Spatially engineering tri-layer nanofiber dressings featuring asymmetric wettability for wound healing

Inspired by the skin structure,an asymmetric wettability tri-layer nanofiber membrane(TNM)consisting of hydrophilic inner layer loaded with lidocaine hydrochloride(LID),hydrophobic middle layer with ciprofloxacin(CIP)and hydrophobic outer layer has been created.The hydrophobic outer layer endows the TNM with waterproof function and anti-adhesion from contaminants.The hydrophobic middle layer with CIP preserves long-term inhibition of bacteria growth and the hydrophilic inner layer with LID possesses optimal waterabsorbing capacity and air permeability.The TNM dramatically elevates the water contact angles from 10°(inner layer)to 120(outer layer),indicating an asymmetric wettability,which could directionally transport wound exudate within the materials and meanwhile maintain a comfortable and moist environment to promote wound healing.Furthermore,the sequential release of LID and CIP could relieve pain rapidly and achieve antibacterial effect in the long run,respectively.In addition,the TNM shows superior biocompatibility towards L929 cells.The in vivo results show the TNM could prevent infection,accelerate epithelial regeneration and significantly accelerate wound healing.This study indicates the developed TNM with asymmetrical wettability and synergetic drug release shows great potential as a wound dressing in clinical application.

Electrospun antibacterial nanofibers for wound dressings and tissue medicinal fields:A Review

Bacterial infections are a major cause of chronic infections.Thus,antibacterial material is an urgent need in clinics.Antibacterial nanofibers,with expansive surface area,enable efficient incorporation of antibacterial agents.Meanwhile,structure similar to the extracellular matrix can accelerate cell growth.Electrospinning,the most widely used technique to fabricate nanofiber,is often used in many biomedical applications including drug delivery,regenerative medicine,wound healing and so on.Thus,this review provides an overview of all recently published studies on the development of electrospun antibacterial nanofibers in wound dressings and tissue me-dicinal fields.This reviewer begins with a brief introduction of electrospinning process and then discusses electrospun fibers by incorporating various types of antimicrobial agents used as in wound dressings and tissue.Finally,we finish with conclusions and further perspectives on electrospun antibacterial nanofibers as 2D biomedicine materials.

Antibacterial and angiogenic dual-functional fibrous membrane dressing for infected wound healing

Background:Skin,being a vital organ that regulates physiological responses in the human body,is prone to injury from external environmental factors.Healing full-thickness skin defects becomes especially challenging when infections and vascular injuries are involved.Traditional wound dressings with single functions,such as antibacterial or angiogenic properties,fall short in achieving rapid wound healing.To address this,there is a need to develop wound dressing materials that possess both effective antibacterial and angiogenic properties.Methods:In this study,we utilized electrospinning technology to fabricate hyaluronic acid-cellulose acetate fibrous membrane dressings,incorporating poly(ionic liquid)as an antibacterial polymer and deferoxamine as an angiogenic agent.Results:The resulting fibrous membrane dressing contained poly(ionic liquid)and deferoxamin showcased a microporous structure,drug-releasing capabilities,and excellent air permeability.It not only demonstrated highly effective antibacterial properties but also exhibited remarkable angiogenesis,thereby promoting the healing of full-thickness skin defect wounds in both in vitro and in vivo assays.Conclusion:These findings highlight the immense potential of this wound dressing material for future clinical applications.

Janus hydrogel/electrospun-membrane dressing enhancing wound healing in rats

Background:Excessive exudate secreted from chronic wounds often leads to overhydration and infection.Although a variety of dressings are currently available in clinical applications,they frequently fail to provide multifunction to promote chronic wound healing.The dressings with a Janus structure,featuring distinct properties on each side,are potential to improve wound healing.Methods:Composite dressings with a Janus structure were fabricated,comprising freeze-dried polycaprolactone(PCL)electrospun membrane and alginate-based hydrogel.The PCL fibrous membrane provided air permeability,while the hydrogel loaded with Deferoxamine,composed of alginate and poly(N-isopropylacrylamide)(PNIPAM),exhibited hygroscopic properties.The inclusion of PNIPAM imparted thermo-responsivity.Results:The hydrogel(thickness of 2.778±0.082 mm)exhibited a robust adhesion to the fiber membrane(thickness of 0.261±0.041 mm).For ANDC(Alginate-PNIPAM hydrogel with Deferoxamine/PCL membrane)samples,the water vapor transmission rate(WVTR)was measured to be 3364.80±23.23 g∙m−2∙day−1 and the swelling ratio at 2 h was determined to be 1179±125%.The thermo-responsivity of ANDC samples manifested in an increased swelling rate,escalating from 797±189%at 37°C to 1132±147%at 4°C.The elastic modulus was assessed for lyophilized and rehydrated ANDC sample.When theωof the rheometer rotor was decreased from 10 rad/s to 0.1 rad/s,the lyophilized dressing exhibited a decrease from 2.65±0.01 MPa to 1.80±0.90 MPa,while the rehydrated dressing demonstrated an increase from 133.65±55.68 Pa to 264.23±141.71 Pa.The pro-healing properties of the dressings were evaluated using full-thickness skin defect model on SD rats,and a circular wound of diameter 10 mm healed completely by day 12.Conclusion:The dressings not only protected the wound and absorbed excess exudate,but also demonstrated nondestructive peelability upon cooling,providing a novel approach for accelerating wound healing and management.

Application Experience of Moist Wound Healing Theory Combined with Modern New Dressings in the Treatment of Pressure Ulcers

Objective:Research on the effect of moist wound healing theory in a combination with modern new dressing treatment in patients diagnosed with pressure ulcers.Method:Selected 30 patients with pressure ulcers from our hospital,which is Shandong Tai an Municipal Hospital,from January 2019 to January 2021 were divided into experimental group(15 cases,treated with moist wound healing theory combined with modern new dressings)and control group(15 cases,applied conventional treatments).The treatment effect,time of wound edema subsidence,wound healing time,number of dressing changes,granulation tissue growth time,and diameter reduction time were compared between the two groups.Results:The total effective rate of the experimental group(93.33%,14/15)was higher than that of the control group(53.33%,8/15),P<0.05;the time to subsidence of wound edema in the experimental group was(3.11±0.22),and the time for wound healing was(12.78±0.45),the number of dressing changes(7.13±0.34)times,the growth time of granulation tissue(5.43±2.22),the diameter reduction time(6.25±3.75),compared with the control group,P<0.05.Conclusion:In the clinical treatment of patients diagnosed with pressure ulcers,the effective combination of moist healing theory and modern new dressing therapy has significant effects,whereby it speeds up the healing process of the pressure ulcers,and it is proven to be worthy to be promoted for usage.

Functionalization of carbopol with NVP for designing antibiotic drug loaded hydrogel dressings for better wound management

In the present work an attempt has been made to design the antibiotic drug loaded carbopolpoly( NVP) based hydrogel wound dressings for better wound care. The polymer films were characterized by SEM-EDX, AFM, FTIR, 13CNMR, TGA/DTA/DTG, DSC, and swelling studies. Besides drug release, various biomedical properties (viz. blood compatibility, mucoadhesion, oxygen permeability, water vapour transmission rate, microbial penetration, tensile strength, bursting strength, resilience, stress relaxation, and folding endurance) have also been studied. The polymer films have been observed to be biocompatible, permeable to oxygen and water vapour and have absorbed simulated wound fluid 11.37±0.31g/g of polymer film. The drug release profile followed the Case-II diffusion mechanism and release profile best fitted in Hixson-Crowell’s kinetic models. Mechanical properties results showed that the polymer film had 0.65±0.12 Nmm??2 tensile strength, 119.38±14.26% elongationand 25.49±0.72% resilience.

Development of polyurethane foam dressing containing silver and asiaticoside for healing of dermal wound

Polyurethane foam dressings for dermal wounds were formulated with natural polyols in order to improve the foam characteristics and the release of 2 active agents,silver and asiaticoside(AS)as an antimicrobial agent and an herbal wound healing agent,respectively.The foam was instantly formed by interaction of polyols and diisocyanate.Hydroxypropyl methylcellulose,chitosan and sodium alginate were individually mixed with themain polyols,polypropylene glycol,in the formulation while the active componentswere impregnated into the obtained foam dressing sheets.Although the type and amount of the natural polyols slightly affected the pore size,water sorption-desorption profile and compression strength of the obtained foam sheets,a prominent effect was found in the release of both active components.Among natural polyols formulations,foam sheets with alginate showed the highest silver and AS release.Non-cytotoxicity of these foam sheets to human fibroblast cells was confirmed.Antimicrobial testing on four bacteria strains showed that 1mg/cm^2 silver in formulations with 6%of natural polyols and without natural polyols had sufficient content of the silver release with comparable inhibition zone and significantly larger zone than other formulations.In pig study,the foam dressing with 6%alginate,1mg/cm^2 silver and 5%AS could improve wound healing in both the percentage of the wound closure and histological parameters of the dermal wound without any dermatologic reactions.In conclusion,this innovative foam dressing had potential to be a good candidate for wound treatment.

Antibacterial biomaterials for skin wound dressing

Bacterial infection and the ever-increasing bacterial resistance have imposed severe threat to human health.And bacterial contamination could significantly menace the wound healing process.Considering the sophisticated wound healing process,novel strategies for skin tissue engineering are focused on the integration of bioactive ingredients,antibacterial agents included,into biomaterials with different morphologies to improve cell behaviors and promote wound healing.However,a comprehensive review on antibacterial wound dressing to enhance wound healing has not been reported.In this review,various antibacterial biomaterials as wound dressings will be discussed.Different kinds of antibacterial agents,including antibiotics,nanoparticles(metal and metallic oxides,lightinduced antibacterial agents),cationic organic agents,and others,and their recent advances are summarized.Biomaterial selection and fabrication of biomaterials with different structures and forms,including films,hydrogel,electrospun nanofibers,sponge,foam and three-dimension(3D)printed scaffold for skin regeneration,are elaborated discussed.Current challenges and the future perspectives are presented in thismultidisciplinary field.We envision that this review will provide a general insight to the elegant design and further refinement of wound dressing.

Molecular design, synthesis strategies and recent advances of hydrogels for wound dressing applications

With the changes in the modern disease spectrum,pressure ulcers,diabetic feet,and vascular-derived diseases caused refractory wounds is increasing rapidly.The development of wound dressings has partly improved the effect of wound management.However,traditional wound dressings can only cover the wound and block bacteria,but are generally powerless to recurrent wound infection and tissue healing.There is an urgent need to develop a new type of wound dressing with comprehensive performance to achieve multiple effects such as protecting the wound site from the external environment,absorbing wound exudate,anti-inflammatory,antibacterial,and accelerating wound healing process.Hydrogel wound dressings have the aforementioned characteristics,and can keep the wound in a moist environment because of the high water content,which is an ideal choice for wound treatment.This review introduces the wound healing process and the development and performance advantages of hydrogel wound dressings.The choice of different preparation materials gives the particularities of different hydrogel wound dressings.It also systematically explains the main physical and chemical crosslinking methods for hydrogel synthesis.Besides,in-depth discussion of four typical hydrogel wound dressings including double network hydrogels,nanocomposite hydrogels,drug-loaded hydrogels and smart hydrogels fully demonstrates the feasibility of developing hydrogels as wound dressing products and their future development trends.

Beneficial effects of a novel shark-skin collagen dressing for the promotion of seawater immersion wound healing

Background: Wounded personnel who work at sea often encounter a plethora of difficulties. The most important of these difficulties is seawater immersion. Common medical dressings have little effect when the affected area is immersed in seawater, and only rarely dressings have been reported for the treatment of seawater-immersed wounds. The objective of this study is to develop a new dressing which should be suitable to prevent the wound from seawater immersion and to promote the wound healing.Methods: Shark skin collagen(SSC) was purified via ethanol de-sugaring and de-pigmentation and adjusted for p H. A shark skin collagen sponge(SSCS) was prepared by freeze-drying. SSCS was attached to an anti-seawater immersion polyurethane(PU) film(SSCS+PU) to compose a new dressing. The biochemical properties of SSC and physicochemical properties of SSCS were assessed by standard methods. The effects of SSCS and SSCS+PU on the healing of seawaterimmersed wounds were studied using a seawater immersion rat model. For the detection of SSCS effects on seawaterimmersed wounds, 12 SD rats, with four wounds created in each rat, were divided into four groups: the 3 rd day group, 5 th day group, 7 th day group and 12 th day group. In each group, six wounds were treated with SSCS, three wounds treated with chitosan served as the positive control, and three wounds treated with gauze served as the negative control. For the detection of the SSCS+PU effects on seawater-immersed wounds, 36 SD rats were divided into three groups: the gauze(GZ)+PU group, chitosan(CS)+PU group and SSCS+PU group, with 12 rats in each group, and two wounds in each rat. The wound sizes were measured to calculate the healing rate, and histomorphology and the immunohistochemistry of the CD31 and TGF-β expression levels in the wounded tissues were measured by standard methods.Results: The results of Ultraviolet-visible(UV-vis) spectrum, Fourier-transform infrared(FTIR) spectrum, circular dichroism(CD) spectra, sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE), and amino acid composition analyses of SSC demonstrated that SSC is type I collagen. SSCS had a homogeneous porous structure of approximately 200μm, porosity rate of 83.57%±2.64%, water vapor transmission ratio(WVTR) of 4500 g/m2, tensile strength of 1.79±0.41 N/mm, and elongation at break of 4.52%±0.01%. SSCS had significant beneficial effects on seawater-immersed wound healing. On the 3 rd day, the healing rates in the GZ negative control, CS positive control and SSCS rats were 13.94%±5.50%, 29.40%±1.10% and 47.24%±8.40%, respectively. SSCS also enhanced TGF-in the initial stage of the healing period. The SSCS+PU dressing effectively protected woundsβ and CD31 expression from seawater immersion for at least 4 h, and accelerated re-epithelialization, vascularization and granulation formation of seawater-immersed wounds in the earlier stages of wound healing, and as well as significantly promoted wound healing. The SSCS+PU dressing also enhanced expression of TGF-n and gauze dressings.β and CD31. The effects of SSCS and SSCS+PU were superior to those of both the chitosaConclusion: SSCS has significant positive effects on the promotion of seawater-immersed wound healing, and a SSCS+PU dressing effectively prevents seawater immersion, and significantly promotes seawater-immersed wound healing.

Effects and mechanisms of a microcurrent dressing on skin wound healing: a review

The variety of wound types has resulted in a wide range of wound dressings, with new products frequently being introduced to target different aspects of the wound healing process. The ideal wound dressing should achieve rapid healing at a reasonable cost, with minimal inconvenience to the patient. Microcurrent dressing, a novel wound dressing with inherent electric activity, can generate low-level microcurrents at the device-wound contact surface in the presence of moisture and can provide an advanced wound healing solution for managing wounds. This article offers a review of the effects and mechanisms of the microcurrent dressing on the healing of skin wounds.

Improving the Antibacterial Property of Chitosan Hydrogel Wound Dressing with Licorice Polysaccharide

A series of hydrogels with different ratios of chitosan and licorice polysaccharide(LP)were prepared by crosslinking to different concentrations of genipin(gp).They were characterized by FTIR(Fourier transform infrared spectroscopy),SEM(Scanning electron microscope),swelling ratio,rheological measurements,degradation with time,cytotoxicity,and antibacterial efficacy.Results show that the hydrogels have porous structures.With an increase in LP content,the swelling rate grows in the early stage of immersion in buffer and drops later.The swelling ratio ranged from 986%to 1677%,and stiffness varied from 777 Pa to 1792 Pa.The addition of LP reduced the mechanical strength and delayed gelation and degradation of the hydrogels.However,the most important discovery was that gp increases the viability of NIH 3T3 cells from 94%to 137%,and LP raises the bacteriostatic efficacy from 51%to 78%.Hydrogels synthesized from 1%genipin,3%chitosan,and 4%licorice polysaccharide showed the best antibacterial and fibroblast proliferation promoting activities.They exhibited moderate swelling and degradation rates over time,while being more suitable to affect healing of chronic wound infections.These results provide a new strategy to improve the antibacterial effectiveness and cyto-compatibility of chitosan hydrogels with water soluble active LPs from Glycyrrhiza that derive from traditional Chinese medicine.

Collagen/Chitosan Electrospun Nanofibrous Membrane for Wound Dressing

Collagen(Col)/chitosan(CS)nanofibrous membrane has great potential to be used as wound dressing.However,current Col/CS nanofibrous membrane produced from electrospinning can not offer sufficient mechanical strength for practical applications.Herein,a novel mixed solvent was used to prepare next-generation high-strength Col/CS nanofibrous membrane.Meanwhile,the optimal Col to CS weight ratio was investigated as well.The asproduced membrane was examined by scanning electron microscopy(SEM),attenuated total reflectance Fourier transform infrared spectroscopy(ATR-FTIR),differential scanning calorimetry(DSC),and XF-1A tester to study its morphological,chemical,thermal and mechanical properties.The preliminary results demonstrated that the mechanical properties of Col/CS nanofibrous membranes were enhanced substantially with the increase of CS weight ratios from 0 to 90%and the optimal Col to CS weight ratio was determined to be 1∶1.A promising way was presented to fabricate Col/CS electrospun nanofibrous membrane with sufficient mechanical strength for practical wound dressing applications.

Enhancement of Gingival Wound Healing by Local Application of Silver Nanoparticles Periodontal Dressing Following Surgery: A Histological Assessment in Animal Model

Background: The value of periodontal dressing and its effects on periodontal wound healing have been questioned. Besides, the early healing of the gingival and periodontal wounds in oral cavity should be emphasized to promote the treatment outcome. Several studies pointed out a potential positive effect of silver nanoparticles (NPs) on the healing process of skin wounds. The present work aimed to design silver NPs periodontal dressing and then, evaluated its effects on gingival wound healing following operation. Methods: Thirty healthy adolescent female rabbits were used in this study. They had intact teeth and the clinical and radiographic examination revealed no periodontal disease. Silver NPs were added to carbonate methyl cellulose as base with two different concentrations of 25% v/v (Group A) and 50% v/v (Group B). On the basis of simple randomized allocation, gingivectomy was performed at the buccal gingiva of the left and right mandibular incisors and subsequently, untreated wounds in the control area were covered with periodontal pack and periodontal dressings A and B were applied in the test regions. Histological changes were monitored in day 4 and 7 post operation to evaluate the inflammatory and repair stage of healing process. Results: We observed significant difference in the inflammatory and repair parameters of the healing process between surgical sites treated with this periodontal dressing and control group. Besides, wounds treated with silver NPs dressing in general terms had all the hallmarks of relatively complete healing one week post operatively. Conclusion: The results indicated positive potential therapeutic effects for this new formulation of periodontal dressing on acceleration of surgical wound healing that led to improvement of periodontal treatment consequences following operation.

Preliminary Clinical Study Using a Novel Wound Dressing Composed of Hyaluronic Acid and Collagen Containing EGF

This clinical trial aimed to evaluate the efficacy and safety of a novel wound dressing composed of hyaluronic acid (HA) and collagen (Col) containing epidermal growth factor (EGF), referred to as EGF-wound dressing. EGF-wound dressing was prepared by freeze-drying a mixed aqueous solution of high-molecular-weight HA, low-molecular-weight HA and heat-denatured Col containing EGF. EGF-wound dressing was applied to skin defects, such as intractable skin ulcers, burn ulcers, traumatic skin defects and skin donor-site wounds. The dressing was changed twice a week for a period of 6 weeks or longer, if necessary. The primary endpoints were size of wound area, formation of granulation tissue, extent of epithelialization, infection control and macroscopic appearance. Effectiveness, safety and overall clinical evaluation were scored by plastic surgeons, as authorized by the Japanese Society of Plastic and Reconstructive Surgery. This study was registered with the University Hospital Medical Information Network (UMIN0000005264). Healthy granulation tissue and rapid epithelialization were observed for a given period after application of EGF-wound dressing onto the wounds. Most cases were assessed as having achieved good or excellent results. This clinical study demonstrated that EGF-wound dressing was beneficial in the treatment of various skin defects.

A novel microcurrent dressing for wound healing in a rat skin defect model

Background:The exogenous application of low-intensity electric stimulation(ES)may mimic a natural endogenous bioelectric current and accelerate the repair process of skin wounds.This study designed a novel microcurrent dressing(MCD)and evaluated its potential effects on wound healing in a rat skin defect model.Methods:First,wireless ES was integrated into a medical cotton cushion to fabricate the MCD,and its electrical property was examined by using a universal power meter.Then,animal experiments were conducted to evaluate the MCD’s effect.Forty-five rats were randomized into control(Con)group,Vaseline gauze(VG)group and MCD group.A full-thickness round skin incision 1.5 cm in diameter was made on the back of each animal.Apart from routine disinfection,the Con rats were untreated,whereas the other two groups were treated with VG or MCD.On days 3,7 and 14 post injury,the wound areas were observed and measured using image analysis software following photography,and the skin samples were harvested from wound tissue.Then,histopathological morphology was observed routinely by hematoxylin and eosin(HE)staining;tumor necrosis factorα(TNF-α)and interleukin(IL)-1βexpression were detected by Western blotting.Vascular endothelial growth factor(VEGF)and epidermal growth factor(EGF)expression were detected with immunohistochemistry.Results:The MCD generated a sf electric potential greater than 0.95 V.Animal experiments showed that the woundhealing rate in the MCD group was significantly increased compared with the Con and VG groups(P<0.05 or P<0.01).Histopathological observation revealed an alleviated inflammatory response,induced vascular proliferation and accelerated epithelization in the MCD group.Moreover,samples from the MCD group expressed reduced TNF-αand IL-1βlevels and increased VEGF and EGF levels compared with those of the other two groups(P<0.05 or P<0.01).However,no significant difference was noted between the Con and VG groups at each time point.Conclusions:The MCD generates a stable and lasting ES and significantly promotes wound healing by reducing inflammation duration and increasing growth factors expression.Thus,MCD may act as a promising biomaterial device for skin wound healing.

Development of a poly(arylene sulfide sulfone)antibacterial electrospun film as a skin wound dressing application

Tissue engineering has become a hot issue for skin wound healing because it can be used as an alternative treatment to traditional grafts.Nanofibrous films have been widely used due to their excellent properties.In this work,an organic/inorganic composite poly(arylene sulfide sulfone)/ZnO/graphene oxide(PASS/ZnO/GO)nanofibrous film was fabricated with the ZnO nano-particles blending in an electrospun solution and post-treated with the GO deposition.The optimal PASS/ZnO/GO nanofibrous film was prepared by 2%ZnO nanoparticles,3.0g/mL PASS electrospun solution,and 1%GO dispersion solution.The morphology,hydrophilicity,mechanical property,and cytotoxicity of the PASS/ZnO/GO nanofibrous film were character-ized by using scanning electron microscopy,transmission electron microscope,water contact angle,tensile testing,and a Live/Dead cell staining kit.It is founded that the PASS/ZnO/GO nanofibrous film has outstanding mechanical properties and no cytotoxicity.Furthermore,the PASS/ZnO/GO nanofibrous film exhibits excellent antibacterial activity to both Escherichia coli and Staphylococcus aureus.Above all,this high mechanical property in the non-toxic and antibacterial nanofibrous film will have excellent application prospects in skin wound dressing.

β-Chitin/Chitosan Obtained from Loligo and Humboldt Squids Effectiveness as Wound Dressing Material

A number of materials are utilized to develop wound care dressing materials with metallic treatments such as ionic silver and zinc. Metallic ions if used for a prolonged time may lead to toxicity. Alternatively chitin,a natural polysaccharide found in nature, is utilized. It is found in fungi, crabs, mushrooms,squids, octopus, and many other living organisms. Chitin has similar structure to cellulose but its deacetylated derivate chitosan has amine groups that provide potential antibacterial properties along with a number of other advantages. Chitin in its natural form is found in three different structural forms,namely α,β,and γ.The β-chitin and chitosan are mostly found in the exoskeleton of squids. Loligo and Humboldt squids were studied. It is anticipated that Humboldt chitin is more effective in serving as antibacterial material and can be utilized for wound care. Differences in steriochemical structure were observed among β-chitin structures obtained and amine group's presences were found along with ability of materials to swell.

Development of Composite Textile Structures for Wound Dressing Applications

The main objective of this research work was the development of novel and responsive nonwoven composite structures containing gelling materials for wound management. The development of novel all inclusive collagen booster(CB) therapeutic nonwoven wound dressings was mainly focused on. It provides essential functional properties such as high absorption,vertical and lateral wicking,and antibacterial and acidic pH properties. The developed composite wound dressing consisted of carboxymethylcellulose(CMC) fibre and also it was reinforced with polylactic acid( PLA) fibre. The produced composite wound dressings were treated with two different CBs at 4% by using the spray method. The details of the CBs have not been disclosed in this paper due to the Intellectual Property Rights( IPR) issues. The important benefit of using CB treatment is that it allows the maintenance of an acidic pH environment at the wound area. It is well known that acidic pH reduces the wound healing time and enhances the wound healing process. Furthermore,one of the CBs not only promotes the proliferation of the epithelial cells in wounds but also can provide antibacterial action. The PLA fibre reinforced CMC composite dressing has enhanced wicking properties which help to minimise the pooling of exudate on the wound bed and as a result maceration is prevented. The CBs treated dressings maintain the wound bed in an acidic pH condition which also improves the wound healing process. In addition to the above-mentioned properties,the CB treatment imparts antimicrobial activity against Gram-positive and Gram-negative bacteria,thus resulting in the reduction in the propensity for wound infection. Ultimately,the research has proved that the 4% CB treatment enhances the antimicrobial activity and the acidic pH characteristics of the developed CMC /PLA composite wound dressings.

Electrospun P(LLA-CL) Nanofibers Loaded with Vitamins E TPGS as Antibacterial Wound Dressing Materials

To obtain the wound dressings which can accelerate healing effectively,vitamin E D-α-Tocopherol polyethylene glycol succinate(vitamin E TPGS),one of the common derivatives of the unstable vitamins E,was successfully incorporated into P(LLA-CL)nanofibers by electrospinning.Electron microscopy showed that the smooth cylindrical fibers were obtained,albeit with a small amount of beading visible for the vitamins-loaded fibers.The diameters of the P(LLA-CL)fibers decreased with the addition of vitamins.The incorporation of the vitamin E TPGS in the electrospun fibers was confirmed by Fourier transform infrared spectroscopy(FTIR).Moreover,X-ray diffraction(XRD)indicated that vitamin E TPGS existed in the amorphous physical form after electrospinning.Fibers containing vitamin E TPGS showed a sustained release profile over more than 100 h in vitro.Antibacterial tests demonstrated that fibers loaded with vitamin E TPGS were effective in inhibiting the growth of E.coli and S.aureus.MTT assay showed that the fibers could promote the proliferation of L929 fibroblasts.These results above demonstrate the potential of P(LLA-CL)/vitamins E TPGS(P/E)as advanced wound dressing materials.