The effect of particle size on the cytotoxicity, inflammation, developmental toxicity and genotoxicity of silver nanoparticles

Advanced bioactive nanomaterials for biomedical applications

Bioactive materials are a kind of materials with unique bioactivities, which can change the cellular behaviors and elicit biological responses from living tissues. Bioactive materials came into the spotlight in the late 1960s when the researchers found that the materials such as bioglass could react with surrounding bone tissue for bone regeneration. In the following decades, advances in nanotechnology brought the new development opportunities to bioactive nanomaterials. Bioactive nanomaterials are not a simple miniaturization of macroscopic materials. They exhibit unique bioactivities due to their nanoscale size effect, high specific surface area, and precise nanostructure, which can significantly influence the interactions with biological systems. Nowadays, bioactive nanomaterials have represented an important and exciting area of research. Current and future applications ensure that bioactive nanomaterials have a high academic and clinical importance. This review summaries the recent advances in the field of bioactive nanomaterials, and evaluate the influence factors of bioactivities. Then, a range of bioactive nanomaterials and their potential biomedical applications are discussed. Furthermore, the limitations, challenges, and future opportunities of bioactive nanomaterials are also discussed.

Toxicological effects of silver nanoparticles and cadmium chloride in macrophage cell line (RAW 264.7): An in vitro approach

BACKGROUND

Silver nanoparticles (AgNP) are largely used in nanotechnological products, but the real risks for human and environment are still poorly understood if we consider the effects of mixtures of AgNP and environmental contaminants, such as non-essential metals.

METHODS

The aim of the present study was to investigate the cytotoxicity and toxicological interaction of AgNP (1-4 nm, 0.36 and 3.6 μg mL^-1) and cadmium (Cd, 1 and 10 μM) mixtures. The murine macrophage cell line RAW 264.7 was used as a model.

RESULTS

Effects were observed after a few hours (4 h) on reactive oxygen species (ROS) and became more pronounced after 24 h-exposure. Cell death occurred by apoptosis, and loss of cell viability (24 h-exposure) was preceded by increases of ROS levels and DNA repair foci, but not of NO levels. Co-exposure potentiated some effects (decrease of cell viability and increase of ROS and NO levels), indicating toxicological interaction.

CONCLUSION

These effects are important findings that must be better investigated, since the interaction of Cd with AgNP from nanoproducts may impair the function of macrophages and represent a health risk for humans.

Intracellular Exposure Dose-Associated Susceptibility of Steatotic Hepatocytes to Metallic Nanoparticles

Non-alcoholic fatty liver disease (NAFLD), mainly characterized by the accumulation of excess fat in hepatocytes, is the most prevalent liver disorder afflicting ~25% of adults worldwide. In vivo studies have shown that adult rodents with NAFLD were more sensitive to metallic nanoparticles (MNPs) than healthy MNPs. However, due to the complex interactions between various cell types in a fatty liver, it has become a major challenge to reveal the toxic effects of MNPs to specific types of liver cells such as steatotic hepatocytes. In this study, we reported the susceptibility of steatotic hepatocytes in cytotoxicity and the induction of oxidative stress to direct exposures to MNPs with different components (silver, ZrO₂, and TiO₂ NPs) and sizes (20-30 nm and 125 nm) in an oleic acid (OA) -induced steatotic HepG2 (sHepG2) cell model. Furthermore, the inhibitory potential of MNPs against the process of fatty acid oxidation (FAO) were obvious in sHepG2 cells, even at extremely low doses of 2 or 4 μg/mL, which was not observed in non-steatotic HepG2 (nHepG2) cells. Further experiments on the differential cell uptake of MNPs in nHepG2 and sHepG2 cells demonstrated that the susceptibility of steatotic hepatocytes to MNP exposures was in association with the higher cellular accumulation of MNPs. Overall, our study demonstrated that it is necessary and urgent to take the intracellular exposure dose into consideration when assessing the potential toxicity of environmentally exposed MNPs.

Green Synthesis of Gold and Iron Nanoparticles for Targeted Delivery: An In Vitro and In Vivo Study

Nanotechnology has vast applications in almost all fields of science and technology. The use of medicinal plants for the synthesis of metallic nanoparticles has gained much attention nowadays. In the current research work, six medicinal plants were used for the synthesis of gold nanoparticles (AuNPs) and iron nanoparticles (FeNPs). The synthesized nanoparticles were characterized by different techniques including UV-visible spectrophotometry, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Furthermore, the activities of green synthesized nanoparticles were screened in vitro using, for example, antibacterial, antioxidant, cytotoxic, and DNA protection assays. Both FeNPs and AuNPs had spherical shapes with an average size less than 50 nm and were found to have good antimicrobial and nontoxic effects. Furthermore, FeNPs from Ficus microcarpa demonstrated high drug loading efficiency (65%) as compared to an anti-inflammatory drug (diclofenac potassium, DFP). We also evaluated the drug delivery potential, as well as anti-inflammatory and anticoagulant properties, of nanoparticles in vivo. Interestingly, AuNPs of Syzygium cumini exhibited strong anti-inflammatory potential as compared to DFP and diclofenac-loaded FeNPs of Ficus microcarpa. The results suggest potential pharmacological applications of biogenic synthesized AuNPs and FeNPs which can be explored further. The study revealed that the green synthesized AuNPs and FeNPs provide a promising approach for the synthesis of drug-loaded nanoparticles and consequently in the field of targeted drug delivery.

Integrating Porphyrinic Metal-Organic Frameworks in Nanofibrous Carrier for Photodynamic Antimicrobial Application

The rise and spread of antimicrobial resistance is creating an ever greater challenge in wound management. Nanofibrous membranes (NFMs) incorporated with antibiotics have been widely used to remedy bacterial wound infections owing to their versatile features. However, misuse of antibiotics has resulted in drug resistance, and it remains a significant challenge to achieve both high antibacterial efficiency and without causing bacterial resistance. Here, the ‘MOF-first’ strategy was adopted, the porphyrinic metal-organic frameworks nanoparticles (PCN−224 NPs) were pre-synthesized first, and then the composite antibacterial PCN−224 NPs @ poly (ε-caprolactone) (PM) NFMs were fabricated via a facile co-electrospinning technology. This strategy allows large amounts of effective MOFs to be integrated into nanofibers to effectively eliminate bacteria without bacterial resistance and to realize a relatively fast production rate. Upon visible light (630 nm) irradiation for 30 min, the PM−25 NFMs have the best ¹O₂ generation performance, triggering remarkable photodynamic antibacterial effects against both S. aureus, MRSA, and E. coli bacteria with survival rates of 0.13%, 1.91%, and 2.06% respectively. Considering the photodynamic antibacterial performance of the composite nanofibrous membranes functionalized by porphyrinic MOFs, this simple approach may provide a feasible way to use MOF materials and biological materials to construct wound dressing with the versatility to serve as an antibacterial strategy in order to prevent bacterial resistance.

Genotoxic Potential of Nanoparticles: Structural and Functional Modifications in DNA

The rapid advancement of nanotechnology enhances the production of different nanoparticles that meet the demand of various fields like biomedical sciences, industrial, material sciences and biotechnology, etc. This technological development increases the chances of nanoparticles exposure to human beings, which can threaten their health. It is well known that various cellular processes (transcription, translation, and replication during cell proliferation, cell cycle, cell differentiation) in which genetic materials (DNA and RNA) are involved play a vital role to maintain any structural and functional modification into it. When nanoparticles come into the vicinity of the cellular system, chances of uptake become high due to their small size. This cellular uptake of nanoparticles enhances its interaction with DNA, leading to structural and functional modification (DNA damage/repair, DNA methylation) into the DNA. These modifications exhibit adverse effects on the cellular system, consequently showing its inadvertent effect on human health. Therefore, in the present study, an attempt has been made to elucidate the genotoxic mechanism of nanoparticles in the context of structural and functional modifications of DNA.

Engineering Bioactive Scaffolds for Skin Regeneration

Large skin wounds pose a major clinical challenge. Scarcity of donor site and postsurgical scarring contribute to the incomplete or partial loss of function and aesthetic concerns in skin wound patients. Currently, a wide variety of skin grafts are being applied in clinical settings. Scaffolds are used to overcome the issues related to the misaligned architecture of the repaired skin tissues. The current review summarizes the contribution of biomaterials to wound healing and skin regeneration and addresses the existing limitations in skin grafting. Then, the clinically approved biologic and synthetic skin substitutes are extensively reviewed. Next, the techniques for modification of skin grafts aiming for enhanced tissue regeneration are outlined, and a summary of different growth factor delivery systems using biomaterials is presented. Considering the significant progress in biomaterial science and manufacturing technologies, the idea of biomaterial-based skin grafts with the ability for scarless wound healing and reconstructing full skin organ is more achievable than ever.

Cyanobacteria as biochemical energy source for the synthesis of inorganic nanoparticles, mechanism and potential applications: a review

Green synthesis of nanoparticles (NPs) has gained great concern among researchers due to their unique properties, excellent applications and efficient route of synthesis. From the last decades, the number biologicals such as plants, fungus, bacteria, yeast, algae, and cyanobacteria and their products are using by various researchers for the synthesis of different NPs. However, the pillar of green chemistry keeps touching new heights to improve the performance. This review paper unveils almost recent cyanobacteria-assisted greener NP synthesis technique, characterization and application. The enormous potency of cyanobacteria in NP synthesis (silver, gold, copper, zinc, palladium, titanium, cadmium sulfide, and selenium) and significance of reducing enzymes were summarized. The extracellular and intracellular entity such as metabolites, enzyme, protein, pigments in cyanobacteria play a significant role in the conversion of metal ions to metal NPs with unique properties discussed briefly. The green synthesis of nanomaterials is valuable because of their cost-effective, nontoxic and eco-friendly prospects as well as the potential application metal NPs such as antibacterial, antifungal, anticancerous, catalytic, drug delivery, bioimaging, nanopesticide, nanofertilizer, sensing properties, etc. Therefore, in the present review, we have systematically discussed the mechanisms of synthesis and applications of cyanobacteria-assisted green synthesis of NPs.

Effects of nano metal oxide particles on activated sludge system: Stress and performance recovery mechanism

Nano metal oxide particles (NMOPs) are widely used in daily life because of their superior performance, and inevitably enter the sewage treatment system. Pollutants in sewage are adsorbed and degraded in wastewater treatment plants (WWTPs) depending on the microbial aggregates of activated sludge system to achieve sewage purification. NMOPs may cause ecotoxicity to the microbial community and metabolism due to their complex chemical behavior, resulting in a potential threat to the safe and steady operation of activated sludge system. It is of great significance to clarify the influencing mechanism of NMOPs on activated sludge system and reduce the risk of WWTPs. Herein, we first introduce the physicochemical behavior of six typical engineering NMOPs including ZnO, TiO₂, CuO, CeO₂, MgO, and MnO₂ in water environment, then highlight the principal mechanisms of NMOPs for activated sludge system. In particular, the performance recovery mechanisms of activated sludge systems in the presence of NMOPs and their future development trends are well documented and discussed extensively. This review can provide a theoretical guidance and technical support for predicting and evaluating the potential threat of NMOPs on activated sludge systems, and promoting the establishment of effective control strategies and performance recovery measures of biological wastewater treatment process under the stress of NMOPs.

Oxidation process of lead sulfide nanoparticle in the atmosphere or natural water and influence on toxicity toward Chlorella vulgaris

Lead sulfide nanoparticle (nano-PbS) released into environment can cause hazards to human or ecosystem. Nano-PbS potentially undergoes oxidation in the environment, but oxidation mechanism is not understood yet. Herein, oxidation kinetics and products of nano-PbS by ozone (O₃), hydrogen peroxide (H₂O₂) and hydroxyl radical (HO·) in the atmosphere or natural water were investigated. Results show that oxidation process of nano-PbS can be divided into three stages, producing sulfate, ions and oxides of lead in sequence. O₃ or HO·leads to faster release of ionic lead from nano-PbS in the initial stage than H₂O₂, but causes significant decrease of ionic lead by transforming divalent lead to tetravalent lead oxides in the second or third stage. Toxicity determined taking Chlorella Vulgaris as an example follows an order of PbO₂ < Pb₃O₄ < nano-PbS < PbO < PbSO₄. Toxicity of lead particles is mainly determined by sizes influencing cellular uptake and solubility product constant (K_sp) related with dissolution of lead in cells. The results indicate that the toxicity of nano-PbS increases in an initial oxidation stage and decreases in further oxidation stages. This study provides new insights into environmental behavior of nano-PbS and mechanism understandings for assessing ecological risks of nano-PbS.

Environmental footprint of voltammetric sensors based on screen-printed electrodes: An assessment towards "green" sensor manufacturing

Voltammetric sensors based on screen-printed electrodes (SPEs) await diverse applications in environmental monitoring, food, agricultural and biomedical analysis. However, due to the single-use and disposable characteristics of SPEs and the scale of measurements performed, their environmental impacts should be considered. A life cycle assessment was conducted to evaluate the environmental footprint of SPEs manufactured using various substrate materials (SMs: cotton textile, HDPE plastic, Kraft paper, graphic paper, glass, and ceramic) and electrode materials (EMs: platinum, gold, silver, copper, carbon black, and carbon nanotubes (CNTs)). The greatest environmental impact was observed when cotton textile was used as SM. HDPE plastic demonstrated the least impact (13 out of 19 categories), followed by ceramic, glass and paper. However, considering the end-of-life scenarios and release of microplastics into the environment, ceramic, glass or paper could be the most suitable options for SMs. Amongst the EMs, the replacement of metals, especially noble metals, by carbon-based EMs greatly reduces the environmental footprint of SPEs. Compared with other materials, carbon black was the least impactful on the environment. On the other hand, copper and waste-derived CNTs (WCNTs) showed low impacts except for terrestrial ecotoxicity and human toxicity (non-cancer) potentials. In comparison to commercial CNTs (CCNTs), WCNTs demonstrated lower environmental footprint and comparable voltammetric performance in heavy metal detections, justifying the substitution of CCNTs with WCNTs in commercial applications. In conclusion, a combination of carbon black or WCNTs EMs with ceramic, glass or paper SMs represents the most environmentally friendly SPE configurations for voltammetric sensor arrangement.

State of the Art on Toxicological Mechanisms of Metal and Metal Oxide Nanoparticles and Strategies to Reduce Toxicological Risks

Metal nanoparticles have been extensively investigated for different types of pharmaceutical applications. However, their use has raised some concerns about their toxicity involving the increase of reactive oxygen species causing cellular apoptosis. Therefore, in this review we summarize the most relevant toxicity mechanisms of gold, silver, copper and copper oxide nanoparticles as well as production methods of metal nanoparticles. Parameters involved in their toxicity such as size, surface charge and concentration are also highlighted. Moreover, a critical revision of the literature about the strategies used to reduce the toxicity of this type of nanoparticles is carried out throughout the review. Additionally, surface modifications using different coating strategies, nanoparticles targeting and morphology modifications are deeply explained.

Acute Oral Toxicity Evaluation of Andrographolide Self-Nanoemulsifying Drug Delivery System (SNEDDS) Formulation

Context:

Andrographolide (AND) is an active compound of well-known medicinal plant Andrographis paniculata. It has been widely published for various activities. AND is difficult to develop into dosage form due to its poor solubility and bioavailability. This problem could be solved by using self-nanoemulsifying drug delivery system (SNEDDS) for its formulation. However, the increase of bioavailability might result in potential toxicity as a large amount of drug is absorbed.

Aims:

The aim of this study is to evaluate the acute potential toxicity using Organization for Economic Cooperation and Development (OECD) test: 401 methods.

Subjects and Methods:

The OECD 401 method employs groups of animals treated by a single dose or repeated dose (<24 h) of the drug with three variances of doses. In this study, thirty male Wistar rats were divided into five groups which consisted two groups of control and three groups of AND SNEDDS formulation (500, 700, and 900 mg/kg body weight [BW], respectively). Intensive observation of toxicity symptom was performed during the first 30 minutes followed by periodic observation for 14 days. Posttermination, histopathological examination of the liver and kidney was conducted to confirm the toxicity symptoms. To determine the level of toxicity, the lethal dose 50 (LD₅₀) value was calculated at the end of the study.

Results:

The result showed that all groups presented similar toxicological symptoms such as salivation, lethargy, and cornea reflex. However, based on histopathological examination, there were abnormalities, but still in an early stage. The toxicological symptom that emerged seems related to the SNEDDS formulation with lipophilic properties. Furthermore, the value of LD₅₀ was 832.6 mg/kg BW (po).

Conclusions:

The AND SNEDDS formulation was slightly toxic in male Wistar rats po.

Two-Dimensional Silicene/Silicon Nanosheets: An Emerging Silicon-Composed Nanostructure in Biomedicine

Silicon-composed nanomedicines are one of the most representative inorganic nanosystems in theranostic biomedicine. The emerging of new family members of silicon-composed nanosystems substantially contributes to their further clinical translation. 2D silicene/silicon nanosheets have recently been developed as an emerging topology of silicon-composed nanoparticles, which features unique planar nanostructure with large surface area, abundant surface chemistry, specific physiochemical property, and desirable biological effects. This progress report highlights and discusses the state-of-art developments of the elaborate construction of 2D silicene/silicon nanosheets for versatile biomedical applications, including top-down fabrication, multifunctionalization, surface engineering, and their available biomedical applications in tumor theranostics (e.g., bioimaging, photothermal ablation, chemotherapy, chemoreactive nanotherapy, radiotherapy, and synergistic nanotherapy) and antibacteria. Their large surface area originating from 2D nanostructure not only enables efficient loading and delivery of chemotherapeutic drugs, but also guarantees the multifunctionalization. Especially, 2D silicene/silicon nanosheets harness desirable photothermal-conversion performance for photonic hyperthermia and photoacoustic imaging in the near infrared biowindow, accompanied with the desirable biodegradability and biocompatibility, which is typically not possessed in other silicon-composed counterparts. The multivariate analysis on the facing challenges and future developments of these 2D silicene/silicon nanosheets have also been conducted and outlooked for further underpinning their clinical translations.

Targeting Intracellular Mycobacteria Using Nanosized Niosomes Loaded with Antibacterial Agents

BACKGROUND

Pathogenic intracellular mycobacteria are challenging to treat because of the waxy and complex cell wall characterizing the genus. Niosomes are vesicles with biomimetic cell membrane composition, which allow them to efficiently bind to the eukaryotic cells and deliver their cargo into the cytoplasm. The objective of this study was to develop a new platform based on niosomes loaded with antimicrobial agents to target intracellular mycobacteria. Nanoniosomes were fabricated and loaded with antibiotics and lignin-silver nanoparticles. The efficacy of these nanoniosomes was tested against the intracellular pathogen Mycobacterium abscessus used as a model of infection of human-derived macrophages (THP-1). The cytotoxicity and the immunological response of the agents were tested on THP-1 cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the secretion of pro- and anti-inflammatory cytokines, respectively.

RESULTS

M. abscessus was susceptible to the nanoniosomes in infected THP-1 macrophages, suggesting that the nanoniosomes were internalized due to their fusion to the macrophage cellular membrane. Moreover, nanoniosomes showed no upregulation of pro-inflammatory cytokines when exposed to THP-1 macrophages.

CONCLUSIONS

Nanoniosomes improved drug efficacy while decreasing toxicity and should be considered for further testing in the treatment of intracellular pathogenic mycobacteria or as a new platform for precise intracellular delivery of drugs.

In vitro coronal protein signatures and biological impact of silver nanoparticles synthesized with different natural polymers as capping agents

Biopolymer-capped particles, sodium alginate-, gelatin- and reconstituted silk fibroin-capped nanosilver (AgNPs), were synthesized with an intention to study, simultaneously, their in vitro and in vivo haemocompatibility, one of the major safety factors in biomedical applications. Solid state characterization showed formation of spherical nanoparticles with 5 to 30 nm primary sizes (transmission electron microscopy) and X-ray photoelectron spectroscopy analysis of particles confirmed silver bonding with the biopolymer moieties. The degree of aggregation of the biopolymer-capped AgNPs in the synthesis medium (ultrapure water) is relatively low, with comparable hydrodynamic size with those of the control citrate-stabilized NPs, and remained relatively unchanged even after 6 weeks. The polymer-capped nanoparticles showed different degrees of aggregation in biologically relevant media - PBS (pH 7.4) and 2% human blood plasma - with citrate- (control) and alginate-capped particles showing the highest aggregation, while gelatin- and silk fibroin-capped particles revealed better stability and less aggregation in these media. In vitro cytotoxicity studies revealed that the polymer-capped particles exhibited both concentration and (hydrodynamic) size-dependent haemolytic activity, the extent of which was higher (up to 100% in some cases) in collected whole blood samples of healthy human volunteers when compared to that in the washed erythrocytes. This difference is thought to result from the detected protein corona formation on the nanoparticle surface in the whole blood system, which was associated with reduced particle aggregation, causing more severe cytotoxic effects. At the tested particle concentration range in vitro, we observed a negligible haemolysis effect in vivo (Balb/c mice). Polymer-capped particles did accumulate in organs, with the highest levels detected in the liver (up to 422 μg per g tissue), yet no adverse behavioural effects were observed in the mice during the duration of the nanoparticle exposure.

Characterization of dextran particle size: How frit-inlet asymmetrical flow field-flow fractionation (FI-AF4) coupled online with dynamic light scattering (DLS) leads to enhanced size distribution

Accurate determinations of particle size and particle size distribution (PSD) are essential to achieve the clinical translation of medical nanoparticles (NPs). Herein, dextran-based NPs produced via a water-in-oil emulsification/crosslinking process and developed as nanomedicines were studied. NPs were first characterized using traditional batch-mode techniques as dynamic light scattering (DLS) and laser diffraction. In a second step, their analysis by frit-inlet asymmetrical flow field-flow fractionation (FI-AF4) was explored. The major parameters of the AF4 procedure, namely, crossflow, detector flow, crossflow decay programming and relaxation time were set up. The sizes of the particle fractions eluted under optimized conditions were measured using DLS as an online detector. We demonstrate that FI-AF4 is a powerful method to characterize dextran-NPs in the 200 nm -1 µm range. It provided a more realistic and comprehensive picture of PSD, revealing its heterogenous character and clearly showing the ratio of different populations in the sample, while batch-mode light scattering techniques only detected the biggest particle sizes.

Impact of Physico-Chemical Properties of Cellulose Nanocrystal/Silver Nanoparticle Hybrid Suspensions on Their Biocidal and Toxicological Effects

There is a demand for nanoparticles that are environmentally acceptable, but simultaneously efficient and low cost. We prepared silver nanoparticles (AgNPs) grafted on a native bio-based substrate (cellulose nanocrystals, CNCs) with high biocidal activity and no toxicological impact. AgNPs of 10 nm are nucleated on CNCs in aqueous suspension with content from 0.4 to 24.7 wt%. XANES experiments show that varying the NaBH4/AgNO3 molar ratio affects the AgNP oxidation state, while maintaining an fcc structure. AgNPs transition from 10 nm spherical NPs to 300 nm triangular-shaped AgNPrisms induced by H2O2 post-treatment. The 48 h biocidal activity of the hybrid tested on B. Subtilis is intensified with the increase of AgNP content irrespective of the Ag+/Ag0 ratio in AgNPs, while the AgNSphere-AgNPrism transition induces a significant reduction of biocidal activity. A very low minimum inhibitory concentration of 0.016 mg AgNP/mL is determined. A new long-term biocidal activity test (up to 168 h) proved efficiency favorable to the smaller AgNPs. Finally, it is shown that AgNPs have no impact on the phagocytic capacity of mammalian cells.

Identification and interaction mechanism of protein corona on silver nanoparticles with different sizes and the cellular responses

With the potential biomedical applications of nanomaterials such as silver nanoparticles (SNPs), nanotoxicity concerns are growing, and the importance of NP and protein interactions is far from being addressed enough. Here, we identified the major binding protein on SNPs in blood as human serum albumin (HSA) using polyacrylamide gel electrophoresis and liquid chromatography-mass spectrometry/mass spectrometry. By comparing with the previous methods, we emphasized surface area concentration as a new dose metric to address the importance of NP curvature. SNPs interacted with cysteine and cystine, disrupting the secondary structure and conformation of HSA, and this tendency became stronger on small SNPs than large ones. The protein corona significantly alleviated the toxicity and decreased SNPs' internalization in a particle size-dependent manner, where more significant inhibition effects occurred on larger particles at the same area concentration. These findings may shed light on nanotoxicity and also the design of safe nanomaterials by a comprehensive preconsideration of the metrological method.

Inhibition of DNA replication initiation by silver nanoclusters

Silver nanoclusters (AgNCs) have outstanding physicochemical characteristics, including the ability to interact with proteins and DNA. Given the growing number of diagnostic and therapeutic applications of AgNCs, we evaluated the impact of AgNCs on DNA replication and DNA damage response in cell-free extracts prepared from unfertilized Xenopus laevis eggs. We find that, among a number of silver nanomaterials, AgNCs uniquely inhibited genomic DNA replication and abrogated the DNA replication checkpoint in cell-free extracts. AgNCs did not affect nuclear membrane or nucleosome assembly. AgNCs-supplemented extracts showed a strong defect in the loading of the mini chromosome maintenance (MCM) protein complex, the helicase that unwinds DNA ahead of replication forks. FLAG-AgNCs immunoprecipitation and mass spectrometry analysis of AgNCs associated proteins demonstrated direct interaction between MCM and AgNCs. Our studies indicate that AgNCs directly prevent the loading of MCM, blocking pre-replication complex (pre-RC) assembly and subsequent DNA replication initiation. Collectively, our findings broaden the scope of silver nanomaterials experimental applications, establishing AgNCs as a novel tool to study chromosomal DNA replication.

Incorporation of silver nanoparticles into active antimicrobial nanocomposites: Release behavior, analyzing techniques, applications and safety issues

Employing new strategies to develop novel composite systems has become a popular area of interest among researchers. Raising people's awareness and their attention to the health and safety issues are key parameters to achieve this purpose. One of the recommended strategies is the utilization of nanoparticles within the matrix of composite materials to improve their physical, mechanical, structural and antimicrobial characteristics. Silver nanoparticles (Ag NPs) have attracted much attention for nanocomposite applications mainly due to their antimicrobial characteristics. Herein, the current review will focus on the different methods for preparing antimicrobial nanocomposites loaded with Ag NPs, the release of Ag NPs from these nanostructures in different media, analyzing techniques for the evaluation of Ag release from nanocomposites, potential applications, and safety issues of nanocomposites containing Ag NPs. The applications of Ag NPs-loaded nanocomposites have been extensively established in food, biomedical, textile, environmental and pharmacological areas mainly due to their antibacterial attributes. Several precautions should be addressed before implementation of Ag NPs in nanocomposites due to the health and safety issues.

Differential Action of Silver Nanoparticles on ABCB1 (MDR1) and ABCC1 (MRP1) Activity in Mammalian Cell Lines

Silver nanoparticles (AgNPs), due to their unique properties have been receiving immense attention in recent years. In addition to their antibacterial and antifungal activities, AgNPs also cause apoptosis, mitochondria disfunction, nucleic acid damage and show potent anticancer properties in both multidrug resistance (MDR) and sensitive tumors. The MDR phenomenon, caused by the presence of ATP-binding cassette (ABC) proteins, is responsible for the failure of chemotherapy. Thus, investigating the influence of widely used AgNPs on ABC transporters is crucial. In the present study, we have examined the cytotoxicity of silver nanoparticles of a nominal size of 20 nm (Ag20) on the cell lines of different tissue origins. In addition, we have checked the ATP-binding cassette transporters’ activity and expression under AgNP exposure. The results indicate that Ag20 shows a toxic effect on tested cells, as well as modulating the expression and transport activity of ABC proteins.

Biotransformation of Silver Nanoparticles into Oro-Gastrointestinal Tract by Integrated In Vitro Testing Assay: Generation of Exposure-Dependent Physical Descriptors for Nanomaterial Grouping

Grouping approaches of nanomaterials have the potential to facilitate high throughput and cost effective nanomaterial screening. However, an effective grouping of nanomaterials hinges on the application of suitable physicochemical descriptors to identify similarities. To address the problem, we developed an integrated testing approach coupling acellular and cellular phases, to study the full life cycle of ingested silver nanoparticles (NPs) and silver salts in the oro-gastrointestinal (OGI) tract including their impact on cellular uptake and integrity. This approach enables the derivation of exposure-dependent physical descriptors (EDPDs) upon biotransformation of undigested nanoparticles, digested nanoparticles and digested silver salts. These descriptors are identified in: size, crystallinity, chemistry of the core material, dissolution, high and low molecular weight Ag-biomolecule soluble complexes, and are compared in terms of similarities in a grouping hypothesis. Experimental results indicate that digested silver nanoparticles are neither similar to pristine nanoparticles nor completely similar to digested silver salts, due to the presence of different chemical nanoforms (silver and silver chloride nanocrystals), which were characterized in terms of their interactions with the digestive matrices. Interestingly, the cellular responses observed in the cellular phase of the integrated assay (uptake and inflammation) are also similar for the digested samples, clearly indicating a possible role of the soluble fraction of silver complexes. This study highlights the importance of quantifying exposure-related physical descriptors to advance grouping of NPs based on structural similarities.

Silver Nanoparticles Stable to Oxidation and Silver Ion Release Show Size-Dependent Toxicity In Vivo

Silver nanoparticles (AgNPs) are widely used in commerce, however, the effect of their physicochemical properties on toxicity remains debatable because of the confounding presence of Ag+ ions. Thus, we designed a series of AgNPs that are stable to surface oxidation and Ag+ ion release. AgNPs were coated with a hybrid lipid membrane comprised of L-phosphatidylcholine (PC), sodium oleate (SOA), and a stoichiometric amount of hexanethiol (HT) to produce oxidant-resistant AgNPs, Ag-SOA-PC-HT. The stability of 7-month aged, 20-100 nm Ag-SOA-PC-HT NPs were assessed using UV-Vis, dynamic light scattering (DLS), and inductively coupled plasma mass spectrometry (ICP-MS), while the toxicity of the nanomaterials was assessed using a well-established, 5-day embryonic zebrafish assay at concentrations ranging from 0-12 mg/L. There was no change in the size of the AgNPs from freshly made samples or 7-month aged samples and minimal Ag+ ion release (<0.2%) in fishwater (FW) up to seven days. Toxicity studies revealed AgNP size- and concentration-dependent effects. Increased mortality and sublethal morphological abnormalities were observed at higher concentrations with smaller nanoparticle sizes. This study, for the first time, determined the effect of AgNP size on toxicity in the absence of Ag+ ions as a confounding variable.

Photoactive Silver Nanoagents for Backgroundless Monitoring and Precision Killing of Multidrug-Resistant Bacteria

Purpose: The growing prevalence of multidrug-resistant (MDR) bacteria makes it clinically urgent to develop an agent able to detect and treat infections simultaneously. Silver has served as a broad-spectrum antimicrobial since ancient times but suffers from major challenges such as moderate antimicrobial activity, nonspecific toxicity, and difficulty to be visualized in situ. Here, we propose a new photoactive silver nanoagent that relies on a photosensitizer-triggered cascade reaction to liberate Ag⁺ on bacterial surfaces exclusively, allowing the precise killing of MDR bacteria. Additionally, the AgNP core acts as a backgroundless surface-enhanced Raman scattering (SERS) substrate for imaging the distribution of the nanoagents on bacterial surfaces and monitoring their metabolic dynamics in the infection sites. Methods: In this strategy, the photoactive antibacterial AgNP was decorated with photosensitizers (Chlorin e6, Ce6) and Raman reporter (4-Mercaptobenzonitrile, 4-MB) to provide new opportunities for clinically monitoring and fighting MDR bacterial infections. Upon 655 nm laser activation, the Ce6 molecules produce ROS efficiently, triggering the rapid release of Ag⁺ from the AgNP core to kill bacteria. Poly[4-O-(α-D-glucopyranosyl)-D-glucopyranose] (GP) was introduced as bacteria-specific targeting ligands. SERS spectra of the prepared GP-Ce6/MB-AgNPs were recorded after injecting for 0.5, 4, 8, 12, 24, and 48 h to track the dynamic metabolism of the nanoagents and thus guiding the antibacterial therapy. Results: This new antimicrobial strategy exerts a dramatically enhanced antibacterial activity. The in vitro antibacterial efficiencies of this non-antibiotic technique were up to 99.6% against Methicillin-resistant Staphylococcus aureus (MRSA) and 98.8% against Escherichia coli (EC), while the in vivo antibacterial efficiencies for MRSA- and Carbapenem-resistant Pseudomonas aeruginosa (CRPA)-infected mice models were 96.8% and 93.6%, respectively. Besides, backgroundless SERS signal intensity of the wound declined to the level of normal tissue until 24 h, indicating that the nanoagents had been completely metabolized from the infected area. Conclusion: Given the backgroundless monitoring ability, high antibacterial efficacy, and low toxicity, the photoactive cascading agents would hold great potential for MDR-bacterial detection and elimination in diverse clinical settings.

Alleviating the toxicity concerns of antibacterial cinnamon-polycaprolactone biomaterials for healthcare-related biomedical applications

Fibrous constructs with incorporated cinnamon-extract have previously been shown to have potent antifungal abilities. The question remains to whether these constructs are useful in the prevention of bacterial infections in fiber form and what the antimicrobial effects means in terms of toxicity to the native physiological cells. In this work, cinnamon extract containing poly (ε-caprolactone) (PCL) fibers were successfully manufactured by pressurized gyration and had an average size of ∼2 μm. Cinnamon extract containing PCL fibers were tested against Escherichia coli, Staphylococcus aureus, Methicillin resistant staphylococcus aureus, and Enterococcus faecalis bacterial species to assess their antibacterial capacity; it was found that these fibers were able to reduce viable cell numbers of the bacterial species up to two orders of magnitude lower than the control group. The results of the antibacterial tests were assessed by scanning electron microscopy (SEM). The constructs were also tested under indirect MTT tests where they showed little to no toxicity, similar to the control groups. Additionally, cell viability fluorescent imaging displayed no significant toxicity issues with the fibers, even at their highest tested concentration. Here we present a viable method for the production the non-toxic and naturally abundant cinnamon extracted fibers for numerous biomedical applications.

Polystyrene particles combined with di-butyl phthalate cause significant decrease in photosynthesis and red lettuce quality

Microplastics, an emerging pollutant in the environment, have attracted extensive attention in recent years for their possible negative impact on organisms. However, direct and indirect effects of polystyrene (PS) microplastics on vegetables are still not completely known. In this study, we used red lettuce (Lactuca sativa L. Red Sails) in a hydroponic system to investigate the effects of nano- and micro-sized PS and dibutyl phthalate (DBP) on the photosynthesis and red lettuce quality. The results clearly indicated that PS reduced the bioavailability of DBP while causing a decrease in the photosynthetic parameters as well as the total chorophyll content compared to DBP alone by affecting the crystalline structure of the water-soluble chlorophyll protein. Compared with DBP monotherapy, the presence of PS significantly increased hydrogen peroxide and malondialdehyde content in the lettuce treated with DBP, indicating serious oxidative damage. Furthermore, the soluble protein and sugar content in lettuce leaves decreased with higher PS concentration and smaller PS size. It may be due to PS inhibited lettuce root and ribulose-1,5-bisphosphate carboxylase/oxygenase activities. In contrast, nitrite content increased significantly with the induction of the glutathione-ascorbic acid cycle, indicating that the presence of PS reduced the quality of DBP-treated-red lettuce. Additionally, the nano-sized PS greatly inhibited lettuce growth and quality more than the micro-sized PS. This study described the interactions between microplastics and phthalates using molecular simulation and experimental validation to highlight the potential risks of microplastics on vegetable crop production.

Single-Particle Hyperspectral Imaging Reveals Kinetics of Silver Ion Leaching from Alloy Nanoparticles

Gold-silver alloy nanoparticles are interesting for multiple applications, including heterogeneous catalysis, optical sensing, and antimicrobial properties. The inert element gold acts as a stabilizer for silver to prevent particle corrosion, or conversely, to control the release kinetics of antimicrobial silver ions for long-term efficiency at minimum cytotoxicity. However, little is known about the kinetics of silver ion leaching from bimetallic nanoparticles and how it is correlated with silver content, especially not on a single-particle level. To characterize the kinetics of silver ion release from gold-silver alloy nanoparticles, we employed a combination of electron microscopy and single-particle hyperspectral imaging with an acquisition speed fast enough to capture the irreversible silver ion leaching. Single-particle leaching profiles revealed a reduction in silver ion leaching rate due to the alloying with gold as well as two leaching stages, with a large heterogeneity in rate constants. We modeled the initial leaching stage as a shrinking-particle with a rate constant that exponentially depends on the silver content. The second, slower leaching stage is controlled by the electrochemical oxidation potential of the alloy being steadily increased by the change in relative gold content and diffusion of silver atoms through the lattice. Interestingly, individual nanoparticles with similar sizes and compositions exhibited completely different silver ion leaching yields. Most nanoparticles released silver completely, but 25% of them appeared to arrest leaching. Additionally, nanoparticles became slightly porous. Alloy nanoparticles, produced by scalable laser ablation in liquid, together with kinetic studies of silver ion leaching, provide an approach to design the durability or bioactivity of alloy nanoparticles.

Prosthetic meshes for hernia repair: State of art, classification, biomaterials, antimicrobial approaches, and fabrication methods

Worldwide, hernia repair represents one of the most frequent surgical procedures encompassing a global market valued at several billion dollars. This type of surgery usually requires the implantation of a mesh that needs the appropriate chemical, physical and biological properties for the type of repair. This review thus presents a description of the types of hernias, current hernia repair methods, and the state of the art of prosthetic meshes for hernia repair providing the most important meshes used in clinical practice by surgeons working in this area classified according to their biological or chemical nature, morphology and whether bioabsorbable or not. We emphasise the importance of surgical site infection in herniatology, how to deal with this microbial problem, and we go further into the future research lines on the production of advanced antimicrobial meshes to improve hernia repair and prevent microbial infections, including multidrug-resistant strains. A great deal of progress has been made in this biomedical field in the last decade. However, we are still far from an ideal antimicrobial mesh that can also provide excellent integration to the abdominal wall, mechanical performance, low visceral adhesion and minimal inflammatory or foreign body reactions, among many other problems.

Impact of biosynthesized silver nanoparticles cytotoxicity on dental pulp of albino rats (histological and immunohistochemical study)

This study aimed to evaluate the potential cytotoxic effect of oral administration of silver nanoparticles (Ag-NPs) on adult albino rats' pulp tissue; due to the enormous uses of Ag-NPs in the medical and dental field. The Ag-NPs were synthesized via the green process using peels of pomegranate extract. The pomegranate-mediated Ag-NPs were subjected to morphological and spectral analysis through ultraviolet visible absorption spectra, transmission electron microscopy, Fourier transforms infrared, Zeta-potential measurements, and energy dispersive X-ray spectroscopy. The structural and morphological characterization techniques confirmed the proper synthesis of biosynthesized Ag-NPs with a size around 20 ​nm and the surface plasmon resonance peak within 400-450 ​nm. The oral cytotoxic effect of Ag-NPs was assessed through detecting the histological (hematoxylin & eosin, Masson's trichrome) and immunohistochemical (vascular endothelial growth factor (VEGF), Caspase-3 proteins) variations. The data was analyzed statistically through using the SPSS software. Dental pulp tissues of albino rats-treated with Ag-NPs revealed that most of the odontoblasts with marked hydropic degeneration, vacuolization of their cytoplasm, loss of organization and apoptosis. Marked vasodilatation and cognition of blood vessels were detected. There was weak to moderate positive reactivity to Masson's trichrome stain. There was statistically significant decrease in the expression of VEGF in the treated group and highly statistically significant increase in the expression of Caspase-3 in comparison with the control group.

Conclusion

Oral administration of Ag-NPs induced size and dose-dependent structural changes in the pulp tissue of adult male albino rats.

Exploitation of Antimicrobial Nanoparticles and Their Applications in Biomedical Engineering

Antibiotic resistance is a major threat to public health, which contributes largely to increased mortality rates and costs in hospitals. The severity and widespread nature of antibiotic resistance result in limited treatments to effectively combat antibiotic-resistant pathogens. Nanoparticles have different or enhanced properties in contrast to their bulk material, including antimicrobial efficacy towards a broad range of microorganisms. Their beneficial properties can be utilised in various bioengineering technologies. Thus, antimicrobial nanoparticles may provide an alternative to challenge antibiotic resistance. Currently, nanoparticles have been incorporated into materials, such as fibres, glass and paints. However, more research is required to elucidate the mechanisms of action fully and to advance biomedical applications further. This paper reviews the antimicrobial efficacies and the intrinsic properties of different metallic nanoparticles, their potential mechanisms of action against certain types of harmful pathogens and how these properties may be utilised in biomedical and healthcare products with the aim to reduce cross contaminations, disease transmissions and usage of antibiotics.

Interdependency of influential parameters in therapeutic nanomedicine

Introduction:Current challenges to successful clinical translation of therapeutic nanomedicine have discouraged many stakeholders, including patients. Significant effort has been devoted to uncovering the reasons behind the less-than-expected success, beyond failures or ineffectiveness, of therapeutic nanomedicine products (e.g. cancer nanomedicine). Until we understand and address the factors that limit the safety and efficacy of NPs, both individually and in combination, successful clinical development will lag.Areas covered:This review highlights the critical roles of interdependent factors affecting the safety and therapeutic efficacy of therapeutic NPs for drug delivery applications.Expert opinion:Deep analysis of the current nanomedical literature reveals ahistory of unanticipated complexity by awide range of stakeholders including researchers. In the manufacture of nanomedicines themselves, there have been persistent difficulties with reproducibility and batch-to-batch variation. The unanticipated complexity and interdependency of nano-bio parameters has delayed our recognition of important factors affecting the safety and therapeutic efficacy of nanomedicine products. These missteps have had many factors including our lack of understanding of the interdependency of various factors affecting the biological identity and fate of NPs and biased interpretation of data. All these issues could raise significant concern regarding the reproducibility- or even the validity- of past publications that in turn formed the basis of many clinical trials of therapeutic nanomedicines. Therefore, the individual and combined effects of previously overlooked factors on the safety and therapeutic efficacy of NPs need to be fully considered in nanomedicine reports and product development.

Anticancer Potential of Biogenic Silver Nanoparticles: A Mechanistic Study

The continuous loss of human life due to the paucity of effective drugs against different forms of cancer demands a better/noble therapeutic approach. One possible way could be the use of nanostructures-based treatment methods. In the current piece of work, we have synthesized silver nanoparticles (AgNPs) using plant (Heliotropiumbacciferum) extract using AgNO3 as starting materials. The size, shape, and structure of synthesized AgNPs were confirmed by various spectroscopy and microscopic techniques. The average size of biosynthesized AgNPs was found to be in the range of 15 nm. The anticancer potential of these AgNPs was evaluated by a battery of tests such as MTT, scratch, and comet assays in breast (MCF-7) and colorectal (HCT-116) cancer models. The toxicity of AgNPs towards cancer cells was confirmed by the expression pattern of apoptotic (p53, Bax, caspase-3) and antiapoptotic (BCl-2) genes by RT-PCR. The cell viability assay showed an IC₅₀ value of 5.44 and 9.54 µg/mL for AgNPs in MCF-7 and HCT-116 cell lines respectively. We also observed cell migration inhibiting potential of AgNPs in a concentration-dependent manner in MCF-7 cell lines. A tremendous rise (150–250%) in the production of ROS was observed as a result of AgNPs treatment compared with control. Moreover, the RT-PCR results indicated the difference in expression levels of pro/antiapoptotic proteins in both cancer cells. All these results indicate that cell death observed by us is mediated by ROS production, which might have altered the cellular redox status. Collectively, we report the antimetastasis potential of biogenic synthesized AgNPs against breast and colorectal cancers. The biogenic synthesis of AgNPs seems to be a promising anticancer therapy with greater efficacy against the studied cell lines.

A harmonized and standardized in vitro approach produces reliable results on silver nanoparticles toxicity in different cell lines

Despite the widespread use of silver nanoparticles (AgNPs) in different fields and the amount of investigations available, to date, there are many contradictory results on their potential toxicity. In the present study, extensively characterized 20-nm AgNPs were investigated using optimized protocols and standardized methods to test several toxicological endpoints in different cell lines. The agglomeration/aggregation state of AgNPs in culture media was measured by dynamic light scattering (DLS). DNA and chromosomal damage on BEAS-2B and RAW 264.7 cells were evaluated by comet and micronucleus assays, while oxidative DNA damage by modified comet assay and 8-oxodG/8-oxodA detection. We also investigated immunotoxicity and immunomodulation by cytokine release and NO production in RAW 264.7 and MH-S cells, with or without lipopolysaccharide (LPS) stimulus. Transmission electron microscope (TEM) analysis was used to analyze cellular uptake of AgNPs. Our results indicate different values of AgNPs hydrodynamic diameter depending on the medium, some genotoxic effect just on BEAS-2B and no or slight effects on function of RAW 264.7 and MH-S in absence or presence of LPS stimulus. This study highlights the relevance of using optimized protocols and multiple endpoints to analyze the potential toxicity of AgNPs and to obtain reliable and comparable results.

USE OF TOPICAL TREATMENTS AND EFFECTS OF WATER TEMPERATURE ON WOUND HEALING IN COMMON CARP (CYPRINUS CARPIO)

Skin lesions are frequently diagnosed in fish medicine. Although systemic fish treatments exist, little is known about the efficacy of topical drugs on fish skin lesions. This study aimed to investigate the efficacy of medical-grade honey and silver sulfadiazine on skin lesions using common carp (Cyprinus carpio) as a model. Additionally, the effect of temperature on the wound healing process was evaluated. Punch biopsies were generated on six fish per treatment group under anesthesia. Treatment groups received one of the following topical medications after wounding: Dr. Nordyke's Wound Honey, MicroLyte Ag Vet, or SilvaSorb Gel. Nontreated positive control groups were similarly wounded but did not receive topical treatment. Fish were housed at 10°C to 13°C or 18°C to 21°C for 29 days. Macroscopic evaluation and image collection of wounds were performed on days 0, 4, 8, 12, 21, and 29 after wounding to compare changes in wound areas and inflammation over time. On day 29, tissue samples were collected for histologic analysis. From day 12 after wounding onward, wounds in positive controls maintained at 18°C to 21°C were significantly smaller (days 12, 21, and 29: P < 0.0001) compared with positive controls kept at 10°C to 13°C. There was an overall improvement in macroscopic appearance in honey-treated groups compared with positive controls on day 12 after wounding at 18°C to 21°C (P = 0.001), whereas with the use of Microlyte and Silvasorb, wounds had increased inflammation grades (P < 0.0001 and P < 0.0001, respectively) with enlarged wound areas (P < 0.0001 and P < 0.001, respectively) in comparison with positive controls on day 12 after wounding at 18°C to 21°C. This study suggests that topical use of medical-grade honey produces positive effects on wound healing in the carp model and higher water temperatures enhance the effects, whereas the use of silver sulfadiazine and lower water temperatures delays or worsens the wound healing process.

Ultrabroad-spectrum, multidrug resistant bacteria-killing, and biocompatible quaternized chitin derivative for infected wound healing

Wound infections have consistently been recognized as serious threats to human. The design of antimicrobial and biocompatible wound dressings for infected wounds is an area of constant research. Herein, we homogeneously synthesized an ultrabroad-spectrum antimicrobial and biocompatible quaternized chitin derivative (QC-4) in a high-efficiency and sustainable route using aqueous KOH/urea solution. Particularly, QC-4 displayed powerful multidrug resistant bacteria-killing activities even at a very low antimicrobial concentration range from 500 ng/mL to 5 μg/mL, including clinically prevalent multidrug-resistant Escherichia coli (MDR-E. coli), methicillin resistant Staphylococcus aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa (MRPA), and multidrug-resistant Acinetobacter baumannii (MDR-A. baumannii). With the aim to facilitate clinical translation, we validated the biocompatibility and safety of QC-4 both in vitro and in vivo, and further assessed the effects of QC-4 on infected wound healing in a porcine infectious full-thickness skin wound model. QC-4 demonstrated significant reduction of microbial aggregates and enhanced wound-healing effects by promoted re-epithelialization and collagen deposition, which were quite comparable to that of commercial Alginate-Ag dressing and absolutely superior to commercial Chitoclot Bandage dressing. Additionally, we provided clear evidences that QC-4 had a unique mechanism of action by attracting electrostatically to the negatively charged microbial surface, thus damaging the microbial cell wall and membrane. Findings of this work provided robust preclinical rationale for the future translational applications of QC-4 as a novel ultrabroad-spectrum and multidrug resistant bacteria-killing antimicrobial wound dressing for clinical wound management.

Understanding nanoparticle endocytosis to improve targeting strategies in nanomedicine

Nanoparticles (NPs) have attracted considerable attention in various fields, such as cosmetics, the food industry, material design, and nanomedicine. In particular, the fast-moving field of nanomedicine takes advantage of features of NPs for the detection and treatment of different types of cancer, fibrosis, inflammation, arthritis as well as neurodegenerative and gastrointestinal diseases. To this end, a detailed understanding of the NP uptake mechanisms by cells and intracellular localization is essential for safe and efficient therapeutic applications. In the first part of this review, we describe the several endocytic pathways involved in the internalization of NPs and we discuss the impact of the physicochemical properties of NPs on this process. In addition, the potential challenges of using various inhibitors, endocytic markers and genetic approaches to study endocytosis are addressed along with the principal (semi) quantification methods of NP uptake. The second part focuses on synthetic and bio-inspired substances, which can stimulate or decrease the cellular uptake of NPs. This approach could be interesting in nanomedicine where a high accumulation of drugs in the target cells is desirable and clearance by immune cells is to be avoided. This review contributes to an improved understanding of NP endocytic pathways and reveals potential substances, which can be used in nanomedicine to improve NP delivery.

Environmental aspect and applications of nanotechnology to eliminate COVID-19 epidemiology risk

Herein, we discuss fast development of the new coronavirus disease COVID-19, emerged in late 2019 in Wuhan, Hubei Province, China, the ground zero of the coronavirus pandemic, and associated with relatively high mortality rate. COVID-19 risk originates from its ability to transmit easily from person to person through the respiratory droplets released during sneezing, breathing, talking, singing, or coughing within a range of nearly 1.5–2 m. The review begins with an overview of COVID-19 origin and symptoms that range from common cold to severe respiratory illnesses and death. Then, it sheds light on the role of nanotechnology as an effective tool for fighting COVID-19 via contributions in diagnosis, treatment, and manufacture of protective equipment for people and healthcare workers. Emergency-approved therapeutics for clinical trial and prospective vaccines are discussed. Additionally, the present work addresses the risk of severe acute respiratory syndrome coronavirus transmission via wastewater and means of wastewater treatment and disinfection via nanoscale materials. The review concludes with a brief assessment of the government's efforts and contemporary propositions to minimize COVID-19 hazard and spreading.

Bioresponsive supramolecular hydrogels for hemostasis, infection control and accelerated dermal wound healing

Injectable, drug-releasing hydrogel scaffolds with multifunctional properties including hemostasis and anti-bacterial activity are essential for successful wound healing; however, designing ideal materials is still challenging. Herein, we demonstrate the fabrication of a biodegradable, temperature-pH dual responsive supramolecular hydrogel (SHG) scaffold based on sodium alginate/poly(N-vinyl caprolactam) (AG/PVCL) through free radical polymerization and the subsequent chemical and ionic cross-linking. A natural therapeutic molecule, tannic acid (TA)-incorporated SHG (AG/PVCL-TA), was also fabricated and its hemostatic and wound healing efficiency were studied. In the AG/PVCL-TA system, TA acts as a therapeutic molecule and also substitutes as an effective gelation binder. Notably, the polyphenol-arm structure and diverse bonding abilities of TA can hold polymer chains through multiple bonding and co-ordinate cross-linking, which were vital in the formation of the mechanically robust AG/PVCL-TA. The SHG formation was successfully balanced by varying the composition of SA, VCL, TA and cross-linkers. The AG/PVCL-TA scaffold was capable of releasing a therapeutic dose of TA in a sustained manner under physiological temperature-pH conditions. AG/PVCL-TA displayed excellent free radical scavenging, anti-inflammatory, anti-bacterial, and cell proliferation activity towards the 3T3 fibroblast cell line. The wound healing performance of AG/PVCL-TA was further confirmed in skin excision wound models, which demonstrated the potential application of AG/PVCL-TA for skin regeneration and rapid wound healing.

Nanomaterials in Wound Healing and Infection Control

Wounds continue to be a serious medical concern due to their increasing incidence from injuries, surgery, burns and chronic diseases such as diabetes. Delays in the healing process are influenced by infectious microbes, especially when they are in the biofilm form, which leads to a persistent infection. Biofilms are well known for their increased antibiotic resistance. Therefore, the development of novel wound dressing drug formulations and materials with combined antibacterial, antibiofilm and wound healing properties are required. Nanomaterials (NM) have unique properties due to their size and very large surface area that leads to a wide range of applications. Several NMs have antimicrobial activity combined with wound regeneration features thus give them promising applicability to a variety of wound types. The idea of NM-based antibiotics has been around for a decade at least and there are many recent reviews of the use of nanomaterials as antimicrobials. However, far less attention has been given to exploring if these NMs actually improve wound healing outcomes. In this review, we present an overview of different types of nanomaterials explored specifically for wound healing properties combined with infection control.

Nanoparticles approaches in neurodegenerative diseases diagnosis and treatment

The World Health Organization (WHO) has declared that neurodegenerative diseases will be the biggest health issues of the twenty-first century. Among these, Alzheimer's and Parkinson's diseases can be considered as the most acute incurable neurological diseases. Researchers are studying and developing a new treatment approach that uses nanotechnology to diagnosis and treatment neurodegenerative diseases. This treatment strategy will be used to regress neurodegenerative diseases such as Alzheimer's disease. Alzheimer's disease (AD) is one of the most common forms of reduced brain function, which causes many devastating complications. Current neurodegenerative diseases treatment protocols only help to treat symptoms nevertheless with nanotechnology approaches, can regress nerve cells apoptosis, reduce inflammation, and improve brain drug delivery. In this paper, new nanotechnology methods such as nanobodies, nano-antibodies, and lipid nanoparticles have been investigated. Correspondingly blood-brain barrier drug delivery improvement methods have been suggested.

Promotion of Surgical Masks Antimicrobial Activity by Disinfection and Impregnation with Disinfectant Silver Nanoparticles

BACKGROUND

The COVID-19 pandemic is requesting highly effective protective personnel equipment, mainly for healthcare professionals. However, the current demand has exceeded the supply chain and, consequently, shortage of essential medical materials, such as surgical masks. Due to these alarming limitations, it is crucial to develop effective means of disinfection, reusing, and thereby applying antimicrobial shielding protection to the clinical supplies.

PURPOSE

Therefore, in this work, we developed a novel, economical, and straightforward approach to promote antimicrobial activity to surgical masks by impregnating silver nanoparticles (AgNPs).

METHODS

Our strategy consisted of fabricating a new alcohol disinfectant formulation combining special surfactants and AgNPs, which is demonstrated to be extensively effective against a broad number of microbial surrogates of SARS-CoV-2.

RESULTS

The present nano-formula reported a superior microbial reduction of 99.999% against a wide number of microorganisms. Furthermore, the enveloped H5N1 virus was wholly inactivated after 15 min of disinfection. Far more attractive, the current method for reusing surgical masks did not show outcomes of detrimental amendments, suggesting that the protocol does not alter the filtration effectiveness.

CONCLUSION

The nano-disinfectant provides a valuable strategy for effective decontamination, reuse, and even antimicrobial promotion to surgical masks for frontline clinical personnel.

Metal oxide nanoparticles and polycyclic aromatic hydrocarbons alter nanoplastic's stability and toxicity to zebrafish

Co-occurrence of nanoplastics (NPs) with metal oxide nanoparticles (nMOx) and polycyclic aromatic hydrocarbons (PAHs) have been widely reported. However, there is a scarcity of information on their interactions and combined toxic effects. In this study, we used two different sized NPs [55 nm (NP1) and 100 nm (NP2)] to understand the effect of nMOx (nCuO and nZnO) and PAHs [chrysene (Chr) and fluoranthene (Flu)] on NPs' stability and toxicity to zebrafish. Results revealed that increasing the concentration of nMOx, zeta-potential increased, and charge reversal was observed in NPs suspension while PAH produced no major changes. Aggregation kinetics performed with nMOx exhibited higher aggregation of NPs in presence of NaCl that alleviated critical coagulation concentration. NP1 stabilized the size of otherwise unstable nMOx suspension in the tap-water for a longer period, whereas, aggregation was observed with NP2. The in vivo comet assay results showed that NP1 was more genotoxic than NP2 owing to their lower size. Interestingly the DNA damage was highest in NPs+nMOx followed by nMOx and NPs. Unlike nMOx, Chr/Flu+NPs showed reduced DNA damage as compared to NPs or PAH alone. Alteration in catalase activity and lipid peroxidation value indicated oxidative stress in all exposure groups.