Nanoparticles: Properties, applications and toxicities

Biofilm inhibition, modulation of virulence and motility properties by FeOOH nanoparticle in Pseudomonas aeruginosa

Biofilm formation is one of the resistance mechanisms of Pseudomonas aeruginosa against antimicrobial compounds. Biofilm formation also characterizes for the infection and pathogenesis of P. aeruginosa, along with production of various virulence factors. With recent development of nanotechnology, the present study aims to employ the synthetic iron nanoparticle (FeOOH-NP) as an active agent to inhibit the formation of P. aeruginosa biofilm. The FeOOH-NP was synthesized and characterized with rod shape and average size of 40 nm. Inhibition of biofilm formation by the FeOOH-NP is in a concentration-dependent manner, with inhibition of biofilm formation increased as the FeOOH-NP concentration increased. Microscopic observations also confirmed the disruption of the biofilm architecture in the presence of the FeOOH-NP. In addition, the presence of the FeOOH-NP was also found to modulate bacterial motility as well as some other important virulence factors produced simultaneously with biofilm formation. These findings provide insights to anti-biofilm effect of a new iron NP, contributing to the search for an effective agent to combat P. aeruginosa infections resulted from biofilm formation.

Nanoparticles Functionalized with Venom-Derived Peptides and Toxins for Pharmaceutical Applications

Venom-derived peptides display diverse biological and pharmacological activities, making them useful in drug discovery platforms and for a wide range of applications in medicine and pharmaceutical biotechnology. Due to their target specificities, venom peptides have the potential to be developed into biopharmaceuticals to treat various health conditions such as diabetes mellitus, hypertension, and chronic pain. Despite the high potential for drug development, several limitations preclude the direct use of peptides as therapeutics and hamper the process of converting venom peptides into pharmaceuticals. These limitations include, for instance, chemical instability, poor oral absorption, short halflife, and off-target cytotoxicity. One strategy to overcome these disadvantages relies on the formulation of bioactive peptides with nanocarriers. A range of biocompatible materials are now available that can serve as nanocarriers and can improve the bioavailability of therapeutic and venom-derived peptides for clinical and diagnostic application. Examples of isolated venom peptides and crude animal venoms that have been encapsulated and formulated with different types of nanomaterials with promising results are increasingly reported. Based on the current data, a wealth of information can be collected regarding the utilization of nanocarriers to encapsulate venom peptides and render them bioavailable for pharmaceutical use. Overall, nanomaterials arise as essential components in the preparation of biopharmaceuticals that are based on biological and pharmacological active venom-derived peptides.

Algae-based metallic nanoparticles: Synthesis, characterization and applications

Nanomaterials (NMs) tailored via conventional physicochemical routes play havoc with the environment that has led to the evolution of competent green routes for the actualization of a circular economy on an industrial-scale. Algae belonging to the class Cyanophyceae, Chlorophyceae, Phaeophyceae and Rhodophyceae have been harnessed as nano-machineries through intracellular and extracellular synthesis of gold (Au), silver (Ag) and several other metallic nanoparticles. Algae are an appealing platform for the production of diverse NMs, primarily due to the presence of bioactive compounds such as pigments and antioxidants in their cell extracts that act as biocompatible reductants. Chlorella spp. and Sargassum spp. have been extensively explored for the synthesis of nanoparticles having antimicrobial properties, which can potentially substitute conventional antibiotics. Characterization of nanoparticles (NPs) synthesised from algae has been done using advanced spectroscopic, diffractographic and microscopic techniques such as UV-Vis FT-IR, DLS, XPS, XRD, SEM, TEM, AFM, HR-TEM, and EDAX. The present paper reviews the information available on algae-mediated biosynthesis of various NPs, their characterization and applications in different domains.

A Review of The Lesser-Studied Microemulsion-Based Synthesis Methodologies Used for Preparing Nanoparticle Systems of The Noble Metals, Os, Re, Ir and Rh

This review focuses on the recent advances in the lesser-studied microemulsion synthesis methodologies of the following noble metal colloid systems (i.e., Os, Re, Ir, and Rh) using either a normal or reverse micelle templating system. The aim is to demonstrate the utility and potential of using this microemulsion-based approach to synthesize these noble metal nanoparticle systems. Firstly, some fundamentals and important factors of the microemulsion synthesis methodology are introduced. Afterward, a review of the investigations on the microemulsion syntheses of Os, Re, Ir, and Rh nanoparticle (NP) systems (in all forms, viz., metallic, oxide, mixed-metal, and discrete molecular complexes) is presented for work published in the last ten years. The chosen noble metals are traditionally very reactive in nanosized dimensions and have a strong tendency to aggregate when prepared via other methods. Also, the particle size and particle size distribution of these colloids can have a significant impact on their catalytic performance. It is shown that the microemulsion approach has the capability to better stabilize these metal colloids and can control the size of the synthesized NPs. This generally leads to smaller particles and higher catalytic activity when they are tested in applications.

A review on anti-bacterials to combat resistance: From ancient era of plants and metals to present and future perspectives of green nano technological combinations

In the primitive era, humans benefited partially from plants and metals to treat microbial infections. Later these infections were cured with antibiotics but further suffered from resistance issues. In searching of an alternative, researchers developed an adjuvant therapy but were hampered by spreading resistance. Subsequently, nanoparticles (NPs) were proposed to cease the multi-drug resistant bacteria but were hindered due to toxicity issues. Recently, a novel adjuvant therapy employed metals and botanicals into innovative nanotechnology as nano-antibiotics. The combination of green synthesized metallic NPs with antibiotics seems to be a viable platform to combat against MDR bacteria by alleviating resistance and toxicity. This review focuses on the primitive to present era dealings with bacterial resistance mechanisms, newer innovations of nanotechnology and their multiple mechanisms to combat resistance. In addition, special focus is paid on greener NPs as antibiotic carriers, and their future prospects of controlled release and toxicity study.

Characterization of Nanoparticles: Advances

Over the past two decades, the unique properties of engineered nanoparticles (NPs) have placed them at the centre of revolutionary advancements in many sectors of science, technology and commerce. Multi-technique and multi-disciplinary analytical approaches are required to identify, quantify, and characterize the chemical composition, size and size distribution, surface properties and the number and concentration of NPs. In this chapter, an overview of the recent advances in the characterization of NPs will be presented.

Lipidomics reveals insights on the biological effects of copper oxide nanoparticles in a human colon carcinoma cell line

Engineered nanomaterials have unique properties compared to their bulk counterparts. Copper oxide nanoparticles (CuO NPs) are one example of nanomaterials used in a wide range of consumer products due to their conductivity and biocidal properties. While CuO NPs can induce toxicity in various organisms, their interactions with different organisms and how they affect cellular homeostasis is yet to be fully understood. In this work, the toxicity of CuO NPs was evaluated in different human cell lines (colorectal carcinoma, cervical cancer, embryonic kidney, and lung fibroblast), showing a dose-dependent toxicity. An untargeted lipidomics approach using liquid chromatography-quadrupole time of flight mass spectrometry was employed in a human colon carcinoma cell line to investigate the impact of CuO NP exposure at the cellular level. A 24 h CuO NP exposure at 2.5 and 5 μg mL-1 resulted in upregulation of different metabolites: triacylglycerols, phosphatidylcholines, and ceramides accumulated. The most profound increase in a dose-dependent manner was observed in ceramides, specifically in C18:0, C18:1, and C22:0 species, with up to ∼10 fold accumulations. Further experiments suggested that activation of autophagy and oxidative stress could be responsible for the toxicity observed in these cell lines. Increases in the level of glutathione oxide (∼7 fold) also supported the activation of oxidative stress upon CuO NP treatment. Based on the changes in different metabolites induced by CuO NP exposure and previous studies from our laboratory, we propose that autophagy and oxidative stress could play a role in CuO NP-induced toxicity.

Novel therapeutic approaches for targeting TB and HIV reservoirs prevailing in lungs

INTRODUCTION

Coinfection with Mycobacterium tuberculosis is the leading cause of death in HIV positive patients. In 2017, about 0.3 million HIV positive people died of tuberculosis. There is high load of mycobacteria and HIV in the lungs and eradication of the same is vital for patient survival.

AREAS COVERED

This review focuses on the pathogenesis of HIV-TB coinfection and the current management approaches of this coinfection. It presents a detailed discussion of current investigations in novel drug delivery systems for effective targeting of HIV-TB lung reservoirs, especially via pulmonary drug delivery. Additionally, emphasis is given to the need of HIV-TB cotargeting, an unmet need in management of HIV-TB coinfection.

EXPERT OPINION

To achieve the goal of complete eradication of HIV-TB reservoirs in lungs requires focused research strategies to be undertaken in the area of pulmonary delivery systems. These endeavors could eventually lead to better patient compliance and improved treatment outcomes. The treatment regimen of HIV-TB coinfection is associated with a major drawback of low therapeutic concentration of drugs in lungs. Nanotechnology provides an excellent platform for delivery of anti-TB and anti-HIV drugs via the pulmonary route thereby serving as a viable and effective means of managing the mycobacterial and HIV reservoirs in the lungs.

Nickel oxide nanoparticles cause substantial physiological, phytochemical, and molecular-level changes in Chinese cabbage seedlings

Nickel oxide nanoparticles (NiO NPs) are utilized in various industries and their release into the environment may lead to the pollution of agricultural areas. However, assessing the toxicity of NiO NPs in major food crops is difficult due to the limited information available on their toxicity. The present investigation was carried out to evaluate how NiO NPs affect plant growth, photosynthetic efficiency, and phytochemical content, as well as changes at the transcriptional level of these phytochemicals in Chinese cabbage seedlings. Chlorophyll, carotenoid, and sugar contents were reduced, while proline and the anthocyanins were significantly upregulated in NiO NPs-treated seedlings. The levels of malondialdehyde, hydrogen peroxide, and reactive oxygen species, as well as peroxidase (POD) enzyme activity, were all enhanced in seedlings exposed to NiO NPs. The levels of glucosinolates and phenolic compounds were also significantly increased in NiO NPs-treated seedlings compared to control seedlings. The expression of genes related to oxidative stress (CAT, POD, and GST), MYB transcription factors (BrMYB28, BrMYB29, BrMYB34, and BrMYB51), and phenolic compounds (ANS, PAP1, and PAL) were significantly upregulated. We suggest that NiO NPs application stimulates toxic effects and enhances the levels of phytochemicals (glucosinolates and phenolic compounds) in Chinese cabbage seedlings.

Preparation of Hydrogel/Silver Nanohybrids Mediated by Tunable-Size Silver Nanoparticles for Potential Antibacterial Applications

In this study, a versatile synthesis of silver nanoparticles of well-defined size by using hydrogels as a template and stabilizer of nanoparticle size is reported. The prepared hydrogels are based on polyvinyl alcohol and maleic acid as crosslinker agents. Three hydrogels with the same nature were synthesized, however, the crosslinking degree was varied. The silver nanoparticles were synthesized into each prepared hydrogel matrix achieving three significant, different-sized nanoparticles that were spherical in shape with a narrow size distribution. It is likely that the polymer network stabilized the nanoparticles. It was determined that the hydrogel network structure can control the size and shape of the nanoparticles. The hydrogel/silver nanohybrids were characterized by swelling degree, Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscope (TEM). Antibacterial activity against Staphylococcus aureus was evaluated, confirming antimicrobial action of the encapsulated silver nanoparticles into the hydrogels.

Remote Magnetic Control of Autophagy in Mouse B-Lymphoma Cells with Iron Oxide Nanoparticles

Autophagy is the spontaneous degradation of intracellular proteins and organelles in response to nutrient deprivation. The phagocytosis of iron oxide nanoparticles (IONPs) results in intracellular degradation that can be exploited for use in cancer treatment. Non-invasive magnetic control has emerged as an important technology, with breakthroughs achieved in areas such as magneto-thermal therapy and drug delivery. This study aimed to regulate autophagy in mouse B-lymphoma cells (A20) through the incorporation of IONPs-quantum dots (QDs). We hypothesized that with the application of an external magnetic field after phagocytosis of IONPs-QDs, autophagy of intracellular IONPs-QDs could be regulated in a non-invasive manner and subsequently modulate the regulation of inflammatory responses. The potential of this approach as a cancer treatment method was explored. The application of IONPs and an external magnetic force enabled the non-invasive regulation of cell autophagy and modulation of the self-regulatory function of cells. The combination of non-invasive magnetic fields and nanotechnology could provide a new approach to cancer treatment.

Systematic determination of the relationship between nanoparticle core diameter and toxicity for a series of structurally analogous gold nanoparticles in zebrafish

Predictive models for the impact of nanomaterials on biological systems remain elusive. Although there is agreement that physicochemical properties (particle diameter, shape, surface chemistry, and core material) influence toxicity, there are limited and often contradictory, data relating structure to toxicity, even for core diameter. Given the importance of size in determining nanoscale properties, we aimed to address this data gap by examining the biological effects of a defined series of gold nanoparticles (AuNPs) on zebrafish embryos. Five AuNPs samples with narrowly spaced core diameters (0.8-5.8 nm) were synthesized and functionalized with positively charged N,N,N-trimethylammonium ethanethiol (TMAT) ligands. We assessed the bioactivity of these NPs in a high-throughput developmental zebrafish assay at eight concentrations (0.5-50 µg/mL) and observed core diameter-dependent bioactivity. The smaller diameter AuNPs were the most toxic when expressing exposures based on an equal mass. However, when expressing exposures based on total surface area, toxicity was independent of the core diameter. When holding the number of nanoparticles per volume constant (at 6.71 × 10¹³/mL) in the exposure medium across AuNPs diameters, only the 5.8 nm AuNPs exhibited toxic effects. Under these exposure conditions, the uptake of AuNPs in zebrafish was only weakly associated with core diameter, suggesting that differential uptake of TMAT-AuNPs was not responsible for toxicity associated with the 5.8 nm core diameter. Our results indicate that larger NPs may be the most toxic on a per particle basis and highlight the importance of using particle number and surface area, in addition to mass, when evaluating the size-dependent bioactivity of NPs.

Exploring the potential of environment friendly silver nanoparticles for DNA interaction: Physicochemical approach

Nanosilver, being the most prominent nanoproduct has diverse bio-medical applications and hence the effects associated with their exposure need to be investigated in detail. The interaction of metal nanoparticles with DNA has become a matter of interest, as their effect on structural integrity, synthesis and replication could be explored through it. Present work aims at the facile synthesis and characterization of spherical silver nanoparticles (AgNPs) using Epipremnum aureum leaves extract. Nanoparticles were characterized using UV-Visible spectroscopy, Transmission Electron Microscopy (TEM), High Resolution X-ray Diffraction (HR-XRD) and Dynamic Light Scattering (DLS) studies. The interaction of AgNPs with Calf thymus DNA (CT-DNA) was investigated using different spectroscopic techniques like UV-Visible spectroscopy, UV-thermal melting, Circular Dichroism and fluorescence spectroscopic studies. Fluorescence results suggest van der Waals and H-bonding interactions, which are predominantly responsible for the interaction of AgNPs with CT-DNA. Circular dichroism and thermal melting studies are pointing towards the groove binding of AgNPs to CT-DNA. DNA duplex destabilization was confirmed by the decreased thermal melting temperature of CT-DNA on addition of AgNPs. Present study might open up new vistas for the study of unusual kind of DNA binders, which can destabilize DNA and may further be used for various biomedical applications.

Radio-sensitization efficacy of gold nanoparticles in inhalational nanomedicine and the adverse effect of nano-detachment due to coating inactivation

Gold nanoparticles (GNPs) are an emerging area of interest in radiation therapy due to their unique radio-sensitizing properties. In the literature, the enhancing capability of GNPs is usually quantified using the metric dose enhancement ratio (DER). Traditionally, the focus of the vast majority of studies has always been on intravenous administration of GNPs. However, recent work showed the potential of using GNP inhalation, rather than intravenous injection, to enhance the dose to the lung. Yet, some of these studies are employing simplistic analytical methods to calculate DER and, thus far, there are no detailed computations of the enhancement profiles therein. Moreover, the coating on the GNP surface can be adversely affected by the large gradient of the radiation dose in the immediate vicinity of GNPs, leading to the rupture of ligands and detachment of GNPs from the surface of the membrane, and hence the loss of its efficacy. In this study, a next-generation deterministic code was used to resolve the DER profile at the interface between the septum, air, and surface of GNPs when they are attached and detached. The results show that the large values of DER in conjunction with the developed hot spots are very effective in lung treatment; on the other hand, coating rupture can lead to significant reduction in DER that may reach 64%. Thus, GNPs can be beneficial in inhalational medicine to treat lung cancer, provided that more comprehensive studies on the characteristics of the coating are addressed to maximize the radio-therapeutic benefit of GNPs.

Rare-Earth-Doped Calcium Carbonate Exposed to X-ray Irradiation to Induce Reactive Oxygen Species for Tumor Treatment

Conventional photodynamic therapy (PDT) is limited by its penetration depth due to the photosensitizer and light source. In this study, we developed X-ray induced photodynamic therapy that applied X-ray as the light source to activate Ce-doped CaCO₃ (CaCO₃:Ce) to generate an intracellular reactive oxygen species (ROS) for killing cancer cells. The A549 cell line was used as the in vitro and in vivo model to evaluate the efficacy of X-ray-induced CaCO₃:Ce. The cell viability significantly decreased and cell cytotoxicity obviously increased with CaCO₃:Ce exposure under X-ray irradiation, which is less harmful than radiotherapy in tumor treatment. CaCO₃:Ce produced significant ROS under X-ray irradiation and promoted A549 cancer cell death. CaCO₃:Ce can enhance the efficacy of X-ray induced PDT, and tumor growth was inhibited in vivo. The blood analysis and hematoxylin and eosin stain (H & E) stain fully supported the safety of the treatment. The mechanisms underlying ROS and CO₂ generation by CaCO₃:Ce activated by X-ray irradiation to induce cell toxicity, thereby inhibiting tumor growth, is discussed. These findings and advances are of great importance in providing a novel therapeutic approach as an alternative tumor treatment.

Nanolubricants dispersed with graphene and its derivatives: an assessment and review of the tribological performance

Graphene, being a path-breaking discovery of this millennium, has become one of the most researched materials lately. Recently, researchers have been exploring the possibilities of utilizing graphene as a dispersoid in a nanolubricant (a stable colloidal suspension of nanoparticles in conventional lubricant). This state-of-the-art review presents an overview of recent developments that have taken place regarding the tribological performance of different types of nanolubricants dispersed with graphene and its derivatives. The derivatives of graphene include surface functionalized graphene, graphene decorated with nanoparticles and composites of graphene with other nanomaterials. The authors have thoroughly assessed the tribological performance of graphene nanolubricants which exhibit improved tribological performances in comparison to existing lubricants. The most important parameters which affect friction characteristics of interacting solid surfaces under the influence of graphene nanolubricants are concentration of the dispersoid, number of layers of graphene nanosheets, dispersion stability and the lubrication conditions. The effects of different parameters and underlying mechanisms explaining the superior performance of these nanolubricants are thoroughly surveyed in this article. The authors also explored various domains of applications in which graphene nanolubricants, having improved tribological performance, are potential candidates for future applications.

Advances of nanosystems containing cyclodextrins and their applications in pharmaceuticals

For many years, researchers have worked with supramolecular structures involving inclusion complexes with cyclodextrins. These studies have resulted in new commercially available drugs which have been of great benefit. More recently, studies using nanoparticles, including nanosystems containing cyclodextrins, have become a focus of academic research due to the versatility of the systems and their remarkable therapeutic potential. This review focuses on studies published between 2002 and 2018 involving nanosystems containing cyclodextrins. We consider the type of nanosystems, their importance in a health context, the physicochemical techniques used to show the quality of these systems and their potential for the development of novel pharmaceutical formulations. These have been developed in recent studies which have mainly been focusing on basic science with no clinical trials as yet being performed. This is important to note because it means that the studies do not include any toxicity tests. Despite this limitation, the characterization assays performed suggest that these new formulations may have therapeutic potential. However, more research is required to assess the efficacy and safety of these nanosystems.

Development of multifunctional modified cotton fabric with tri-component nanoparticles of silver, copper and zinc oxide

A facile method, cost-effective and highly efficient with shortened-time operation was devised for unprecedented modification of cotton fabrics. This modification induced the formation of metallic and metal oxide nanoparticles within cotton fabrics in such a way that cotton samples loaded with AgNPs- or AgNPs/ZnONPs or AgNPs/ZnONPs/CuNPs respectively. Presence of the trimetallic nanoparticles concomitantly within microstructural features of cotton imparts durable antibacterial, UV protection and conductivity properties to yield ultimately cotton fabrics with multifunctional performance. The nanoparticles were formed and stabilized independently by Polymethylol compound (PMC) and functionalized polyethyleneimine (FPEI) as per one bath. The results obtained proved that the solution of these metal compounds are turned from colourless to yellow and black green colour up on addition of PMC or FPEI compound. It was found that UV-vis spectra display maximum surface plasmon peak of around 410-415 confirming the successful synthesis of AgNPs stabilized by PMC or FPEI chains. In addition, the results obtained indicated that the as formed nanoparticles are successfully deposited into the surface of cellulose fabrics and reveal changes in crystalline structure. Fabrics underwent structural changes during their treatments as per the designed practice exhibit multifunctional properties and manifold performance. The resultant treated cotton fabric gives good antibacterial properties event after 20 washing cycles additionally to the excellent ultra-violet properties and excellent electrical conductivity.

Review of Current Strategies for Delivering Alzheimer's Disease Drugs across the Blood-Brain Barrier

Effective therapy for Alzheimer’s disease is a major challenge in the pharmaceutical sciences. There are six FDA approved drugs (e.g., donepezil, memantine) that show some effectiveness; however, they only relieve symptoms. Two factors hamper research. First, the cause of Alzheimer’s disease is not fully understood. Second, the blood-brain barrier restricts drug efficacy. This review summarized current knowledge relevant to both of these factors. First, we reviewed the pathophysiology of Alzheimer’s disease. Next, we reviewed the structural and biological properties of the blood-brain barrier. We then described the most promising drug delivery systems that have been developed in recent years; these include polymeric nanoparticles, liposomes, metallic nanoparticles and cyclodextrins. Overall, we aim to provide ideas and clues to design effective drug delivery systems for penetrating the blood-brain barrier to treat Alzheimer’s disease.

Importance of Theranostics in Rare Brain-Eating Amoebae Infections

Pathogenic free-living amoebae including Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri cause infections of the central nervous system (CNS), which almost always prove fatal. The mortality rate is high with the CNS infections caused by these microbes despite modern developments in healthcare and antimicrobial chemotherapy. The low awareness, delayed diagnosis, and lack of effective drugs are major hurdles to overcome these challenges. Nanomaterials have emerged as vital tools for concurrent diagnosis and therapy, which are commonly referred to as theranostics. Nanomaterials offer highly sensitive diagnostic systems and viable therapeutic effects as a single modality. There has been good progress to develop nanomaterials based efficient theranostic systems against numerous kinds of tumors, but this field is yet immature in the context of infectious diseases, particularly parasitic infections. Herein, we describe the potential value of theranostic applications of nanomaterials against brain infections due to pathogenic amoebae.

Zingerone Nanotetramer Strengthened the Polypharmacological Efficacy of Zingerone on Human Hepatoma Cell Lines

We base this study on the concept of drug repositioning to reconstitute the natural product of zingerone as zingerone nanoparticles (zingerone NPs) through a one-pot synthesized process. The as-fabricated zingerone NPs were characterized; they possessed a particle size of 1.42 ± 0.67 nm and a reconstituted structure of zingerone nanotetramer. We further validate the effects of zingerone NPs on the antitumor activity and investigate the relative underlying mechanisms on the human hepatoma SK-Hep-1 and Huh7 cell lines. Our results demonstrated that zingerone NPs significantly inhibit Akt activity and NFκB expression as well as activate the caspases cascade signaling pathway which are involved in the antiproliferation, antitumorigenicity, disturbing cell cycle progression, and induction of DNA damage as well as cell apoptosis. These findings were promising to provide a "Nano-chemoprevention" strategy in future cancer therapeutics and medical and clinical applications.

Superparamagnetic nanoarchitectures for disease-specific biomarker detection

Synthesis, bio-functionalization, and multifunctional activities of superparamagnetic-nanostructures have been extensively reviewed with a particular emphasis on their uses in a range of disease-specific biomarker detection and associated challenges.

Ultrasonic assisted fabrication of first MoO3/copper complex bio-nanocomposite based on Sesbania sesban plant for green oxidation of alcohols

MoO₃ nanoparticles were obtained using Sesbania sesban. Novel Schiff base ligand and its nanocomplex of copper were synthesized under ultrasonic irradiation. First MoO₃/Copper Schiff base complex nanocomposite (NMCS) based on this natural plant was prepared and characterized by TEM, SEM, AFM, FT-IR, TGA, EDAX and elemental analysis. Then atom-efficient and selective oxidation of alcohols using hydrogen peroxide catalyzed by NMCS bio-nanocomposite under ultrasonic irradiation was reported. Structurally diverse set of alcohols was transformed into desired aldehyde and ketone products with high conversion and excellent selectivity under solvent free conditions. Products were isolated easily from green media, and the catalyst could be reused six times without any appreciable decrease in catalytic activity and selectivity.

Herbonanoceuticals: A Novel Beginning in Drug Discovery and Therapeutics

The Indian pharmaceutical industry is the world’s second largest industry (by volume) that develops products and market drugs licensed for use as medications. Medicines manufactured in the modern era are associated with major controversies such as non–target specificity, resistance, repeated administration, immune rejection, and other adverse effects on the body. Thus, there is a great need to find drugs that do not raise the aforementioned issues. Nature is an excellent hub providing a diverse range of phytoconstituents that open the way to phototherapeutics, which need a scientific path to deliver the active elements in a supported way to increase patient compliance and reduce the need for repeated administration. To discover a novel phytochemical as a lead compound for a therapeutic purpose is a real challenge. In former times, drug discovery was a complex process, as it took several years to find a lead compound for use against a particular disease. Nowadays, however, virtual screening methods have been developed, which are target specific, time consuming, and cost effective. To avoid increased and repeated administration of a drug, nanosized drug delivery systems for herbal drugs have been developed to enhance the activity and overcome problems associated with synthetic medicines. This review summarizes three main fields: drug discovery, docking for drug design, and last—but not least—drug delivery systems. Nowadays, nanobased drug delivery systems are in demand for delivery of herbal medicines used for therapeutic purposes. Herbonanoceuticals—herbal drugs of a nanosize—have better remedial value and fewer detrimental effects than modern medicines. Therefore, herbonanoceuticals can be a boon in the field of therapeutics.

Biosynthesis of Metal Nanoparticles via Microbial Enzymes: A Mechanistic Approach

During the last decade, metal nanoparticles (MtNPs) have gained immense popularity due to their characteristic physicochemical properties, as well as containing antimicrobial, anti-cancer, catalyzing, optical, electronic and magnetic properties. Primarily, these MtNPs have been synthesized through different physical and chemical methods. However, these conventional methods have various drawbacks, such as high energy consumption, high cost and the involvement of toxic chemical substances. Microbial flora has provided an alternative platform for the biological synthesis of MtNPs in an eco-friendly and cost effective way. In this article we have focused on various microorganisms used for the synthesis of different MtNPs. We also have elaborated on the intracellular and extracellular mechanisms of MtNP synthesis in microorganisms, and have highlighted their advantages along with their challenges. Moreover, due to several advantages over chemically synthesized nanoparticles, the microbial MtNPs, with their exclusive and dynamic characteristics, can be used in different sectors like the agriculture, medicine, cosmetics and biotechnology industries in the near future.

Reduction of Gold (III) and Tellurium (IV) by Enterobacter cloacae MF01 Results in Nanostructure Formation Both in Aerobic and Anaerobic Conditions

Microorganism survival in the presence of toxic substances such as metal(loid)s lies chiefly on their ability to resist (or tolerate) such elements through specific resistance mechanisms. Among them, toxicant reduction has attracted the attention of researchers because metal(loid)-reducing bacteria are being used to recover and/or decontaminate polluted sites. Particularly, our interest is to analyze the toxicity of gold and tellurium compounds for the environmental microorganism Enterobacter cloacae MF01 and also to explore the generation of nanostructures to be used in future biotechnological processes. Resistance of E. cloacae MF01 to gold and tellurium salts as well as the putative mechanisms involved -both in aerobic and anaerobic growth conditions- was evaluated. These metal(loid)s were selected because of their potential application in biotechnology. Resistance to auric tetrachloride acid (HAuCl₄) and potassium tellurite (K₂TeO₃) was assessed by determining areas of growth inhibition, minimum inhibitory concentrations, and growth curves as well as by viability tests. E. cloacae MF01 exhibited higher resistance to HAuCl₄ and K₂TeO₃ under aerobic and anaerobic conditions, respectively. In general, their toxicity is mediated by the generation of reactive oxygen species and by a decrease of intracellular reduced thiols (RSH). To assess if resistance implies toxicant reduction, intra- and extra-cellular toxicant-reducing activities were evaluated. While E. cloacae MF01 exhibited intra- and extra-cellular HAuCl₄-reducing activity, tellurite reduction was observed only intracellularly. Then, Au- and Te-containing nanostructures (AuNS and TeNS, respectively) were synthesized using crude extracts from E. cloacae MF01 and their size, morphology, and chemical composition was evaluated.

Transferrin receptors-targeting nanocarriers for efficient targeted delivery and transcytosis of drugs into the brain tumors: a review of recent advancements and emerging trends

Treatment of glioblastoma multiforme (GBM) is a predominant challenge in chemotherapy due to the existence of blood-brain barrier (BBB) which restricts delivery of chemotherapeutic agents to the brain together with the problem of drug penetration through hard parenchyma of the GBM. With the structural and mechanistic elucidation of the BBB under both physiological and pathological conditions, it is now viable to target central nervous system (CNS) disorders utilizing the presence of transferrin (Tf) receptors (TfRs). However, overexpression of these TfRs on the GBM cell surface can also help to avoid restrictions of GBM cells to deliver chemotherapeutic agents within the tumor. Therefore, targeting of TfR-mediated delivery could counteract drug delivery issues in GBM and create a delivery system that could cross the BBB effectively to utilize ligand-conjugated drug complexes through receptor-mediated transcytosis. Hence, approach towards successful delivery of antitumor agents to the gliomas has been making possible through targeting these overexpressed TfRs within the CNS and glioma cells. This review article presents a thorough analysis of current understanding on Tf-conjugated nanocarriers as efficient drug delivery system.

Evaluating nanomedicine with microfluidics

Nanomedicines are engineered nanoscale structures that have an extensive range of application in the diagnosis and therapy of many diseases. Despite the rapid progress in and tremendous potential of nanomedicines, their clinical translational process is still slow, owing to the difficulty in understanding, evaluating, and predicting their behavior in complex living organisms. Microfluidic techniques offer a promising way to resolve these challenges. Carefully designed microfluidic chips enable in vivo microenvironment simulation and high-throughput analysis, thus providing robust platforms for nanomedicine evaluation. Here, we summarize the recent developments and achievements in microfluidic methods for nanomedicine evaluation, categorized into four sections based on their target systems: single cell, multicellular system, organ, and organism levels. Finally, we provide our perspectives on the challenges and future directions of microfluidics-based nanomedicine evaluation.

Impact of Nanoparticles on Brain Health: An Up to Date Overview

Nanoparticles are zero-dimensional nanomaterials and, based on their nature, they can be categorized into organic, inorganic, and composites nanoparticles. Due to their unique physical and chemical properties, nanoparticles are extensively used in a variety of fields, including medicine, pharmaceutics, and food industry. Although they have the potential to improve the diagnosis and treatment of brain diseases, it is fundamentally important to develop standardized toxicological studies, which can prevent the induction of neurotoxic effects. The focus of this review is to emphasize both the beneficial and negative effects of nanoparticles on brain health.