Medical Dressings Research Articles

Progress in Antibacterial Hydrogel Dressing.

Antibacterial hydrogel has excellent antibacterial property and good biocompatibility, water absorption and water retention, swelling, high oxygen permeability, etc.; therefore, it widely applied in biomedicine, intelligent textiles, cosmetics, and other fields, especially for medical dressing. As a wound dressing, the antibacterial hydrogel has the characteristics of absorbing wound liquid, controlling drug release, being non-toxic, being without side effects, and not causing secondary injury to the wound. Its preparation method is simple, and can crosslink via covalent or non-covalent bond, such as γ-radiation croFsslinking, free radical polymerization, graft copolymerization, etc. The raw materials are easy to obtain; usually these include chondroitin sulfate, sodium alginate, polyvinyl alcohol, etc., with different raw materials being used for different antibacterial modes. According to the hydrogel matrix and antibacterial mode, the preparation method, performance, antibacterial mechanism, and classification of antibacterial hydrogels are summarized in this paper, and the future development direction of the antibacterial hydrogel as wound dressing is proposed.

Organic-free growth of gold nanosheets inside 3D bacterial cellulose as highly efficient and robust antibacterial biopolymers.

Without any chemical agent, gold nanosheets (AuNSs) were controllable synthesized through a facile photo-induced reduction within bacterial cellulose (BC) biopolymers. Compared with traditional polymers, AuNSs modified BC biopolymers (AuNSs@BC) biopolymers exhibited similar levels of softness, ductility, and better tensile strength. The in situ constructing of AuNSs@BC biopolymers was demonstrated to provide great reusability and antibacterial activities and towards both of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The optimized AuNSs@BC biopolymers remain at least 95% antibacterial activities after three cycles. The facile and shape-controlled synthesis of AuNSs@BC biopolymers is believed to be useful for the design and application of biomass-based medical dressing.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10853-022-07273-x.

Scalable Electrospinning Methods to Produce High Basis Weight and Uniform Drug Eluting Fibrous Biomaterials

Electrospinning is a process for fabricating nonwoven fibrous materials of versatile composition and form that has shown enormous promise as medical wound dressings, tissue engineered scaffolds, and for pharmaceutical delivery. However, pharmaceutical application and clinical translation of electrospun fibers requires a scalable process to control mass deposition and uniformity in the finished materials. Here, we show that free-surface electrospinning using a stationary wire electrode can generate fiber materials with high productivity and controllable deposition to achieve uniform area density (basis weight) that is relevant for scalable pharmaceutical dosage form production. Using a production-scale instrument, we performed statistically designed optimization experiments to identify a combination of parameters that improved productivity up to 13 g/h. By combining this optimization with process controls for dynamic movement of the electrospinning substrate, we also demonstrate the production of uniform and high area density materials of 50–120 G per square meter. We verified our process by fabricating a triple drug solid dosage form at a high area target density (100 g/m2) that largely showed less than a 10% coefficient of variation in mass or drug content. The process developed here provides a general approach for optimizing different material compositions for high productivity and uniformity, and advances the use of free-surface electrospinning for manufacturing fiber-based biomedical materials.

Coupling between acid precipitation and resin adsorption for purifying alkaline extracted hemicellulose from sugarcane bagasse

Hemicellulose is considered the second most renewable component in lignocellulosic biomass after cellulose, and can be used in value-added industrial applications including medical dressing, packaging materials and hydrogels. Hence, the purification methods of different acid precipitation conditions, ethanol precipitation and resin adsorption were investigated. In this paper, the results showed that most of the lignin was removed by acid precipitation. With the adjustment of pH value from 6 to 2 by acid precipitation, the less lignin remains in hemicellulose samples, the higher the purity of hemicellulose. After resin adsorption treatment, the molecular weight of hemicellulose increased slightly and the weight average molecular weight of Ha2 (Ha2 is hemicelluloses precipitated at pH = 2) is 7.91 × 104 g/mol among, the branching degree of hemicellulose decreased slightly, the thermal stability of hemicellulose increased slightly. It can be shown from 2D HSQC NMR that the structure of hemicellulose did not change significantly before or after adsorption and at different pH values. Trace lignin-carbohydrate complexes (LCCs) structures were remained in hemicellulose sample. The slight loss of hemicellulose caused by resin adsorption is due to LCCs. The sensitivity of XAD-16N resin to phenyl glycoside bond (PhGlc) of different forms was different.

The contribution of undergraduate medical education dress codes to systemic discrimination: A critical policy analysis.

Critical review of institutional policies is necessary to identify and eliminate structural discrimination in medical schools. Dress code policies are well known to facilitate discrimination in other settings. In this critical policy analysis, the authors used qualitative inquiry guided by feminist critical policy analysis (FCPA) and critical race feminism (CRF) frameworks to understand how Canadian undergraduate medical school dress code policies may contribute to discrimination and a hostile culture for marginalised groups. Dress code policies were obtained from 14 of 17 Canadian medical schools in September 2021. Deductive content analysis of dress codes was performed independently and in parallel by all four members of a racially diverse study team using Edwards and Marshalls' established framework for applying FCPA and CRF to dress code policy statements. Inductive content analysis was used to classify statements that fell outside this framework. Using a historical and contemporary legal understanding of how dress code policies have been used to discriminate against marginalised groups, the authors analysed how recommendations or restrictions may contribute to discrimination of marginalised medical students. Fourteen dress code policies were analysed. Overall, there were five feminine-coded restrictions for every one masculine-coded restriction (n = 77/213 and n = 16/213, respectively). Some policies prohibited feminine-coded items (e.g. perfumes and bracelets) while specifically allowing masculine-coded items (e.g. cologne and watches). A discourse of 'professionalism' based on patient preferences prioritised Eurocentric patriarchal norms for appearance, potentially penalising racially and culturally diverse students. Most policies did not include a policy for appeals or accommodations. Canadian undergraduate medical school dress code policies overregulate women and gender, racially and culturally diverse students by explicitly and implicitly enforcing white patriarchal social norms. Administrators should apply best practices to these policies to avoid discrimination and a hostile culture to marginalised groups.

The Antimicrobial Effects of Bacterial Cellulose Produced by Komagataeibacter intermedius in Promoting Wound Healing in Diabetic Mice.

As a conventional medical dressing, medical gauze does not adequately protect complex and hard-to-heal diabetic wounds and is likely to permit bacterial entry and infections. Therefore, it is necessary to develop novel dressings to promote wound healing in diabetic patients. Komagataeibacter intermedius was used to produce unmodified bacterial cellulose, which is rarely applied directly to diabetic wounds. The produced cellulose was evaluated for wound recovery rate, level of inflammation, epidermal histopathology, and antimicrobial activities in treated wounds. Diabetic mices’ wounds treated with bacterial cellulose healed 1.63 times faster than those treated with gauze; the values for the skin indicators in bacterial cellulose treated wounds were more significant than those treated with gauze. Bacterial cellulose was more effective than gauze in promoting tissue proliferation with more complete epidermal layers and the formation of compact collagen in the histological examination. Moreover, wounds treated with bacterial cellulose alone had less water and glucose content than those treated with gauze; this led to an increase of 6.82 times in antimicrobial protection, lower levels of TNF-α and IL-6 (39.6% and 83.2%), and higher levels of IL-10 (2.07 times) than in mice wounds treated with gauze. The results show that bacterial cellulose produced using K. intermedius beneficially affects diabetic wound healing and creates a hygienic microenvironment by preventing inflammation. We suggest that bacterial cellulose can replace medical gauze as a wound dressing for diabetic patients.

Facile fabrication of polylactic acid/polyethylene glycol micro-nano fabrics with aligned fibrous roughness for enhancing liquid anisotropic wetting performance via double-stage drafting melt blowing process

The liquid anisotropic wetting properties have garnered considerable interest due to the rapidly rising usage of functional micro-nano fabrics in sanitary product applications. However, designing and preparing such materials in a manner that is easy, safe, and vast in a large scale remains a problematic issue. In this work, a poly (lactic acid) / poly (ethylene glycol) (PLA/PEG) micro-nano fabric with aligned fibrous roughness inspired by bamboo leaves was designed and prepared via a simple double-stage drafting melt blowing process. The results indicate that aligned fibrous roughness and homogenized fiber diameters ranging from 4.4 to 2.7 µm were successfully tailed by adjusting the drafting ratios from 1.0 to 3.0. Additionally, benefiting from the aligned fibrous roughness, the PLA/PEG micro-nano fabric demonstrated excellent anisotropic wetting performance, evidenced by a clear contrast between parallel static water contact angles (θ//) and perpendicular (θ⊥) to the longitudinal direction, as well as remarkable contact angle hysteresis. Additionally, the samples had a significant aspect ratio of 3.16. As a result, this PLA/PEG micro-nano fabric may be an alternative for medical and health applications such as medical dressings and meshes.

An all-in-one CO gas therapy-based hydrogel dressing with sustained insulin release, anti-oxidative stress, antibacterial, and anti-inflammatory capabilities for infected diabetic wounds

To effectively treat diabetic wounds, the development of versatile medical dressings that can long-term regulate blood glucose and highly effective anti-oxidative stress, antibacterial and anti-inflammatory are critical. Here, an all-in-one CO gas-therapy-based versatile hydrogel dressing (ICOQF) was developed via the dynamic Schiff base reaction between the amino groups on quaternized chitosan (QCS) and the aldehyde groups on benzaldehyde-terminated F108 (F108-CHO) micelles. CORM-401 (an oxidant-sensitive CO-releasing molecules) was encapsulated in the hydrophobic core of F108-CHO micelles and insulin was loaded in the three-dimensional network structure of ICOQF. The dynamic Schiff base bonds not only endowed ICOQF with good tissue adhesion, injectability and self-healing, but also gave it sustained and controllable insulin release ability. In addition, ICOQF could quickly generate CO in inflamed wound tissue by consuming reactive oxygen species. The generated CO could effectively anti-oxidative stress by activating the expression of heme oxygenase; antibacterial by inducing the rupture of bacterial cell membranes and mitochondrial dysfunction and inhibiting the synthesis of adenosine triphosphate; and anti-inflammatory by inhibiting the proliferation of activated macrophages and promoting the polarization of the M1 phenotype to the M2 phenotype. Due to these outstanding properties, ICOQF significantly promoted the healing of STZ-induced MRSA-infected diabetic wounds accompanied by good biocompatibility. This study clearly shows that ICOQF is a versatile hydrogel dressing with great application potential for the management of diabetic wounds. Statement of significanceThe development of some versatile hydrogel dressings that can not only provide a prolonged and controlled insulin release property but also utilize a non-antibiotic treatment modality for highly effective antibacterial, anti-inflammatory, and anti-oxidative stress effects is vital for the successful treatment of diabetic wounds. Herein, we developed an all-in-one CO gas-therapy-based versatile hydrogel dressing (ICOQF) with sustained and controllable insulin release abilities. Moreover, ICOQF could not only quickly release CO in the inflamed wound tissue by consumption of reactive oxygen species but also utilize the generated CO to highly effectively anti-oxidative stress, antibacterial, and anti-inflammatory. ICOQF therapy substantially promoted the healing of STZ-induced MRSA-infected diabetic wounds. Overall, this work provides a multifunctional hydrogel dressing for the management of diabetic wounds.

Antibacterial and superhydrophobic hemostatic properties of fluorinated random copolymer composite nanocoatings

Hemorrhage is the main obstacle to wound healing and can trigger microbial infections, delay the healing process, and seriously threaten human life. Many multifunctional antibacterial hemostatic surfaces have been explored to prevent bacterial attachment, biofilm formation and uncontrolled hemorrhage; however, unnecessary blood loss and tissue adhesion still need to be solved. Here, a fluorinated, biocompatible, superhydrophobic coating that can be used in medical wound dressings to improve their antibacterial and hemostasis function is introduced. The coating is formed by multifunctional antibacterial composite nanoparticles, which are generated from acrylic acid (AA) and 1H,1H,2H,2H-perfluorododecyl acrylate (PFDA) and poly (hexamethylene biguanide) hydrochloride (PHMB). The PAA-co-PFDA/PHMB composite nanoparticles can be used for various substrate materials and form transparent coatings. It has been proven that PAA-co-PFDA/PHMB composite nanocoatings not only have good antibacterial adhesion but also have bactericidal properties. In vitro and in vivo hemostatic experiments show that PAA-co-PFDA/PHMB composite nanocoated gauze has good hemostatic and antiadhesion properties. Comprehensive anti-adhesive, bactericidal and hemostatic properties are the best when the fluorine content is 5.0 wt%. The multifunctional fluoropolymer coating with antifouling, antibacterial and hemostatic properties may have a great potential in biomedical applications.

High Versus Low Frequency Transcutaneous Electric Nerve Stimulation On Chronic Venous Lower Limb Ulceration Randomized Controlled Trial.

The major objective of the current paper is to trace and investigate which method is more effective whether the high or the low Transcutaneous electric Nerve Stimulations (TENS) on venous ulcers. A single-blinded, randomized, and controlled trial was done successfully. Sixty venous ulcer patients were divided randomly into three groups; Group (A): control group, Group(B): High-TENS group, and Group(C): Low-TENS group. Group (A), contains twenty participants who received routine medical care and dressing. As for group (B), includes twenty participants who obtained high-frequency TENS; Frequency (80-120) HZ, Intensity (15 - 30 amp), Pulse duration 250 Micro sec, 60 min per session with routine medical care and dressing. The third group (c) L-TENS, encompasses twenty participants who received low-frequency TENS (1-5) HZ; Intensity (30 -80 amp), Pulse duration 250 Micro sec, 60 min per session with routine medical care and dressing. All the participants were examined before and after two months of intervention; four weeks (post1), then after eight weeks (post2). Participants were examined by using (image j) to measure the ulcer area. Saline was used for measuring the ulcer volume, and a visual analog scale was adopted to evaluate pain. After drawing a comparison among the three groups after four weeks and after eight weeks of treatment, a statistically significant decrease (P <0.05) in wound surface area, wound volume, and pain in favor of L-TENS was noticed. It has been found that L- TENS is more effective than H -TENS and is highly recommended in the treatment protocol for such debilitating conditions.

Performances and Biocompatibility of Prepared pH-Sensitive Cotton/Polyamide 6 Medical Dressings Dyed with Halochromic Dyes

Performances and Biocompatibility of Prepared pH-Sensitive Cotton/Polyamide 6 Medical Dressings Dyed with Halochromic Dyes

Effect of Laser Vocal Cord Surgery under Laryngeal Microscope Combined with Nano-silver Dressing Antibacterial Nursing on Efficacy and Quality of Life of Patients with Laryngeal Cancer.

To explore the adoption effect of nano-silver medical antibacterial dressing in the perioperative treatment of patients with laryngeal cancer, 120 patients with early laryngeal cancer were selected as the research objects. According to the different treatments, they were averagely divided into the test group (laser vocal cord surgery under a laryngeal microscope and nano-silver medical antibacterial dressing) and the control group (laser vocal cord surgery under a laryngeal microscope and sterilized vaseline gauze). The results showed that there were considerable differences in dressing-change times, dressing-change cost, hospital stay, and recovery time between both groups (P<0.05). The number of mild pain cases in the test group was more than that in the control group at 1, 3, and 5 days after surgery, with statistically considerable differences (P<0.05). There were substantial differences in wound area between the two groups at 3 and 5 days after surgery, and the test group was larger than the control group (P<0.05). In the test group, 0 patients had postoperative reinfection, wound dehiscence, and wound hernia. In the control group, 3 patients had postoperative reinfection, 1 had wound dehiscence, and 1 had wound hernia. In summary, compared with traditional sterilized vaseline gauze, the nano-silver medical antibacterial dressing could reduce postoperative dressing pain and promote the recovery of wounds, thus shortening the hospital stay and improving the quality of life of patients after surgery.

Effects of Natural Brown Cotton Bleached Gauze on Wound Healing.

Natural brown cotton has favorable antibacterial and antioxidant properties. In this study, we explored the effect of gauze made from natural brown cotton after scouring and bleaching on wound healing in rats. In this work, a control experiment was adopted. The control group used absorbent cotton gauze, and the experimental group utilized natural brown cotton bleached gauze. The materials were applied to rat models to explore the effects of the two dressings on wound healing. By analyzing the wound healing state of rats, calculating the healing rate, and combining the pathological HE staining, Masson staining, and CD31 immunohistochemical staining, the results showed that both gauzes have positive effects on the wound healing of the rats. Moreover, compared with the control group, the wound healing rate of rats in the experimental group increased by 14.81%, the number of inflammatory cells decreased by 12.93%, the number of new blood vessels increased by 6.88%, the growth rate of the granulation tissue area was 10.76%, the step-up rate of the area occupied by collagen was 33.71%, and the increase rate of optical density value was 10.00%. This study found that natural brown cotton bleached gauze has a better effect on wound healing than ordinary absorbent cotton gauze, and can be used as medical dressings.

A New Medical Dressing with Silver Nanoparticles to Treat Diabetic Foot Patient

In this study, we prepared medical dressings with silver nanoparticles to treat diabetic foot patient by photochemical reduction process of silver ions using sodium citrate and UV radiation. Antibacterial activity of dressing with silver nanoparticles against bacteria associated with diabetic foot was studied by disk diffusion method. It was observed that the bacteria did not grow on the culture medium where the medical gauze was impregnated with silver nanoparticles.

Functional extracellular matrix hydrogel modified with MSC-derived small extracellular vesicles for chronic wound healing.

ObjectivesDiabetic wound healing remains a global challenge in the clinic and in research. However, the current medical dressings are difficult to meet the demands. The primary goal of this study was to fabricate a functional hydrogel wound dressing that can provide an appropriate microenvironment and supplementation with growth factors to promote skin regeneration and functional restoration in diabetic wounds.Materials and MethodsSmall extracellular vesicles (sEVs) were bound to the porcine small intestinal submucosa‐based hydrogel material through peptides (SC‐Ps‐sEVs) to increase the content and achieve a sustained release. NIH3T3 cell was used to evaluate the biocompatibility and the promoting proliferation, migration and adhesion abilities of the SC‐Ps‐sEVs. EA.hy926 cell was used to evaluate the stimulating angiogenesis of SC‐Ps‐sEVs. The diabetic wound model was used to investigate the function/role of SC‐Ps‐sEVs hydrogel in promoting wound healing.ResultsA functional hydrogel wound dressing with good mechanical properties, excellent biocompatibility and superior stimulating angiogenesis capacity was designed and facilely fabricated, which could effectively enable full‐thickness skin wounds healing in diabetic rat model.ConclusionsThis work led to the development of SIS, which shows an unprecedented combination of mechanical, biological and wound healing properties. This functional hydrogel wound dressing may find broad utility in the field of regenerative medicine and may be similarly useful in the treatment of wounds in epithelial tissues, such as the intestine, lung and liver.

Application of Alginate-Based Hydrogels in Hemostasis.

Hemorrhage, as a common trauma injury and clinical postoperative complication, may cause serious damage to the body, especially for patients with huge blood loss and coagulation dysfunction. Timely and effective hemostasis and avoidance of bleeding are of great significance for reducing body damage and improving the survival rate and quality of life of patients. Alginate is considered to be an excellent hemostatic polymer-based biomaterial due to its excellent biocompatibility, biodegradability, non-toxicity, non-immunogenicity, easy gelation and easy availability. In recent years, alginate hydrogels have been more and more widely used in the medical field, and a series of hemostatic related products have been developed such as medical dressings, hemostatic needles, transcatheter interventional embolization preparations, microneedles, injectable hydrogels, and hemostatic powders. The development and application prospects are extremely broad. This manuscript reviews the structure, properties and history of alginate, as well as the research progress of alginate hydrogels in clinical applications related to hemostasis. This review also discusses the current limitations and possible future development prospects of alginate hydrogels in hemostatic applications.

The combined effect of humidity and electron beam irradiation on collagen type I - implications for collagen-based devices

Collagen is a biocompatible and bioresorbable material, an excellent active component for the formulation of medical dressings and scaffolds. Its current popularity and the developing methods of producing such medical materials imply the need for methods of controlling and processing collagen used in medicine. One of the basic methods used to sterilize medical devices is radiation sterilization. In this study, we undertook the determination of the influence of humidity, radiation sterilization, and the influence of these factors on the structure of collagen. Spectroscopic tests (EPR, DRS UV–VIS, FTIR), gas chromatography, and thermal methods (TGA, DSC) were used. Humidity appears to affect the amount, and especially the rate, of oxidative damage and the reorganization of oxygen addition products. Despite radiation damage observed by spectral methods, from the point of view of its thermal properties, collagen I remains stable upon irradiation within the dose range up to 50 kGy, probably due to its unique macromolecular and intermolecular structure, containing numerous crosslinks. The high thermal stability of collagen I in response to radiation gives good indications for radiation sterilization of collagen I based medical products. This is in agreement with the observed structural stability of radiation-sterilized collagen scaffolds used in skin wound healing. Nevertheless, oxidative modification was observed, which ultimately introduced new oxygen-containing functional groups in collagen. The result should be considered when designing and sterilizing collagen-based dressing materials and scaffolds.

Preparation and Characterization of Polyvinyl Alcohol‐Chitosan/Cerium‐Nanocellulose Hydrogel for Medical Dressing Application

AbstractMedical dressings require good antibacterial and mechanical properties. Polyvinyl alcohol based medical dressings are commercially available, and the antimicrobial properties of chitosan and cerium ions are known, and nanocellulose possesses excellent comprehensive properties, such as non‐toxicity, biocompatibility, and biodegradability. In this study, polyvinyl alcohol‐chitosan/cerium‐nanocellulose (PVA‐Cs/Ce‐CNF) composite hydrogels are prepared by a freeze‐thaw method and characterized by scanning electron microscope and X‐ray diffraction. It is expected to improve antibacterial activity of the composite hydrogels by adding a small amount of cerium, and their biological activity will not be affected. In addition, the effects of chitosan/cerium (Cs/Ce) complexes and nanocellulose with different contents on properties are investigated. The results show that PVA‐Cs/Ce‐CNF composite hydrogels have a 3D, highly porous structure with distributed pores of 8–30µm, good skin viscosity, efficient ability to absorb fluid, and suitable water vapor transmission rate of 2000—2500 g m−2 day−1. Two hydrogels in specific ratio show good strong tensile strength of 132.6 and 130.1 kPa respectively, and their elongation at break are over 400%. The PVA‐Cs/Ce‐CNF composite hydrogels are non‐toxic, and they have inhibitory effect on Escherichia coli and Staphylococcus aureus. These results suggest that the PVA‐Cs/Ce‐CNF composite hydrogels have great potential as medical dressings.

A multifunctional 3D dressing unit based on the core-shell hydrogel microfiber for diabetic foot wound healing.

The healing mechanism of diabetic foot wounds is very complicated, and it is difficult for a single-function medical dressing to achieve good therapeutic effects. We propose a simple coaxial biological 3D printing technology, which uses one-step 3D deposition to continuously produce multifunctional medical dressings on the basis of core-shell hydrogel fibers. These dressings have good biocompatibility, controlled drug-release performance, excellent water absorption and retention, and antibacterial and anti-inflammatory functions. In vivo experiments with type 2 diabetic rats were performed over a 14-day period to compare the performance of the multifunctional 3D dressing with a gauze control; the multifunctional 3D dressing reduced inflammation, effectively increased the post-healing thickness of granulation tissue, and promoted the formation of blood vessels, hair follicles, and highly oriented collagen fiber networks. Therefore, the proposed multifunctional dressing is expected to be suitable for clinical applications for healing diabetic foot wounds.

Sustainable wheat gluten foams used in self-expansion medical dressings

Wheat gluten (WG) foam was successfully prepared by heating, stirring and freeze-drying. The effects of WG concentration, content of glycerol and glutaraldehyde on the macroscopic appearance, microstructure, swelling property and self-expansion, as well as mechanical compressibility, were studied. Results showed that the density and structure of foam can be changed by adjusting the concentration of WG, glycerol, and glutaraldehyde. The addition of glycerol softens the WG foams, while glutaraldehyde significantly improved their mechanical properties and stability in wet state. The swollen foams were repeatedly pressed and exhibited rapid water-triggered shape recovery performance (less than 3 ​s). Moreover, WG foams displayed excellent biodegradability and hemocompatibility. In vitro studies of drug loading and release were performed using an antibacterial drug, chlorhexidine gluconate (CHG), and showed sustained drug-release activity. The above advantages make the foams hold great potential for application in self-expanding, antibacterial hemostatic medical dressings.