs, can significantly enhance crop productivity. Nanotechnology can contribute to agro-food sector with novel tools viz., disease diagnosis and management, nanocide-pesticide delivery including green pesticides and biopesticides, slow and sustained release of micro-nutrients and fertilizers etc. Nanobiotechnology is expected to offer critical biological aspects of various crops; which inevitably will enhance the corresponding nutritional values. Further, these ideas will also help in meeting the food security and of environmental challenges. However, before implementation, these products need to be thoroughly evaluated for any toxicity concerns. Unfortunately, research outcomes of this field are mostly restricted to the lab and the concerned rules and regulations are also not well documented. To add to this, due to high initial production investments, industry experts are reluctant to invest significantly in this field. Thus, concentrated efforts from all directions are required to meet these global challenges. The present review will be covering all these aspects related to agriculture nanotechnology by citing specific examples from the existing recent literature reports and will also comment on the future prospects of this area.

Background:Nanomaterials offer significant advantages in delivery of different biomolecules which suffer from drawbacks like poor bioavailability, low stability and retention time, degradation in biological systemsetc. Nanotechnological approach has shown promising results for the sustained release of these biomolecules with minimal toxicity concerns. The present review describes a comprehensive outlook of the different nanomaterials used for the delivery of these biomolecules.Methods:Current literature reports related to protein, peptide and gene delivery agents have been reviewed and classified according to their applications.Results:Studies suggested that the nanomaterial based delivery agents can be broadly classified in to five categories which include metallic NPs, polymeric NPs, magnetic NPs, liposomes and micelles. All these materials provided significant improvement in the targeted delivery of biomolecules.Conclusion:Concerns regarding the bioavailability, stability and delivery of proteins, peptides, genes need to be investigated to improve their therapeutic potential in the biological milieu. The use of nanoparticles as drug delivery vehicles may avoid undesirable hazards and may increase their pharmaceutical efficacy.

Nanocomposites of plant cellulose nanocrystals (CNCs) were developed by binding model proteins BSA and HSA onto CNCs by physical adsorption and chemical conjugation methods The spectroscopy and microscopy studies confirmed the protein binding onto CNCs. Phosphate buffer saline (pH=4.0, 7.4) and simulated gastric and intestinal fluids (SGF/SIF; pH=1.1/6.5) showed maximum protein release of ∼62% over a period of time. The released proteins were found to retain both structural integrity as well as≥90% of bioactivity. Further, these cytocompatible nanocomposites showed ∼58-85% cholesterol release from HUVEC whereas no selectivity was observed for HCAEC. It is speculated that due to the presence of combination of shuttles (albumins) and sinks (CNCs and albumins), these prepared nanocomposites with increased cholesterol effluxing ability may serve as a potential candidate for future biomedical applications in pharmaceuticals.

A colorimetric chemo-sensor based on citric acid-coated gold NPs (C-GNP) showed a linear increase in fluorescence intensity with increasing concentration of pesticide dimethoate (DM). The limit of detection was found to be between ~8.25± 0.3 and 20 ± 9.5 ppm. The increase in fluorescence intensity was suggested to have originated from the soft–soft interaction between C-GNPs and DM via sulfur group which is absent in pesticide dicofol (DF). Similar studies with citric acid-coated silver NPs (C-SNPs) did not result any change in the fluorescence intensity. The microscopic studies suggested aggregation of C-GNPs in the presence of DM but not in case of DF.

Nanoparticles (NPs) are being extensively used in the field of nanomedicines. Different types of NPs are administered into the body by various routes. NPs come in contact with cells inside the body. Cellular response of NPs is affected by size, shape, surface chemistry, and cellular uptake pathways of NPs. In addition to this, type of cells, various cell lines, and growth media are also found to affect the cellular response of NPs. NPs induce diverse cellular responses like apoptosis, necrosis, and reactive oxygen species (ROS) production. NPs also form a protein corona inside the biological media which may alter their identity and behaviour as compared to bare NPs. In this chapter, we have made an attempt to throw light on cellular uptake pathways of NPs, monitoring of endocytic pathways followed by NPs, factors affecting cellular responses of therapeutic NPs, and protein corona formation, characterisation and its implications on fate of NPs.

Nanoscale materials (NSMs) are gaining attention due to their small size and unique physiochemical properties. Different approaches are used for the synthesis of NSMs. NSMs cannot be visualized by ordinary instruments. Instruments with high resolution are required for their characterisation. NSMs offer enhanced activity and specificity to encapsulate drugs. NSM are used as vehicles for site specific delivery of drugs inside the body. In this chapter, approaches for the synthesis of NSMs, and characterisation techniques for NSMs like SEM, TEM, AFM, DLS, XRD, and FTIR have been explained briefly. In addition, this chapter also covers zero dimensional one dimensional, two dimensional and three dimensional NSMs briefly. Detailed information about approaches of targeted delivery like passive and active have been covered in this chapter. NSMs like polymeric nanoparticles, metallic nanoparticles, liposomes, quantum dots, polymeric micelles, carbon nanotubes, dendrimers, and magnetic nanoparticles used in targeted drug delivery have also been explained in this chapter.

Theragnostic NPs give new hope in simultaneous diagnosis and therapy of a disease at curable stage. Theragnosis is the fundamental requirement of personalized medicine. For successful theragnosis applications, the imaging agents and drugs should be efficiently delivered, resulting in adequate imaging signal or drug concentration in the targeted disease site. The selection of NPs for imaging, diagnosis and therapy was based on their biomimetic features with higher surface to volume ratio of the nanomaterials. The essential properties of nanomedicines involve early and precise diagnosis of clinical conditions providing an efficient treatment without secondary effects. Thus, nanotheragnostic probes are much better than conventional treatments where the diagnosis and therapy are way apart from each other. This chapter briefs about the recent advancement of nanotheragnosis research with future scope and associated hurdles.