Polyhexamethylene Biguanide Research Articles

The Infected Diabetic Foot: Does Negative Pressure Wound Therapy with Irrigation Reduce Bioburden and Improve Wound Healing?

The aim of this study was to compare the microbial loads of patients with diabetic foot infections treated with negative pressure wound therapy (NPWT) with and without irrigation with polyhexamethylene biguanide (NPWTi-P). This is a post hoc analysis of combined data of two randomized clinical trials. We evaluated people with diabetes treated with moderate and severe diabetic foot infections that required surgery. Tissue specimens were obtained after the initial surgery and following a second planned return to the operating room after 48-72 h of NPWT or NPWTi-P, prior to the second surgery. We used quantitative polymerase chain reaction (qPCR) to determine the total microbial loads (Log10 16S copies per gram of tissue). There was no difference in mean quantitative bacterial cultures among patients that received NPWT and NPWTi-P (before first surgery Log10: NPWT = 6.4 ± 1.8, NPWTi-P = 7.5 ± 1.7 vs before second surgery Log10: NPWT = 6.7 ± 1.8, NPWTi-P = 7.6 ± 1.9 p = .12). There was no difference in wound healing (59.5% vs 50.0%, p = .51) or time to heal (127 ± 109.3 vs 143 ± 95.9), p = .71). There were fewer re-infections in people that received traditional NPWT (28.6% vs 56.3%, p = .05). Level of Clinical Evidence: Level 1.

The Development of Disinfectant Tolerance in Klebsiella pneumoniae.

Disinfectants are a critical infection control measure that are relied upon globally in a range of settings including healthcare, food production, and domestic environments. However, bacteria have been shown to survive disinfectant treatments when harboured in dry surface biofilms or when disinfectants are used ineffectively. This provides an opportunity for organisms to develop low-level tolerance to various disinfectants. The capability of bacteria to develop adaptations to non-antibiotic antimicrobial agents is often overlooked. This study investigates the ability of Klebsiella pneumoniae NDM-1 strain NCTC 13443 to adapt to a range of common chemical disinfectants (benzalkonium chloride, didecyldimethylammonium chloride, polyhexamethylene biguanide, chlorocresol and bronopol) via serial passage exposure method. After long-term adaptation K. pneumoniae developed tolerance to all tested disinfectants, exhibiting a minimum inhibitory concentration increase of between 30-413% compared to the untreated parent samples. Characterisation of disinfectant cross-tolerance showed that while cross-tolerance can occur, most adapted samples became more susceptible to the second disinfectant treatment, likely because of the fitness cost of adaptation. Observed cross-tolerance/increased susceptibility was not always reciprocated between disinfectant-tolerant samples, indicating that the order of disinfectant exposure is important during tolerance development. This has significant implications for disinfectant cleaning routines, and is likely due to variations in the underpinning tolerance mechanisms, even when the disinfectants display similar mechanisms of action. This study reports the capability and readiness of clinically relevant K. pneumoniae to adapt to common disinfectants that are relied upon every day across the world, delivering much-needed insights into an often-overlooked aspect of antimicrobial resistance.

Comparative evaluation of chlorhexidine gluconate with alcohol and polyhexamethylene biguanide with Tris-EDTA as antiseptic solutions for pre-operative skin preparation in dogs

Background and Aim: Skin antisepsis plays a crucial role in pre-operative skin preparation, with chlorhexidine gluconate and alcohol being historically the preferred choice. However, concerns have risen regarding the development of bacterial resistance to chlorhexidine. Polyhexamethylene biguanide (PHMB) combined with Tris-ethylenediaminetetraacetic acid (Tris-EDTA) has recently emerged as a skin and wound antiseptic. This study aimed to compare the antibacterial efficacy and local safety of 2% chlorhexidine gluconate with 70% alcohol (CG+Alc) and 0.3% PHMB with 6% Tris and 1.86% EDTA (PHMB+Tris-EDTA) for pre-operative skin preparation in dogs. Materials and Methods: Twenty-four adult dogs underwent aseptic preparation on both sides of their ventral abdomens, with one side receiving CG+Alc and the other side receiving PHMB+Tris-EDTA, assigned randomly. Skin swab samples were collected pre-antisepsis and at 3-, 10-, and 60-min post-antisepsis to quantify bacterial colony-forming units (CFUs). Local skin reactions (erythema and edema) were evaluated after hair clipping, pre-antisepsis, and at 3-, 10-, 30-, and 60-min post-antisepsis. Results: There was no significant difference in bacterial CFU counts between the two antiseptic groups pre-antiseptic. Both solutions significantly reduced CFU counts (p < 0.05) at all post-antisepsis sampling times compared with pre-antisepsis. However, dogs treated with PHMB+Tris-EDTA showed a significantly higher incidence of edema at 10 min (p = 0.02) and 30 min (p = 0.003) and a higher incidence of erythema at 10 min (p = 0.043) post-antisepsis compared with CG+Alc. No skin reactions were observed in either group at 60 min post-antisepsis. Conclusion: CG+Alc and PHMB+Tris-EDTA reduced bacterial counts in pre-operative skin preparation in dogs. However, acute transient skin reactions were observed more frequently following the application of PHMB+Tris-EDTA. Keywords: alcohol, antisepsis, chlorhexidine gluconate, dogs, polyhexamethylene biguanide, skin preparation, tris-ethylenediaminetetraacetic acid.

Encapsulation of the PHMB with nanoliposome and attachment to wound dressing for long-term antibacterial activity and biocompatibility.

Concentration control of some drug are used commonly however their uncontrolled concentration renders severe side effects. Therefore, it is substantial to come up with innovation release control methods. There is a strong affinity between the phospholipid of nanoliposomes and wool cells which facilitate the diffusion of liposomes into the wool structure. On the other hand, polyhexamethylene biguanide (PHMB) has gained popularity as an antibacterial agent; however, the compound's cytotoxicity has limited its usefulness. By compounding these facts, this work introduces a novel method for sustained drug release via internalization. In this method, PHMB was detained into nanoliposomes infiltrated the wool to generate an extremely regulated release, which was established using various techniques. SEM pictures demonstrated effective absorption of nanoliposome-encapsulated PHMB within the wool fabric. The developed wound dressing showed a sustained drug release, and consequently, perfect biocompatibility and enduring antibacterial activity.

The efficacy of combination of sodium hypochlorite (NaOCL)/hypochlorous acid (HOCL) in wound management: A systematic review and network meta-analysis

Introduction Antiseptic and antibacterial solutions are increasingly used in the treatment of various types of wounds. The successful stabilization of wounds using a combination Sodium Hypochlorite/Hypochlorous acid (NaOCl/HOCl) or superoxidized solution (SOS) has been reported, serving as an effective solution without irritating mammal cells and without posing a carcinogenic hazard. Presently, no systematic review or meta-analysis is available that compares the effectiveness of these antiseptic solutions. The present study aims to investigate the role of NaOCl/HOCl in the treatment of wounds. Methods The systematic review with extended to network meta-analysis (NMA) was conducted using NaOCl/HOCl, povidone-iodine, octenidine dihydrochloride, polyhexamethylene biguanide, alcohol, and silver compared with normal saline. The primary outcome was wound healing. Using surface under the cumulative ranking curve (SUCRA), the direct and indirect comparisons were conducted with the probability of selecting the best treatment. Results A total of 507 studies were identified from PUBMED and SCOPUS databases, and 64 articles were duplicates. Among 29 studies included, 22 randomized controlled trials (RCTs) and 7 cohort studies met our inclusion criteria. NaOCl/HOCl had a higher chance of wound healing 1.07-1.30 times compared with all the regimens. NaOCl/HOCl has the probability of providing the best treatment, followed by silver and octenidine with SUCRAs of 36.9, 23.1, and 21.8, respectively. Conclusions NaOCl/HOCl ranks first and proves to have the highest efficacy, followed by silver, octenidine, and PHMB for treatment.

Effectiveness of Polyhexamethylene biguanide Liquid for Chronic Wound Washing

Background: Chronic wounds occur due to a failure in the wound healing process and are currently one of the health problems that require proper management. Some types of chronic wounds include venous leg ulcer (VLU), diabetic foot ulcer (DFU). The use of wound washes is one of the factors that play an important role in chronic wound healing. Purpose: Effectiveness of Polyhexamethylene biguanide in cleaning wounds from old dressing residue and reducing bacterial counts. Methods: Quasi experiment without control group to 30 samples using Polyhexamethylene biguanide with BWAT wound assessment instrument (Bates Jensen Wound Assessment Tool), data processing using SPSS program with Wilcoxon test. Results: 17 (40%) were late elderly (56-65 years), 3 (20%) were early elderly (46-55 years), and 10 (20%) were seniors (> 65 years). The bivariate Wilcoxon test shows that Polyhexamethylene biguanide wound cleansing liquid significantly changes mean values before and after wound care. Before wound care, the mean value was 34.65 ± 14.15, and after treatment, it was 7.87 ± 3.16. The mean difference is -5.14 (-12.24 to 2.56) with a 95% confidence interval, and the p value is 0.031. Conclusion: Polyhexamethylene biguanide was shown to be effective as a wound wash to support the healing process of chronic wounds. Suggestions based on the results of this study can be used for efficient chronic wound washing for patients.

MXene and cellulose nanofibers reinforced hydrogel with high strength and photothermal self-healing performances for marine antifouling

Biological fouling is a considerable threat to the marine industry because attached microcontaminants and microorganisms inflict serious damage on marine installations and aquacultures. Although there has been tremendous effort in researching marine antifouling, it is yet challenging to develop a long-term and consistent antifouling strategy and materials. Here, polyhexamethylene-biguanide (PHMB) and MXene are introduced into the carboxylated cellulose nanofibers (CNF) reinforced polyvinyl alcohol (PVA) hydrogel to obtain a self-healing and ultra-high toughness antifouling hydrogel. The as-prepared double network (DN) hydrogels have extremely high toughness (16,050 kJ/m3), superior anti-protein adhesion (100 %) and anti-algal adhesion (100 %), exceptional antibacterial activity (99.97 %), and remarkable photothermal self-healing capability. Furthermore, the DN hydrogel provide outstanding antifouling performance for at least six months in the actual marine field. This work provides an effective and feasible strategy to prevent marine biofouling and also initiates new approaches to the application of hydrogel.

Limbal Subconjunctival Abscess: A Rare Complication of Acanthamoeba Keratitis.

Acanthamoeba keratitis (AK) is a rare infection affecting the cornea. Immune-mediated sclerokeratitis is a well-documented late complication often requiring systemic immunosuppression. We present an alternative clinical presentation of subconjunctival abscesses caused by direct invasion of the Acanthamoeba and a proposed management strategy. This study was a single case report performed at a tertiary care center in the United Kingdom. A 42-year-old contact lens wearer with a history of swimming in contact lenses presented with 2 days of pain, redness, and photophobia. There was clinical suspicion for AK that was later confirmed on confocal microscopy and cultures. Four months into treatment with polyhexamethylene biguanide 0.06% monotherapy, they experienced a relapse of symptoms and developed multiple subconjunctival limbal abscesses with associated scleritis. These were drained in the office, and topical treatment changed to chlorhexidine 0.2%. The aspirate was culture-positive Acanthamoeba. Despite initially improving, the abscess reoccurred within a month. Repeat drainage was performed, and topical and oral voriconazole was added to the treatment regime. The abscess resolved leaving an area of scleromalacia. Despite immune-mediated sclerokeratitis being a more common complication of AK, infectious scleritis can also occur. Correct identification of the cause of scleritis is required to prevent mistreatment of infectious scleritis with systemic immunosuppression. The abscess resolved with repeated drainage and the use of topical and systemic voriconazole.

Synthetic vs. natural antimicrobial agents for safer textiles: a comparative review.

Textiles in all forms act as carriers in transmitting pathogens and provide a medium of microbial growth, especially in those fabrics which are used in sports, medical and innerwear clothing. More attention towards hygiene and personal healthcare made it a necessity to develop pathogen-free textiles. Synthetic and natural antimicrobial compositions are used to control and reduce microbial activity by killing or inhibiting microbial growth on textiles. Synthetic metallic nanoparticles of Ag, Zn, Cu Ti and Ga are the most commonly and recently used advanced nanocomposites. Synthetic organic materials such as triclosan, quaternary ammonium compounds, polyhexamethylene biguanide, and N-halamines have proven antimicrobial activity. Carbon quantum dots are one of the advanced nanomaterials prepared from different kinds of organic carbon material with photoluminescence efficiency also work efficiently in antimicrobial textiles. A greener approach for producing natural antimicrobial textiles has gained significant importance and demand for personal care due to their less toxic effects on health and the environment In comparison to synthetic. The naturally existing materials including extracts and essential oils of plants have significant applications for antimicrobial textiles. Additionally, a number of animal extracts are also used as antimicrobial agents include chitosan, alginate, collagen hydrolysate to prepare naturally treated antimicrobial textiles. This review focuses on the comparative performance of antimicrobial fabrics between synthetic and natural materials. Textiles with synthetic substances cause health and environmental concerns whereas textiles treated with natural compositions are more safe and eco-friendly. Finally, it is concluded that textiles modified with natural antimicrobial compositions may be a better alternative and option as functional textiles.

Injectable Salecan/hyaluronic acid-based hydrogels with antibacterial, rapid self-healing, pH-responsive and controllable drug release capability for infected wound repair

Designing materials for wound dressings with superior therapeutic benefits, self-healing and injectable characteristics is important in clinical practice. Herein, a new self-healing injectable hydrogel was prepared via thermal treatment and dynamic Schiff base reaction by mixing oxidized hyaluronic acid (OHA) and hydrazided Salecan (Sal-ADH). The versatility of the wound dressing was confirmed by studying the inherent rheological properties, high swelling rate, sustained-release behavior of the drug, pH/hyaluronidase-dependent biodegradation, in vitro antimicrobial as well as in vivo wound healing performance. The presence of the antimicrobial drug polyhexamethylene biguanide (PHMB) conferred good antimicrobial properties to the Sal-ADH/OHA/PHMB (SOP) hydrogel, which could effectively prevent wound infection (the width of the inhibition circle of SOP-0.20 hydrogel was 4.97 mm, 5.93 mm for Staphylococcus aureus and Escherichia coli, respectively). The findings suggested that SOP hydrogel exhibited remarkable self-healing and injectability properties, as well as excellent hemostasis and biocompatibility. In vivo experiments indicated that the application of SOP hydrogels would obviously accelerate wound healing and attenuate the inflammatory response while increasing collagen deposition and angiogenesis. Altogether, antibacterial SOP hydrogels with moderate mechanical properties, pH-responsive release, excellent injectability, exceptional self-healing ability and anti-inflammatory effects could expand potential applications of injectable hydrogels in the biomedical field.

Long-term and high-efficiency capture of Escherichia coli using cellulose acetate nanofiber membrane functionalized with reactive 19 dye and polyhexamethylene biguanide

Cellulose acetate (CA) nanofibers have been popularly applied in various biomedical and textile products. In this work, a textile azo-dye Reactive Green 19 (RG19) was selected to be chemically coupled to the CA nanofiber membrane to form dyed CA nanofiber membrane (namely CA-RG19) and then poly(hexamethylene biguanide) (PHMB) as an antibacterial reagent was physically attached to the dyed CA nanofiber membrane, forming CA-RG19-PHMB nanofiber membrane. The nanofiber membranes were evaluated for their physical and mechanical properties, including functional group analysis, morphological characterization, and thermal stability assessment. To investigate the antibacterial properties of the nanofiber membrane, various concentrations of RG19 dye and PHMB were tested to evaluate the antibacterial efficiency (AE) against Escherichia coli of the membranes. It was found that the CA-RG19-PHMB nanofiber membrane exhibited an AE value of approximately 100 %, with the immobilization concentrations of RG19 dye and PHMB being 373.46 mg/g and 0.333 mg/g, respectively. The CA-RG19-PHMB nanofiber membrane showed 100 % antibacterial efficacy after 10 min against E. coli cells. Furthermore, the storage stability of the CA-RG19-PHMB nanofiber membrane remained at approximately 100 % of its initial antibacterial efficacy after 60 days, and it exhibited excellent antibacterial efficacy after five cycles.

Suspended whispering gallery mode resonators made of different polymers and fabricated using drop-on-demand inkjet printing for gas sensing applications

Investigation of drop-on-demand inkjet printing as a fabrication method for an optical gas sensor reveals its potential to incorporate multiple sensing materials on a single microchip. Through this additive method, three distinct polymers—SU-8, polystyrene (PS), and polyhexamethylene biguanide (PHMB)—were deposited onto a silicon substrate and suspended, allowing the polymer microdroplets to expand freely. The coupling to these whispering gallery mode resonators with a tapered optical fiber allows measuring high quality factors exceeding 106. The gas sensing capabilities of all three polymers were studied for three different gases: isopropanol, water, and carbon dioxide. Sensitivities of up to 0.25pm/ppmv and limits of detection as low as 14ppmv were achieved.

REGECEL (an Oxidized Regenerated Cellulose) Provides Superior Bioactivity Effect on Microorganisms.

Patients who need to be readmitted to the hospital because of complications from infections or require long-term care and rehabilitation face substantial financial hardships. To ensure the safety of patients undergoing surgery, it is crucial to implement measures that prevent wound infections before and after the procedure. Antibacterial wound dressings are essential to prevent infections during surgical procedures. There are various types of antibacterial wound dressings available on the market, such as silver-based dressings, hydrocolloid dressings, polyhexamethylene biguanide, alginate dressings, collagen-based dressings, and iodine-based dressings. We used each type (standard, knit, fibril, and non-woven) of a commercial brand of oxidized regenerated cellulose (ORC) called Regecel to test bacterial growth. The choice of antibacterial wound dressing depends on the type of wound being treated. Different bacterial strains require specific culture conditions to thrive and grow in laboratory settings. To obtain accurate and reliable results, it is vital to follow the precise culture conditions required for each bacterial strain. The evaluation of ORC highlighted its potential to inhibit bacterial growth, showing promising results against various bacterial strains and Candida albicans. Different variants of ORC, such as Regecel, have demonstrated impressive capacity to hinder the growth of 32 distinct bacterial strains, with inhibition rates ranging from 40-100%. These bacteria include methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and penicillin-resistant Streptococcus pneumoniae. This study supports the usage and development of ORC (Regecel) as an innovative approach to treating bacterial infections.

Efficacy and Safety of Preoperative Prophylaxis in Cataract Surgery with Combined Topical Antiseptics: A Microbiological Study.

To evaluate the antimicrobial efficacy of an ophthalmic formulation containing hexamidine diisethionate (HD) 0.05%, polyhexamethylene biguanide (PHMB) 0.0001%, and edetate disodium (EDTA) 0.01% (Keratosept®, Bruschettini, Genova, Italy) on the microbial flora of a healthy ocular surface. Patients were enrolled consecutively. Each patient applied two drops of Keratosept® in the eye scheduled for cataract surgery (study eye) three times daily in the 2 days prior to surgery and one time in the morning of surgery. The contralateral eyes were considered as control (control eye). Bilateral conjunctival swabs were collected before the first administration (T0) and the morning of surgery (T1). The swabs were processed within 3 h from sampling for the automated detection of the presence of replicating microorganisms (colony-forming units, CFU/mL) and the provision of real-time growth curves. Conjunctival swabs of 32 patients (n = 128) were examined. Six patients were excluded from the efficacy analysis because of microbial load < 50 CFU/mL at T0 in the study eye. No difference between study and control eyes was observed at T0 (p = 0.40). Compared with T0, 20 (76.9%) study eyes and 10 (38.5%) control eyes showed a ≥ 1 log reduction of the microbial load at T1, with a significant difference between groups (p = 0.005). Keratosept® showed good tolerability, and no adverse events or eye discomfort were recorded. This study showed that the low-dose combination of antiseptic agents in the Keratosept® ophthalmic solution effectively reduces the bacterial load of healthy flora on the ocular surface.

Electrospun PCL/PVA/PHMB nanofibers incorporating Ziziphus jujuba fruit extract as promising wound dressings with potent antibacterial and antidiabetic properties

This investigation examined the potential antibacterial and antidiabetic effects of wound dressings created using electrospun nanofibers containing Ziziphus jujuba fruit extract (ZJ). These nanofibers were composed of a combination of Polycaprolactone (PCL), Polyvinyl Alcohol (PVA), and Polyhexamethylene Biguanide (PHMB). The process of creating these nanofibers involved electrospinning. The nanofiber products, which included PCL, PCL/PVA, PCL/PVA/ZJ, PCL/PVA/PHMB, and PCL/PVA/PHMB/ZJ, underwent a morphology, physicochemical, and biological assessment. Incorporating PHMB into the nanofibers enhanced the antibacterial properties, effectively preventing bacterial infections in wounds. Furthermore, including ZJ fruit extract in the nanofibers provided antidiabetic properties, making these dressings suitable for diabetic patients. The PCL/PVA/PHMB/ZJ combination exhibited exceptional healing capabilities and superior antibacterial efficiency in MRSA-infected wounds. The histological assay confirmed complete wound healing by day 14, accompanied by reduced inflammation. Based on these findings, using PCL/PVA/PHMB/ZJ as innovative wound dressings is recommended, as they can expedite wound healing while offering significant antidiabetic and antibacterial features. Ultimately, these electrospun nanofibers possess the potential to serve as advanced wound dressings with enhanced antibacterial and anti-diabetes properties.

Enhancing diabetic wound healing through anti-bacterial and promoting angiogenesis using dual-functional slow-release microspheres-loaded dermal scaffolds

Bacterial infections and the degeneration of the capillary network comprise the primary factors that contribute to the delayed healing of diabetic wounds. However, treatment modalities that cater to effective diabetic wounds healing in clinical settings are severely lacking. Herein, a dual-functional microsphere carrier was designed, which encapsulates polyhexamethylene biguanide (PHMB) or recombinant human vascular endothelial growth factor (rhVEGF) together. The in vitro release experiments demonstrated that the use of the microspheres ensured the sustained release of the drugs (PHMB or rhVEGF) over a period of 12 days. Additionally, the integration of these controlled-release microspheres into a dermal scaffold (DS-PLGA@PHMB/rhVEGF) imbued both antibacterial and angiogenic functions to the resulting material. Accordingly, the DS-PLGA@PHMB/rhVEGF scaffold exhibited potent antibacterial properties, effectively suppressing bacterial growth and providing a conducive environment for wound healing, thereby addressing the drawbacks associated with the susceptibility of rhVEGF to deactivation in inflammatory conditions. Additionally, the histological analysis revealed that the use of the DS-PLGA@PHMB/rhVEGF scaffold accelerated the process of wound healing by inhibiting inflammatory reactions, stimulating the production of collagen formation, and enhancing angiogenesis. This provides a novel solution for enhancing the antibacterial and vascularization capabilities of artificial dermal scaffolds, providing a beacon of hope for improving diabetic wound healing.

Develop Targeted Protein Drug Carriers through a High-Throughput Screening Platform and Rational Design.

Protein-based drugs offer advantages, such as high specificity, low toxicity, and minimal side effects compared to small molecule drugs. However, delivery of proteins to target tissues or cells remains challenging due to the instability, diverse structures, charges, and molecular weights of proteins. Polymers have emerged as a leading choice for designing effective protein delivery systems, but identifying a suitable polymer for a given protein is complicated by the complexity of both proteins and polymers. To address this challenge, a fluorescence-based high-throughput screening platform called ProMatch to efficiently collect data on protein-polymer interactions, followed by in vivo and in vitro experiments with rational design is developed. Using this approach to streamline polymer selection for targeted protein delivery, candidate polymers from commercially available options are identified and a polyhexamethylene biguanide (PHMB)-based system for delivering proteins to white adipose tissue as a treatment for obesity is developed. A branched polyethylenimine (bPEI)-based system for neuron-specific protein delivery to stimulate optic nerve regeneration is also developed. The high-throughput screening methodology expedites identification of promising polymer candidates for tissue-specific protein delivery systems, thereby providing a platform to develop innovative protein-based therapeutics.

Biodegradable gelatin/pectin films containing cellulose nanofibers and biguanide polymers: Characterization and application in sweet cherry packaging

To expand the utilization of gelatin and pectin derived from agricultural by-products, the composite films composed of gelatin, citrus pectin, cellulose nanofibers (CNF), and polyhexamethylene biguanide hydrochloride (PHMB) were prepared through the solvent casting method. Fourier infrared spectroscopy analysis verified the successful integration of CNF and PHMB into the gelatin-pectin matrix. The incorporation of CNF as a reinforcing agent substantially enhanced the barrier capabilities of the composite film. Moreover, the addition of PHMB, functioning as an antimicrobial agent, not only granted the film with antibacterial properties but also improved its physical characteristics and biodegradability. A water contact angle experiment revealed the film presented a certain degree of hydrophobicity. The optimal performances were attained with a composition in which CNF and PHMB constituted 8 % and 3 %, respectively, of the total weight of gelatin and pectin. As a packaging film, the composite film demonstrated its effectiveness by reducing the decay index and weight loss rate of sweet cherries during a 12-day storage period. In the soil degradation test, the composite film exhibited notable structural degradation by the 16th day. Consequently, the composite film will be used as an innovative and biodegradable packaging material to provide a sustainable solution for food packaging industries.

Dual-mode microring resonator for humidity sensing with temperature compensation

On-chip refractive index (RI) sensors, which use resonant shifts of micro-cavities to detect environment change, have the advantages of high sensitivity, real-time detection, and compact footprints. However, the cross-sensitivity of the temperature variation severely interferes with sensing results. In this paper, we present a dual-mode microring resonator (MRR) with a cladding layer of polyhexamethylene biguanide hydrochloride (PHMB) for relative humidity (RH) sensing to overcome the limitation. Specifically, the influences of the RH-induced RI change of the PHMB cladding and temperature variations on the effective RIs of TE0 and TE1 modes can be decoupled based on the transmission spectral measurements. Using this method, we have demonstrated the temperature-compensated RH sensing which achieved a maximum sensitivity of −54.7 pm/%RH and a limit of detection of 0.8 %RH under the room temperature condition. Besides, a computational model based on the sensing response of the device was proposed and verified, which demonstrated that the structure can accurately measure changes in RH and temperature simultaneously. Our methodology has the potential to become a new reference for developing on-chip RI sensors with temperature compensation.

Quality of life case series review: wound bed preparation from a UK perspective.

Previous studies have reported that polyhexamethylene biguanide (PHMB) and betaine solution and gels remove biofilm, improve wound healing and reduce infection rates. Quality of life (QoL) outcomes are not commonly reported on when it comes to wound care. This review aims to summarise QoL data from a cohort of case studies previously published on chronic lower limb ulcers using PHMB products (Prontosan® Solution, Prontosan® Wound Gel X and Prontosan® Debridement Pad). Here, we report on and review a total of 38 case studies describing 56 wounds. From these 38 case studies, 36 reported that all the wounds involved had either healed or improved by the end of their respective study period. QoL themes explore malodour, slough, and exudate, pain, mobility, hair growth, antibiotic intake, return to work, social life and mood. This case series demonstrates that treatment with Prontosan® products improves many QoL outcomes for patients with non-healing wounds.