Nanotoxicity in Systemic Circulation and Wound Healing

Construction and Performance Study of a Dual-Network Hydrogel Dressing Mimicking Skin Pore Drainage for Photothermal Exudate Removal and On-Demand Dissolution

In recent years, negative pressure wound dressings have garnered widespread attentions. However, it is challenging to drain the accumulated fluid under negative pressures for hydrogel dressings. To address this issue, this study prepared a chemical/physical duel-network PEG-CMCS/AG/MXene hydrogel composed by chemical disulfide crosslinked network of four-arm polyethylene glycol/carboxymethyl chitosan (4-Arm-PEG-SH/CMCS), and the physical network of hydrogen bond of agar (AG). Under near-infrared light (NIR) irradiation, the PEG-CMCS/AG/MXene hydrogel undergoes photothermal heating due to integrate of MXene, which destructs the hydrogen bond network and allows the removal of exudate through a mechanism mimicking the sweat gland-like effect of skin pores. The photothermal heating effect also enables the antimicrobial activity to prevent wound infections. The excellent electrical conductivity of PEG-CMCS/AG/MXene can promote cell proliferation under the external electrical stimulation (ES) in vitro. The animal experiments of full-thickness skin defect model further demonstrate its ability to accelerate wound healing. The conversion between thioester and thiol achieved with L-cysteine methyl ester hydrochloride (L-CME) can provides the on-demand dissolution of the dressing in situ. This study holds promises to provide a novel solution to the issue of fluid accumulations under hydrogel dressings and offers new approaches to alleviating or avoiding the significant secondary injuries caused by frequent dressing changes.

Diabetic wound healing function of PCL/cellulose acetate nanofiber engineered with chitosan/cerium oxide nanoparticles

The use of cerium oxide nanoparticles (CeO2NPs) in diabetic wound repair substances has shown promising results. Therefore, the study was conducted to introduce a novel nano-based wound dressing containing chitosan nanoparticles encapsulated with green synthesized cerium oxide nanoparticles using Thymus vulgaris extract (CeO2-CSNPs). The physical properties and structure of the nanoparticles were analyzed using XRD, DLS, FESEM and FTIR techniques. The electrospun PCL/cellulose acetate-based nanofiber was prepared and CeO2-CSNPs were integrated on the PCL/CA membrane by electrospraying. The physicochemical properties, morphology and biological characteristics of the electrospun nanocomposite were evaluated. The results showed that the nanocomposite with 0.1 % CeO2-CSNPs exhibited high antibacterial performance against S. aureus (<58.59 µg/mL). The PCL/CA/CeO2-CSNPs nanofiber showed significant antioxidant activity up to 89.59 %, cell viability improvement, and cell migration promotion up to 90.3 % after 48 h. The in vivo diabetic wound healing experiment revealed that PCL/CA/CeO2-CSNPs nanofibers can significantly increase the repair rate of diabetic wounds by up to 95.47 % after 15 days. The results of this research suggest that PCL/CA nanofiber mats functionalized with CeO2-CSNPs have the potential to be highly effective in treating diabetes-related wounds.

Electrospun Nanofiber Scaffolds Loaded with Metal-Based Nanoparticles for Wound Healing

Failures of wound healing have been a focus of research worldwide. With the continuous development of materials science, electrospun nanofiber scaffolds loaded with metal-based nanoparticles provide new ideas and methods for research into new tissue engineering materials due to their excellent antibacterial, anti-inflammatory, and wound healing abilities. In this review, the stages of extracellular matrix and wound healing, electrospun nanofiber scaffolds, metal-based nanoparticles, and metal-based nanoparticles supported by electrospun nanofiber scaffolds are reviewed, and their characteristics and applications are introduced. We discuss in detail the current research on wound healing of metal-based nanoparticles and electrospun nanofiber scaffolds loaded with metal-based nanoparticles, and we highlight the potential mechanisms and promising applications of these scaffolds for promoting wound healing.

Bandage modified with antibacterial films of quaternized chitosan & sodium carboxymethyl cellulose microgels/baicalein nanoparticles for accelerating infected wound healing

Wound dressings capable of sterilizing pathogenic bacteria and scavenging free radicals are important to inhibit bacterial invasion and accelerate wound healing. The target of this work is to develop an antibacterial dressing by modifying bandages with films composed of biological macromolecule microgels and baicalein@tannic acid (Bai@TA) nanoparticles (NPs). Firstly, hydrophobic Bai was made into water soluble Bai@TA NPs using a solvent exchange method with TA as stabilizer. Polymeric microgels of sodium carboxymethyl cellulose (CMC)&hydroxypropyltrimethyl ammonium chloride chitosan (HACC) were then prepared by a simple blending method. Further, CMC&HACC/Bai@TA multilayer films were deposited on medical bandages by using a layer-by-layer assembly technique to obtain an antibacterial dressing. The as-prepared dressings showed great antibacterial ability against E. coli, S. aureus and methicillin resistant Staphylococcus aureus (MRSA), excellent antioxidant activity and good biological safety. In addition, compared to conventional medical bandages, the dressings could efficaciously diminish inflammation in the wound, accelerate skin regeneration and functional restoration, and promote the in vivo healing speed of full-thickness skin wounds infected by MRSA. We believe that as a low-cost but effective wound dressing, the antibacterial bandage modified with CMC&HACC/Bai@TA films has potentials to replace traditional dressings in the clinical management of infected wounds.

Applications of drug delivery systems, organic, and inorganic nanomaterials in wound healing

The skin is known to be the largest organ in the human body, while also being exposed to environmental elements. This indicates that skin is highly susceptible to physical infliction, as well as damage resulting from medical conditions such as obesity and diabetes. The wound management costs in hospitals and clinics are expected to rise globally over the coming years, which provides pressure for more wound healing aids readily available in the market. Recently, nanomaterials have been gaining traction for their potential applications in various fields, including wound healing. Here, we discuss various inorganic nanoparticles such as silver, titanium dioxide, copper oxide, cerium oxide, MXenes, PLGA, PEG, and silica nanoparticles with their respective roles in improving wound healing progression. In addition, organic nanomaterials for wound healing such as collagen, chitosan, curcumin, dendrimers, graphene and its derivative graphene oxide were also further discussed. Various forms of nanoparticle drug delivery systems like nanohydrogels, nanoliposomes, nanofilms, and nanoemulsions were discussed in their function to deliver therapeutic agents to wound sites in a controlled manner.

Nanomaterial-Based Therapy for Wound Healing

Poor wound healing affects millions of people globally, resulting in increased mortality rates and associated expenses. The three major complications associated with wounds are: (i) the lack of an appropriate environment to enable the cell migration, proliferation, and angiogenesis; (ii) the microbial infection; (iii) unstable and protracted inflammation. Unfortunately, existing therapeutic methods have not solved these primary problems completely, and, thus, they have an inadequate medical accomplishment. Over the years, the integration of the remarkable properties of nanomaterials into wound healing has produced significant results. Nanomaterials can stimulate numerous cellular and molecular processes that aid in the wound microenvironment via antimicrobial, anti-inflammatory, and angiogenic effects, possibly changing the milieu from nonhealing to healing. The present article highlights the mechanism and pathophysiology of wound healing. Further, it discusses the current findings concerning the prospects and challenges of nanomaterial usage in the management of chronic wounds.

Hemolytic Response of Iron Oxide Magnetic Nanoparticles at the Interface and in Bulk: Extraction of Blood Cells by Magnetic Nanoparticles

Surface-active and water-soluble magnetic nanoparticles (NPs) were synthesized in the presence of a series of amphiphilic molecules of different functional groups to determine the hemolytic response and their ability to extract blood cells across the interface and aqueous bulk while maintaining minimum hemolysis. Amphiphilic molecules such as Gemini surfactants of strong hydrophobicity and low hydrophilic-lipophilic balance produced surface-active magnetic NPs, which were highly cytotoxic even when placed at the blood suspension (aqueous)-air interface. A similar behavior was shown by water-soluble magnetic NPs produced using monomeric ionic and nonionic surfactants and different amino acids. The NPs produced using mild biological surfactants and mono- and oligosaccharides of the same functional group proved to be excellent blood cell extractors with minimum hemolysis. α/β-cyclodextrin and dextrose-stabilized magnetic NPs induced negligible hemolysis and extracted more than 50% of blood cells. The results showed that nontoxic magnetic NPs are excellent blood cell extractors from the blood suspension when tagged with amphiphilic molecules possessing good biocompatibility with cell membranes without inducing hemolysis. The work highlights the biological applicability of nontoxic magnetic NPs at biointerfaces and in blood suspensions.

Extraction of Bionanomaterials from the Aqueous Bulk by Using Surface Active and Water-Soluble Magnetic Nanoparticles

Surface active and water-soluble magnetic nanoparticles (NPs) were used to demonstrate the extraction of bionanomaterials from the aqueous bulk. Au NPs conjugated with different water-insoluble and water-soluble proteins were used as model bionanomaterials. UV-visible studies, zeta potential, and microscopic analyses were performed to quantify the extraction. Sodium dodecyl sulfate and dimethylene bis(dodecyldimethylammonium bromide) (12-2-12) stabilized surface active magnetic NPs were fully capable of extracting Au NPs conjugated with predominantly hydrophobic proteins from the aqueous bulk when placed at the aqueous-air interface. However, they were poor in extracting Au NPs from the aqueous bulk which were coated with predominantly hydrophilic water-soluble protein. On the other hand, water-soluble dodecyldimethyl-3-ammonio-1-propanesulfonate stabilized magnetic NPs proved to be fully capable of extracting all kinds of Au NPs conjugated with either water-soluble or water-insoluble proteins. The results highlight the remarkable ability of magnetic NPs in the extraction of bionanomaterials when placed at either biointerfaces or in the aqueous bulk of biological systems.

Cerium oxide nanoparticle-loaded polyvinyl alcohol nanogels delivery for wound healing care systems on surgery

This study was designed to establish the composition of wound bandages based on Cerium nanoparticle (CeNP)-loaded polyvinyl alcohol (PVA) nanogels. The CeNP nanogel (Ce-nGel) was fabricated by the fructose-mediated reduction of Cerium oxide solutions within the PVA matrix. The influences of different experimental limitations on PVA nanogel formations were examined. The nanogel particle sizes were evaluated by transmission electron microscopy and determined to range from ∼10 to 50 nm. Additionally, glycerol was added to the Ce-nGels, and the resulting compositions (Ce-nGel-Glu) were coated on cotton fabrics to generate the wound bandaging composite. The cumulative drug release profile of the Cerium from the bandage was found to be ∼38% of the total loading after two days. Additionally, antibacterial efficacy was developed for Gam positive and negative microorganisms. Moreover, we examined in vivo healing of skin wounds formed in mouse models over 24 days. In contrast to the untreated wounds, rapid healing was perceived in the Ce-nGel-Glu-treated wound with less damage. These findings indicate that Ce-nGel-Glu-based bandaging materials could be a potential candidate for wound healing applications in the future.

Local anesthetic lidocaine-encapsulated polymyxin-chitosan nanoparticles delivery for wound healing: in vitro and in vivo tissue regeneration

In relieving local pains, lidocaine, one of ester-type local anesthetics, has been used. To develop the lidocaine membranes of enhanced local anesthetic effects, we have designed to establish the composition of wound dressings based on lidocaine chloride (LCH) (anesthetic drug)-loaded chitosan (CS)/polymyxin B sulfate (PMB). The LCH membranes (LCH-CS/PMB) was fabricated by the LCH oxide solutions within the CS/PMB matrix. The influences of different experimental limitations on CS/PMB membrane formations were examined. The double membrane particle sizes were evaluated by scanning electron microscopy (HR-SEM). Additionally, antibacterial efficacy was developed for gram-positive and negative microorganisms. Moreover, we examined in vivo healing of skin wounds formed in mouse models over 16 days. In contrast to the untreated wounds, rapid healing was perceived in the LCH-CS/PMB-treated wound with less damaging. These findings indicate that LCH-CS/PMB-based bandaging materials could be a potential innovative biomaterial for tissue repair and regeneration for wound healing applications in an animal model.

Silica/Protein and Silica/Polysaccharide Interactions and Their Contributions to the Functional Properties of Derived Hybrid Wound Dressing Hydrogels

Multifunctional and biocompatible hydrogels are on the focus of wound healing treatments. Protein and polysaccharides silica hybrids are interesting wound dressing alternatives. The objective of this review is to answer questions such as why silica for wound dressings reinforcement? What are the roles and contributions of silane precursors and silica on the functional properties of hydrogel wound dressings? The effects of tailoring the porous, morphological, and chemical characteristics of synthetic silicas on the bioactivity of hybrid wound dressings hydrogels are explored in the first part of the review. This is followed by a commented review of the mechanisms of silica/protein and silica/polysaccharide interactions and their impact on the barrier, scaffold, and delivery matrix functions of the derived hydrogels. Such information has important consequences for wound healing and paves the way to multidisciplinary researches on the production, processing, and biomedical application of this kind of hybrid materials.

"Plug and Play" Functionalized Erythrocyte Nanoplatform for Target Atherosclerosis Management

For atherosclerosis (AS) management, a therapeutic drug intervention is the most widely used strategy. However, there are some problems such as low location specificity, high intake, and side effects. Nanomedicine can prolong the half-life of drug solubilization, reduce toxic and side effects, and improve the distribution of drug objects. Herein, to overcome the challenges, an erythrocyte-based "plug and play" nanoplatform was developed by incorporating the vascular cell adhesion molecule-1 (VCAM-1) targeting and the acid stimulus responsibility. After the function moieties conjugated with DSPE-PEG, the targeting peptide and the acid-sensitive prodrug were conveniently integrated into red blood cells' surface for enhancing target AS drug delivery and controlling local drug release. As a proof of principle, a plug and play nanoplatform with targeted drug delivery and acid-control drug release is demonstrated, achieving a marked therapeutic effect for AS.

Nanomaterials applied in wound healing: Mechanisms, limitations and perspectives

Internal and external factors cause various types of wounds on the skin. Infections, nonhealing chronic wounds, and aesthetic and functional recovery all cause challenges for clinicians. The development of nanotechnology in biomedicine has brought many new materials, methods and therapeutic targets for the treatment of wounds, which are believed to have great prospects. In this work, the nanomaterials applied in different stages to promote wound healing and systematically expounded their mechanisms were reviewed. Then, the difficulties and defects of the present research and suggested methods for improvement were pointed out. Moreover, based on the current application status of nanomaterials in wound treatment, some new ideas for subsequent studies were proposed and the feasibility of intelligent healing by real-time monitoring, precision regulation, and signal transmission between electronic signals and human nerve signals in the future were discussed. This review will provide valuable directions and spark new thoughts for researchers.

Nanocarriers for Biomedicine: From Lipid Formulations to Inorganic and Hybrid Nanoparticles

Encapsulation of cargoes in nanocontainers is widely used in different fields to solve the problems of their solubility, homogeneity, stability, protection from unwanted chemical and biological destructive effects, and functional activity improvement. This approach is of special importance in biomedicine, since this makes it possible to reduce the limitations of drug delivery related to the toxicity and side effects of therapeutics, their low bioavailability and biocompatibility. This review highlights current progress in the use of lipid systems to deliver active substances to the human body. Various lipid compositions modified with amphiphilic open-chain and macrocyclic compounds, peptide molecules and alternative target ligands are discussed. Liposome modification also evolves by creating new hybrid structures consisting of organic and inorganic parts. Such nanohybrid platforms include cerasomes, which are considered as alternative nanocarriers allowing to reduce inherent limitations of lipid nanoparticles. Compositions based on mesoporous silica are beginning to acquire no less relevance due to their unique features, such as advanced porous properties, well-proven drug delivery efficiency and their versatility for creating highly efficient nanomaterials. The types of silica nanoparticles, their efficacy in biomedical applications and hybrid inorganic-polymer platforms are the subject of discussion in this review, with current challenges emphasized.

Carboxymethyl Cellulose, Pluronic, and Pullulan-Based Compositions Efficiently Enhance Antiadhesion and Tissue Regeneration Properties without Using Any Drug Molecules

Pharmacological-based treatment approaches have been used over time to prevent postlaparotomy adhesion. However, the rapid elimination of therapeutics from the peritoneum, and their unwanted side effects, easy flow from the wound site by gravity, and low therapeutic efficacy increase the urgent need for the next generation of antiadhesion agents. This article represents the development of biocompatible and biodegradable antiadhesion agents that consist of carboxymethyl cellulose (CMC) and pullulan with three different types of physical characteristics such as the solution type (ST), film type (FT), and thermosensitive type (TST). These antiadhesion agents that contain no drugs exhibit excellent physical characteristics and superior stability over 30 days in the operative sites without any toxicity and side effects that make the compositions strong candidates as novel antiadhesion agents. Also, the proposed samples reveal superior antiadhesion and tissue regeneration properties in Sprague-Dawley (SD) rats after surgery over Medicurtain. Medicurtain effectively prevented postlaparotomy adhesion in ∼42% of experimental animals, whereas ST 2.25-10, ST 2.5-5, ST 2.5-10, FT 20, and TST 1.5 were effective in 100% of animals. Thus, we believe these antiadhesion agents could be promising to reduce adhesion-related complications during and post-surgical operations and deserve consideration for further study for clinical purposes.

Avoiding Hemolytic Anemia by Understanding the Effect of the Molecular Architecture of Gemini Surfactants on Hemolysis

Hemolytic behavior of a series of different categories of Gemini surfactants was determined in their low concentration range. Cationic Gemini surfactants of different molecular architectures prove to be highly cytotoxic even at 0.1 mM. Anionic and amino acid-based Gemini surfactants were minimally cytotoxic, although their toxicity was concentration-dependent. With respect to monomeric surfactants of comparable hydrocarbon chain lengths, cationic Gemini surfactants were much more toxic than anionic Gemini surfactants. Incubation temperature was another important parameter that significantly drove the hemolysis irrespective of the molecular structure of the surfactant. Results indicated that the surface activity or liquid-blood cell membrane adsorption tendency of a surfactant molecule determined the degree of hemolytic anemia. Greater surface activity induced greater cytotoxicity, especially when the surfactant possessed a stronger ability to interact with the membrane proteins through hydrophilic interactions. That provided cationic Gemini surfactants a higher ability for hemolytic anemia because they were able to interact with an electronegative cell membrane with favorable interactions in comparison to anionic or amino acid-based Gemini surfactants. These findings are expected to help in designing surface-active drugs with a suitable molecular architecture that can avoid hemolytic anemia.

Graphene-Based Scaffolds for Regenerative Medicine

Leading-edge regenerative medicine can take advantage of improved knowledge of key roles played, both in stem cell fate determination and in cell growth/differentiation, by mechano-transduction and other physicochemical stimuli from the tissue environment. This prompted advanced nanomaterials research to provide tissue engineers with next-generation scaffolds consisting of smart nanocomposites and/or hydrogels with nanofillers, where balanced combinations of specific matrices and nanomaterials can mediate and finely tune such stimuli and cues. In this review, we focus on graphene-based nanomaterials as, in addition to modulating nanotopography, elastic modulus and viscoelastic features of the scaffold, they can also regulate its conductivity. This feature is crucial to the determination and differentiation of some cell lineages and is of special interest to neural regenerative medicine. Hereafter we depict relevant properties of such nanofillers, illustrate how problems related to their eventual cytotoxicity are solved via enhanced synthesis, purification and derivatization protocols, and finally provide examples of successful applications in regenerative medicine on a number of tissues.

Protein-Coated Aryl Modified Gold Nanoparticles for Cellular Uptake Study by Osteosarcoma Cancer Cells

Gold nanoparticles coated with proteins have shown extraordinary biocompatibility which advanced to several nanomedicine engineering applications. We synthesized protein-coated gold nanoparticles using green and chemical reduction routes for cellular uptake study. In the current work, we coated gold-aryl nanoparticles of the type AuNPs-C₆H₄-4-COOH with bovine serum albumin (BSA), collagen, zein, and lysozyme proteins. Both routes were carried out without phase-transfer catalysts or extraneous stabilizing agents. High crystallinity of the AuNPs synthesized by the green route can be seen in transmission electron microscopy images. Osteosarcoma cancer cells are malignant bone tumors with abnormal cellular functions. Studies using MG-63 cells will provide mechanistic suggestions on the details of the amplification in tumors. We studied the cellular uptake of the bioconjugates by MG-63 osteosarcoma cells using laser confocal fluorescence microscopy (LCFM) and flow cytometry. In the LCFM study, BSA-AuNPs were uptaken most efficiently of all protein-coated gold nanoparticles synthesized by the green route. Lysozyme-AuNPs synthesized by the chemical reduction method were mostly efficiently internalized by MG-63 cells among all AuNPs. Zein- and lysozyme-coated AuNPs, though of relatively small size, prepared by the green method were not efficiently uptaken by MG-63. The two nanoparticles are negatively charged, and zein is also a hydrophobic coat. The difference in hydrophobicity and charge might have affected the internalization. All of those coated nanoparticles that were efficiently uptaken can potentially be used as diagnostic and therapeutic agents for osteosarcoma.

Effect of Sintering Temperature of Bioactive Glass Nanoceramics on the Hemolytic Activity and Oxidative Stress Biomarkers in Erythrocytes

INTRODUCTION

The nature of the surface is critical in determining the biological activity of silica powders. A novel correlation between toxicity and surface properties of bioactive glass ceramics (BGCs) synthesized via the sol-gel method was attempted in this study.

METHODS

The behavior of BGCs after their attachment to the surface of red blood cells (RBCs) was evaluated and their toxic effects were determined based on hemolysis, membrane injury via anti-phosphotyrosine immunoblot of Band 3, lipid peroxidation, potential to generate reactive oxygen species, and antioxidant enzyme production. In particular, three BGCs were synthesized and treated at three sintering temperatures (T1 = 835 °C, T2 = 1000 °C and T3 = 1100 °C) to investigate possible relation between surface charge or structure and hemolytic potential.

RESULTS

Their toxicity based on hemolysis was dose dependent, while BGC-T2 had the best hemocompatibility in compare with the other BGCs.No BGCs in dosages lower than 0.125 mg/mL could damage erythrocytes. On the other hand, all BGCs promoted the production of reactive oxygen species in certain concentrations, with the BGC-T2 producing the lowest ROS and increasing the glutathione levels in RBCs protecting their damage.

CONCLUSIONS

The results suggest that various factors such as size, a probable different proportion of surface silanols, a balanced mechanism between calcium and magnesium cellular uptake or the different crystalline nature may have contributed to this finding; however, future research is needed to clarify the underlying mechanisms.

Green and cytocompatible carboxyl modified gold-lysozyme nanoantibacterial for combating multidrug-resistant superbugs

The dissemination of multi-drug resistant (MDR) superbugs in hospital environments, communities and food animals and the very dynamic bacterial mutation frequency require the development of prolonged therapeutic strategies to gain mastery over antibiotic resistance. A AuNP-lysozyme nanoantibacterial was fabricated by the conjugation of AuNPs-C6H4-4-COOH with lysozyme via green reduction of aryldiazonium gold(iii) salt [HOOC-4-C6H4N[triple bond, length as m-dash]N]AuCl4. Results from molecular docking calculations aimed at revealing the binding mode of benzoic acid with the lysozyme structure clearly showed the lowest energy conformation with benzoic acid bound in the deep buried hydrophobic cavity of the protein active site through strong hydrogen bonding and hydrophobic interactions, thus validating the experimental outcomes of the current study which also exhibited the binding of -COOH functional groups in the interior of the protein structure. The superiority of the lysozyme bioconjugate against superbugs was demonstrated by the enhanced and broadened lysozyme antibacterial activities of 98-99% against extended spectrum beta lactamase (ESBL) producing Escherichia coli and imipenem-resistant Pseudomonas aeruginosa clinical isolates and a selection of Gram-negative and Gram-positive standard ATCC strains. Selective toxicity against bacteria was confirmed by the high viability of HeLa and fibroblast cell lines and the outstanding hemocompatibility at the minimum bacterial inhibitory concentrations (MICs). Turbidimetric enzyme kinetic assay showed the enhancement of the lysozyme hydrolytic activity by gold nanoparticles on the Micrococcus lysodeikticus bacterial substrate. Using gel electrophoresis, the induced cell wall breakdown was confirmed by detecting the leaked-out bacterial genomic DNA. The integrity and morphology changes of the E. coli bacteria were investigated using a scanning electron microscope after one hour of contact with the lysozyme-gold bioconjugate. The antibacterial functionalities showed little or no damage to healthy human cells and can be applied to wound dressings and medical devices.

Impact of nanomaterials on ecosystems: Mechanistic aspects in vivo

Nanotechnologies are becoming increasingly popular in modern era of human development in every aspect of life. Their impact on our ecosystem in air, soil, and water is largely unknown because of the limited amount of information available, and hence, they require considerable attention. This account highlights the important routes of nanomaterials toxicity in air, soil, and water, their possible impact on the ecosystem and aquatic life. The mechanistic aspects have been focused on the size, shape, and surface modifications of nanomaterials. The preventive measures and future directions along with appropriate designs and implementation of nanotechnologies have been proposed so as to minimize the interactions of nanomaterials with terrestrial flora and aquatic life. Specifically, the focus largely remains on the toxicity of metallic nanoparticles such as gold (Au) and silver (Ag) because of their applications in diverse fields. The account lists some prominent mechanistic routes of nanotoxicity along with in vivo experimental results based on the fundamental understanding that how nanometallic surfaces interact with plant as well as animal biological systems. The appropriate modifications of the nanometallic surfaces with biocompatible molecules are considered to be the most effective preventive measures to reduce the nanotoxicity.

Role of Gluten in Surface Chemistry: Nanometallic Bioconjugation of Hard, Medium, and Soft Wheat Protein

Hard, medium, and soft wheat proteins, based on gluten content, were studied for their important roles in nanometallic surface chemistry. In situ synthesis of Au nanoparticles (NPs) was followed to determine the surface adsorption behavior of wheat protein based on the gluten contents. A greater amount of gluten contents facilitated the nucleation to produce Au NPs. X-ray photoelectron spectroscopy (XPS) surface analysis clearly showed the surface adsorption of protein on nanometallic surfaces which was almost equally prevalent for the hard, medium, and soft wheat proteins. Wheat protein conjugated NPs were highly susceptible to phase transfer from aqueous to organic phase that was entirely related to the amount of gluten contents. The presence of higher gluten content in hard wheat protein readily enabled the hard wheat protein conjugated NPs to move across the aqueous-organic interface followed by medium and soft wheat protein conjugated NPs. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS page) analysis allowed us to determine molar masses of nanometallic surface adsorbed protein fractions. Only two protein fractions of high molar masses (74 and 85 kDa) from SDS solubilized hard, medium, and soft wheat proteins preferred to adsorb on nanometallic surfaces out of more than 15 protein fractions of pure wheat protein. This made the surface adsorption of wheat protein highly selective and closely related to gluten content. Cetyltrimethylammonium bromide (CTAB) solubilized wheat protein conjugated NPs demonstrated their strong antimicrobial activities against both Gram negative and Gram positive bacteria making them suitable for their applications in food industry.

Silver nanomaterials in the natural environment: An overview of their biosynthesis and kinetic behavior

Silver nanomaterials (Ag NMs) are fabricated by many biological components in our environment. Recently, research on their biosynthesis and reactions has become a focus of attention. Due to the complexity of biological systems and samples, specific processes and mechanisms involving Ag NMs are difficult to identify and elucidate on the molecular and chemical-bond level. The microorganisms and composite components of plant extracts are of great interest in many biological syntheses. Although potential biomolecules have been shown to play essential roles in biological systems in Ag NM biosynthesis, the detailed mechanism of the electron transfer process and crucial molecules that control this reaction have only recently come into focus. The reactive behavior of the Ag NMs is of great significance for understanding their overall behavior and toxicity. Additionally, only limited knowledge is available about their kinetics. All reactions involve chemical bond formation, electron transfer, or electrostatic interactions. An overview is presented of the biosynthesis of Ag NMs based on molecular supports including a nitrate reductase/NADH oxidase-involved electron transfer reaction and their mechanisms in Ag⁺ reduction: quinol-mediated mechanism and superoxide-dependent mechanism, and molecular supports in plant extracts, is presented. The environmental reaction kinetics and mechanisms of the interactions of Ag NMs with substances are introduced based on the formation and classification of chemical bonds. The particle-particle reaction kinetics of Ag NMs in the environment are discussed to directly explain their stability and aggregation behavior. The toxicity of Ag NMs is also presented. In addition, future prospects are summarized. This review is the first to provide an insight into the mediating molecules and chemical bonds involved in the biosynthesis, kinetics, and mechanisms of action of Ag NMs.

Keto-Enol Tautomerism of Temperature and pH Sensitive Hydrated Curcumin Nanoparticles: Their Role as Nanoreactors and Compatibility with Blood Cells

In order to provide a solution for the poor aqueous solubility and poor bioavailability of curcumin, we present the synthesis and characteristic features of water-soluble curcumin hydrated nanoparticles (CNPs). They are stable and nearly monodisperse in the aqueous phase where the keto form of curcumin self-assembles into spherical CNPs, which are highly sensitive to temperature and pH variations. The CNPs are quite stable up to 40 °C and at neutral pH. A higher temperature range reduces their hydration and makes them unstable, thereby disintegrating them into smaller aggregates. Similarly, a higher pH converts the keto form of CNPs into the enol form by promoting their interparticle fusions driven by hydrogen bonding with a remarkable color change from yellow to bright orange-red which demonstrates their excellent photophysical behavior. The stable keto form CNPs are highly efficient nonreactors for the in situ synthesis of Au, Ag, and Pd NPs which are simultaneously entrapped in curcumin aggregates, thus promoting the metal NP carrying ability of curcumin aggregates. The CNPs also demonstrate their excellent dose-dependent biocompatibility with blood cells. A concentration range up to 5 mM of CNPs is quite safe for their applications in biological systems.

Biocompatibility, hemocompatibility and antimicrobial properties of xyloglucan-based hydrogel film for wound healing application

Crosslinked xyloglucan-poly(vinyl alcohol) based hydrogel films are interesting materials for wound healing applications. This work focuses on the hydrolytic degradation and consequent morphological modification of a XG-PVA film and on its interaction with cells, blood, bacteria. Biocompatibility of the film was assessed in vitro by investigating different aspects, such as cell viability, oxidative stress level, mitochondrial dysfunction and specific stress biomarkers. Partial adhesiveness was demonstrated by performing different attaching assays and phalloidin staining. Hemocompatibility of XG-PVA film after interaction with blood was evaluated by using a multi-parametric approach, including human Red Blood Cells (RBC) count, hemolytic response and platelets activation. Thrombin and fibrinogen concentrations were examined as marker of the coagulation cascade. After direct contact with human blood and peripheral blood mononuclear cells (PBMC), no evidence of cell defense response was observed. Antimicrobial activity of XG-PVA film was tested against Escherichia coli (E.coli). XG-PVA film promotes bacterial retentivity and provides mechanical protection against bacterial infiltration. After loading the film with ampicillin, an inhibitory E. coli growth zone was observed. All together these results indicate that the XG-PVA system is a promising material to be tested in vivo for wound healing applications.

Applications of rice protein in nanomaterials synthesis, nanocolloids of rice protein, and bioapplicability

Rice protein conjugated nanomaterials were synthesized and characterized by using anionic and cationic forms of rice protein. Both forms showed unique characteristic features when used in in situ reaction conditions for synthesizing the protein stabilized gold (Au) and silver (Ag) nanoparticles (NPs). Au NPs synthesis was highly facilitated than Ag NPs synthesis while the reverse was true when rice protein was simply used in the basic medium. Photophysical behavior clearly showed the contributions of both electrostatic and non-electrostatic interactions driving the rice protein surface adsorption on nanometallic surfaces. Rice protein conjugated NPs were easily transferred and extracted into the organic phase while the extraction process was related to the amount of protein coating. Under the controlled pH reaction conditions, rice protein - dye colored NPs were synthesized which were further characterized by the DLS and SDS Page analysis. Both rice protein conjugated Au/Ag NPs and rice protein NPs showed remarkable biocompatibility with blood cells. These NPs demonstrated their excellent ability to selectively extract protein fractions from complex biological fluid like serum. The results proposed significant applications of rice protein conjugated NPs in biological systems as well as bio-nanotechnology.