Nanomotor-hydrogel Delivery System with Enhanced Antibacterial Performance for Wound Treatment

In this study, we present a novel system consisting of nanomotors and a hydrogel. Calcium carbonate nanomotors are prepared using layer-by-layer self-assembly technology with calcium carbonate nanoparticles as the core and catalase (CAT) and polydopamine (PDA) as the shell. Calcium carbonate nanomotors were loaded into a Schiff base hydrogel to synthesize the CaCO3@NM-hydrogel system. A nanomotor is a device that works on the nanoscale to convert some form of energy to mechanical energy. The motion speed of the system in 5.0 mM H2O2 aqueous solution under near-infrared light (NIR) irradiation with a power density of 1.8 W/cm2 is 13.6 μm/s. The addition of CaCO3@NM further promotes gelation and improves the mechanical properties. The energy storage modulus increases to 4.0 × 103 Pa, which is 50 times higher. Schiff base hydrogels form dynamic reversible chemical bonds due to inter- and intramolecular hydrogen bonding. They also have good self-healing properties, as observed by measuring the energy storage modulus versus the loss modulus at 1 versus 10 kHz. The results show that the system significantly inhibited the growth of both Gram-positive bacteria, Staphylococcus aureus, and Gram-negative bacteria, Escherichia coli, after 48 h, with an inhibition rate of nearly 95%. These findings provide a basis for further research and potential applications of the system in wound dressings.

Recent progress of electrospun nanofibers as burning dressings

Burns are a global public health problem, which brings great challenges to public health and the economy. Severe burns often lead to systemic infection, shock, multiple organ failure, and even death. With the increasing demand for the therapeutic effect of burn wounds, traditional dressings have been unable to meet people's needs due to their single function and many side effects. In this context, electrospinning shows a great prospect on the way to open up advanced wound dressings that promote wound repairing and prevent infection. With its large specific surface area, high porosity, and similar to natural extracellular matrix (ECM), electrospun nanofibers can load drugs and accelerate wound healing. It provides a promising solution for the treatment and management of burn wounds. This review article introduces the concept of burn and the types of electrospun nanofibers, then summarizes the polymers used in electrospun nanofiber dressings. Finally, the drugs (plant extracts, small molecule drugs and nanoparticles) loaded with electrospun burn dressings are summarized. Some promising aspects for developing commercial electrospun burn dressings are proposed.

Glycosaminoglycans' Ability to Promote Wound Healing: From Native Living Macromolecules to Artificial Biomaterials

Glycosaminoglycans (GAGs) are important for the occurrence of signaling molecules and maintenance of microenvironment within the extracellular matrix (ECM) in living tissues. GAGs and GAG-based biomaterial approaches have been widely explored to promote in situ tissue regeneration and repair by regulating the wound microenvironment, accelerating re-epithelialization, and controlling ECM remodeling. However, most approaches remain unacceptable for clinical applications. To improve insights into material design and clinical translational applications, this review highlights the innate roles and bioactive mechanisms of native GAGs during in situ wound healing and presents common GAG-based biomaterials and the adaptability of application scenarios in facilitating wound healing. Furthermore, challenges before the widespread commercialization of GAG-based biomaterials are shared, to ensure that future designed and constructed GAG-based artificial biomaterials are more likely to recapitulate the unique and tissue-specific profile of native GAG expression in human tissues. This review provides a more explicit and clear selection guide for researchers designing biomimetic materials, which will resemble or exceed their natural counterparts in certain functions, thereby suiting for specific environments or therapeutic goals.

Emerging advances in hydrogel-based therapeutic strategies for tissue regeneration

Significant developments in cell therapy and biomaterial science have broadened the therapeutic landscape of tissue regeneration. Tissue damage is a complex biological process in which different types of cells play a specific role in repairing damaged tissues and growth factors strictly regulate the activity of these cells. Hydrogels have become promising biomaterials for tissue regeneration if appropriate materials are selected and the hydrogel properties are well-regulated. Importantly, they can be used as carriers for living cells and growth factors due to the high water-holding capacity, high permeability, and good biocompatibility of hydrogels. Cell-loaded hydrogels can play an essential role in treating damaged tissues and open new avenues for cell therapy. There is ample evidence substantiating the ability of hydrogels to facilitate the delivery of cells (stem cell, macrophage, chondrocyte, and osteoblast) and growth factors (bone morphogenetic protein, transforming growth factor, vascular endothelial growth factor and fibroblast growth factor). This paper reviewed the latest advances in hydrogels loaded with cells or growth factors to promote the reconstruction of tissues. Furthermore, we discussed the shortcomings of the application of hydrogels in tissue engineering to promote their further development.

Green Synthesis of Polycyclodextrin/Drug Inclusion Complex Nanofibrous Hydrogels: pH-Dependent Release of Acyclovir

The development of an approach or a material for wound healing treatments has drawn a lot of attention for decades and has been an important portion of the research in the medical industry. Especially, there is growing interest and demand for the generation of wound care products using eco-friendly conditions. Electrospinning is one of these methods that enables the production of nanofibrous materials with attractive properties for wound healing under mild conditions and by using sustainable sources. In this study, starch-derived cyclodextrin (hydroxypropyl-β-cyclodextrin (HPβCD)) was used both for forming an inclusion complex (IC) with acyclovir, a well-known antiviral drug, and for electrospinning of free-standing nanofibers. The nanofibers were produced in an aqueous system, without using a carrier polymer matrix and toxic solvent/chemical. The ultimate HPβCD/acyclovir-IC nanofibers were thermally cross-linked by using citric acid, listed in the generally regarded as safe (GRAS) category by the US Food and Drug Administration (FDA). The cross-linked HPβCD/acyclovir-IC nanofibers displayed stability in aqueous medium. The hydrogel-forming feature of nanofibers was confirmed with their high swelling profile in water in the range of ∼610-810%. Cellulose acetate (CA)/acyclovir nanofibers were also produced as the control sample. Due to inclusion complexation with HPβCD, the solubility of acyclovir was improved, so cross-linked HPβCD/acyclovir-IC nanofibrous hydrogels displayed a better release performance compared to CA/acyclovir nanofibers. Here, a pH-dependent release profile was obtained (pH 5.4 and pH 7.4) besides their attractive swelling features. Therefore, the cross-linked HPβCD/acyclovir-IC nanofibrous hydrogel can be a promising candidate as a wound healing dressing for the administration of antiviral drugs by holding the unique properties of CD and electrospun nanofibers.

Stimuli-Activable Metal-Bearing Nanomaterials and Precise On-Demand Antibacterial Strategies

Bacterial infections remain the leading cause of death worldwide today. The emergence of antibiotic resistance has urged the development of alternative antibacterial technologies to complement or replace traditional antibiotic treatments. In this regard, metal nanomaterials have attracted great attention for their controllable antibacterial functions that are less prone to resistance. This review discusses a particular family of stimuli-activable metal-bearing nanomaterials (denoted as SAMNs) and the associated on-demand antibacterial strategies. The various SAMN-enabled antibacterial strategies stem from basic light and magnet activation, with the addition of bacterial microenvironment responsiveness and/or bacteria-targeting selectivity and therefore offer higher spatiotemporal controllability. The discussion focuses on nanomaterial design principles, antibacterial mechanisms, and antibacterial performance, as well as emerging applications that desire on-demand and selective activation (i.e., medical antibacterial treatments, surface anti-biofilm, water disinfection, and wearable antibacterial materials). The review concludes with the authors' perspectives on the challenges and future directions for developing industrial translatable next-generation antibacterial strategies.

Chondroitin sulfate-based composites: a tour d'horizon of their biomedical applications

Chondroitin sulfate (CS), a natural anionic mucopolysaccharide, belonging to the glycosaminoglycan family, acts as the primary element of the extracellular matrix (ECM) of diverse organisms. It comprises repeating units of disaccharides possessing β-1,3-linked N-acetyl galactosamine (GalNAc), and β-1,4-linked D-glucuronic acid (GlcA), and exhibits antitumor, anti-inflammatory, anti-coagulant, anti-oxidant, and anti-thrombogenic activities. It is a naturally acquired bio-macromolecule with beneficial properties, such as biocompatibility, biodegradability, and immensely low toxicity, making it the center of attention in developing biomaterials for various biomedical applications. The authors have discussed the structure, unique properties, and extraction source of CS in the initial section of this review. Further, the current investigations on applications of CS-based composites in various biomedical fields, focusing on delivering active pharmaceutical compounds, tissue engineering, and wound healing, are discussed critically. In addition, the manuscript throws light on preclinical and clinical studies associated with CS composites. A short section on Chondroitinase ABC has also been canvassed. Finally, this review emphasizes the current challenges and prospects of CS in various biomedical fields.

Polydopamine Biomaterials for Skin Regeneration

Designing biomaterials capable of biomimicking wound healing and skin regeneration has been receiving increasing attention recently. Some biopolymers behave similarly to the extracellular matrix (ECM), supporting biointerfacial adhesion and intrinsic cellular interactions. Polydopamine (PDA) is a natural bioadhesive and bioactive polymer that endows high chemical versatility, making it an exciting candidate for a wide range of biomedical applications. Moreover, biomaterials based on PDA and its derivatives have near-infrared (NIR) absorption, excellent biocompatibility, intrinsic antioxidative activity, antibacterial activity, and cell affinity. PDA can regulate cell behavior by controlling signal transduction pathways. It governs the focal adhesion behavior of cells at the biomaterials interface. These features make melanin-like PDA a fascinating biomaterial for wound healing and skin regeneration. This paper overviews PDA-based biomaterials' synthesis, properties, and interactions with biological entities. Furthermore, the utilization of PDA nano- and microstructures as a constituent of wound-dressing formulations is highlighted.

An Updated Account On Formulations And Strategies For The Treatment Of Burn Infection – A Review

Background:

Burn injury is considered one of the critical injuries of the skin. According to WHO (World Health Organization), approximately 3,00,000 deaths are caused each year mainly due to fire burns, with additional deaths attributed to heat and other causes of burn e.g., electric devices, chemical materials, radioactive rays, etc. More than 95% of burn injuries occur in developing countries.

Introduction:

Burn injuries have been a prominent topic of discussion in this present era of advancements. Burns are one of the common and devastating forms of trauma. Burn injuries are involved in causing severe damage to skin tissues and various other body parts triggered particularly by fire,blaze, or exposure to chemicals and heated substances. They leave a long-lasting negative impact on the patients in terms of their physical and mental health.

Method:

The various methods and bioactive hydrogels, a viable and widely utilised approach for treating chronic wounds remains a bottleneck. Many traditional approaches such as woven material, conventional antimicrobial agents, hydrogel sheets, creams are utilised in wound healing. Nowadays, lipid-based nanoparticles, nanofibres systems, and foam-based formulations heal the wound.

Result:

The prepared formulation shows wound healing activity when tested on rat model. The nanofibres containing SSD help in the burn-wound healing study on Male Sprague Dawley (SD) rats. The healing effect on rats was examined by western blot analysis, digital camera observation, and histological analyses.

Conclusion:

Burn is also considered the most grievous form of trauma. Nowadays, several large and foam-based formulations are used in wound healing, which heals the wound better than previously existing formulations and is less prone to secondary infection. Recently, nanofiber delivery has piqued the interest of academics over the years because of its excellent features, which include an extraordinarily high surface to volume ratio, a highly porous structure, and tiny pore size.

Electrospun Fibers Loaded with Natural Bioactive Compounds as a Biomedical System for Skin Burn Treatment. A Review

Burns are a major threat to public health and the economy due to their costly and laborious treatment and high susceptibility to infection. Efforts have been made recently to investigate natural bioactive compounds with potential use in wound healing. The importance lies in the capacities that these compounds could possess both in infection control by common and resistant microorganisms, as well as in the regeneration of the affected tissues, having in both cases low adverse effects. However, some bioactive molecules are chemically unstable, poorly soluble, and susceptible to oxidative degradation or have low bioavailability. Therefore, developing new technologies for an efficient treatment of wound healing poses a real challenge. In this context, electrospun nanofibers have gained increasing research interest because bioactive molecules can be easily loaded within the nanofiber, resulting in optimal burst control and enhanced drug stability. Additionally, the nanofibers can mimic the extracellular collagen matrix, providing a suitable highly porous structural support for growing cells that facilitate and accelerate skin burns healing. This review gives an overview of the current state of electrospun fibers loaded with natural bioactive compounds as a biomedical system for skin burn treatment.

Challenges and Potential Solutions for 100% Recycling of Medical Textiles

Medical textiles are all fiber-based products and structures which are utilized for emergency treatment, clinical, surgical and hygienic purposes. It is an exceptionally particular and bio viable specialized material, utilized for clinical and cleanliness applications. Volumes of clinical waste being created in excess of 60 million tons yearly around the world. According to the current investigation reports and information, the worldwide clinical waste administration market was esteemed at USD 11.77 billion in the year 2018 and will reach at 17.89 billion by the year 2026 at a compound annual growth rate (CAGR) of 5.3%. Over the world, out of the measure of waste created by medical care activities, about 85% is general waste and staying 15% is viewed as unsafe material that might be irresistible, poisonous or radioactive. The following particular reasons are very harmful for the environment in the upcoming future. The waste management policy of medical textile is a vital fact for the world. The potential and effectual solution is recycling of these medical wastes. Current solutions for 100% recycling of medical textiles are chemical treatment, incineration, and autoclaving. But the most innovative solution of medical textiles is molecular tagging/tagging of fibers. Medical textile market is producing state-of-the-art polymeric textile implantable devices that are redefining traditional materials and methods of surgery. Developing polymer innovation has yielded a wide scope of uses of implantable clinical material or biotextiles. Due to world Covid-19 pandemic situation, the requirement of medical textiles already has been increased almost double from last year. It has been observed that the market value of medical textiles will be in optimum position. In the year 2019, the global market worth of medical textiles was US$ 17.5 billion. In the present world, the current medical textiles like implantable and non-implantable categories are not applying for recycling process or end used of their life cycle. In this paper, we will discuss about potential solutions for recycling medical textiles like—by using conductive polymers, maintaining ε-Poly-lysine, non-fibrous biomass, bioactive fibers, etc. But there are still some challenges for recycling like—maintain 100% polymeric bonds, bacterial effect, flexibility and sustainability for clinical performance after recycling the specific product. In this paper, we are presenting the scientific methods, mechanisms, and procedures that used to overcome the aforementioned challenges in the recycling methods.

Performance of Polydopamine Complex and Mechanisms in Wound Healing

Polydopamine (PDA) has been gradually applied in wound healing of various types in the last three years. Due to its rich phenol groups and unique structure, it can be combined with a variety of materials to form wound dressings that can be used for chronic infection, tissue repair in vivo and serious wound healing. PDA complex has excellent mechanical properties and self-healing properties, and it is a stable material that can be used for a long period of time. Unlike other dressings, PDA complexes can achieve both photothermal therapy and electro activity. In this paper, wound healing is divided into four stages: antibacterial, anti-inflammatory, cell adhesion and proliferation, and re-epithelialization. Photothermal therapy can improve the bacteriostatic rate and remove reactive oxygen species to inhibit inflammation. Electrical signals can stimulate cell proliferation and directional migration. With low reactive oxygen species (ROS) levels, inflammatory factors are down-regulated and growth factors are up-regulated, forming regular collagen fibers and accelerating wound healing. Finally, five potential development directions are proposed, including increasing drug loading capacity, optimization of drug delivery platforms, improvement of photothermal conversion efficiency, intelligent electroactive materials and combined 3D printing.

Cationic Lignin-Based Hyperbranched Polymers to Circumvent Drug Resistance in Pseudomonas Keratitis

The rise of antimicrobial-resistant bacteria strains has been a global public health concern due to their ability to cause increased patient morbidity and a greater burden on the healthcare system. As one of the potential solutions to overcome such bacterial infections, hyperbranched copolymers with cationic charges were developed. These copolymers were assessed for their antimicrobial efficacy and their bactericidal mechanisms. They were found to be potent against mobile colistin-resistant 1 strains, which was significant as colistin is known to be the last-resort antibiotic against Gram-negative bacteria. Furthermore, there was no sign of mutational resistance developed by E. Coli ATCC 25922 and MCR 1+ E. Coli against the copolymer even up to 20 passages. The ability to evade inducing resistance would provide invaluable insights for future antibiotic development. Our studies suggest that the bactericidal efficacy comes from the ability to target the outer membrane efficaciously. In vivo study using a Pseudomonas keratitis model showed that the copolymer was compatible with the eye and further supported that the copolymer treatment was effective for complete bacteria elimination.

Efficacy of Water-Soluble Pearl Powder Components Extracted by a CO2 Supercritical Extraction System in Promoting Wound Healing

Pearl powder is a biologically active substance that is widely used in traditional medicine, skin repair and maintenance. The traditional industrial extraction processes of pearl powder are mainly based on water, acid or enzyme extraction methods, all of which have their own drawbacks. In this study, we propose a new extraction process for these active ingredients, specifically, water-soluble components of pearl powder extracted by a CO2 supercritical extraction system (SFE), followed by the extraction efficiency evaluation. A wound-healing activity was evaluated in vitro and in vivo. This demonstrated that the supercritical extraction technique showed high efficiency as measured by the total protein percentage. The extracts exhibited cell proliferation and migration-promoting activity, in addition to improving collagen formation and healing efficiency in vivo. In brief, this study proposes a novel extraction process for pearl powder, and the extracts were also explored for wound-healing bioactivity, demonstrating the potential in wound healing.

Core-Shell Structured Antimicrobial Nanofiber Dressings Containing Herbal Extract and Antibiotics Combination for the Prevention of Biofilms and Promotion of Cutaneous Wound Healing

Burn wounds are susceptible to microbial invasion from both resident and exogenous bacteria, which becomes a critical public health issue and causes substantial economic burden. There is a perceived demand to produce new antimicrobial wound dressings that hinder bacterial colonization while accelerating the healing process and hence would provide an improved standard of care for patients. Since ancient times, herbal extracts from medicinally important plants have extensively been used for treating burn injuries. This work reports the utility of electrospun nanofibers containing plant extracts and antibiotics combination as a multifunctional scaffold for treating second-degree burns. First, we determined the various components of plant extracts from Gymnema sylvestre by two different processing methods and their synergism with minocycline antibiotics. Then, we prepared core-shell nanofibrous dressings with poly-ε-caprolactone/gelatin laden with minocycline hydrochloride as a shell and gelatin infused with G. sylvestre extracts (ultrasound-assisted extracts and cold macerated extracts) as the core using coaxial electrospinning. The electrospun nanofibers displayed a smooth, continuous, and bead-free morphology with adequate wettability. The presence of extract components in the core-shell nanofibers resulted in enhanced mechanical properties when compared to pristine mats. The core-shell structures resulted in sustained release of the bioactive components when compared to nanofiber blends. Core-shell nanofiber mats containing plant extracts and antibiotic combinations displayed potent antimicrobial and antibiofilm properties while promoting the spread and proliferation of skin cells when compared to pristine mats. In a porcine model of cutaneous second-degree burns, we showed that wounds treated with the antimicrobial dressing improved re-epithelialization and collagen organization in comparison to untreated wounds.

Toward the prevention of coronavirus infection: what role can polymers play?

Severe acute respiratory syndrome-associated coronavirus 2 has caused a global public health crisis with high rates of infection and mortality. Treatment and prevention approaches include vaccine development, the design of small-molecule antiviral drugs, and macromolecular neutralizing antibodies. Polymers have been designed for effective virus inhibition and as antiviral drug delivery carriers. This review summarizes recent progress and provides a perspective on polymer-based approaches for the treatment and prevention of coronavirus infection. These polymer-based partners include polyanion/polycations, dendritic polymers, macromolecular prodrugs, and polymeric drug delivery systems that have the potential to significantly improve the efficacy of antiviral therapeutics.

A New Potent Antimicrobial Metalloporphyrin

A series of bis-acryl functionalized porphyrins and their corresponding metalloporphyrins (M=Co, Mn) were synthesized and investigated for their antimicrobial properties through MIC screening and bacteria time-kill kinetic studies. The Mn(III) 4-(bis)methylphenyl-substituted-porphyrins showed superior batericidal activities even in the dark with low hemotoxicity and good cytotoxicity profile.

Nanocomposites for the delivery of bioactive molecules in tissue repair: vital structural features, application mechanisms, updated progress and future perspectives

In recent years, nanocomposites have attracted great attention in tissue repair as carriers for bioactive molecule delivery due to their biochemical and nanostructural similarity to that of physiological tissues, and controlled delivery of bioactive molecules. In this review, we aim to comprehensively clarify how the applications of nanocomposites for bioactive molecule delivery in tissue repair are achieved by focusing on the following aspects: (1) vital structural features (size, shape, pore, etc.) of nanocomposites that have crucial effects on the biological properties and function of bioactive molecule-delivery systems, (2) delivery performance of bioactive molecules possessing high entrapment efficiency of bioactive molecules and good controlled- and sustained-release of bioactive molecules, (3) application mechanisms of nanocomposites to deliver and release bioactive molecules in tissue repair, (4) updated research progress of nanocomposites for bioactive molecule delivery in hard and soft tissue repair, and (5) future perspectives in the development of bioactive molecule-delivery systems based on nanocomposites.

Bio-Based Electrospun Fibers for Wound Healing

Being designated to protect other tissues, skin is the first and largest human body organ to be injured and for this reason, it is accredited with a high capacity for self-repairing. However, in the case of profound lesions or large surface loss, the natural wound healing process may be ineffective or insufficient, leading to detrimental and painful conditions that require repair adjuvants and tissue substitutes. In addition to the conventional wound care options, biodegradable polymers, both synthetic and biologic origin, are gaining increased importance for their high biocompatibility, biodegradation, and bioactive properties, such as antimicrobial, immunomodulatory, cell proliferative, and angiogenic. To create a microenvironment suitable for the healing process, a key property is the ability of a polymer to be spun into submicrometric fibers (e.g., via electrospinning), since they mimic the fibrous extracellular matrix and can support neo- tissue growth. A number of biodegradable polymers used in the biomedical sector comply with the definition of bio-based polymers (known also as biopolymers), which are recently being used in other industrial sectors for reducing the material and energy impact on the environment, as they are derived from renewable biological resources. In this review, after a description of the fundamental concepts of wound healing, with emphasis on advanced wound dressings, the recent developments of bio-based natural and synthetic electrospun structures for efficient wound healing applications are highlighted and discussed. This review aims to improve awareness on the use of bio-based polymers in medical devices.