Comparative Assessment of Silver Nanocomposites' Biological Effects on the Natural and Synthetic Matrix.

The aim of our investigation was to make a comparative assessment of the biological effects of silver nanoparticles encapsulated in a natural and synthetic polymer matrix. We carried out a comparative assessment of the biological effect of silver nanocomposites on natural (arabinogalactan) and synthetic (poly-1-vinyl-1,2,4-triazole) matrices. We used 144 three-month-old white outbred male rats, which were divided into six groups. Substances were administered orally for 9 days at a dose 500 µg/kg. Twelve rats from each group were withdrawn from the experiment immediately after nine days of exposure (early period), and the remaining 12 rats were withdrawn from the experiment 6 months after the end of the nine-day exposure (long-term period). We investigated the parietal-temporal area of the cerebral cortex using histological (morphological assessments of nervous tissue), electron microscopic (calculation of mitochondrial areas and assessment of the quality of the cell nucleus), and immunohistochemical methods (study of the expression of proteins regulating apoptosis bcl-2 and caspase 3). We found that the effect of the nanocomposite on the arabinogalactan matrix causes a disturbance in the nervous tissue structure, an increase in the area of mitochondria, a disturbance of the structure of nerve cells, and activation of the process of apoptosis.

Green synthesis and characterization of silver nanoparticles from Moringa oleifera flower and assessment of antimicrobial and sensing properties.

The present study aimed to explore the biosynthesis and characterization of silver nanoparticles (AgNPs) from Moringa oleifera flower (MOF) extract and its antimicrobial and sensing properties. The prepared AgNPs were characterized by Transmission Electron Microscopy (TEM), UV-visible spectral analysis (UV-vis), X-Ray Diffraction (X-RD), Energy Dispersive Spectroscopy (EDS), and Fourier Infra-Red Spectroscopy (FTIR) respectively. Antimicrobial and sensing properties of the prepared nanoparticles were also determined. Face-Centered Cubic (FCC) lattice of the AgNPs was observed in X-RD pattern. FTIR measurement evidenced the band pattern at 686, 1653, 2062 and 3456 cm-1 proved the presence of proteins and phenolic components in MOF responsible for reduction. TEM analysis indicated the formation of monodispersed spherical particles with 8 nm. UV-vis of the prepared AgNPs authenticated the surface plasmon resonance (SPR) at 429 nm and stable for six months. AgNPs have produced highest zone of inhibition (ZOI) of 17 mm and 29 mm against Klebsiella pneumoniae and Staphylococcus aureus respectively. In addition, the AgNPs effectively detected the presence of Copper ions from 1 mM to 12 mM concentrations. Copper sensitivity of these biosynthesized nanoparticles was carried out by optical sensor based SPR. Thus the obtained antimicrobial and optical properties, suggested the use of obtained AgNPs in water purification.

Assessment of MMP29 Gene Expression and Silver Nanoparticles Effects on Colon Cancer Cell Line (HT29).

BACKGROUND: Colon cancer is a major cause of death around the world. The evaluation of novel approaches on corresponding genes would be a vital strategy toward eradication of cancer cells. In this study, the toxicity of silver nanoparticle on the colon cancer cell line (HT29) and expression of matrix metalloproteinase (MMP29) gene was investigated. MATERIALS AND METHODS: The silver nanoparticle (AgNPs) was synthesized and assessed by transmission electron microscopy (TEM). The cytotoxicity of synthesized AgNP on the HT29 cell line was evaluated using the MTT assay. Furthermore, the expression of MMP29 gene was investigated by the quantitative real-time PCR (RT-qPCR). RESULTS: The TEM results revealed that the fabricated AgNPs were mostly spherical in shape and had an average diameter of 22 nm. The results outlined that AgNPs significantly decreased the viability of cells in a dose- and time-dependent manner (p < 0.001). Additionally, we observed a significant difference among various concentrations. CONCLUSION: The findings indicated that the green fabricated AgNPs have the potential as a promising approach toward the colon cancer therapy. Furthered studies are essential to evaluate against other cancer cell lines and genes participating in the cancer progress.

[A Noval Method for Producing Antibacterial Wound Dressing by Using Fused Deposition Molding with Post-3D-printed Process].

Using three-dimensional printing to produce antibacterial wound dressing is a new topic that will change the production style of wound dressing industry. Combining with post-3D-printed process, a desktop fused deposition molding equipment can be used to produce wound dressing containing polyvinyl alcohol, alginate and chitosan. The wound dressing produced by FDM has good aspects of absorbency, moisture vapour transmission rate and mechanical property. After loaded with antibacterial agent iodine and silver nano particle, the antibacterial activity rate increases to 99% and it is suitable to use as antibacterial wound dressing. This method affects the production of wound dressing to a more cost-effective way, and provides a possible individualized treatment for patient in the future.

In vitro and in vivo Assessment of Silver Nanoparticles Against Clostridium botulinum Type A Botulinum.

BACKGROUND: Clostridium botulinum causes botulism, a serious paralytic illness that results from the ingestion of a botulinum toxin. Because silver nanoparticle products exhibit strong antimicrobial activity, applications for silver nanoparticles in healthcare have expanded. Therefore, the objective of the current study was to assess a therapeutic strategy for the treatment of botulism toxicity using silver nanoparticles. METHODS: A preliminary test was conducted using doses that produce illness in laboratory animals to determine the absolute lethal dose (LD100) of botulinum toxin type A (BoNT/A) in mice. Next, the test animals were divided into six groups containing six mice each. Groups I, II and III were the negative control (botulinum toxin only), positive control-1 (nano-silver only) and positive control-2 (no treatment), respectively. The remaining groups were allocated to the toxin that was supplemented with three nano-silver treatments. RESULTS: The mortality rates of mice caused by BoNT/A significantly reduced in the treatment groups with different doses and injection intervals of nano-silver when compared to the negative control group. BoNT/A toxicity induced by intraperitoneal injection of the toxin of Clostridium botulinum causes rapid death while when coupled with nano-osilver results in delayed death in mice. CONCLUSION: These results, while open to future improvement, represent a preliminary step towards the satisfactory control of BoNT/A with the use of silver nanoparticles for human protection against this bioterrorism threat. Further study in this area can elucidate the underlying mechanism for detoxifying BoNT/A by silver nanoparticles.

In vivo bio-distribution, clearance and toxicity assessment of biogenic silver and gold nanoparticles synthesized from Abutilon indicum in Wistar rats.

This study reports the bio-distribution and clearance of Abutilon indicum silver and gold nanoparticles (AIAgNPs and AIAuNPs) in Wistar rats. Rats in different groups were orally administered with 5 and 10 mg/Kg BW of AIAgNPs and AIAuNPs (size 1-25 nm) for 28 days and few were maintained until 58 days of washout period. Serum biochemical parameters were not changed significantly at both doses of AIAuNPs and at lower concentration of AIAgNPs. But, with 10 mg/Kg BW of AIAgNPs rats showed elevated levels of AST, ALP and ALT on day 29, however, these levels were restored to normal after washout period. Liver oxidative stress markers were not altered with the treatment of AIAgNPs and AIAuNPs. ICP-OES analysis indicated bio-distribution of Ag and Au more in liver, kidney and spleen on day 29 and was found cleared on day 59. Histological analysis of nine vital organs indicated normal tissue architecture at both doses of AIAuNPs and lower dose of AIAgNPs. While the rats treated with higher dose of AIAgNPs showed mild liver sinusoid cell swelling on day 29, which also was recovered on day 59. Findings of this preclinical study indicate biocompatible nature of biogenic nanoparticles supporting their future biomedical applications.

Contribution of cutlery and serving dishes to the human daily intake of silver An in vitro assessment.

Silver cutlery and serving dishes are a potential source of exposure of humans that was never quantified. Release of silver was assessed in vitro in an acidic solution mimicking food fluid in two conditions: i] the JRC guidelines for hot fill conditions with stable high temperature over a 2 hour-period of time, and ii] a more realistic condition with spontaneous progressive decline from 90̊C to ambient temperature over the same period of time. Massive silver 95% strips were exposed to a 5% citric acid solution: i) cooling down from 90̊C to ambient or ii) 70̊C maintained, during 2 hours. Spectrometry with optical emission was used to measure silver in solution. In the spontaneous cooling down study, the time-course of temperature was close to the Newton's law of cooling and the released quantities were detected but too low to be measured. The 70̊C exposition resulted in a non-linear release that became quantifiable after one hour of heating up to an apparent plateau at 120 min with a mean concentration [extreme] of 24.6 [22.3-26.8] µg/L. The results of the present study allow concluding that 95% silver used for cutlery and serving dishes may be released in foods. However, the extent of release depends on the condition of use. At a stable 70̊C temperature over a 2 h-period of time, silver is released in a non-linear model up to a mean concentration of 24.6 µg/L. In contrast, in conditions fitting with the routine recommendations of use, infinitesimal detectable amounts of silver were released.

A Randomized Controlled Trial on the Outcome in Comparing an Alginate Silver Dressing With a Conventional Treatment of a Necrotizing Fasciitis Wound.

Necrotizing fasciitis (NF) is a high morbidity and mortality disease and also demands high economic resources. The standard treatment of NF is surgical debridement and proper dressing for wound bed preparation. The efficacy of silver alginate dressing can inhibit the growth of microorganisms and keep the environment clean for wound bed preparation. However an optimal dressing to manage such wounds has yet to emerge. NF patients who were admitted between April 2013 and May 2016 were randomized to have wound dressing using either silver dressing (Ag group) or normal saline solution gauze (NSS group). The 4 main outcomes for comparison between the 2 groups were the duration of wound bed preparation, total cost during hospital stay, the duration of hospital stay, and the pain score. Thirty-nine patients were included in the study: 19 patients in the NSS group and 20 patients in the Ag group. The mean duration of wound bed preparation in the NSS group was 31.87 days, and in Ag group it was 21.39 days, but this trend was not statistically significant ( P = .057). The mean cost of treatment in the NSS and Ag groups was not significantly different ( P = .434; US$3308.83 and US$2647.82, respectively). The duration of hospital days in the 2 groups was not significantly different either (29.19 days [NSS group] and 20.99 days [Ag group]; P = .222). The pain score was significantly lower in the Ag group than those in the NSS group. Although silver dressing seems to be expensive, the cost of total treatment during hospital stay and the duration of hospital stay were not significantly different between groups. However, the mean duration of wound bed preparation seems to trend favoring toward the silver dressing group.

In vitro assessment of the antimicrobial activity of silver and zinc oxide nanoparticles against fish pathogens.

BACKGROUND: Antibiotic resistance is a global issue that threatens public health. The excessive use of antibiotics contributes to this problem as the genes of antibiotic resistance can be transferred between the bacteria in humans, animals and aquatic organisms. Metallic nanoparticles could serve as future substitutes for some conventional antibiotics because of their antimicrobial activity. The aim of this study was to evaluate the antimicrobial effects of silver and zinc oxide nanoparticles against major fish pathogens and assess their safety in vitro. Silver nanoparticles were synthesized by chemical reduction and characterized with UV-Vis spectroscopy, transmission electron microscopy and zeta sizer. The concentrations of silver and zinc oxide nanoparticles were measured using inductively coupled plasma-mass spectrometry. Subsequently, silver and zinc oxide nanoparticles were tested for their antimicrobial activity against Aeromonas hydrophila, Aeromonas salmonicida subsp. salmonicida, Edwardsiella ictaluri, Edwardsiella tarda, Francisella noatunensis subsp. orientalis, Yersinia ruckeri and Aphanomyces invadans and the minimum inhibitory concentrations were determined. MTT assay was performed on eel kidney cell line (EK-1) to determine the cell viability after incubation with nanoparticles. The interaction between silver nanoparticles and A. salmonicida was investigated by transmission electron microscopy. RESULTS: The tested nanoparticles exhibited marked antimicrobial activity. Silver nanoparticles inhibited the growth of both A. salmonicida and A. invadans at a concentration of 17 µg/mL. Zinc oxide nanoparticles inhibited the growth of A. salmonicida, Y. ruckeri and A. invadans at concentrations of 15.75, 31.5 and 3.15 µg/mL respectively. Silver nanoparticles showed higher cell viability when compared to zinc oxide nanoparticles in the MTT assay. Transmission electron microscopy showed the attachment of silver nanoparticles to the bacterial membrane and disruption of its integrity. CONCLUSIONS: This is the first study on inhibitory effects of silver and zinc oxide nanoparticles towards A. salmonicida and A. invadans. Moreover, zinc oxide nanoparticles inhibited the growth of Y. ruckeri. In low concentrations, silver nanoparticles were less cytotoxic than zinc oxide nanoparticles and represent an alternative antimicrobial compound against A. hydrophila, A. salmonicida and A. invadans.

Nano-silver-decorated microfibrous eggshell membrane: processing, cytotoxicity assessment and optimization, antibacterial activity and wound healing.

An ideal wound dressing can both promote wound healing and prevent bacterial infection. Here, we report a potential dressing prepared by incorporating an optimized concentration of silver nanoparticles (AgNPs) into the microfibers of a natural eggshell membrane (EM) using environmentally friendly and mussel-inspired dopamine. Briefly, acid-treated EM was used as a porous membrane for polydopamine-reduced AgNPs synthesis. To obtain the optimal cytocompatible silver concentration, cellular attachment and MTT assay were performed with different concentrations of AgNPs. The morphology of the EM and AgNPs was confirmed by scanning electronic microscopy, scanning transmission electronic microscopy and Fourier transform infrared spectroscopy. The synthesized EM/AgNPs exhibited steady and safe AgNPs release, which was further tested for antibacterial activity against Escherichia coli and Staphylococcus aureus by disc diffusion method and bacterial suspension assay. Finally, in a murine full-thickness skin wound model, we found that EM/AgNPs could promote re-epithelialization, granulation tissue formation and wound healing via enhancing cell proliferation, as demonstrated by the expression of proliferating cell nuclear antigen (PCNA), and controlling inflammation response, as demonstrated by the expression of interleukin-1ß (IL-1ß). These findings suggest that EM/AgNPs may have a promising application in wound management.

Assessment of DNA damage and molecular responses in Labeo rohita (Hamilton, 1822) following short-term exposure to silver nanoparticles.

The increasing application of silver nanoparticles (Ag-NPs) both in industries and in agricultural fields has led to its accumulation in the aquatic ecosystem through water run-off. In the present study, the effects of Ag-NPs in the liver of Labeo rohita, were investigated at genomic and cellular level for seven days at the concentrations of 100, 200, 400 and 800 µg l(-1) by using 18 and 29 nm sizes of Ag-NPs. The Ag-NPs sizes of 18 and 29 nm were synthesized by a chemical method using atomic force microscopy with the zeta potential of -55 mV and-31.4 mV respectively. They were found to be spherical with smooth surfaces. Assessment of genotoxic effects of the particles in the fish using single-cell gel electrophoresis showed DNA damage on exposure to concentrations of 400 and 800 µg l(-1). Histopathological examination of the liver revealed vacuolar degeneration, hepatocytes have undergone total degeneration and high accumulation of Ag-NPs that depicted both time and dose-dependent relationships. Furthermore, the expression study of stress-related genes showed down-regulation, due to the production of free radicals and reactive oxygen species. Ag-NPs can cause both DNA damage and affect the cellular responses of L. rohita.

Assessment of orally dosed commercial silver nanoparticles on human ex vivo platelet aggregation.

Enhanced in vitro human and ex vivo rat platelet aggregation from direct exposure to silver nanoparticles is previously reported. Given the increasing human use of engineered silver nanoscale products, platelet aggregation prompted by silver nanoparticles may contribute to human cardiovascular events. To understand how direct washed platelet exposure to silver nanoparticles translates to ex vivo platelet aggregation, the authors conducted a placebo-controlled, single-blind, dose-monitored, cross-over study design in 18 healthy human volunteers. After 2 weeks of daily oral silver nanoparticle ingestion, platelet aggregation was evaluated by light transmission aggregometry in response to collagen and ADP agonists, both at baseline and after silver nanoparticle or placebo diluent oral dosing. Final percent aggregation (PA) and the changes in PA were determined using a paired design (i.e., active and placebo solutions). Enhanced ex vivo platelet activation was not detectable at peak serum silver concentrations <10 µg/L. Further studies of colloidal silver nanoparticles on human platelet activities are warranted.

A randomized controlled trial to assess the efficacy and cost-effectiveness of urinary catheters with silver alloy coating in spinal cord injured patients: trial protocol.

BACKGROUND: Patients with non-acute spinal cord injury that carry indwelling urinary catheters have an increased risk of urinary tract infection (UTIs). Antiseptic Silver Alloy-Coated Silicone Urinary Catheters seems to be a promising intervention to reduce UTIs; however, actual evidence cannot be extrapolated to spinal cord injured patients. The aim of this trial is to make a comparison between the use of antiseptic silver alloy-coated silicone urinary catheters and the use of standard urinary catheters in spinal cord injured patients to prevent UTIs. METHODS/DESIGN: The study will consist in an open, randomized, multicentre, and parallel clinical trial with blinded assessment. The study will include 742 spinal cord injured patients who require at least seven days of urethral catheterization as a method of bladder voiding. Participants will be online centrally randomized and allocated to one of the two study arms (silver alloy-coated or standard catheters). Catheters will be used for a maximum period of 30 days or removed earlier if the clinician considers it necessary. The main outcome will be the incidence of UTIs by the time of catheter removal or at day 30 after catheterization, the event that occurs first. Intention-to-treat analysis will be performed, as well as a primary analysis of all patients. DISCUSSION: The aim of this study is to assess whether silver alloy-coated silicone urinary catheters improve ITUs in spinal cord injured patients. ESCALE is intended to be the first study to evaluate the efficacy of the silver alloy-coated catheters in spinal cord injured patients. TRIAL REGISTRATION: NCT01803919.

Types of urethral catheter for reducing symptomatic urinary tract infections in hospitalised adults requiring short-term catheterisation: multicentre randomised controlled trial and economic evaluation of antimicrobial- and antiseptic-impregnated urethral catheters (the CATHETER trial).

BACKGROUND: Catheter-associated urinary tract infection (CAUTI) is a major preventable cause of harm for patients in hospital and incurs significant costs for health-care providers such as the UK NHS. Many preventative strategies and measures have been introduced to minimise CAUTI risk, including the use of antimicrobial catheters. However, there is considerable uncertainty regarding their usefulness in terms of reducing symptomatic CAUTI, and whether or not they are cost-effective. OBJECTIVES: Do antimicrobial catheters reduce the rate of symptomatic urinary tract infection (UTI) during short-term hospital use and is their use cost-effective for the UK NHS? DESIGN: A pragmatic multicentre UK randomised controlled trial comparing three catheters as they would be used in the UK NHS: antimicrobial-impregnated (nitrofurazone) and antiseptic-coated (silver alloy) catheters with the standard polytetrafluoroethylene (PTFE)-coated catheters. Economic evaluation used a decision model populated with data from the trial. Sensitivity analysis was used to explore uncertainty. SETTING: Relevant clinical departments in 24 NHS hospitals throughout the UK. PARTICIPANTS: Adults requiring temporary urethral catheterisation for a period of between 1 and 14 days as part of their care, predominantly as a result of elective surgery. INTERVENTIONS: Eligible participants were randomised 1 : 1 : 1 to one of three types of urethral catheter in order to make the following pragmatic comparisons: nitrofurazone-impregnated silicone catheter compared with standard PTFE-coated latex catheter; and silver alloy-coated hydrogel latex catheter compared with standard PTFE-coated latex catheter. MAIN OUTCOME MEASURES: The primary outcome for clinical effectiveness was the incidence of UTI at any time up to 6 weeks post randomisation. This was defined as any symptom reported during catheterisation, up to 3 days or 1 or 2 weeks post catheter removal or 6 weeks post randomisation combined with a prescription of antibiotics, at any of these times, for presumed symptomatic UTI. The primary economic outcome was incremental cost per quality-adjusted life-year (QALY). Health-care costs were estimated from NHS sources with QALYs calculated from participant completion of the European Quality of Life-5 Dimensions (EQ-5D). RESULTS: Outcome analyses encompassed 6394 (90%) of 7102 participants randomised. The rate of symptomatic UTI within 6 weeks of randomisation was 10.6% in the nitrofurazone group (n = 2153; -2.1% absolute risk difference), 12.5% in the silver alloy group (n = 2097; -0.1% absolute risk difference) and 12.6% in the PTFE group (n = 2144). The effect size {odds ratio (OR) [97.5% confidence interval (CI)]} was 0.82 (97.5% CI 0.66 to 1.01) for nitrofurazone (p = 0.037) and 0.99 (97.5% CI 0.81 to 1.22) for silver alloy (p = 0.92) catheters. The nitrofurazone catheters were more likely to cause discomfort during use and on removal. The primary economic analysis suggested that nitrofurazone-impregnated catheters would be, on average, the least costly (> £7 less than PTFE) and most effective option at current NHS prices. There was a 73% chance that nitrofurazone would be cost saving and an 84% chance that the incremental cost per QALY would be < £30,000. At the trial price (£6.46), silver alloy catheters were very unlikely to be cost-effective. These results were unchanged in sensitivity analyses, although when the length of stay cost was excluded the incremental cost per QALY for nitrofurazone against PTFE was £28,602. CONCLUSIONS: The trial estimate of clinical effectiveness for nitrofurazone-impregnated catheters was less than the pre-specified minimum absolute risk difference that we considered important (-3.3%), and the surrounding CI included zero, indicating that any reduction in catheter-associated UTI was uncertain. Economic analysis, although associated with uncertainty, suggested that nitrofurazone-impregnated catheters may be cost-effective for the NHS. The trial ruled out the possibility that silver alloy-coated catheters might reach the pre-set degree of clinical effectiveness and that their use was unlikely to be cost-effective. These findings should be considered by patients, clinicians and health-care policy-makers to determine whether or not a change in practice is worthwhile. Future research should be aimed at determining the minimum clinically important difference in terms of CAUTI prevention in comparative trials, and to identify reliable methods which can detect the impact of the intervention on quality of life and other drivers of cost, when the intervention is a subsidiary part of overall treatment plans.

An in vitro assessment of MRI issues at 3-Tesla for antimicrobial, silver-containing wound dressings.

Although no reports of adverse events have been published to date, the presence of metallic dressing ingredients may present an magnetic resonance imaging (MRI) safety concern for patients using silver-containing wound dressings. The purpose of this in vitro study was to test magnetic field interactions (ie, translational attraction and torque), heating, artifacts, and conductivity (ie, electrical resistance) when using MRI at 3-Tesla for two (nonborder and border) silver-containing wound dressings. The results indicated the dressings displayed no magnetic field interactions (deflection angle 0˚; no torque), and in each case, MRI-related heating effects were at the same levels as the background temperature increases (ie, <1.8˚C). The dressings created extremely subtle artifacts (one-for-one relationship) on the MR images. With regard to the conductivity assessments, the average resistance values were 20 kOhm and 1.1 kOhm, respectively, for the nonborder and border wound dressings, which were acceptable levels. The findings show the two silver-containing wound dressings tested will not pose hazards or risks to patients and, thus, are considered "MR safe" according to the current labeling terminology used for medical products, and each dressing may be left in place when a patient undergoes an MRI examination. To date, only a hydrofiber silver-containing dressing has been tested for MRI safety. Because of potential variances in material characteristics, MRI test results are specific to the dressings tested and cannot be applied to other products. Future studies to define the level of silver concentration in dressings that may pose a hazard for performing an MRI are warranted.

[Comparative experimental assessment of the impact of gold and silver nanoparticles on the phagocyting cells of the lower airways].

Judging by the cytological characteristics of the free cell population of the lower airways obtained with assistance of the bronchoalveolar lavage in 24 hours after the intratracheal instillation of equal doses of equidimensional gold or silver nanoparticles, both metals result in active recruitment of phagocytes with domination of neutrophile leukocytes, especially marked after the instillation of the nanosilver. The higher ratio of these cells count to that of alveolar macrophages gives evidence for the significantly higher cytotoxicity of the nanosilver comparing with both nanogold and even the smallest silver particles in the micrometric range. Transmission electron microscopy demonstrates similar pictures of intracellular distribution and ultra-structural damages caused by internalized nanoparticles in both types of phagocytes, while there are significant differences between cells under impact of nanosilver vs. those under impact of nanogold. The highest importance is higher propensity of the nanosilver particles to aggregation and to ingression into mitochondria with damaging these organelles.

Dose-dependent in-vivo toxicity assessment of silver nanoparticle in Wistar rats.

This study aims to suggest the limits of silver nanoparticle (AgNP) uses for medicinal purpose and was performed to explore the effect of various doses of silver nanoparticle in rats. Four different doses of AgNP (4, 10, 20, and 40 mg/kg) were injected intravenously. For safety evaluation of injected AgNP, body weight, organ coefficient, whole blood count, and biochemistry panel assay for liver function enzyme (AST, ALT, ALP, and GGTP), comet assay, ROS, and histological parameter were performed; 10-12 week old animals were randomly divided into groups of six individuals each for control, and doses of 40, 20, 10, and 4 mg/kg AgNP injected. Significant changes were observed (p < 0.01) in hematological parameters (WBC count, platelets counts, haemoglobin, and RBC count) in the 40 and 20 mg/kg groups. The changes were non-significant in the other groups (4 and 10 mg/kg group). In the 40 mg/kg group, a significant increase was also found in liver function enzymes like ALT and AST (p < 0.01), ALP (p < 0.01), GGTP (p < 0.01), and bilirubin (p < 0.01). ROS in blood serum increased in the high dose group. Tail migration in single cell gel electrophoresis in the 40, 20, 10, 4 mg/kg, and control groups was 34.9, 29.5, 17.8, 5.8, and 0.0 µm, respectively, which indicated damage in the DNA strand in the high dose group. EDXRF showed a ∼ 10-times increase in silver concentration in the 40 mg/kg group and TEM image also showed particle deposition in the 40 mg/kg group. This study indicates that the AgNP in doses (< 10 mg/kg) is safe for biomedical application and has no side-effects, but its high dose (> 20 mg/kg) is toxic.

Nanocrystalline silver: a systematic review of randomized trials conducted on burned patients and an evidence-based assessment of potential advantages over older silver formulations.

The aim of this meta-analysis was to collect data from randomized trials in burn patients and to analyze them with a meta-analytic approach to give a clear message of potential advantages of nanocrystalline silver (NC) versus older silver formulations (SS). A review of all-English prospective randomized trials that compared NC versus silver sulfadiazine or silver nitrate was conducted. Primary outcome was the evaluation of differences in the infection rate of burns. Secondary outcomes were the eventual differences in the pain experienced during medications, the length of hospitalization (LOS) and costs. Five articles that met the inclusion criteria were selected (n = 285 patients). The NC group had a significant lower incidence of infections compared with the SS group (9.5% vs. 27.8%, odds ratio: 0.14 [95% CI: 0.06-0.35]; chi2 test, P < 0.001), with a 2.9-fold decrease of the risk. Not all studies investigated the pain during change of dressings, LOS and costs. However, when data were available, these showed lower costs (US $1533 per patient for the SS group and US $946 per patient for the NC group) and decreased pain values in the NC group (Hedges' G: -1.44 [95% CI: -1.86/-1.01]; P < 0.0001), while contrasting results were obtained for LOS. Nanocrystalline silver is a relatively new product with a significant stronger antimicrobial activity compared with older formulations. Its long lasting properties reduce dressing change frequency and are probably responsible for the decreased pain and the minor costs experienced.

Assessment of antimicrobial microspheres as a prospective novel treatment targeted towards the repair of perianal fistulae.

BACKGROUND: None of the proposed materials tested for the management of perianal fistulae has proven to be a definitive treatment. AIM: To assess a new repair scaffold and drug delivery device conceived to target perianal fistula repair. METHODS: Poly(D,L-lactide-co-glycolide) porous microspheres containing either antibacterial silver-releasing degradable phosphate glass or metronidazole were prepared using thermally induced phase separation. RESULTS: Ion- and drug-release profiling of the microspheres revealed continued release of silver ions from microspheres filled with silver-doped phosphate glass and high encapsulation efficiency for metronidazole [78% and 82% for microspheres loaded with 2.5% and 1.3% (w/w), respectively]. Microbicidal activity was confirmed by growth inhibition of bacterial species (Staphylococcus aureus, Escherichia coli and Bacteroides fragilis), which characteristically dominate the colonization of perianal fistula tracts. Microspheres containing >3 mol% silver or metronidazole resulted in strong bacterial inhibition/kill against B. fragilis; the presence of one sphere containing >3 mol% silver had a potent inhibitory effect against all the microbes studied. Microspheres became rapidly integrated with host tissue following subcutaneous implantation into a rodent wound model. CONCLUSION: The study demonstrates a novel scaffold for guided tissue regeneration providing local release of antimicrobial agents sufficient to counter bacterial colonization and warrants further investigation.