A systematic review and meta-analysis of clinical outcomes associated with nanocrystalline silver use compared to alternative silver delivery systems in the management of superficial and deep partial thickness burns

Effectiveness of four topical treatment methods in a rat model of superficial partial-thickness burn injury: the advantages of combining zinc-hyaluronan gel with silver foam dressing

BACKGROUND

There are several options available for conservative treatment of partial-thickness burns, however, reliable, affordable, and easily obtainable animal testing models are hard to find for the comparison of the different treatment methods. We aimed at developing a preclinical testing model and at comparing four treatment methods for superficial partial-thickness burns.

METHODS

Burn injury was induced in 90 adult male Wistar rats by placing the 130°C hot tip of a commercially obtainable soldering device for 30 s on the clipped skin of the interscapular region at a steady pressure. Skin histology was studied on days 5, 10, and 22 after the induction of the burn injury, on which days, respectively, the ratio of the not epithelialized wound (%), the extent of re-epithelialization (score), and the scar thickness (µm) were assessed. We compared 4 groups: silver-sulfadiazine cream, zinc-hyaluronan gel, silver foam dressing, and the combination of zinc-hyaluronan gel with a silver foam dressing.

RESULTS

On day 5, the induction of superficial partial-thickness burn injury was confirmed histologically in the rats. The zinc-hyaluronan gel and the combination treatment resulted in a markedly smaller ratio of the non-epithelialized area (29 ± 10% and 28 ± 13%, respectively) than silver-sulfadiazine cream (69 ± 4%; p < 0.01). On day 10, the extent of re-epithelialization was the lowest (∼0.2) in the silver-sulfadiazine cream group, while the other 3 treatments performed significantly better. The combination treatment lead to the maximal score of 2 in all rats, which was higher than in the other 3 treatment groups. On day 22, the scar thickness was the smallest in the combination treatment group (560 ± 42 µm), which was significantly less than in the silver-sulfadiazine cream group (712 ± 38 µm; p < 0.05).

CONCLUSIONS

We designed and histologically confirmed a reproducible method for induction of superficial partial-thickness burns in rats for preclinical testing. In our model, the combination of zinc-hyaluronan gel with silver foam dressing was more effective than either of its components alone or than silver-sulfadiazine cream.

Efficacy and costs of nanocrystalline silver dressings versus 1% silver sulfadiazine dressings to treat burns in adults in the outpatient setting: A randomized clinical trial

BACKGROUND

Nanocrystalline silver dressings can reduce the number of changes, facilitating burn wound management. However, the evidence regarding their efficacy and cost-consequences compared to well-established treatments, such as 1% silver sulfadiazine, is still scarce.

OBJECTIVE

To determine the efficacy, safety, and costs of nanocrystalline silver dressings compared to 1% silver sulfadiazine dressings to treat adult patients with burns.

STUDY DESIGN AND SETTING

Randomized, single-center, single-blind trial conducted at a referral hospital in São Paulo, Brazil.

METHODS

100 adult patients were randomized 1:1 to nanocrystalline silver (n = 50) or 1% silver sulfadiazine (n = 50). The primary outcome was the proportion of participants with complete re-epithelization at day 15 after randomization. Secondary outcomes included the number of dressing changes, direct medical costs (in international dollars, I$), pain intensity, the incidence of infections, number of patients undergoing surgery, and adverse events.

RESULTS

On day 15, the proportion of patients who reached the primary outcome did not differ significantly between participants treated with nanocrystalline silver dressings (24 [48%]) and those treated with 1% silver sulfadiazine dressings (26 [52%]); risk difference of -4.0 percentage points (95% confidence interval [CI], -17 to 9; P = 0.56). The number of patients undergoing surgical intervention was similar between groups (6% vs. 6%), and no local or serious adverse events were reported. The mean (standard deviation, SD) number of dressing changes in the nanocrystalline silver group was 4.1 (2.3), and the corresponding estimate in the 1% silver sulfadiazine group was 9.6 (6.7); mean difference of -5.56 (95% CI), -7.57 to -3.55, P < 0.001). Treatment with nanocrystalline silver dressing incurred significant cost reductions in medical materials, human resources, and administrative labor. However, the mean total cost with nanocrystalline silver dressing was higher compared to 1% silver sulfadiazine dressings: I$496.37 (445.90) vs. I$274.73 (182.76); mean difference = 221.63 (95% CI, 89.04 to 354.23, P = 0.001). The main driver of higher mean total costs among nanocrystalline silver-treated participants was the purchase cost of the dressings, representing 79.3% of the total cost in the nanocrystalline silver group but only 15.2% in the 1% silver sulfadiazine group.

CONCLUSION

We found no evidence of a difference between nanocrystalline silver and 1% silver sulfadiazine dressings regarding efficacy and safety outcomes. Nanocrystalline silver dressings were associated with an increase in the total costs, but they could result in important savings for an institution (less changes of dressings, reducing human resources burden), especially if acquisition costs can be decreased. Additional cost-effectiveness studies are warranted.

TRIAL REGISTRATION NUMBER

NCT02108535.

Management of non-severe burn wounds in children and adolescents: optimising outcomes through all stages of the patient journey

Paediatric burn injuries are common, especially in children younger than 5 years, and can lead to poor physical and psychosocial outcomes in the long term. In this Review, we aim to summarise the key factors and interventions before hospital admission and following discharge that can improve the long-term outcomes of paediatric burns. Care can be optimised through first aid treatment, correct initial assessment of burn severity, and appropriate patient referral to a burns centre. Scar prevention or treatment and patient follow-up after discharge are also essential. As most burn injuries in children are comparatively small and readily survivable, this Review does not cover the perioperative management associated with severe burns that require fluid resuscitation, or inhalational injury. Burns disproportionately affect children from low socioeconomic backgrounds and those living in low-income and middle-income countries, with ample evidence to suggest that there remains scope for low-cost interventions to improve care for those patients with the greatest burden of burn injury. Current knowledge gaps and future research directions are discussed.

Wound healing in second-degree burns in rats treated with silver sulfadiazine: a systematic review and meta-analysis

Objective:

This study aims to assess the wound healing efficacy in second-degree burns in rats treated with 1% silver sulfadiazine (SSD)—a sulfonamide antibiotic.

Method:

This is a systematic literature review and meta-analysis performed according to the PICO (Population, Intervention, Comparison and Outcomes) strategy.

Results:

The review found 100 studies in PubMed, Web of Science and other search engines. Of these, 70 studies were pre-selected after removing duplicates. After independent analysis by two reviewers, only seven studies met the inclusion criteria for meta-analysis. All studies except one showed faster wound closure by the application of silver sulfadiazine ointment. Using a random effects model, healing was faster in SSD-treated groups when compared to the control group on day 21, with a statistically significant mean difference of –2.72 days (95% confidence interval: –4.99, –0.45) between treatment and control groups (p<0.01).

Conclusion:

The results of this meta-analysis revealed that SSD aided in faster healing of second-degree burns.

Changes in Number and Antibacterial Activity of Silver Nanoparticles on the Surface of Suture Materials during Cyclic Freezing

This article presents the results of the 10-fold cyclic freezing (−37.0 °C) and thawing (0.0 °C) effect on the number and size range of silver nanoparticles (AgNPs). AgNPs were obtained by the cavitation-diffusion photochemical reduction method and their sorption on the fiber surface of various suture materials, perlon, silk, and catgut, was studied. The distribution of nanoparticles of different diameters before and after the application of the cyclic freezing/thawing processes for each type of fibers studied was determined using electron microscopy. In general, the present study demonstrates the effectiveness of using the technique of 10-fold cyclic freezing. It is applicable to increase the absolute amount of AgNPs on the surface of the suture material with a simultaneous decrease in the size dispersion. It was also found that the application of the developed technique leads to the overwhelming predominance of nanoparticles with 1 to 15 nm diameter on all the investigated fibers. In addition, it was shown that after the application of the freeze/thaw method, the antibacterial activity of silk and catgut suture materials with AgNPs was significantly higher than before their treatment by cyclic freezing.

Comparison of antimicrobial and wound-healing effects of silver nanoparticle and chlorhexidine mouthwashes: an in vivo study in rabbits

The objective is to formulate a silver nanoparticle mouthwash and then evaluate its antimicrobial and wound-healing effects in rabbit animal models. Microbial samples were collected from the oral cavity of 60 rabbits. Thereafter, standardized wounds were created in the lateral border of the tongue on the right side for all rabbits. After surgery, digital photographs were obtained from the wounds with standardized settings. To characterize the silver nanoparticles used in the synthetic mouthwash, transmission electron microscopy (TEM) and digital light scattering analysis were used. The animal models were then randomly divided into 4 groups: group 1 received 9.80 wt% silver nanoparticle mouthwash; group 2 received all the ingredients of the formulated mouthwash except for silver nanoparticles; group 3 received chlorhexidine 2.0% mouthwash; and the negative control group did not receive any postoperative mouthwash. Microbial samples were collected from oral cavity of the rabbits each day for four postoperative days. Colony-forming unit (CFU) counts were compared post-operatively with the pre-operative counts. In addition, standardized digital photographs were taken each day from the wounds and the area of the wounds was compared in postoperative and pre-operative images. Data were statistically analyzed using one-way ANOVA and repeated measures variance analysis (α = 0.05). TEM revealed spherical morphology of silver nanoparticles and digital light scattering showed an average size of 5 nm and optimal distribution of the nanoparticles. CFU count significantly decreased in groups 1 and 3 (P < 0.001), while it significantly increased in groups 2 and 4 (P < 0.001). Moreover, a significant difference was observed between the experimental groups (P < 0.001). In addition, wound area decreased significantly in all groups (P < 0.001). However, the difference between wound areas in the groups was not significant, except for the 4th postoperative day (P < 0.001). However, the antibacterial effects and the wound-healing characteristics of the synthetic silver nanoparticle and chlorhexidine mouthwashes were not significantly different (P > 0.05). Silver nanoparticle mouthwash possesses favorable antibacterial and wound-healing effects. The formulated 9.80 wt% silver nanoparticle mouthwash with a particle size of 5 nm can be a promising alternative for application after oral surgical procedures.

Variation in definitions of burn wound infection limits the validity of systematic review findings in burn care: A systematic review of systematic reviews

INTRODUCTION

Systematic reviews (SR) of high-quality randomised controlled trials can identify effective treatments for burn wound infections (BWIs). Clinical heterogeneity in outcome definitions can prevent valid evidence synthesis, which may limit the reliability of the findings of SRs affected by this heterogeneity. This SR aimed to investigate whether there is variation BWI definitions across studies in SRs of burn care interventions and its impact on identification of effective treatments for patients with burn injuries.

METHODS

A systematic search of five databases was conducted. Included SRs were: in English, published from January 2010 to October 2018, assessed intervention effects for patients with a burn injury, and reported data about BWI.

RESULTS

Twenty-nine SRs, which included 248 studies reporting BWI outcomes, were included in our final dataset. Three SRs used a definition of BWI to select studies for inclusion. Fourteen reported BWI definitions from included studies in the review results. There was heterogeneity of BWI definition in their included studies; across 29 SRs, 32 different BWI indicators were used, with the median across SRs ranging from 1 to 7 (range 1-14). Fourteen SRs accounted for BWI definition heterogeneity in their conclusions, indicating that the issue impacted whether a conclusion could be drawn, and limited the validity of the SR findings.

CONCLUSIONS

There is variation in BWI definition across SRs and within the studies included in SRs of interventions assessing BWI outcomes. This heterogeneity has prevented conclusions about intervention effects being drawn, and only half of the SR authors have accounted for it in their findings. Reviews that have collated this data without reference to the heterogeneity should be viewed with caution, since it may limit the validity of evidence for the identification of effective treatments for BWI. The use of a newly developed core indicator set to support consistent reporting of indicators and standardisation of BWI outcome reporting will enable effective evidence synthesis.

Efficacy and safety of nano-silver dressings combined with recombinant human epidermal growth factor for deep second-degree burns: A meta-analysis

OBJECTIVE

The purpose of this meta-analysis was to assess the efficacy and safety of nano-silver dressing combined with recombinant human epidermal growth factor for deep second-degree burns.

METHODS

PubMed, Web of Science, EMBASE, Cochrane Library and other databases were searched to identify relevant randomised controlled trials.

RESULTS

Twelve studies that assessed nano-silver dressing combined with recombinant human epidermal growth factor were identified. Nano-silver dressing combined with recombinant human epidermal growth factor for deep second-degree burns could significantly reduce the duration of wound healing (mean difference -5.68, 95% CI -7.38 - -3.99, P<0.00001), the wound healing rate (risk ratio [RR] 0.34, 95% CI 0.23-0.48, P<0.00001), the rate of scar hyperplasia (RR 0.67, 95% CI 0.54-0.84, P=0.0004), the wound bacterial positive rate (RR 0.50, 95% CI 0.28-0.89, P=0.02), and the adverse reactions rate (RR 0.31, 95% CI 0.16-0.58, P=0.0003).

CONCLUSION

This comprehensive meta-analysis of the available evidence suggest that the use of nano-silver dressing combined with recombinant human epidermal growth factor results in shorter duration of wound healing, reduced wound bacterial positive rates and adverse reactions rate, and improved wound healing rates.

A Systematic Review and Meta-Analysis of Clinical Effectiveness and Safety of Hydrogel Dressings in the Management of Skin Wounds

The purpose of this systematic review and meta-analysis is to assess the clinical effectiveness and safety of the medical hydrogel dressings used in skin wounds and therefore to weight the evidence for their clinical application. PubMed/Medline (1980–2019), Cochrane Library (1980–2019), ClinicalTrials.gov, Cochrane CENTRAL, Chinese Journal Full-text Database (CNKI, 1994–2019), and China Biomedy Medicine disc (CBM, 1978–2019), Chinese Scientific Journal Database (VIP, 1989–2019), and Wanfang Database (WFDATA, 1980–2019) were searched to identify relevant clinical trials and studies. Forty-three studies that assessed hydrogel vs. non-hydrogel dressings were identified. Compared to the latter, hydrogel dressings associated with a significantly shortened healing time of degree II burn (superficial and deep) wounds, diabetic foot ulcers, traumatic skin injuries, radioactive skin injuries, dog bites, and body surface ulcers. In addition, hydrogel dressing obviously increased the cure rate of diabetic foot ulcers, surgical wounds, dog bites, and body surface ulcers. Moreover, hydrogel dressing significantly relieved pain in degree II burn (superficial and deep) wounds, traumatic skin injuries, and laser treatment-induced wounds. However, no significant differences obtained between hydrogel and non-hydrogel dressings in the healing time of surgical wounds, the cure rate of inpatients' pressure ulcers, and phlebitis ulcers. This comprehensive systematic review and meta-analysis of the available evidence reveals that the application of hydrogel dressings advances the healing of various wound types and effectively alleviates the pain with no severe adverse reactions. These results strongly indicate that hydrogel products are effective and safe in wound management.

Antimicrobial Silver Nanoparticles for Wound Healing Application: Progress and Future Trends

Recent data have reported that the burden of infections related to antibiotic-resistant bacteria in the European Union and European Economic Area (EEA) can be estimated as the cumulative burden of tuberculosis, influenza, and human immunodeficiency virus (HIV). In wound management, the control of infections represents a crucial issue and a multi-billion dollar industry worldwide. For diabetic wounds ulcers, in particular, infections are related to the majority of amputations in diabetic patients, which today represent an increasing number of the elderly. The greatest barrier to healing is represented by the biofilm, an organized consortium of bacteria encapsulated in a self-produced extracellular polymeric substance with high resistance to conventional antimicrobial therapies. There is an urgent need for novel anti-biofilm strategies and novel antimicrobial agents and, in this scenario, silver nanotechnology has received tremendous attention in recent years in therapeutically enhanced healthcare. Due to its intrinsic therapeutic properties and the broad-spectrum antimicrobial efficacy, silver nanoparticles have opened new horizons towards novel approaches in the control of infections in wound healing. This review aims at providing the reader with an overview of the most recent progress in silver nanotechnology, with a special focus on the role of silver in the wound healing process.

Nanoparticles in dermatologic surgery

Nanotechnology is an emerging branch of science that involves the engineering of functional systems on the nanoscale (1-100 nm). Nanotechnology has been used in biomedical and therapeutic agents with the aim of providing novel treatment solutions where small molecule size may be beneficial for modulation of biologic function. Recent investigation in nanomedicine has become increasingly important to cutaneous pathophysiology, such as functional designs directed towards skin cancers and wound healing. This review outlines the application of nanoparticles relevant to dermatologic surgery.

The discovery and development of topical medicines for wound healing

INTRODUCTION

Chronic, nonhealing skin wounds claim >3% of the health-care budget in industrialized countries, and the incidence is rising. Currently, two parallel trends influence innovations within the field of wound healing: the need to reduce spread of antibiotic resistance and the emerging use of health economy and value-based models. Areas covered: This review focuses on the discovery of drug candidates and development of treatments aiming to enhance wound healing in the heterogeneous group of patients with nonhealing wounds. Expert opinion: Nonhealing wounds are multifaceted and recognized as difficult indications. The majority of products currently in use are medical device dressings, or concepts of negative pressure or hyperbaric oxygen treatment. Global best practice guidelines for the treatment of diabetic foot ulcers recommend debridement, redressing, as well as infection control, and are critical to the lack of coherent clinical evidence for many approved products in active wound care. To accelerate wound healing, there is an emerging trend toward biologics, gene therapy, and novel concepts for drug delivery in research and in the pipeline for clinical trials. Scientific delineation of the therapeutic mechanism of action is, in our opinion, vital for clinical trial success and for an increased fraction of medical products in the pharmaceutical pipeline.

Antimicrobial Silver in Medicinal and Consumer Applications: A Patent Review of the Past Decade (2007⁻2017)

The use of silver to control infections was common in ancient civilizations. In recent years, this material has resurfaced as a therapeutic option due to the increasing prevalence of bacterial resistance to antimicrobials. This renewed interest has prompted researchers to investigate how the antimicrobial properties of silver might be enhanced, thus broadening the possibilities for antimicrobial applications. This review presents a compilation of patented products utilizing any forms of silver for its bactericidal actions in the decade 2007⁻2017. It analyses the trends in patent applications related to different forms of silver and their use for antimicrobial purposes. Based on the retrospective view of registered patents, statements of prognosis are also presented with a view to heightening awareness of potential industrial and health care applications.

Antimicrobial Silver in Medicinal and Consumer Applications: A Patent Review of the Past Decade (2007⁻2017)

The use of silver to control infections was common in ancient civilizations. In recent years, this material has resurfaced as a therapeutic option due to the increasing prevalence of bacterial resistance to antimicrobials. This renewed interest has prompted researchers to investigate how the antimicrobial properties of silver might be enhanced, thus broadening the possibilities for antimicrobial applications. This review presents a compilation of patented products utilizing any forms of silver for its bactericidal actions in the decade 2007–2017. It analyses the trends in patent applications related to different forms of silver and their use for antimicrobial purposes. Based on the retrospective view of registered patents, statements of prognosis are also presented with a view to heightening awareness of potential industrial and health care applications.

Enhanced Antimicrobial Efficacy of Bimetallic Porous CuO Microspheres Decorated with Ag Nanoparticles

The antimicrobial action of porous CuO microspheres (μCuO), Ag nanoparticles (nAg), and bimetallic porous CuO microspheres decorated with Ag nanoparticles (μCuO/nAg) was evaluated against surrogate microorganisms representative of pathogens commonly implicated in foodborne and healthcare-associated human infections. This work addressed the Gram-negative bacteria E. coli (Escherichia coli O157:H7-GFP B6-914), Salmonella (Salmonella enterica serovar enteritidis phage-type PT21), and the Gram-positive bacteria Listeria (Listeria innocua), as well as environmental microorganisms derived from local river water. Compared to particles composed only of CuO or Ag, the bimetallic porous μCuO/nAg particle exhibits enhanced antimicrobial efficacy. The antimicrobial action of bimetallic porous μCuO/nAg particles is dose-dependent, with 50 μg/mL particle concentration completely inhibiting the growth of both the Gram-negative (Salmonella) and the Gram-positive (Listeria) bacteria after 6 h. To assess the mechanism of antimicrobial action, the changes in surface morphologies of bacteria treated with the particles were observed using scanning electron microscopy. In the case of the Gram-negative bacteria, the bacterial cell membrane is damaged, likely due to the release of metal ions from the particles; however, particle-induced cell membrane damage is not observed for Gram-positive bacteria. Collectively, results from this work shed further light on possible mechanisms of antimicrobial action of micro-/nanoparticles and highlight the potential for bimetallic particle-based inhibition of microbial infections.