Bioadhesive and biocompatible films as wound dressing materials based on a novel dendronized chitosan loaded with ciprofloxacin

A biguanide chitosan-based hydrogel adhesive accelerates the healing of bacterial-infected wounds

The development of tissue adhesives with good biocompatibility and potent antimicrobial properties is crucial for addressing the high incidence of surgical site infections in emergency and clinical settings. Herein, an injectable hydrogel adhesive composed of chitosan biguanidine (CSG), oxidized dextran (ODex) and tannin (TA) was synthesized primarily through Schiff-base reactions, hydrogen bonding, and electrostatic interactions. TA was introduced into the CSG/ODex hydrogel to prepare a physicochemically double cross-linked hydrogel. The hydrogel formulation incorporating 2 wt% TA (CSG/ODex-TA2) exhibited rapid gelation, moderate mechanical properties, good tissue adhesion, and sustained release behavior of TA. Both in vitro and in vivo studies demonstrated that CSG/ODex-TA2 showed significantly enhanced adhesion and antibacterial effectiveness compared to the CSG/ODex hydrogel and commercial fibrin glue. Leveraging the positive charge of CSG, the CSG/ODex-TA2 hydrogel demonstrated a strong contact antibacterial effect, while the sustained release of TA provided diffusion antibacterial capabilities. By integrating contact and diffusion antibacterial mechanisms into the hydrogel, a promising approach was developed to boost antibacterial efficiency and accelerate the healing of wounds infected with methicillin-resistant Staphylococcus aureus (MRSA). The CSG/ODex-TA2 hydrogel has excellent biocompatibility, hemostatic properties, and antibacterial capabilities, making it a promising candidate for improving in vivo wound care and combating bacterial infections.

A 3D bioprinted antibacterial hydrogel dressing of gelatin/sodium alginate loaded with ciprofloxacin hydrochloride

Skin plays a crucial role in human physiological functions, however, it was vulnerable to bacterial infection which delayed wound healing. Nowadays, designing an individual wound dressing with good biocompatibility and sustaining anti-infection capability for healing of chronic wounds are still challenging. In this study, various concentrations of the ciprofloxacin (CIP) were mixed with gelatine (Gel)/sodium alginate (SA) solution to prepare Gel/SA/CIP (GAC) bioinks, following the fabrication of GAC scaffold by an extrusion 3D bioprinting technology. The results showed that the GAC bioinks had good printability and the printed GAC scaffolds double-crosslinked by EDC/NHS and CaCl2 had rich porous structure with appropriate pore size, which were conducive to drug release and cell growth. It demonstrated that the CIP could be rapidly released by 70% in 5 min, which endowed the GAC composite scaffolds with an excellent antibacterial ability. Especially, the antibacterial activities of GAC7.5 against Escherichia coli and Staphylococcus aureus within 24 h were even close to 100%, and the inhibition zones were still maintained 14.78 ± 0.40 mm and 14.78 ± 0.40 mm, respectively, after 24 h. Meanwhile, GAC7.5 also demonstrated impressive biocompatibility which can promote the growth and migration of L929 and accelerate wound healing. Overall, the GAC7.5 3D bioprinting scaffold could be used as a potential skin dressing for susceptible wounds with excellent antibacterial activity and good biocompatibility to meet urgent clinical needs.

Janus structure hydrogels: recent advances in synthetic strategies, biomedical microstructure and (bio)applications

Janus structure hydrogels (JSHs) are novel materials. Their primary fabrication methods and various applications have been widely reported. JSHs are primarily composed of Janus particles (JNPs) and polysaccharide components. They exhibit two distinct physical or chemical properties, generating intriguing characteristics due to their asymmetric structure. Normally, one side (adhesive interface) is predominantly constituted of polysaccharide components, primarily serving excellent adhesion. On the other side (functional surface), they integrate diverse functionalities, concurrently performing a plethora of synergistic functions. In the biomedical field, JSHs are widely applied in anti-adhesion, drug delivery, wound healing, and other areas. It also exhibits functions in seawater desalination and motion sensing. Thus, JSHs hold broad prospects for applications, and they possess significant research value in nanotechnology, environmental science, healthcare, and other fields. Additionally, this article proposes the challenges and future work facing these fields.

Exploring polysaccharide-based bio-adhesive topical film as a potential platform for wound dressing application: A review

Wound dressings act as a physical barrier between the wound site and the external environment, preventing additional harm; choosing suitable wound dressings is essential for the healing process. Polysaccharide biopolymers have demonstrated encouraging findings and therapeutic prospects in recent decades about wound therapy. Additionally, polysaccharides have bioactive qualities like anti-inflammatory, antibacterial, and antioxidant capabilities that can help the process of healing. Due to their excellent tissue adhesion, swelling, water absorption, bactericidal, and immune-regulating properties, polysaccharide-based bio-adhesive films have recently been investigated as intriguing alternatives in wound management. These films also mimic the structure of the skin and stimulate the regeneration of the skin. This review presented several design standards and functions of suitable bio-adhesive films for the healing of wounds. Additionally, the most recent developments in the use of bio-adhesive films as wound dressings based on polysaccharides, including hyaluronic acid, chondroitin sulfate, dextran, alginate, chitosan, cellulose, konjac glucomannan, gellan gum, xanthan gum, pectin, guar gum, heparin, arabinogalactans, carrageen, and tragacanth gum, are thoroughly discussed. Lastly, to create a road map for the function of polysaccharide-based bio-adhesive films in advanced wound care, their clinical performances and future challenges in making bio-adhesive films by three-dimensional bioprinting are summarized.

Self-assembled sodium alginate polymannuronate nanoparticles for synergistic treatment of ophthalmic infection and inflammation: Preparation optimization and in vitro/vivo evaluation

Frequent administrations are often needed during the treatment of ocular diseases due to the low bioavailability of the existing eye drops owing to inadequate corneal penetration and rapid drug washout. Herein, sodium alginate polymannuronate (SA) nanocarriers were developed using ionic gelation method that can provide better bioavailability through mucoadhesivity and sustained drug release by binding to the ocular mucus layer. This study disproves the common belief that only the G block of SA participates in the crosslinking reaction during ionic gelation. Self-assembly capability due to the linear flexible structure of the M block, better biocompatibility than G block along with the feasibility of controlling physicochemical characteristics postulate a high potential for designing efficient ocular drug delivery systems. Initially, four crosslinkers of varied concentrations were investigated. Taguchi design of experiment revealed the statistically significant effect of the crosslinker type and concentration on the particle size and stability. The best combination was detected by analyzing the particle size and zeta potential values that showed the desired microstructural properties for ocular barrier penetration. The desired combination was SA-Ca-1 that had particle size within the optimal corneal penetration range, that is 10-200 nm (135 nm). The drug carriers demonstrated excellent entrapment efficiency (∼89 % for Ciprofloxacin and ∼96 % for Dexamethasone) along with a sustained and simultaneous release of dual drug for at least 2 days. The nanoparticles also showed biocompatibility (4 ± 0.6 % hemolysis) and high mucoadhesivity (73 ± 2 % for 0.25 g) which was validated by molecular docking analysis. The prepared formulation was able to reduce the scleral inflammation of the rabbit uveitis models significantly within 3 days. Thus, the eye drop showed remarkable potential for efficient drug delivery leading to faster recovery.

Combining ZnPc-liposomes and chitosan on a hybrid matrix for enhanced photodynamic therapy

Photodynamic therapy is an alternative treatment for several pathologies, including cancer. This therapy uses a photosensitizer capable of producing reactive oxygen species through irradiation, promoting cellular death. A limitation of photosensitizers is their low solubility in aqueous media. Hence, developing a suitable carrier for photosensitizers for specific applications is a challenge. Cervical cancer is one of the most common cancers in women, and photodynamic therapy could be an attractive alternative therapeutic approach. In this work, we synthesized films composed of chitosan, polyvinylpyrrolidone, and liposomes containing Zn-phthalocyanine. Photophysical characterization of ZnPc incorporated into films was determined by UV-vis and fluorescence. Film properties such as swelling, mechanical properties, and water vapor permeability were performed. Finally, in vitro, photodynamic evaluation of these films was performed on HeLa cells. The results indicate that incorporating Zn-Pc-liposomes into films decreases cell viability by >95 %.

Bioadhesives with Antimicrobial Properties

Bioadhesives with antimicrobial properties enable easier and safer treatment of wounds as compared to the traditional methods such as suturing and stapling. Composed of natural or synthetic polymers, these bioadhesives seal wounds and facilitate healing while preventing infections through the activity of locally released antimicrobial drugs, nanocomponents, or inherently antimicrobial polers. Although many different materials and strategies are employed to develop antimicrobial bioadhesives, the design of these biomaterials necessitates a prudent approach as achieving all the required properties including optimal adhesive and cohesive properties, biocompatibility, and antimicrobial activity can be challenging. Designing antimicrobial bioadhesives with tunable physical, chemical, and biological properties will shed light on the path for future advancement of bioadhesives with antimicrobial properties. In this review, the requirements and commonly used strategies for developing bioadhesives with antimicrobial properties are discussed. In particular, different methods for their synthesis and their experimental and clinical applications on a variety of organs are reviewed. Advances in the design of bioadhesives with antimicrobial properties will pave the way for a better management of wounds to increase positive clinical outcomes.

Dendronization of chitosan to afford unprecedent thermoresponsiveness and tunable microconfinement

Convenient chemical modification of biomacromolecules to create novel biocompatible functional materials satisfies the current requirements of sustainable chemistry. Dendronization of chitosan with dendritic oligoethylene glycols (OEGs) paves a strategy for the preparation of functional dendronized chitosans (DCSs) with unprecedent thermoresponsive behavior, which inherit biological features from polysaccharides and the topological features from dendritic OEGs. In addition, densely packed dendritic OEG chains around the backbone provide efficient cooperative interactions and form an intriguing confined microenvironment based on the degradable biopolymers. In this perspective, we describe the principle for the preparation of the thermoresponsive DCSs, and focus on the molecular envelop effect from the hydrophobic microconfinement to the encapsulated guest molecules or moieties. Particular attention is put on their capacity to regulate behavior and the functions of the encapsulated guests through thermally-mediated dehydration and collapse of the densely packed dendritic OEGs. We believe that the methodology described here may provide prospects for the fabrication of functional materials from biomacromolecules, especially when used as environmentally friendly nanomaterials or in accurate diagnosis and therapy.

Development and characterization of a poloxamer hydrogel composed of human mesenchymal stromal cells (hMSCs) for reepithelization of skin injuries

Wound healing is a natural physiological reaction to tissue injury. Hydrogels show attractive advantages in wound healing not only due to their biodegradability, biocompatibility and permeability but also because provide an excellent environment for cell migration and proliferation. The main objective of the present study was the design and characterization of a hydrogel loaded with human mesenchymal stromal cells (hMSCs) for use in would healing of superficial skin injures. Poloxamer 407® was used as biocompatible biomaterial to embed hMSCs. The developed hydrogel containing 20 % (w/w) of polymer resulted in the best formulation with respect to physical, mechanical, morphological and biological properties. Its high swelling capacity confirmed the hydrogel's capacity to absorb wounds' exudate. LIVE/DEAD® assay confirm that hMSCs remained viable for at least 48 h when loaded into the hydrogels. Adding increasing concentrations of hMSCs-loaded hydrogel to the epithelium did not affect keratinocytes' viability and healing capacity and all wound area was closed in less than one day. Our study opens opportunities to exploit poloxamer hydrogels as cell carriers for the treatment of skin superficial wound.

Polymer based dual drug delivery system for targeted treatment of fluoroquinolone resistant Staphylococcus aureus mediated infections

The present study attempts to treat S. aureus-induced soft skin infections using a combinatorial therapy with an antibiotic, Ciprofloxacin (CIP), and an efflux pump inhibitor 5-Nitro-2-(3-phenylpropoxy) pyridine (5-NPPP) through a smart hydrogel delivery system. The study aims to reduce the increasing rates of infections and antimicrobial resistance; therefore, an efflux pump inhibitor molecule is synthesized and delivered along with an antibiotic to re-sensitize the pathogen towards antibiotics and treat the infections. CIP-loaded polyvinyl alcohol (PVA) hydrogels at varying concentrations were fabricated and optimized by a chemical cross-linking process, which exhibited sustained drug release for 5 days. The compound 5-NPPP loaded hydrogels provided linear drug release for 2 days, necessitating the need for the development of polymeric nanoparticles to alter the release drug pattern. 5-NPPP loaded Eudragit RSPO nanoparticles were prepared by modified nanoprecipitation-solvent evaporation method, which showed optimum average particle size of 230-280 nm with > 90% drug entrapment efficiency. The 5-NPPP polymeric nanoparticles loaded PVA hydrogels were fabricated to provide a predetermined sustained release of the compound to provide a synergistic effect. The selected 7% PVA hydrogels loaded with the dual drugs were evaluated using Balb/c mice models induced with S. aureus soft skin infections. The results of in vivo studies were evidence that the dual drugs loaded hydrogels were non-toxic and reduced the bacterial load causing re-sensitization towards antibiotics, which could initiate re-epithelization. The research concluded that the PVA hydrogels loaded with CIP and 5-NPPP nanoparticles could be an ideal and promising drug delivery system for treating S. aureus-induced skin infections.

Trimesic acid-functionalized chitosan: A novel and efficient multifunctional organocatalyst for green synthesis of polyhydroquinolines and acridinediones under mild conditions

Trimesic acid-functionalized chitosan (Cs/ECH-TMA) material was prepared through a simple procedure by using inexpensive and commercially available chitosan (Cs), epichlorohydrin (ECH) linker and trimesic acid (TMA). The obtained bio-based Cs/ECH-TMA material was characterized using energy-dispersive X-ray (EDX) and Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analysis. The Cs/ECH-TMA material was successfully used, as a multifunctional heterogeneous and sustainable catalyst, for efficient and expeditious synthesis of medicinally important polyhydroquinoline (PHQ) and polyhydroacridinedione (PHA) scaffolds through the Hantzsch condensation in a one-pot reaction. Indeed, the heterogeneous Cs/ECH-TMA material can be considered as a synergistic multifunctional organocatalyst due to the presence of a large number of acidic active sites in its structure as well as hydrophilicity. Both PHQs and PHAs were synthesized in the presence of biodegradable heterogeneous Cs/ECH-TMA catalytic system from their corresponding substrates in EtOH under reflux conditions and high to quantitative yields. The Cs/ECH-TMA catalyst is recyclable and can be reused at least four times without significant loss of its catalytic activity.

Colorimetric pH-responsive and hemostatic hydrogel-based bioadhesives containing functionalized silver nanoparticles

Here we develop and characterize a dual-cross-linked pH-responsive hydrogel based on the carboxyethyl chitosan-oxidized sodium alginate (CAO) containing silver nanoparticles (Ag NPs) functionalized with tannic acid/red cabbage (ATR). This hybrid hydrogel is formed via covalent and non-covalent cross-linking. The adhesive strength measured in contact with cow skin and compression strength is measured more than 3 times higher than that of CAO. Importantly, the incorporation of 1 ​wt% ATR into CAO significantly enhances the compression strength of CAO from 35.1 ​± ​2.1 ​kPa to 97.5 ​± ​2.9 ​kPa. Moreover, the cyclic compression tests confirm significantly higher elastic behavior of CAO after the addition of ATR-functionalized NPs to CAO. The CAO/ATR hydrogel is pH-sensitive and indicated remarkable color changes in different buffer solutions. The CAO/ATR also shows improved hemostatic properties and reduced clotting time compared to the clotting time of blood in contact with CAO hydrogel. In addition, while CAO/ATR is effective in inhibiting the growth of both Gram-positive and Gram-negative bacteria, CAO is only effective in inhibiting the growth of Gram-positive bacteria. Finally, the CAO/ATR hydrogel is cytocompatible with L929 fibroblasts. In summary, the resulting CAO/ATR hydrogel shows promising results in designing and constructing smart wound bioadhesives with high cytocompatibility, antibacterial properties, blood coagulation ability, and fast self-healing properties.

Graphene oxide reinforced biopolymeric (chitosan) hydrogels for controlled cephradine release

In the current study, chitosan, poly (N-vinyl-2-pyrolidone) and polyamidoamine based hydrogels were prepared by Solution Casting Method using different quantity of graphene oxide (GO) for controlled cephradine (CPD) release. The hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thermal analysis, scanning electron microscope and atomic force microscopy. FTIR results endorsed the presence of particular functionalities and developed interfaces in hydrogels. The thermal stability was directly proportional to the amount of GO. Antibacterial activity was investigated against gram-negative bacteria resultantly; CAD-2 exhibited maximum bactericidal activity against Escherichia coli and Psuedomonas aeruginosa. In addition, in-vitro biodegradation was examined in phosphate buffer saline solution and proteinase K for 21 and 07 days respectively. The maximum swelling was exhibited by CAD-133777 % in distilled water that was governed by quasi-Fickian diffusion. The swelling volumes were inversely proportional to the amount of GO. In the same way, pH sensitive CPD release was detected by UV visible spectrophotometer that followed zero order and Higuchi models. However, in 4 h, 89.4 % and 83.7 % of CPD was released in PBS and SIF solution correspondingly. Therefore, the chitosan-based biocompatible and biodegradable hydrogel platforms offered substantial potential for the controlled CPD release in medico-biological applications.

Therapeutic and pro-healing potential of advanced wound dressings loaded with bioactive agents

Chronic skin wound infections are inextricably linked with high mortality rates. With the rise in the aging population and the threat of diabetes, obesity and lifestyle-based diseases, the risk incurred from invasive wound pathogens has been ever escalating. Thus, more efficacious wound care management is necessary to cope with such morbid illnesses. A plethora of bioactive agents, such as antibiotics, phytochemicals, essential oils, phages among others, has been exploited to develop wound dressings, raising tremendous interest in their prospective use as wound care products. The present review critically focuses on the therapeutic implications of advanced wound dressings that have assisted in the expansion of regenerative medicine and also discusses the practical concerns that have limited their bench-to-market entry.

Recent advancements and perspective of ciprofloxacin-based antimicrobial polymers

In recent years, microbial pathogens, which are major sources of infections, have become a widespread concern across the world. The number of deaths caused by infectious diseases is continually rising, according to World Health Organization records. Antimicrobial resistance, particularly resistance to several drugs, is steadily growing in percentages of organisms. Ciprofloxacin is a second-generation fluoroquinolone with significant antimicrobial activity and pharmacokinetic characteristics. According to studies, many bacteria are resistant to the antibiotic ciprofloxacin. In this article, we look into polymers as ciprofloxacin macromolecular carriers with a wide range of antibacterial activity. We also discuss the latter form of coupling, in which ciprofloxacin and polymers are covalently bonded. This article also discusses the use of antimicrobial polymers in combination with ciprofloxacin in a various sectors. The current review article provides an overview of publications in the last five years on polymer loaded or modified with ciprofloxacin having applications in numerous sectors.

Oral organic nanovaccines against bacterial and viral diseases

Vaccines have saved millions of humans and animals from deadly diseases. Many vaccines are still under development to fight against lethal diseases. Indeed, subunit vaccines are a versatile approach with several advantageous attributes, but they lack strong immunogenicity. Nanotechnology is an avenue to vaccine development because nanoparticles may serve as nanocarriers and adjuvants, which are critical aspects for oral vaccines. This review provides an update of oral organic nanovaccines, describing suitable nanomaterials for oral vaccine design and recent (last five-year view) oral nanovaccine developments to fight against those principal pathogens causing human and animal diseases.

Chitosan-EDTA-Cellulose network as a green, recyclable and multifunctional biopolymeric organocatalyst for the one-pot synthesis of 2-amino-4H-pyran derivatives

In this research, cellulose grafted to chitosan by EDTA (Cs-EDTA-Cell) bio-based material is reported and characterized by a series of various methods and techniques such as FTIR, DRS-UV–Vis, TGA, FESEM, XRD and EDX analysis. In fact, the Cs-EDTA-Cell network is more thermally stable than pristine cellulose or chitosan. There is a plenty of both acidic and basic sites on the surface of this bio-based and biodegradable network, as a multifunctional organocatalyst, to proceed three-component synthesis of 2-amino-4H-pyran derivatives at room temperature in EtOH. The Cs-EDTA-Cell nanocatalyst can be easily recovered from the reaction mixture by using filtration and reused for at least five times without significant decrease in its catalytic activity. In general, the Cs-EDTA-Cell network, as a heterogeneous catalyst, demonstrated excellent catalytic activity in an environmentally-benign solvent to afford desired products in short reaction times and required simple experimental and work-up procedure compared to many protocols using similar catalytic systems.

A self-crosslinking, double-functional group modified bacterial cellulose gel used for antibacterial and healing of infected wound

Cellulose/chitosan composite, as a mature commercial antibacterial dressing, is an important type of wound repair material. However, how to achieve the perfect compound of two components and improve antibacterial activity is a major, lingering issue. In this study, a bifunctional group modified bacterial cellulose (DCBC) was prepared by carboxymethylation and selective oxidation. Further, the chitosan (CS) was compounded in the network of DCBC by self-crosslinking to form dialdehyde carboxymethyl bacterial cellulose/chitosan composites (S-DCBC/CS). The aldehyde group can react with amino of CS by Schiff base reaction. The carboxyl group of DCBC and the amorphous distribution of CS molecular chains increase the antimicrobial properties of composites. The bacteriostatic rate of composites could be higher than 95%. Bacteria can be attracted onto the surface of composites, what we call it “directional adhesion antibacterial effects”. In particular, a kind of large animal wound model, deep Ⅱ degree infected scald of Bama miniature pig, was used to research the antimicrobial and healing properties of materials. The S-DCBC/CS can effectively inhibit bacterial proliferation of wound and kill the bacteria. The wound healing rate of S-DCBC/CS was up to 80% after three weeks. The composites show better antibacterial and promoting concrescence effects than traditional chitosan dressings.

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A network composites from dialdehyde carboxylmethyl BC with chitosan that has good antibacterial properties.

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Deep Ⅱ degree infected scald of Bama pig was used to research the antimicrobial and healing properties of S-DCBC/CS.

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The S-DCBC/CS composites could promote epidermal growth and collagen production.

Novel fabrication of antibiotic containing multifunctional silk fibroin injectable hydrogel dressing to enhance bactericidal action and wound healing efficiency on burn wound: In vitro and in vivo evaluations

The development of biologically active multifunctional hydrogel wound dressings can assist effectively to wound regeneration and also has influenced multiple functions on wound injury. Herein, we designed a carbon-based composited injectable silk fibroin hydrogel as multifunctional wound dressing to provide effective anti-bacterial, cell compatibility and in vivo wound closure actions. Importantly, the fabricated injectable hydrogel exhibit sustained drug delivery properties, anti-oxidant and self-healing abilities, which confirm that composition of hydrogel is highly beneficial to tissue adhesions and burn wound regeneration ability. Frequently, designed injectable hydrogel can be injected into deep and irregular burn wound sites and would provide rapid self-healing and protection from infection environment with thoroughly filled wound area. Meanwhile, incorporated carbon nanofillers improve injectable hydrogel strength and also offer high fluid uptake to hydrogel when applied on the wound sites. In vitro MTT cytotoxicity assay on human fibroblast cell lines establish outstanding cytocompatibility of the injectable hydrogel and also have capability to support cell growth and proliferations. In vivo burn wound animal model results demonstrate that the hydrogel dressings predominantly influenced enhanced wound contraction and also promoted greater collagen deposition, granulation tissue thickness and vascularization. This investigation's outcome could open a new pathway to fabricate multifunctional biopolymeric hydrogel for quicker burn wound therapy and effectively prevents microenvironment bacterial infections.

Hyaluronic Acid-Based Scaffolds as Potential Bioactive Wound Dressings

The negative factors that result in delayed and prolonged wound healing process include microbial pathogens, excess wound exudates, underlying conditions, smoking, obesity, etc. Most of the currently used wound dressings demonstrate an inadequate capacity to treat wounds resulting from the factors mentioned above. The commonly used wound dressings include hydrogels, films, hydrocolloids, foams, fibers, sponges, dermal patches, bandages, etc. These wound dressings can be loaded with various types of bioactive agents (e.g., antibiotics, nanoparticles, anti-inflammatory drugs, etc.) to improve their therapeutic outcomes. Biopolymers offer interesting properties suitable for the design of wound dressings. This review article will be based on hyaluronic-acid-based scaffolds loaded with therapeutic agents for the treatment of wounds.

A call for action to the biomaterial community to tackle antimicrobial resistance

The global surge of antimicrobial resistance (AMR) is a major concern for public health and proving to be a key challenge in modern disease treatment, requiring action plans at all levels. Microorganisms regularly and rapidly acquire resistance to antibiotic treatments and new drugs are continuously required. However, the inherent cost and risk to develop such molecules has resulted in a drying of the pipeline with very few compounds currently in development. Over the last two decades, efforts have been made to tackle the main sources of AMR. Nevertheless, these require the involvement of large governmental bodies, further increasing the complexity of the problem. As a group with a long innovation history, the biomaterials community is perfectly situated to push forward novel antimicrobial technologies to combat AMR. Although this involvement has been felt, it is necessary to ensure that the field offers a united front with special focus in areas that will facilitate the development and implementation of such systems. This paper reviews state of the art biomaterials strategies striving to limit AMR. Promising broad-spectrum antimicrobials and device modifications are showcased through two case studies for different applications, namely topical and implantables, demonstrating the potential for a highly efficacious physical and chemical approach. Finally, a critical review on barriers and limitations of these methods has been developed to provide a list of short and long-term focus areas in order to ensure the full potential of the biomaterials community is directed to helping tackle the AMR pandemic.

Ciprofloxacin self-dissolvable Soluplus based polymeric films: a novel proposal to improve the management of eye infections

Infections of the eye are among the leading causes of vision impairment and vision loss worldwide. The ability of a drug to access the anterior parts of the eye is negligible after systemic administration. Effective drug delivery to the eye is a major challenge due to the presence of protective mechanisms and physiological barriers that result in low ocular availability after topical application. The main purpose of this work was the improvement of the corneal and conjunctival permeation of the antibiotic Ciprofloxacin, a wide spectrum antibiotic used for the most common eye infection, using a self-dissolving polymeric film. Films were prepared by the solvent casting technique, using polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft co-polymer (Soluplus), polyvynyl alcohol, and propylene glycol. Films were homogeneous in drug content and thickness, as demonstrated by adapting the Swiss Roll technique followed by microscopy observation. These films proved in vitro to control the release of the Ciprofloxacin. Ex vivo permeability studies using Franz diffusion cells and porcine cornea and sclera showed an effective permeability of the drug without inducing irritation of the tissues. Films swelled in contact with artificial tears forming an in situ gel over 20 min, which will improve drug contact and reduce the need of multiple dosing. The antibiotic activity was also tested in vitro in five types of bacterial cultures, assuring the pharmacological efficacy of the films. The developed films are a promising drug delivery system to topically treat or prevent ocular infections.

Enhancement of Simvastatin ex vivo Permeation from Mucoadhesive Buccal Films Loaded with Dual Drug Release Carriers

BACKGROUND

Simvastatin (SMV), a hypocholesterolemic agent, suffers from very low bioavailability due to its poor aqueous solubility and extensive first-pass metabolism.

METHODS

Two SMV carrier systems, namely, polymeric drug inclusion complex (IC) and mixed micelles (MM) nanoparticles, were developed and loaded into mucoadhesive buccal films to enhance SMV bioavailability. The two carrier systems were characterized and their permeation across human oral epithelial cells (OEC) was studied. The effect of IC to MM ratio (X1) and the mucoadhesive polymer concentration (X2) on the cumulative percent of drug released, elongation percent and the mucoadhesive strength, from the prepared mucoadhesive films, were optimized. Ex vivo permeation across bovine mucosal tissue was investigated. The permeation parameters for the in vitro and ex vivo release data were calculated.

RESULTS

Complexation of SMV with hydroxypropyl beta-cyclodextrin (HP β-CD) was superior to all other polymers as revealed by the equilibrium saturation solubility, stability constant, complexation efficiency and thermodynamic potential. SMV-HP β-CD IC was utilized to develop a saturated polymeric drug solution. Both carrier systems showed enhanced permeation across OEC when compared to pure drug. X1 and X2 were significantly affecting the characteristics of the prepared films. The optimized mucoadhesive buccal film formulation loaded with SMV IC and drug MM nanoparticles demonstrated superior ex vivo permeation when compared to the corresponding pure drug buccal film, and the calculated permeation parameters confirmed this finding.

CONCLUSION

Mucoadhesive buccal films containing SMV IC and drug MM can be used to improve drug bioavailability; however, additional pharmacokinetic and pharmacodynamic studies are required.

Chitosan Film Containing Mansoa hirsuta Fraction for Wound Healing

Chitosan films entrapped with the Mansoa hirsuta fraction (CMHF) was developed as a new dressing for wound care. The chromatographic profile of the M. hirsuta fraction (MHF) was evaluated by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and the results showed that MHF is rich in acid triterpenes. Physicochemical characterization of the films prepared using the solvent casting method was performed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry (TGA), differential scanning calorimetry (DCS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and mechanical properties. CMHF exhibited characteristic bands of both chitosan and MHF, revealing a physical mixture of both. CMHF presented an amorphous nature, thermostability, and dispersion of MHF in the chitosan matrix, resulting in a rough structure. Incorporation of M. hirsuta fraction into chitosan matrix favorably enhanced the mechanical performance and films thickness. The in vivo wound treatment with CMHF for seven days showed a characteristic area of advanced healing, re-epithelization, cell proliferation, and collagen formation. Furthermore, wound closure reached 100% contraction after 10 days of treatment with modulation of interleukins. The incorporation of M. hirsuta fraction into chitosan films was advantageous and showed great potential for stimulating wound repair and regeneration.

Development of cost effective metal oxide semiconductor based gas sensor over flexible chitosan/PVP blended polymeric substrate

In the present work, biodegradable and flexible chitosan/polyvinylpyrrolidone (CHP) polymeric substrate was fabricated by solvent casting method. This is a novel demonstration of the combination of natural polymer (chitosan) and synthetic polymer (PVP) for next-generation semiconductor device applications. The ZnO thin films were successfully synthesized on these polymeric substrates by facile drop-casting method for gas sensing applications. The hydrogen gas sensing properties of ZnO deposited on the polymeric substrate and SiO₂ substrate show similar performance. The structural, morphological, optical, thermal, and tensile strength of the CHP substrate were studied using X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV-visible spectroscopy, Derivative thermogravimetric analysis (DTG), and Universal testing machine (UTM), respectively. Our study suggests that the biodegradable CH/PVP flexible polymeric substrate provides a new way for the implementation of an eco-friendly green substrate in numerous electronic device applications.

Ciprofloxacin-intercalated layered double hydroxide-in-hybrid films as composite dressings for controlled antimicrobial topical delivery

Films based on biopolymers and loaded with antimicrobial agents are convenient pharmaceutical dosage forms for topical application. Inorganic carriers loaded with these agents lead to composite materials, which combined with polymers produce further functionality. Here, hybrid composite films based on layered double hydroxide (LDH) and hyaluronan (HS) as ciprofloxacin (Cip) delivery systems were studied as an alternative for prophylaxis and treatment of opportunistic infections in wounds. Cip-intercalated Zn-Al LDH (LDH-Cip), with high drug loading and crystallinity, were obtained by a precipitation at variable pH method, and then included in a HS dispersion for obtaining the hybrid composite films by solvent casting. Physicochemical characterization of films showed that a composite material where the HS acted as matrix and LDH-Cip aggregates acted as filler were obtained. LDH-Cip were uniformly dispersed along the (LDH-Cip)/HS films, which exhibited roughness in their surface, increasing their swelling capacity in PBS pH = 5.8. Controlled releases of Cip toward PBS at pH = 5.8 and 7.4 were obtained, and the best fits for the release profiles were found with Higuchi and Korsmeyer-Peppas models, respectively. (LDH-Cip)/HS films exhibited antimicrobial activity against S. aureus. These films would then provide sustained release of Cip after topical administration, maintaining a suitable level of antibacterial activity, combined with the wound healing properties of the HS. The interesting properties shown by the (LDH-Cip)/HS films make them a promising alternative for application in skin wounds.

Advances and Impact of Antioxidant Hydrogel in Chronic Wound Healing

The accelerating and thorough treatment of chronic wounds still represents a major unmet medical need owing to the complex symptoms resulting from metabolic disorder of the wound microenvironment. Although numerous strategies and bioactive hydrogels are developed, an effective and widely used method of chronic wound treatment remains a bottleneck. With the aim to accelerate chronic wound healing, many hydrogel dressings with antioxidant functions have emerged and are proven to accelerate wound healing, especially for chronic wound repair. The new strategy in chronic wound treatment brought by antioxidant hydrogels is of great significance to human health. Here, the application of antioxidant hydrogels in the repair of chronic wounds is discussed systematically, aiming to provide an important theoretical reference for the further breakthrough of chronic wound healing.

Polymeric worm-like nanomicellar system for accelerated wound healing

Self-assembly is an unparalleled step in designing macromolecular analogs of nature's simple amphiphiles. Tailoring hydrogel systems - a material with ample potential for wound healing applications - to simultaneously alleviate infection and prompt wound closure is vastly appealing. The poly (DEAEMA-co-AAc) (PDEA) is examined with a cutaneous excisional wound model alterations in wound size, and histological assessments revealed a higher wound healing rate, including dermis proliferation, re-epithelialization, reduced scar formation, and anti-inflammatory properties. Moreover, a mechanism for the formation of spherical and worm-like micelles (WLMs) is delineated using a suite of characterizations. The excellent porosity and ability to absorb exudates impart the PDEA with reliable wound healing. Altogether, this system demonstrates exceptional promise as an infection-mitigating, cell-stimulating, homeostasis-maintaining dressing for accelerated wound healing. The aim and objective of this study is to understand the mechanism of self-assembly in synthesized WLMs from PDEA and their application in wound healing.

Wound dressing from polyvinyl alcohol/chitosan electrospun fiber membrane loaded with OH-CATH30 nanoparticles

Novel nanomaterials have been developed for antimicrobial and wound healing applications. Here, we report the preparation of a polyvinyl alcohol/chitosan (PVA/CS) nanofiber with carboxymethyl chitosan nanoparticles (CMCS-OH30 NPs) encapsulating the antibacterial peptide OH-CATH30 (OH-30). The PVA/CS nanofibers containing OH-30 NPs (NP-30-NFs) obtained via electrospinning could achieve a secondary embedded OH-30. The effect of NP-30-NFs on the release of OH-30 was investigated through high-performance liquid chromatography. The antibacterial activities of NP-30-NFs against Escherichia coli and Staphylococcus aureus were studied by bacterial plate counting. NP-30-NFs containing different concentrations of NPs were applied to mouse skin wounds to determine their effectiveness in promoting wound healing. Results showed that NP-30-NFs exhibited antibacterial properties and promoted skin wound healing.

Superiority of TPGS-loaded micelles in the brain delivery of vinpocetine via administration of thermosensitive intranasal gel

Background: Vinpocetine (VPN) is a synthetic derivative of the Vinca minor alkaloids. The drug is characterized by a short half-life, limited water solubility and high hepatic first-pass effect. The objective was to develop different lipid-based nanocarriers (NCs) loaded into a thermosensitive in situ gelling (ISG) system to improve VPN bioavailability and brain targeting via intranasal (IN) delivery. Methods:  Different lipid-based NCs were developed and characterized for vesicle size, zeta potential, VPN entrapment efficiency (EE) and morphological characterization using transmission electron microscope (TEM). The prepared NCs were loaded into ISG formulations and characterized for their mucoadhesive properties. Ex-vivo permeation and histological study of the nasal mucosa were conducted. Pharmacokinetic and brain tissue distribution were investigated and compared to a marketed VPN product following administration of a single dose to rats. Results: VPN-D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) micelles nano-formulation showed the smallest particle size, highest EE among the studied NCs. TEM images revealed an almost spherical shape for all the prepared NCs. Among the NCs studied, VPN-loaded TPGS micelles demonstrated the highest percent cumulative VPN ex vivo permeation. All the prepared ISG formulations revealed the presence of mucoadhesive properties and showed no signs of inflammation or necrosis upon histological examination. Rats administered IN VPN-loaded TPGS-micelles ISG showed superior VPN concentration in the brain tissue and significant high relative bioavailability when compared to that received raw VPN-loaded ISG and marketed drug oral tablets. VPN-D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) micelles nano-formulation showed the smallest particle size, highest EE among the studied NCs. TEM images revealed an almost spherical shape for all the prepared NCs. Among the NCs studied, VPN-loaded TPGS micelles demonstrated the highest percent cumulative VPN ex vivo permeation. All the prepared ISG formulations revealed the presence of mucoadhesive properties and showed no signs of inflammation or necrosis upon histological examination. Rats administered IN VPN-loaded TPGS-micelles ISG showed superior VPN concentration in the brain tissue and significant high relative bioavailability when compared to that received raw VPN-loaded ISG and marketed drug oral tablets. Conclusion: VPN-loaded TPGS-micelles ISG formulation is a successful brain drug delivery system with enhanced bioavailability for drugs with poor bioavailability and those that are frequently administered.

Enhanced wound healing by PVA/Chitosan/Curcumin patches: In vitro and in vivo study

Biocompatible polymers are being used in recent times for treating skin injuries and burn wounds. Polymers like Poly Vinyl Alcohol and Chitosan are proven to be biocompatible with least toxic to treat injuries with minimal side-effects. Curcumin, a primary component of turmeric has anti-inflammatory properties and anti-microbial activity but has extremely low bioavailability. Converting Curcumin to its nano form increased its bioavailability exponentially allowing it to play a vital role in the process of wound healing. This PVA/Chi/Cur patch increased cell proliferation as shown by the results of cell line studies and MTT assay. Its anti-bacterial activity against four major bacterial strains commonly found in wound sites and water retainability indicates it to be a perfect material for wound treatment. Results of in-vivo studies conducted on wistar rats by testing the patch's healing ability on a surgically induced wound displayed its superiority over commercial ointment. This treatment for epidermal wounds reduces the frequency in which the patch has to be replaced and increases the rate of wound rehabilitation.