Wound healing efficacy of a chitosan-based film-forming gel containing tyrothricin in various rat wound models

In Situ Release of Ulvan from Crosslinked Ulvan/Chitosan Complex Films and Their Evaluation as Wound Dressings

When a wound forms due to any injuries, it should be covered with a functional wound dressing for accelerating wound healing and reducing infection. In this study, crosslinked ulvan/chitosan complex films were prepared with or without the addition of glycerol and chlorophyll, and their wound healing properties were evaluated for potential application in wound dressing. The results showed that the tensile strength and elongation at break of the prepared ulvan/chitosan complex films were 2.23-2.48 MPa and 83.8-108.5%, respectively. Moreover, their water vapor transmission rates (WVTRs) were in the range of 1791-2029 g/m²-day, providing suitable environment for wound healing. Particularly, these complex films could release ulvan in situ in a short time, and the film with chlorophyll added had the highest release rate, reaching 62.8% after 20 min of releasing. In vitro studies showed that they were biocompatible toward NIH 3T3 and HaCaT cells, and promoted the migration of NIH 3T3 cells. These complex films could protect HaCaT cells from oxidative damage and reduce the production of reactive oxygen species (ROS); the addition of chlorophyll also effectively reduced the inflammatory response induced by LPS as found in the reduction in both NO and IL-6. Animal models showed that the complex films added with glycerol and chlorophyll could promote wound healing in the early stage, while accelerating the regeneration of dermal glands and collagen production. Briefly, these ulvan/chitosan complex films had good physiochemical properties and biological activity, and could accelerate wound healing both in vitro and in vivo.

Targeting Antibacterial Effect and Promoting of Skin Wound Healing After Infected with Methicillin-Resistant Staphylococcus aureus for the Novel Polyvinyl Alcohol Nanoparticles

INTRODUCTION

Topical agents typically remain in the wound site for time duration that are too short to effectively eradicate MRSA tradition formation of BZK that can be maintained within the wound site for longer time periods, should be more effective.

METHODS

The novel chitosan and poly (D,L-lactide-co-glycoside) nanoparticles loaded with benzalkonium bromide (BZK) were designed, for the promotion wound healing after MRSA infection. The physical characterization of these nanoparticles, as well as their antibacterial activity in vitro, release profile in simulated wound fluid, cell toxicity, anti-biofilm activity, and their ability to improve the skin wound healing in a mouse model were also studied.

RESULTS

These novel nanoparticles were found to have a significant antibacterial activity (p<0.01), both in vitro and in vivo test. The stronger anti-biofilm ability of the nanoparticles to inhibit the formation of bacterial biofilms, at a concentration of 3.33 μg/mL, and clear existing bacterial biofilms, at a concentration of 5 mg/mL, compared with its water solution. In addition, significant damage to bacterial cell walls also was found, providing insight into the mechanism of antibacterial activity.

CONCLUSION

Taken together, these results demonstrated the ability of BZK-loaded nanoparticles in the promotion of skin wound healing with MRSA infection. The current findings open a new avenue for nanomedicine development and future clinical applications in the treatment of wounds.

Chitosan-polyvinyl alcohol nanoscale liquid film-forming system facilitates MRSA-infected wound healing by enhancing antibacterial and antibiofilm properties

Introduction

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most predominant and fatal pathogens at wound infection sites. MRSA is difficult to treat because of its antibiotic resistance and ability to form biofilms at the wound site.

Methods

In this study, a novel nanoscale liquid film-forming system (LFFS) loaded with benzalkonium bromide was produced based on polyvinyl alcohol and chitosan.

Results

This LFFS showed a faster and more potent effect against MRSA252 than benzalkonium bromide aqueous solution both in vitro and in vivo. Additionally, the LFFS had a stronger ability to destroy biofilms (5 mg/mL) and inhibit their formation (1.33 μg/mL). The LFFS inflicted obvious damage to the structure and integrity of MRSA cell membranes and caused increases in the release of alkaline phosphate and lactate dehydrogenase in the relative electrical conductivity and in K⁺ and Mg²⁺ concentrations due to changes in the MRSA cell membrane permeability.

Conclusion

The novel LFFS is promising as an effective system for disinfectant delivery and for application in the treatment of MRSA wound infections.

Effect of biogenic silver nanocubes on matrix metalloproteinases 2 and 9 expressions in hyperglycemic skin injury and its impact in early wound healing in streptozotocin-induced diabetic mice

Microbial contamination along with over expressions of matrix metalloproteinases 2 and 9 impairs wound healing in diabetic patients. Silver-based antimicrobial agents have been successfully used for treating non-healing chronic wounds associated with infection. However, topical application of silver-ion compounds impairs wound healing process. Thus, usage of biogenic silver nanoparticles appears as a new means to reduce the toxicity of silver compounds in the wound care system. Here, following our previous method, AgNPs was synthesized using the culture filtrate of Brevibacillus brevis KN8(2) then characterized by UV-visible spectrophotometry, TEM, SAED, XRD and DLS measurements. The antibacterial activity of AgNPs was evaluated against the most common wound infecting pathogens Pseudomonas aeruginosa and Staphylococcus aureus by well diffusion assay. Further, the wound healing efficacy of biogenic AgNPs was examined in streptozotocin-induced diabetic mice by measuring wound area closure, histopathology, mRNA and protein expressions of MMP-2, MMP-9. Our results demonstrates that besides antimicrobial activity, biogenic AgNPs decreased the mRNA and protein expression of MMP-2 and MMP-9 in wounded granulation tissues leads to early wound healing in diabetic mice. These findings revealed that biogenic AgNPs synthesized from B. brevis KN8(2) could be an effective therapeutic agent in the management of diabetic foot ulcer with/without infection.

Nanomedicine and advanced technologies for burns: Preventing infection and facilitating wound healing

According to the latest report from the World Health Organization, an estimated 265,000 deaths still occur every year as a direct result of burn injuries. A widespread range of these deaths induced by burn wound happens in low- and middle-income countries, where survivors face a lifetime of morbidity. Most of the deaths occur due to infections when a high percentage of the external regions of the body area is affected. Microbial nutrient availability, skin barrier disruption, and vascular supply destruction in burn injuries as well as systemic immunosuppression are important parameters that cause burns to be susceptible to infections. Topical antimicrobials and dressings are generally employed to inhibit burn infections followed by a burn wound therapy, because systemic antibiotics have problems in reaching the infected site, coupled with increasing microbial drug resistance. Nanotechnology has provided a range of molecular designed nanostructures (NS) that can be used in both therapeutic and diagnostic applications in burns. These NSs can be divided into organic and non-organic (such as polymeric nanoparticles (NPs) and silver NPs, respectively), and many have been designed to display multifunctional activity. The present review covers the physiology of skin, burn classification, burn wound pathogenesis, animal models of burn wound infection, and various topical therapeutic approaches designed to combat infection and stimulate healing. These include biological based approaches (e.g. immune-based antimicrobial molecules, therapeutic microorganisms, antimicrobial agents, etc.), antimicrobial photo- and ultrasound-therapy, as well as nanotechnology-based wound healing approaches as a revolutionizing area. Thus, we focus on organic and non-organic NSs designed to deliver growth factors to burned skin, and scaffolds, dressings, etc. for exogenous stem cells to aid skin regeneration. Eventually, recent breakthroughs and technologies with substantial potentials in tissue regeneration and skin wound therapy (that are as the basis of burn wound therapies) are briefly taken into consideration including 3D-printing, cell-imprinted substrates, nano-architectured surfaces, and novel gene-editing tools such as CRISPR-Cas.

Lung cancer and β-glucans: review of potential therapeutic applications

The potential of natural substances with immunotherapeutic properties has long been studied. β-glucans, a cell wall component of certain bacteria and fungi, potentiate the immune system against microbes and toxic substances. Moreover, β-glucans are known to exhibit direct anticancer effects and can suppress cancer proliferation through immunomodulatory pathways. Mortality of lung cancer has been alarmingly increasingly worldwide; therefore, treatment of lung cancer is an urgent necessity. Numerous researchers are now dedicated to using β-glucans as a therapy for lung cancer. In the present attempt, we have reviewed the studies addressing therapeutic effects of β-glucans in primary and metastatic lung cancer published in the time period of 1991-2016.