Nanosilver: A nanoproduct in medical application

Biological Activity of Propolis Ointment with the Addition of 1% Nanosilver in the Treatment of Experimentally-Evoked Burn Wounds

The main objective of this study was to assess the pharmacological efficacy of ointments containing 1% propolis and 1% nanosilver, compared to the conventional treatment of burn wounds. In the evaluation of the results, we used clinical observation of scars, microbiological examinations, pathomorphological examinations, and analysis of free radicals. The analysis of the experiment results concerning the therapeutic effectiveness of the propolis ointment revealed its wide-ranging antibacterial action (against Gram-positive and Gram-negative bacteria). The 1% propolis ointment was found to accelerate neoangiogenesis and epithelialization, have a positive effect on the healing of burn wounds, improve the cosmetic look of scars, and have no side-effects. The analysis of free radicals in burn wounds showed impressive activity of the 1% nanosilver ointment in the reduction of free radicals. No synergism of pharmacological activity of propolis and nanosilver was shown. A comparative evaluation of the acquired research material allows us to provide a favorable opinion on the topical treatment of burn wounds with 1% propolis. The obtained results show that the 1% propolis ointment reduces healing time, offers antimicrobial action, and has a positive effect on the normal process of scar formation.

Histopathological Changes of Organs (Lungs, Liver, Kidney, and Brain) After Using Two Types of AgiCoat and Acticoat Nanosilver Dressings on Deep Second-Degree Burn in Rat

Prevention of infections is a very important issue in treating the burn wounds. The nanosilver dressings have many promising advantages, but absorption of silver ions and its adverse effects to the body were always a question. The aim of this study was to compare Silver serum levels and acute toxic effects of nanosilver on histopathology of organs (lungs, liver, kidney, spleen, and brain) in two types of AgiCoat and Acticoat (nanosilver) dressings on second-degree deep burn in rat. This is an experimental study conducted in our animal laboratory. We divided 24 Sprague-Dawley male rats weighing 300 to 350 randomly into two groups. After anesthesia, a second deep-degree burn was made over dorsal skins of rats by standard method. For group A, Agicoat and, for group B, Acticoat dressings were used. The dressings were changed every 3 days with AgiCoat and Acticoat, respectively. After 14 days, we got blood samples and tissue samples taken from heart, liver, kidneys, spleen, lungs, and brain and a sample from dorsal skin of the rat for histopathological examinations. The results showed that the levels of serum silver in both groups were significantly higher than the standard level (1.22 part per million (PM); AgiCoat, P = .017; Acticoat, P = .000), but there was no significant difference between the groups (P = .551). Examination of the relationship between the level of serum silver and histopathological changes in liver showed that hepatotoxicity of AgiCoat was higher compared with Acticoat and the difference was significant (P = .002). There were no pathological changes in brain, kidneys, spleen, heart, and lungs. Wound healing was faster in Acticoat group. The nanosilver dressings can cause toxicity in liver but not in kidney, brain, spleen, heart, and lungs. Liver pathology and hepatotoxicity were more prominent in AgiCoat group. Wound healing was faster in Acticoat group.

Hemocompatibility and Hemolytic Effects of Functionalized Nanoparticles on Red Blood Cells: A Recent Review Study

In this paper (from 2010 to 2020), the effects of polymeric, metallic and nonmetallic nanoparticles on red blood cells’ hemocompatibility were investigated for the first time. Here, we have considered the latest findings which can help to improve the hemocompatibility of RBCs. It is important to maintain the quality of red blood cells for improving the hemocompatibility because blood products directly affect the health of patients after blood transfusion. Although RBCs can be stored for up to 42 days at 2–6∘C, hypothermic storage lesions (HSLs) are very common in these products. This problem affects the quality of RBC products. Thus, it is necessary to modify the surface molecules of RBCs during storage time to reduce HSLs and alloimmunization complications. Therefore, we reviewed the reported effects of polymeric, metallic and carbon-based nanoparticles on RBCs between 2010 and 2020. The results of our study have shown that the use of negatively charged dendrimers, unsaturated/uncharged liposomes, and PEGylated forms of NPs and RBCs are the best approaches to improve the hemocompatibility conditions of red blood cells. However, large cationic dendrimers, liposomes composed of saturated lipid with long acyl chain, and cationic chitosan nanoparticles have less RBC compatibility. In addition, polymeric nanoparticles have more capacity for surface modification, which makes it possible to make more hemocompatible derivatives. Among metallic nanoparticles, gold and iron nanoparticles were more RBC compatible. However, the smaller size, higher concentration and longer exposure time of these nanoparticles can induce hemolysis and morphological changes in RBCs. On the other side, nonmetallic nanoparticles mostly had poor RBC compatibility, but their effects on RBCs strongly depended on their concentration and physicochemical properties and could be controllable. As a result, the use of polyethylene glycol (PEG), gold, polymeric, and iron nanoparticles in the design of protocols to maintain the survival, structure and activity of red blood cells for improving hemocompatibility can be more effective.

Sex-related response in mice after sub-acute intraperitoneal exposure to silver nanoparticles

Silver nanoparticles (AgNPs) are among the most commercialized nanomaterials in biomedicine due to their antimicrobial and anti-inflammatory properties. Nevertheless, possible health hazards of exposure to AgNPs are yet to be understood and therefore raise public concern in regards of their safety. In this study, sex-related differences, role of steroidal hormones and influence of two different surface stabilizing agents (polymer vs. protein) on distribution and adverse effects of AgNPs were investigated in vivo. Intact and gonadectomised male and female mice were treated with seven AgNPs doses administered intraperitoneally during 21 days. After treatment, steroid hormone levels in serum, accumulation of Ag levels and oxidative stress biomarkers in liver, kidneys, brain and lungs were determined. Sex-related differences were observed in almost all tissues. Concentration of Ag was significantly higher in the liver of females compared to males. No significant difference was found for AgNP accumulation in lungs between females and males, while the lungs of intact males showed significantly higher Ag accumulation compared to gonadectomised group. Effect of surface coating was also observed, as Ag accumulation was significantly higher in kidneys and liver of intact females, as well as in kidneys and brain of intact males treated with protein-coated AgNPs compared to polymeric AgNPs. Oxidative stress response to AgNPs was the most pronounced in kidneys where protein-coated AgNPs induced stronger effects compared to polymeric AgNPs. Interestingly, protein-coated AgNPs reduced generation of reactive oxygen species in brains of females and gonadectomised males. Although there were no significant differences in levels of hormones in the AgNP-exposed animals compared to controls, sex-related differences in oxidative stress parameters were observed in all organs. Results of this study highlight the importance of including the sex-related differences and effects of protein corona in biosafety evaluation of AgNPs exposure.

Surface chemistry-dependent antiviral activity of silver nanoparticles

The toxicity towards viruses of silver nanoparticles (AgNPs) has been reported to be dependent on several factors such as particle concentration, size, and shape. Although these factors may indeed contribute to the toxicity of AgNPs, the results presented in this work demonstrate that surface chemistry and especially surface charge is a crucial factor governing their antiviral activity. Here, this work investigated the influence of capping agents representing various surface charges ranging from negative to positive. These AgNPs were capped with citrate, polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) mercaptoacetic acid (MAA) and (branched polyethyleneimine (BPEI). We show that AgNPs exhibited surface charge-dependent toxicity towards MS2 bacteriophages. Among the capping agents under investigation, BPEI capped AgNPs (Ag/BPEI) exhibited the highest reduction of MS2 resulting in ≥6 log₁₀-units reductions, followed by 4-5 log₁₀-units reductions with PVP and PEG capping's and 3-4 log₁₀-units with MAA and citrate cappings. Bare nanoparticles reported a mere 1-2 log₁₀-units reduction. Electrostatic interaction between the positively charged BPEI-coating and the negatively charged virus surface played a significant role in bringing the MS2 closer to toxic silver ions (Ag⁺). Further results obtained from TEM showed that Ag/BPEI nanoparticles could directly damage the structure of the MS2 bacteriophages. AgNPs and cationic capping agents' observed synergy can lead to much lower and much more efficient dosing of AgNPs for antiviral applications.

A Systematic Review of Biosynthesized Metallic Nanoparticles as a Promising Anti-Cancer-Strategy

Cancer is one of the foremost causes of death worldwide. Cancer develops because of mutation in genes that regulate normal cell cycle and cell division, thereby resulting in uncontrolled division and proliferation of cells. Various drugs have been used to treat cancer thus far; however, conventional chemotherapeutic drugs have lower bioavailability, rapid renal clearance, unequal delivery, and severe side effects. In the recent years, nanotechnology has flourished rapidly and has a multitude of applications in the biomedical field. Bio-mediated nanoparticles (NPs) are cost effective, safe, and biocompatible and have got substantial attention from researchers around the globe. Due to their safe profile and fewer side effects, these nanoscale materials offer a promising cure for cancer. Currently, various metallic NPs have been designed to cure or diagnose cancer; among these, silver (Ag), gold (Au), zinc (Zn) and copper (Cu) are the leading anti-cancer NPs. The anticancer potential of these NPs is attributed to the production of reactive oxygen species (ROS) in cellular compartments that eventually leads to activation of autophagic, apoptotic and necrotic death pathways. In this review, we summarized the recent advancements in the biosynthesis of Ag, Au, Zn and Cu NPs with emphasis on their mechanism of action. Moreover, nanotoxicity, as well as the future prospects and opportunities of nano-therapeutics, are also highlighted.

Surface-enhanced Raman scattering of water in aqueous dispersions of silver nanoparticles

The resonance Raman effect (RRE) is a phenomenon which results in a strong selective enhancement of Raman signals from the samples. Previous studies showed that the RRE in liquid water directly corresponds to its supramolecular structure. It was also reported that the electric-field-induced orientation of water molecules on the electrode surface results in the surface-enhanced Raman scattering (SERS) effect. In this work, we show the SERS effect for water molecules in the dispersion of silver nanoparticles (AgNPs) without any external electrical field. An enhancement factor was estimated to be (4.8 ± 0.8) × 10⁶ for an excitation wavelength of 514.5 nm and for AgNPs with an average size of 34 ± 14 nm. The temperature experiment results showed a higher enhancement with temperature increase. Performed simulation studies revealed a slowdown of the mobility of the water molecules close to the surface of AgNPs.

Metal-Ligand Interface and Internal Structure of Ultrasmall Silver Nanoparticles (2 nm)

Ultrasmall silver nanoparticles were prepared by reduction with NaBH₄ and surface-terminated with glutathione (GSH). The particles had a solid core diameter of 2 nm as shown by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). NMR-DOSY gave a hydrodynamic diameter of 2 to 2.8 nm. X-ray photoelectron spectroscopy (XPS) showed that silver is bound to the thiol group of the central cysteine in glutathione under partial oxidation to silver(+I). In turn, the thiol group is deprotonated to thiolate. X-ray powder diffraction (XRD) together with Rietveld refinement confirmed a twinned (polycrystalline) fcc structure of ultrasmall silver nanoparticles with a lattice compression of about 0.9% compared to bulk silver metal. By NMR spectroscopy, the interaction between the glutathione ligand and the silver surface was analyzed, also with ¹³C-labeled glutathione. The adsorbed glutathione is fully intact and binds to the silver surface via cysteine. In situ ¹H NMR spectroscopy up to 85 °C in dispersion showed that the glutathione ligand did not detach from the surface of the silver nanoparticle, i.e. the silver-sulfur bond is remarkably strong. The ultrasmall nanoparticles had a higher cytotoxicity than bigger particles in in vitro cell culture with HeLa cells with a cytotoxic concentration of about 1 μg mL^-1 after 24 h incubation. The overall stoichiometry of the nanoparticles was about Ag_∼250GSH_∼155.

Copperpod Plant Synthesized AgNPs Enhance Cytotoxic and Apoptotic Effect in Cancer Cell Lines

The utilization of biological resources on the manufacture of nano silver has attracted the interest of researchers to develop an eco-friendly, cost-effective technology in nanomaterials production. In the present study, plant-mediated silver nanoparticles (AgNPs) were synthesized using aqueous leaf extracts of the Copperpod plant, which was well characterized. The ultraviolet-visible spectrophotometric study showed a maximum absorbance peak at 425 nm, and the observation of transmission electron microscopic features revealed that the nanoparticles size ranged between 20 and 70 nm. The synthesized AgNPs were tested for in vitro cytotoxic effects against cancerous cells, such as HepG2, A549 and MCF-7 cells. The findings showed that the IC50 values of AgNPs against cancerous cells viz., HepG2, MCF-7 and A549 cells, were observed to be 69 µg/mL, 62 µg/mL and 53 µg/mL, respectively. In addition, the apoptosis property was analysed using propidium iodide and acridine orange-ethidium bromide via the DNA fragmentation technique. Thus, the outcomes of the current analysis presume that the plant mediated AgNPs obtained from a synthesized Copperpod plant possess significant anti-cancer properties against various cancerous cells.

Silver Nanoparticle-Coated Ethyl Cellulose Inhibits Tumor Necrosis Factor-α of Breast Cancer Cells

Introduction

Cancer is one of the leading causes of death worldwide. In many cases, cancer is related to the elevated expression of a significant cytokine known as tumor necrosis factor-α (TNF-α). Breast cancer in particular is linked to increased proliferation of tumor cells, high incidence of malignancies, more metastases, and generally poor prognosis for the patient. The research sought to assess the effect of silver nanoparticles reduced with ethyl cellulose polymer (AgNPs-EC) on TNF-α expression in MCF-7 human breast cancer cells.

Methods

The AgNPs-EC were produced using the green synthesis reduction method, and their formation was proofed via UV–VIS spectroscopy. Furthermore, AgNPs-EC were characterized for their size, charge, morphology, Ag ion release, and stability. The MCF-7 cells were treated with AgNPs-EC. Then, the expression of TNF-α genes was determined through PCR in real time, and protein expression was studied using ELISA.

Results

The AgNPs-EC were spherical with an average size of 150±5.1 nm and a zeta-potential of −41.4±0.98 mV. AgNPs-EC had an inhibitory effect on cytokine mRNA and protein expression levels, which suggests that they could be used safely in the fight against cancer. AgNPs-EC cytotoxicity was also found to be non-toxic to MCF-7.

Conclusion

Our data determined AgNPs-EC as a novel inhibitor of TNF-α production. These results are promising for developing novel therapeutic approaches for the future treatment of cancer with safe materials.

Biogenic Silver Nanoparticles of Clinacanthus nutans as Antioxidant with Antimicrobial and Cytotoxic Effects

Silver nanoparticles (AgNPs) previously synthesised using leaf (AgNP-L) and stem (AgNP-S) extracts of Clinacanthus nutans (C. nutans) were tested to evaluate antimicrobial, antioxidant, and cytotoxicity activities. The AgNPs showed good inhibition against bacteria, but not fungi. The inhibition results showed the highest activity against Staphylococcus aureus (S. aureus) with 11.35 mm (AgNP-L) and 11.52 mm (AgNP-S), while the lowest inhibition was against Escherichia coli (E. coli) with 9.22 mm (AgNP-L) and 9.25 mm (AgNP-S) in the disc diffusion method. The same trend of results was noted in the well diffusion method. The IC50 of AgNP-L and AgNP-S in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays was 417.05 μg/mL and 434.60 μg/mL, as well as 304.31 μg/mL and 326.83 μg/mL, respectively. Ferric reducing power (FRAP) assay showed that AgNP-L [872.389 μmol/L Fe(II)] and AgNP-S [612.770 μmol/L Fe(II)] exhibited significantly (p < 0.05) greater antioxidant activities than leaf extract (CNL) [152.260 μmol/L Fe(II)] and stem extract (CNS) [110.445 μmol/L Fe(II)] of C. nutans. The AgNPs were also proven to possess cytotoxic effects on the breast (MCF-7), cervical (HeLa), and colon (HT-29) cancer cells in a dose-dependent manner. AgNP-S and AgNP-L showed significantly (p < 0.05) higher cytotoxicity against MCF-7 (117.43 μg/mL) and HT-29 (78.47 μg/mL), respectively. In conclusion, the biosynthesised AgNPs from aqueous extract leaves and stem of C. nutans have demonstrated promising potential towards antioxidant, antimicrobial, and cytotoxicity activities.

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.

Evaluation of antimicrobial properties of nano-silver particles used in orthodontics fixed retainer composites: an experimental in-vitro study

Background. The present study evaluated the antimicrobial efficacy of composite resins containing nano-silver (NAg) particles used in fixed orthodontic retainers. Methods. Nano-composite resin samples with 1%, 2%, and 5% concentrations of NAg were prepared. The antimicrobial effectiveness of NAg was assessed against Streptococcus mutans, Streptococcus sanguis, and Lactobacillus acidophilus by the biofilm inhibition test (three-day-old biofilms), eluted components test (on days 3, 15, and 30), and disk-diffusion agar test after 48 hours. Measures of central tendency and index of dispersion were used to determine colony-forming units. Kruskal-Wallis test and Mann-Whitney U test were also used. Results. The biofilm inhibition test showed a significant decrease in the colonies of S. mutans (87.64%, 96.47%, and 99.76% decrease), S. sanguis (98.13%, 99.47%, and 99.93% decrease), and L. acidophilus (81.59%, 90.90%, and 99.61% decrease) at 1%, 2%, and 5% concentrations of Nag, respectively, compared to the control groups. The colony-forming unit (CFU)/mL of tested microorganisms continuously decreased with increased NAg concentration. In the eluted component test, no significant differences were noted in the 3rd, 15th, and 30th days between the different concentrations of Nag-containing composite resin disks and control samples. According to the disk-diffusion agar test, there was no growth inhibition zone for the composite resin disks containing 1% and 2% concentrations of Nag. However, the growth inhibition zone was seen with a 5% concentration, with a diameter of 9.5±0.71 mm for S. mutans, 8.5±0.71 mm for S. sanguis, and 8±1.41 for L. acidophilus. Conclusion. The incorporation of NAg into composite resins has antibacterial effects, possibly preventing dental caries around fixed orthodontic retainers.

Developmental exposure to silver nanoparticles leads to long term gut dysbiosis and neurobehavioral alterations

Due to their antimicrobial properties, silver nanoparticles (AgNPs) are used in a wide range of consumer products that includes topical wound dressings, coatings for biomedical devices, and food-packaging to extend the shelf-life. Despite their beneficial antimicrobial effects, developmental exposure to such AgNPs may lead to gut dysbiosis and long-term health consequences in exposed offspring. AgNPs can cross the placenta and blood–brain-barrier to translocate in the brain of offspring. The underlying hypothesis tested in the current study was that developmental exposure of male and female mice to AgNPs disrupts the microbiome–gut–brain axis. To examine for such effects, C57BL6 female mice were exposed orally to AgNPs at a dose of 3 mg/kg BW or vehicle control 2 weeks prior to breeding and throughout gestation. Male and female offspring were tested in various mazes that measure different behavioral domains, and the gut microbial profiles were surveyed from 30 through 120 days of age. Our study results suggest that developmental exposure results in increased likelihood of engaging in repetitive behaviors and reductions in resident microglial cells. Echo-MRI results indicate increased body fat in offspring exposed to AgNPs exhibit. Coprobacillus spp., Mucispirillum spp., and Bifidobacterium spp. were reduced, while Prevotella spp., Bacillus spp., Planococcaceae, Staphylococcus spp., Enterococcus spp., and Ruminococcus spp. were increased in those developmentally exposed to NPs. These bacterial changes were linked to behavioral and metabolic alterations. In conclusion, developmental exposure of AgNPs results in long term gut dysbiosis, body fat increase and neurobehavioral alterations in offspring.

Mutagenicity of silver nanoparticles evaluated using whole-genome sequencing in mouse lymphoma cells

The increasing medical and food applications of silver nanoparticles (AgNPs) raise concerns about their safety, including the potential health consequences of human exposure. Previous studies found that AgNPs were negative in the Ames test due to both their microbicidal activity and the inability of nanoparticles to penetrate bacterial cell walls. Thus, the mutagenicity of AgNPs is still not completely clear, though they do induce chromosome damage, as suggested by many previous genotoxicity studies. In this study, whole-genome sequencing (WGS) was used to analyze the mutagenicity of AgNPs in mouse lymphoma cells expanded from single-cell clones. The cells were treated with AgNPs, 4-nitroquinolone-1-oxide (4-NQO) as the positive control, and vehicle controls. Both AgNPs and 4-NQO significantly increased mutation frequencies over their concurrent controls by 1.12-fold and 4.89-fold with mutation rates at 4-fold and 130-fold, respectively. AgNP-induced mutations mainly occurred at G:C sites with G:C > T:A transversions, G:C > A:T transitions, and deletions as the most commonly observed mutations. AgNPs also induced higher fold changes in tandem mutations. The results suggest that the WGS mutation assay conducted here can detect the low-level mutagenicity of AgNPs, providing substantial support for the use of the WGS method as a possible alternative assay with respect to the mutagenic assessment of nanomaterials.

Effects of metal nanoparticle-mediated treatment on seed quality parameters of different crops

The increasing population of the world requires novel techniques to feed everyone, which can replace or work along with traditional methods to increase production of agricultural crops. In recent times, nanotechnology is considered as a promising and emerging approach to be incorporated in agriculture to improve productivity of different crops by the administration of nanoparticles through seed treatment, foliar spray on plants, nano-fertilizers for balanced crop nutrition, nano-herbicides for effective weed control, nanoinsecticides for plant protection, early detection of plant diseases and nutrient deficiencies using diagnostics kits, and nano-pheromones for effective monitoring of pests. Further, distinct nanoparticles with unique physicochemical and biological properties are used in agriculture to increase the percentage of seed germination, which is the initial step to increase the crop yield. In the context of agricultural crops, nanoparticles have both positive effects on seed quality parameters, such as germination percentage, seedling length, seedling dry weight and vigor indices, as well as negative impacts of causing toxicity toward the environment. Thus, the aim of this review article is to provide a comprehensive overview on the effects of super-dispersive metal powders, such as zinc, silver, and titanium nanoparticles on the seed quality parameters of different crops. In addition, the drawback of conventional seed growth enhancers, impact of metal nanoparticles toward seeds, and mechanism of nanoparticles to increase seed germination were also discussed.

Insights into colloidal nanoparticle-protein corona interactions for nanomedicine applications

Colloidal nanoparticles (NPs) have attracted significant attention due to their unique physicochemical properties suitable for diagnosing and treating different human diseases. Nevertheless, the successful implementation of NPs in medicine demands a proper understanding of their interactions with the different proteins found in biological fluids. Once introduced into the body, NPs are covered by a protein corona (PC) that determines the biological behavior of the NPs. The formation of the PC can eventually favor the rapid clearance of the NPs from the body before fulfilling the desired objective or lead to increased cytotoxicity. The PC nature varies as a function of the different repulsive and attractive forces that govern the NP-protein interaction and their colloidal stability. This review focuses on the phenomenon of PC formation on NPs from a physicochemical perspective, aiming to provide a general overview of this critical process. Main issues related to NP toxicity and clearance from the body as a result of protein adsorption are covered, including the most promising strategies to control PC formation and, thereby, ensure the successful application of NPs in nanomedicine.

Composition of nanoclay supported silver nanoparticles in furtherance of mitigating cytotoxicity and genotoxicity

Silver nanoparticle (Ag-NP) is well known for its high antibacterial efficacy. However, its toxicity toward mammalian cells is still a concern in clinical applications. The aim of our study was to evaluate the composition effects of Ag-NP supported by silicate nanoplatelet (NSP) with respect to the cytotoxicity and genotoxicity, and was in reference to the poly (styrene-co-maleic anhydride)-supported Ag-NP (Ag-NP/SMA). The NSP at the geometric dimension of averaged 80 x 80 x 1 nm3 was prepared from the exfoliation of natural clays and used to support different weight ratio of Ag-NP. The supporting limitation of NSP on Ag-NP was below the weight ratio of 15/85 (Ag-NP to NSP), and the detached Ag-NP from the Ag-NP/NSP (30/70) and Ag-NP/SMA hybrids were observed by TEM. Ames test was performed to assess the mutagenic potential of different compositions of Ag-NP/NSP, only Ag-NP/NSP (30/70) and Ag-NP/SMA hybrids exhibited mutagenicity when the concentration was 1.09 ppm or higher. In viewing of cytotoxicity using MTT tests toward HaCaT cells, the IC30 of Ag-NP/NSP (1/99, 7/93 and 15/85) were 1416.7, 243.6, and 148.9 ppm respectively, while Ag-NP/SMA was 64.8 ppm. The IC30 of Ag-NP/NSP (1/99, 7/93 and 15/85) were at least 833, 78 and 7 folds higher than their corresponding minimum inhibitory concentrations (MIC) respectively, and whereas Ag-NP/SMA was 6.4 folds. The Ag-NP/NSP and Ag-NP/SMA hybrids had been further investigated for genotoxicity by chromosomal aberrations and in vivo micronucleus assay within the concentration at IC10 and IC30, only Ag-NP/SMA showed a higher frequency of chromosomal aberrations. Our findings indicated that the viability of utilizing the NSP to maintain Ag-NP for antimicrobial activity, and the high-surface area of NSP served as an excellent support for associating Ag-NP and consequently rendering the mitigation of the inherent toxicity of Ag-NP in clinical uses.

Microbiologically-Synthesized Nanoparticles and Their Role in Silencing the Biofilm Signaling Cascade

The emergence of bacterial resistance to antibiotics has led to the search for alternate antimicrobial treatment strategies. Engineered nanoparticles (NPs) for efficient penetration into a living system have become more common in the world of health and hygiene. The use of microbial enzymes/proteins as a potential reducing agent for synthesizing NPs has increased rapidly in comparison to physical and chemical methods. It is a fast, environmentally safe, and cost-effective approach. Among the biogenic sources, fungi and bacteria are preferred not only for their ability to produce a higher titer of reductase enzyme to convert the ionic forms into their nano forms, but also for their convenience in cultivating and regulating the size and morphology of the synthesized NPs, which can effectively reduce the cost for large-scale manufacturing. Effective penetration through exopolysaccharides of a biofilm matrix enables the NPs to inhibit the bacterial growth. Biofilm is the consortia of sessile groups of microbial cells that are able to adhere to biotic and abiotic surfaces with the help extracellular polymeric substances and glycocalyx. These biofilms cause various chronic diseases and lead to biofouling on medical devices and implants. The NPs penetrate the biofilm and affect the quorum-sensing gene cascades and thereby hamper the cell-to-cell communication mechanism, which inhibits biofilm synthesis. This review focuses on the microbial nano-techniques that were used to produce various metallic and non-metallic nanoparticles and their "signal jamming effects" to inhibit biofilm formation. Detailed analysis and discussion is given to their interactions with various types of signal molecules and the genes responsible for the development of biofilm.

Transformation of Biowaste for Medical Applications: Incorporation of Biologically Derived Silver Nanoparticles as Antimicrobial Coating

Nanobiotechnology has undoubtedly influenced major breakthroughs in medical sciences. Application of nanosized materials has made it possible for researchers to investigate a broad spectrum of treatments for diseases with minimally invasive procedures. Silver nanoparticles (AgNPs) have been a subject of investigation for numerous applications in agriculture, water treatment, biosensors, textiles, and the food industry as well as in the medical field, mainly due to their antimicrobial properties and nanoparticle nature. In general, AgNPs are known for their superior physical, chemical, and biological properties. The properties of AgNPs differ based on their methods of synthesis and to date, the biological method has been preferred because it is rapid, nontoxic, and can produce well-defined size and morphology under optimized conditions. Nevertheless, the common issue concerning biological or biobased production is its sustainability. Researchers have employed various strategies in addressing this shortcoming, such as recently testing agricultural biowastes such as fruit peels for the synthesis of AgNPs. The use of biowastes is definitely cost-effective and eco-friendly; moreover, it has been reported that the reduction process is simple and rapid with reasonably high yield. This review aims to address the developments in using fruit- and vegetable-based biowastes for biologically producing AgNPs to be applied as antimicrobial coatings in biomedical applications.

Dietary supplementation of silver-silica nanoparticles promotes histological, immunological, ultrastructural, and performance parameters of broiler chickens

Silver nanoparticles (AgNPs) have been used as a promising alternative to antibiotics in poultry feed. In this study, silver-doped silica nanoparticles (SiO₂@AgNPs) were prepared in powder form, using starch, via the chemical reduction method and sol-gel technique followed by full characterization. SiO₂@AgNPs were added to the poultry diet at three doses (2, 4, and 8 mg/kg diet). The safety of the oral dietary supplementation was estimated through the evaluation of the growth performance and hematological, biochemical, and oxidative parameters of birds. Moreover, the immunohistochemical examination of all body organs was also performed. Results of this study showed that SiO₂@AgNPs have no negative effects on the growth performance and hematological, biochemical, and oxidative parameters of birds. Moreover, the immunohistochemical examination revealed the minimum inflammatory reactions and lymphoid depletion under a dose level of 8 mg/kg. In conclusion, SiO₂@AgNPs could be considered as a promising and safe nano-growth promoter in broilers when added to poultry diet under a dose level of 4 mg/kg diet.

Fusarium as a Novel Fungus for the Synthesis of Nanoparticles: Mechanism and Applications

Nanotechnology is a new and developing branch that has revolutionized the world by its applications in various fields including medicine and agriculture. In nanotechnology, nanoparticles play an important role in diagnostics, drug delivery, and therapy. The synthesis of nanoparticles by fungi is a novel, cost-effective and eco-friendly approach. Among fungi, Fusarium spp. play an important role in the synthesis of nanoparticles and can be considered as a nanofactory for the fabrication of nanoparticles. The synthesis of silver nanoparticles (AgNPs) from Fusarium, its mechanism and applications are discussed in this review. The synthesis of nanoparticles from Fusarium is the biogenic and green approach. Fusaria are found to be a versatile biological system with the ability to synthesize nanoparticles extracellularly. Different species of Fusaria have the potential to synthesise nanoparticles. Among these, F. oxysporum has demonstrated a high potential for the synthesis of AgNPs. It is hypothesised that NADH-dependent nitrate reductase enzyme secreted by F. oxysporum is responsible for the reduction of aqueous silver ions into AgNPs. The toxicity of nanoparticles depends upon the shape, size, surface charge, and the concentration used. The nanoparticles synthesised by different species of Fusaria can be used in medicine and agriculture.

Tannic Acid-Stabilized Silver Nanoparticles Used in Biomedical Application as an Effective Antimelioidosis and Prolonged Efflux Pump Inhibitor against Melioidosis Causative Pathogen

Burkholderia pseudomallei is the causative pathogen of melioidosis and this bacterium is resistant to several antibiotics. Silver nanoparticles (AgNPs) are an interesting agent to develop to solve this bacterial resistance. Here, we characterize and assess the antimelioidosis activity of AgNPs against these pathogenic bacteria. AgNPs were characterized and displayed a maximum absorption band at 420 nm with a spherical shape, being well-monodispersed and having high stability in solution. The average size of AgNPs is 7.99 ± 1.46 nm. The antibacterial efficacy of AgNPs was evaluated by broth microdilution. The bactericidal effect of AgNPs was further assessed by time-kill kinetics assay. Moreover, the effect of AgNPs on the inhibition of the established biofilm was investigated by the crystal violet method. In parallel, a study of the resistance induction development of B. pseudomallei towards AgNPs with efflux pump inhibiting effect was performed. We first found that AgNPs had strong antibacterial activity against both susceptible and ceftazidime-resistant (CAZ-resistant) strains, as well as being efficiently active against B. pseudomallei CAZ-resistant strains with a fast-killing mode via a bactericidal effect within 30 min. These AgNPs did not only kill planktonic bacteria in broth conditions, but also in established biofilm. Our findings first documented that the resistance development was not induced in B. pseudomallei toward AgNPs in the 30th passage. We found that AgNPs still showed an effective efflux pump inhibiting effect against these bacteria after prolonged exposure to AgNPs at sublethal concentrations. Thus, AgNPs have valuable properties for being a potent antimicrobial agent to solve the antibiotic resistance problem in pathogens.

Antifungal property of acrylic denture soft liner containing silver nanoparticles synthesized in situ

OBJECTIVES

Denture soft liner is applied to relieve pain from candida-induced denture stomatitis and promote healing, but with shortage of antifungal activity and easily harbors fungi. To overcome this problem, the in-situ method was used to synthesize silver nanoparticles (AgNPs) in acrylic soft liner to obtain antifungal effects.

METHODS

Acrylic soft-liner with various weight percentage of silver 2-ethylhexanoate (0%, 0.1 %, 0.2 %, 0.3 %) were prepared in 10 mm × 10 mm × 3 mm. After chemical polymerization, the diameter of AgNPs synthesized in situ and the degree of conversion of each group were measured. After 3, 7, and 14 days of storage in water, the antifungal rate (AFR) of in vitro direct contact antifungal assays and the antifungal test of non-cumulative extract solution were measured respectively. The release profiles of silver ions from the specimen within 14 days were also evaluated.

RESULTS

Evenly distributed AgNPs (4.7 nm-5.3 nm) were observed, and the degree of conversion had no significant difference among these groups. The AFR increased as the silver concentration rose, while decreasing with the storage time. After 14 days of water storage, the AFR of 0.2 % and 0.3 % groups still reached 63.38 % and 75.51 %, respectively. The non-cumulative extract solution had no antifungal effect.

CONCLUSIONS

Within the service life, the acrylic soft liner containing AgNPs synthesized in situ had effective control of Candida albicans through direct contact.

CLINICAL SIGNIFICANCE

This study suggests that AgNPs synthesized in situ may be an effective strategy in modifying acrylic denture soft liner to treat and prevent denture stomatitis.

DNA damage and ovarian ultrastructural lesions induced by nickel oxide nano-particles in Blaps polycresta (Coleoptera: Tenebrionidae)

Nickel oxide nanoparticles (NiO-NPs) have extensively used in industrial and consumer products. The present study conducted to gain more knowledge about the safe use of NiO-NPs and also to understand their impact on the environment and biological systems. Herein, we examined the genotoxic and ultra-structural effects of a sublethal dose of NiO-NPs (0.03 mg/g) on the ovarian tissues of the ground beetle, Blaps polycresta. The mean diameter of NiO-NPs was 24.49 ± 3.88 nm, as obtained through transmission electron microscopy (TEM). In terms of DNA damage levels, the frequency of micronucleus (MN) formation was highly significant in the NiO-NPs treated group versus the controls. Besides, NiO-NPs treatment resulted in a significant increase in the tail length of comets. Further, electron microscopy revealed a progressive increase in chromatin condensation of the ovarian nurse and follicular cells, in addition to the accumulation of lysosomes and endo-lysosomes in their cytoplasm. In conclusion, NiO-NPs are capable of gaining access to the ovary of B. polycresta and causing DNA damage and a high degree of cellular toxicity in the ovarian cells. The present study highlights, for the first time, the adverse effects of these NPs to female gonads of insects and raised the concern of its genotoxic potential. It would be of interest to investigate NiO-NPs mediated intracellular ROS generation in future studies.

Antibacterial Synergism of Electrospun Nanofiber Mats Functioned with Silver Nanoparticles and Pulsed Electromagnetic Waves

The over-reliance on antibiotics and their enormous misuse has led to warnings of a future without effective medicines and so, the need for alternatives to antibiotics has become a must. Non-traditional antibacterial treatment was performed by using an aray of nanocomposites synergised with exposure to electromagnetic waves. In this manuscript, electrospun poly(vinyl alcohol) (PVA) nanofiber mats embedded with silver nanoparticles (Ag NPs) were synthesized. The nanocomposites were characterized by Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), Current-Voltage (I-V) curves, and Thermogravimetric analysis (TGA) along with analysis of antibacterial impact against E. coli and S. aureus bacteria, studied by bacterial growing analysis, growth kinetics, and cellular cytotoxicity. The results indicated a spherical grain shape of silver of average size 20 nm and nanofibers' mean diameter of less than 100 nm. The nanocomposite mats showed good exposure to bacteria and the ability to sustain release of silver for a relatively long time. Moreover, the applied electromagnetic waves (EMWs) were shown to be a synergistic co-factor in killing bacteria even at low concentrations of Ag NPs. This caused pronounced alterations of the bacterial preserved packing of the cell membrane. Thereby, the treatment with nanocomposite mats under EM wave exposure elucidated maximum inhibition for both bacterial strains. It was concluded that the functioning of nanofiber with silver nanoparticles and exposure to electromagnetic waves improved the antibacterial impact compared to each one alone.

Breakthrough of ZrO2 nanoparticles into fetal brains depends on developmental stage of maternal placental barrier and fetal blood-brain-barrier

Ingestion of nanoparticles may cause various damages to human body. However, how such ingestion by pregnant mother influences fetal development is not known because, presumably, ingested nanoparticles have to cross multiple biological barriers (such as intestinal and placental) to reach fetus. To answer this crucial question, here we investigated how a relatively biocompatible zirconia nanoparticles (ZrO₂ NPs, 16 nm) were translocated to fetal brains in three exposure models of pregnant mice: Model 1, oral exposure of nanoparticles before maternal blood-placental barrier (BPB) was fully developed; Model 2, exposures after BPB was developed, but before fetal blood-brain-barrier (BBB) was fully developed; Model 3, exposures after both maternal BPB and fetal BBB were fully developed. Our experimental results showed that translocation of ZrO₂ NPs into fetal brains was 55 % higher in Model 2 and 96 % higher in Model 1 compared with that in Model 3 after nanoparticles (50 mg/kg) were orally exposed to pregnant mice. Therefore, nanoparticles are able to cross multiple biological barriers and nanotoxicity to fetus is highly dependent on stages of pregnancy and fetal development or the maturity of multiple biological barriers. Oral exposures to nanoparticles during pregnancy are dangerous to fetal brain development, especially in early pregnancy.

Rapid green synthesis of non-cytotoxic silver nanoparticles using aqueous extracts of 'Golden Delicious' apple pulp and cumin seeds with antibacterial and antioxidant activity

Abstract

A simple, facile and rapid microwave irradiated system was applied to synthesize silver nanoparticles using 'Golden Delicious' apple pulp (Malus domestica) and cumin (Cuminum cyminum) seed extracts. The phytosynthesized AgNPs were characterized by Ultraviolet–Visible Spectroscopy (UV–vis), Fourier transform infrared (FTIR), X-ray Diffraction (XRD) Transmission Electron Microscopy (TEM) and Zeta sizer analysis. In the study, the presence of face-centered cubic crystalline structured metallic silver in AgNPs from apple and cumin extracts and the monodisperse nature of AgNPs with the size distribution range of 5.46–20 nm and 1.84–20.57 nm were confirmed, respectively. This study established an efficient green synthesis approach that created so far, the smallest silver nanoparticles by using these two extracts. According to the results obtained, AgNPs synthesized using both extracts were non-toxic against L929 mouse fibroblast cells, while they were effective against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria with a greater effect on S. aureus. Moreover, AgNPs synthesized through cumin extract exhibited a higher ABTS scavenging ability (96.43 ± 0.78% at 160 μg/mL) in comparison to apple pulp extract mediated AgNPs, while both AgNPs showed lower activity for DPPH (27.84 ± 0.56% and 13.12 ± 0.32% from cumin seed and apple pulp extracts, respectively). In summary, our results suggest the green non-cytotoxic AgNPs synthesized in this study could be a promising template for further biological and clinical applications.

Graphical abstract

Polymyxin B-functionalized phthalocyanine for chemo-photodynamic antibacterial therapy in enhanced wound healing

The rapid healing of bacteria-infected wounds was achieved via synergistic photodynamic antimicrobial therapy and chemotherapy using polymyxin B-functionalized phthalocyanine.

Antimicrobial Air Filter Coating with Plant Extracts Against Airborne Microbes

Antimicrobial air filters are required to protect humans from the risk of secondary bioaerosol pollution as well as airborne particles. Three plant extracts (tea-tree oil, rosemary, and garlic) were selected to replace antimicrobial chemicals in air filters. The antimicrobial activity of plant extracts was investigated using Micrococcus luteus and Escherichia coli. Phytochemicals present in the three plant extracts were identified using a gas chromatograph coupled with a mass spectrometer. The extracts were spray-coated on polyethylene terephthalate filter surfaces using silicate polymeric coating and evaluated via X-ray photoelectron spectroscopy and a scanning electron microscope with energy dispersive spectroscopy. After coating, an increase of 9.1% in the pressure drop was observed. The strain Micrococcus luteus was used to evaluate the antimicrobial activity of the air filter. After bioaerosol exposure, the tea-tree oil-coated filters immediately induced M. luteus cell inactivation (40–55%), whereas the rosemary and garlic coated filters did not. However, 48 h after exposure, a significant M. luteus inactivation of 99.99%, 99.0%, and 99.9% was recorded for concentrations of 2.89, 6.73, and 11.51 mg/cm2 for the tea-tree, rosemary, and garlic extracts, respectively. The coated filters exhibited high antimicrobial activity, thereby indicating significant potential for application as self-cleaning air filters.

Preparation of silver-decorated Soluplus® nanoparticles and antibacterial activity towards S. epidermidis biofilms as characterized by STEM-CL spectroscopy

Biofilm infections present a serious problem because antibacterial drugs are not effective against mature biofilms or biofilms formed by drug-resistant bacteria. To address this issue, we developed a drug delivery system based on metal-decorated polymeric particles. Polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus®) is an amphiphilic polymer used in biomedical formulations, while silver nanoparticles are widely acknowledged to have high antibacterial activity. We prepared silver-decorated Soluplus® micelle nanoparticles with high antibacterial activity using the emulsion solvent diffusion method. Decoration of Soluplus® micelles with silver nanoparticles was found to increase their antibacterial activity. Scanning transmission electron microscopy-cathodoluminescence (STEM-CL) spectroscopy allows imaging of the spatial distribution of labeled targets and the chemical identification of materials. However, STEM-CL spectroscopy of fragile polymer materials is challenging. We optimized the STEM-CL spectroscopy technique to determine the distribution of silver nanoparticles in Soluplus® micelles. Additionally, the surface plasmon properties of the silver nanoparticles were successfully characterized without deactivation. The developed silver-decorated Soluplus® nanoparticles were effective against biofilm infections and have the potential to be applied for other biofilm-related diseases. Additionally, the optimized STEM-CL spectroscopy technique is expected to contribute to the analysis and imaging of fragile polymer materials, as well as other soft materials such as cells and tissues.

Biosynthesis, characterization, and in vitro assessment on cytotoxicity of actinomycete-synthesized silver nanoparticles on Allium cepa root tip cells

Background

The industrial production of silver nanoparticles (AgNPs) and its commercial applications are being considerably increased in recent times, resulting in the release of AgNPs in the environment and enhanced probability of contaminations and their adverse effects on living systems. Based on this, the present study was conducted to evaluate the in vitro cytotoxicity of actinomycete-synthesized AgNPs on Allium cepa (A. cepa) root tip cells. A green synthesis method was employed for biosynthesis of AgNPs from Streptomyces sp. NS-33. However, morphological, physiological, biochemical, and molecular analysis were carried out to characterize the strain NS-33. Later, the synthesized AgNPs were characterized and antibacterial activity was also carried out against pathogenic bacteria. Finally, cytotoxic activity was evaluated on A. cepa root tip cells.

Results

Results showed the synthesis of spherical and polydispersed AgNPs with a characteristic UV-visible (UV-Vis.) spectral peak at 397 nm and average size was 32.40 nm. Energy dispersive spectroscopy (EDS) depicted the presence of silver, whereas Fourier transform infrared (FTIR) studies indicated the presence of various functional groups. The phylogenetic relatedness of Streptomyces sp. NS-33 was found with Streptomyces luteosporeus through gene sequencing. A good antibacterial potential of AgNPs was observed against two pathogenic bacteria. Concerning cytotoxicity, a gradually decreased mitotic index (MI) and increased chromosomal aberrations were observed along with the successive increase of AgNPs concentration.

Conclusions

Therefore, the release of AgNPs into the environment must be prevented, so that it cannot harm plants and other beneficial microorganisms.

Green Synthesis of Metallic Nanoparticles and Their Potential Applications to Treat Cancer

Nanoparticle synthesis using microorganisms and plants by green synthesis technology is biologically safe, cost-effective, and environment-friendly. Plants and microorganisms have established the power to devour and accumulate inorganic metal ions from their neighboring niche. The biological entities are known to synthesize nanoparticles both extra and intracellularly. The capability of a living system to utilize its intrinsic organic chemistry processes in remodeling inorganic metal ions into nanoparticles has opened up an undiscovered area of biochemical analysis. Nanotechnology in conjunction with biology gives rise to an advanced area of nanobiotechnology that involves living entities of both prokaryotic and eukaryotic origin, such as algae, cyanobacteria, actinomycetes, bacteria, viruses, yeasts, fungi, and plants. Every biological system varies in its capabilities to supply metallic nanoparticles. However, not all biological organisms can produce nanoparticles due to their enzymatic activities and intrinsic metabolic processes. Therefore, biological entities or their extracts are used for the green synthesis of metallic nanoparticles through bio-reduction of metallic particles leading to the synthesis of nanoparticles. These biosynthesized metallic nanoparticles have a range of unlimited pharmaceutical applications including delivery of drugs or genes, detection of pathogens or proteins, and tissue engineering. The effective delivery of drugs and tissue engineering through the use of nanotechnology exhibited vital contributions in translational research related to the pharmaceutical products and their applications. Collectively, this review covers the green synthesis of nanoparticles by using various biological systems as well as their applications.

DNA damage and genetic aberration induced via different sized silver nanoparticles: Therapeutic approaches of Casimiroa edulis and Glycosmis pentaphylla leaves extracts

Potential of Casimiroa edulis and Glycosmis pentaphylla leaves extracts were investigated against the effect of two different particle sizes of silver nanoparticles induced toxicity in mice. Mice received silver nanoparticles (AgNPs) (100 mg/kg) with 20 and 100 nm for four weeks followed by daily oral dose of extracts (500 mg/kg) for three weeks. C. edulis leaves identified fourteen phenolic compounds while, G. pentaphylla leaves identified, twelve phenolic compounds. Additionally, biochemical, genotoxicity, mutagenicity, and histopathological investigations were carried out, revealed that liver function activities, lipid profile, hydrogen peroxide, and C-reactive protein were significantly elevate post AgNPs exposure. While, superoxide dismutase, glutathione-S-transferases, and glutathione peroxidase significantly reduce. A marked amelioration in all detected biomarkers, improved histopathological changes and repair DNA damage after treated with C. edulis and G. pentaphylla leaves extracts. These extracts are used for the first time as promising candidate therapeutic agents against toxicity induced by AgNPs. PRACTICAL APPLICATIONS: The potential applications of AgNPs make it necessary to investigate the possible toxicity associated with release of free silver ions in the biological system. AgNPs of varying particle sizes had toxic effects as evidenced by alterations in some cellular biochemical parameters, genotoxicity, mutagenicity, and histopathological indices on mice. Casimiroa edulis and Glycosmis pentaphylla leaves extracts are used for the first time as promising candidate therapeutic, where they are able to ameliorate the toxicity induced via AgNPs and record vacillate percentage of improvement in the selected biomarkers, as a result of the bioactive secondary metabolites especially flavonoids and other polyphenolic compounds.

A Concise Review on Multidimensional Silver Nanoparticle Health Aids and Threats

Benefits and Risk:

AgNps have beneficial approaches for cancer treatment and angiogenesisrelated diseases like rheumatoid arthritis, atherosclerosis, diabetic psoriasis, retinopathy, endometriosis, and adiposity.

Result:

The advancing nanotechnology-based therapy needs to be devised better, and it should offload the hitches of prevailing treatment approaches. Essential studies are required to explain the synergistic effect of two different cytotoxic agents.

Silver Nanoparticles Protect Skin from Ultraviolet B-Induced Damage in Mice

Ultraviolet (UV) radiation from sunlight has various adverse effects; thus, UV blockage is recommended for preventing sunburn. Common sunscreen ingredients, such as nanosized titanium dioxide and zinc oxide, offer effective protection and enhance cosmetic appearance; however, health concerns have been raised regarding their photocatalytic activity, which generates reactive oxygen species under UV illumination. Silver nanoparticles (AgNPs) are known as safe materials for use in a wide spectrum of biomedical applications. In vitro studies have revealed that AgNPs may have a protective effect against UV irradiation, but the effects in animal studies remain unclear. The present study demonstrated that AgNPs effectively protect against UVB-induced skin damage both in cell cultures and mouse models. These results suggested that AgNPs are feasible and safe as sunscreen ingredients for protection against UVB-induced skin damage.

Antibacterial Activity of Silver and Its Application in Dentistry, Cardiology and Dermatology

The problem of antimicrobial resistance is increasingly present and requires the discovery of new antimicrobial agents. Although the healing features of silver have been recognized since ancient times, silver has not been used due to newly discovered antibiotics. Thanks to technology development, a significant step forward has been made in silver nanoparticles research. Nowadays, silver nanoparticles are a frequent target of researchers to find new and better drugs. Namely, there is a need for silver nanoparticles as alternative antibacterial nanobiotics. Silver nanoparticles (AgNPs), depending on their size and shape, also have different antimicrobial activity. In addition to their apparent antibacterial activity, AgNPs can serve as drug delivery systems and have anti-thrombogenic, anti-platelet, and anti-hypertensive properties. Today they are increasingly used in clinical medicine and dental medicine. This paper presents silver antimicrobial activity and its use in dentistry, cardiology, and dermatology, where it has an extensive range of effects.

Role of Nanofluids in Drug Delivery and Biomedical Technology: Methods and Applications

Recently, suspensions of several nanoparticles or nanocomposites have attained a vast field of application in biomedical research works in some specified conditions and clinical trials. These valuable suspensions, which allow the nanoparticles to disperse and act in homogenous and stable media, are named as nanofluids. Several studies have introduced the advantages of nanofluids in biomedical approaches in different fields. Few review articles have been reported for presenting an overview of the wide biomedical applications of nanofluids, such as diagnosis and therapy. The review is focused on nanosuspensions, as the nanofluids with solid particles. Major applications are focused on nanosuspension, which is the main type of nanofluids. So, concise content about major biomedical applications of nanofluids in drug delivery systems, imaging, and antibacterial activities is presented in this paper. For example, applying magnetic nanofluid systems is an important route for targeted drug delivery, hyperthermia, and differential diagnosis. Also, nanofluids could be used as a potential antibacterial agent to overcome antibiotic resistance. This study could be useful for presenting the novel and applicable methods for success in current medical practice.

Comparison of Enhanced Photocatalytic Degradation Efficiency and Toxicity Evaluations of CeO2 Nanoparticles Synthesized Through Double-Modulation

We demonstrated that Fe/Cr doped and pH-modified CeO₂ nanoparticles (NPs) exhibit enhanced photocatalytic performance as compared to bare CeO₂ NPs, using photocatalytic degradation. To assess the toxicity level of these double-modified CeO₂ NPs on the human skin, they were introduced into HaCaT cells. The results of our conventional cellular toxicity assays (neutral red uptake and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide for assays) indicated that Cr@CeO_x NPs prompt severe negative effects on the viability of human cells. Moreover, the results obtained by scanning transmission X-ray microscopy and bio-transmission electron microscope analysis showed that most of the NPs were localized outside the nucleus of the cells. Thus, serious genetic toxicity was unlikely. Overall, this study highlights the need to prevent the development of Cr@CeO_x NP toxicity. Moreover, further research should aim to improve the photocatalytic properties and activity of these NPs while accounting for their stability issues.