Supramolecular hydrogels based on cellulose for sustained release of therapeutic substances with antimicrobial and wound healing properties

Insights into Intra Periodontal Pocket Pathogenesis, Treatment, In Vitro-In Vivo Models, Products and Patents, Challenges and Opportunity

Periodontal disease is a multifactorial pathogenic condition involving microbial infection, inflammation, and various systemic complications. Here, a systematic and comprehensive review discussing key-points such as the pros and cons of conventional methods, new advancements, challenges, patents and products, and future prospects is presented. A systematic review process was adopted here by using the following keywords: periodontal diseases, pathogenesis, models, patents, challenges, recent developments, and 3-D printing scaffolds. Search engines used were "google scholar", "web of science", "scopus", and "pubmed", along with textbooks published over the last few decades. A thorough study of the published data rendered an accurate and deep understanding of periodontal diseases, the gap of research so far, and future opportunities. Formulation scientists and doctors need to be interconnected for a better understanding of the disease to prescribe a quality product. Moreover, prime challenges (such as a lack of a vital testing model, scarcity of clinical and preclinical data, products allowing for high drug access to deeper tissue regions for prolonged residence, lack of an international monitoring body, lack of 4D or time controlled scaffolds, and lack of successful AI based tools) exist that must be addressed for designing new quality products. Generally, several products have been commercialized to treat periodontal diseases with certain limitations. Various strategic approaches have been attempted to target certain delivery regions, maximize residence time, improve efficacy, and reduce toxicity. Conclusively, the current review summarizes valuable information for researchers and healthcare professional to treat a wide range of periodontal diseases.

Single-Walled (Magnetic) Carbon Nanotubes in a Pectin Matrix in the Design of an Allantoin Delivery System

Single-walled carbon nanotubes (SWCNTs) outperform other materials due to their high conductivity, large specific surface area, and chemical resistance. They have numerous biomedical applications, including the magnetization of the SWCNT (mSWCNT). The drug loading and release properties of see-through pectin hydrogels doped with SWCNTs and mSWCNTs were evaluated in this study. The active molecule in the hydrogel structure is allantoin, and calcium chloride serves as a cross-linker. In addition to mixing, absorption, and swelling techniques, drug loading into carbon nanotubes was also been studied. To characterize the films, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, surface contact angle measurements, and opacity analysis were carried out. Apart from these, a rheological analysis was also carried out to examine the flow properties of the hydrogels. The study was also expanded to include N-(9-fluorenyl methoxycarbonyl)glycine-coated SWCNTs and mSWCNTs as additives to evaluate the efficiency of the drug-loading approach. Although the CNT additive was used at a 1:1000 weight ratio, it had a significant impact on the hydrogel properties. This effect, which was first observed in the thermal properties, was confirmed in rheological analyses by increasing solution viscosity. Additionally, rheological analysis and drug release profiles show that the type of additive causes a change in the matrix structure. According to TGA findings, even though SWCNTs and mSWCNTs were not coated more than 5%, the coating had a significant effect on drug release control. In addition to all findings, cell viability tests revealed that hydrogels with various additives could be used for visual wound monitoring, hyperthermia treatment, and allantoin release in wound treatment applications.

Metallic-Polyphenolic Nanoparticles Reinforced Cationic Guar Gum Hydrogel for Effectively Treating Burn Wound

The development of injectable hydrogel dressings which are long-term moisturizing, easy-to-apply, and effectively inhibiting infection and inflammatory is essential to promote burn wound repairing. Herein, an injectable hydrogel with moisturizing, antibacterial, and anti-inflammation abilities via multiple reversible interactions between cation guar gum (CG) and metallic-polyphenolic nanoparticles (PA-ZnII NPs) is developed. Specifically, PA-ZnII NPs is formed by synergistic complexation of protocatechualdehyde (PA) and zinc ion (Zn2+ ), provides CGPZ hydrogel with plentiful reversible interactions to inhibit the loss of moist. By interacting with PA-ZnII NPs, the CGPZ hydrogel can provide enhanced moisturization for more than 3 days. Moreover, the CGPZ hydrogel can maintain good adhesion for a period of time with injection and self-healing capabilities due to reversible interactions between CG and PA-ZnII NPs. In addition, CGPZ hydrogel exhibits outstanding broad spectrum antibacterial performance, as its killing efficiency against Escherichia coli and Staphylococcus aureus is all greater than 99.99%. Importantly, compared with commercial dressing, the CGPZ hydrogel can promote wound healing faster by inhibiting tissue damage from dysregulated inflammation and accelerating neovascularization. It is believed that the moisturizing CGPZ hydrogel with antibacterial and anti-inflammation performance can serve as a promising dressing for the effective treatment of burn wound.

The Recent Progress of the Cellulose-Based Antibacterial Hydrogel

Cellulose-based antibacterial hydrogel has good biocompatibility, antibacterial performance, biodegradability, and other characteristics. It can be very compatible with human tissues and degradation, while its good water absorption and moisturizing properties can effectively absorb wound exudates, keep the wound moist, and promote wound healing. In this paper, the structural properties, and physical and chemical cross-linking preparation methods of cellulose-based antibacterial hydrogels were discussed in detail, and the application of cellulose-based hydrogels in the antibacterial field was deeply studied. In general, cellulose-based antibacterial hydrogels, as a new type of biomaterial, have shown good potential in antimicrobial properties and have been widely used. However, there are still some challenges, such as optimizing the preparation process and performance parameters, improving the antibacterial and physical properties, broadening the application range, and evaluating safety. However, with the deepening of research and technological progress, it is believed that cellulose-based antibacterial hydrogels will be applied and developed in more fields in the future.

Research progress related to thermosensitive hydrogel dressings in wound healing: a review

Wound healing is a dynamic and complex process in which the microenvironment at the wound site plays an important role. As a common material for wound healing, dressings accelerate wound healing and prevent external wound infections. Hydrogels have become a hot topic in wound-dressing research because of their high water content, good biocompatibility, and adjustable physical and chemical properties. Intelligent hydrogel dressings have attracted considerable attention because of their excellent environmental responsiveness. As smart polymer hydrogels, thermosensitive hydrogels can respond to small temperature changes in the environment, and their special properties make them superior to other hydrogels. This review mainly focuses on the research progress in thermosensitive intelligent hydrogel dressings for wound healing. Polymers suitable for hydrogel formation and the appropriate molecular design of the hydrogel network to achieve thermosensitive hydrogel properties are discussed, followed by the application of thermosensitive hydrogels as wound dressings. We also discuss the future perspectives of thermosensitive hydrogels as wound dressings and provide systematic theoretical support for wound healing.

Emerging Polymer-Based Nanosystem Strategies in the Delivery of Antifungal Drugs

Nanosystems-based antifungal agents have emerged as an effective strategy to address issues related to drug resistance, drug release, and toxicity. Among the diverse materials employed for antifungal drug delivery, polymers, including polysaccharides, proteins, and polyesters, have gained significant attention due to their versatility. Considering the complex nature of fungal infections and their varying sites, it is crucial for researchers to carefully select appropriate polymers based on specific scenarios when designing antifungal agent delivery nanosystems. This review provides an overview of the various types of nanoparticles used in antifungal drug delivery systems, with a particular emphasis on the types of polymers used. The review focuses on the application of drug delivery systems and the release behavior of these systems. Furthermore, the review summarizes the critical physical properties and relevant information utilized in antifungal polymer nanomedicine delivery systems and briefly discusses the application prospects of these systems.

Treatment of Periodontal Infections, the Possible Role of Hydrogels as Antibiotic Drug-Delivery Systems

With the advancement of biomedical research into antimicrobial treatments for various diseases, the source and delivery of antibiotics have attracted attention. In periodontal diseases, antibiotics are integral in positive treatment outcomes; however, the use of antibiotics is with caution as the potential for the emergence of resistant strains is of concern. Over the years, conventional routes of drug administration have been proven to be effective for the treatment of PD, yet the problem of antibiotic resistance to conventional therapies continues to remain a setback in future treatments. Hydrogels fabricated from natural and synthetic polymers have been extensively applied in biomedical sciences for the delivery of potent biological compounds. These polymeric materials either have intrinsic antibacterial properties or serve as good carriers for the delivery of antibacterial agents. The biocompatibility, low toxicity and biodegradability of some hydrogels have favoured their consideration as prospective carriers for antibacterial drug delivery in PD. This article reviews PD and its antibiotic treatment options, the role of bacteria in PD and the potential of hydrogels as antibacterial agents and for antibiotic drug delivery in PD. Finally, potential challenges and future directions of hydrogels for use in PD treatment and diagnosis are also highlighted.

Delivery Systems in Ocular Retinopathies: The Promising Future of Intravitreal Hydrogels as Sustained-Release Scaffolds

Slow-release delivery systems are needed to ensure long-term sustained treatments for retinal diseases such as age-related macular degeneration and diabetic retinopathy, which are currently treated with anti-angiogenic agents that require frequent intraocular injections. These can cause serious co-morbidities for the patients and are far from providing the adequate drug/protein release rates and required pharmacokinetics to sustain prolonged efficacy. This review focuses on the use of hydrogels, particularly on temperature-responsive hydrogels as delivery vehicles for the intravitreal injection of retinal therapies, their advantages and disadvantages for intraocular administration, and the current advances in their use to treat retinal diseases.

Sustained release of alginate hydrogel containing antimicrobial peptide Chol-37(F34-R) in vitro and its effect on wound healing in murine model of Pseudomonas aeruginosa infection

BACKGROUND

Antibiotic resistance is a significant public health concern around the globe. Antimicrobial peptides exhibit broad-spectrum and efficient antibacterial activity with an added advantage of low drug resistance. The higher water content and 3D network structure of the hydrogels are beneficial for maintaining antimicrobial peptide activity and help to prevent degradation. The antimicrobial peptide released from hydrogels also hasten the local wound healing by promoting epithelial tissue regeneration and granulation tissue formation.

OBJECTIVE

This study aimed at developing sodium alginate based hydrogel loaded with a novel antimicrobial peptide Chol-37(F34-R) and to investigate the characteristics in vitro and in vivo as an alternative antibacterial wound dressing to treat infectious wounds.

METHODS

Hydrogels were developed and optimized by varying the concentrations of crosslinkers and subjected to various characterization tests like cross-sectional morphology, swelling index, percent water contents, water retention ratio, drug release and antibacterial activity in vitro, and Pseudomonas aeruginosa infected wound mice model in vivo.

RESULTS

The results indicated that the hydrogel C proved superior in terms of cross-sectional morphology having uniformly sized interconnected pores, a good swelling index, with the capacity to retain a higher quantity of water. Furthermore, the optimized hydrogel has been found to exert a significant antimicrobial activity against bacteria and was also found to prevent bacterial infiltration into the wound site due to forming an impermeable barrier between the wound bed and external environment. The optimized hydrogel was found to significantly hasten skin regeneration in animal models when compared to other treatments in addition to strong inhibitory effect on the release of pro-inflammatory cytokines (interleukin-1β and tumor necrosis factor-α).

CONCLUSIONS

Our results suggest that sodium alginate -based hydrogels loaded with Chol-37(F34-R) hold the potential to be used as an alternative to conventional antibiotics in treating infectious skin wounds.

Recent progress of antibacterial hydrogels in wound dressings

Hydrogels are essential biomaterials due to their favorable biocompatibility, mechanical properties similar to human soft tissue extracellular matrix, and tissue repair properties. In skin wound repair, hydrogels with antibacterial functions are especially suitable for dressing applications, so novel antibacterial hydrogel wound dressings have attracted widespread attention, including the design of components, optimization of preparation methods, strategies to reduce bacterial resistance, etc. In this review, we discuss the fabrication of antibacterial hydrogel wound dressings and the challenges associated with the crosslinking methods and chemistry of the materials. We have investigated the advantages and limitations (antibacterial effects and antibacterial mechanisms) of different antibacterial components in the hydrogels to achieve good antibacterial properties, and the response of hydrogels to stimuli such as light, sound, and electricity to reduce bacterial resistance. Conclusively, we provide a systematic summary of antibacterial hydrogel wound dressings findings (crosslinking methods, antibacterial components, antibacterial methods) and an outlook on long-lasting antibacterial effects, a broader antibacterial spectrum, diversified hydrogel forms, and the future development prospects of the field.

The Antimicrobial Activity of Micron-Thin Sol-Gel Films Loaded with Linezolid and Cefoxitin for Local Prevention of Orthopedic Prosthesis-Related Infections

Orthopedic prosthesis-related infections (OPRI) are an essential health concern. OPRI prevention is a priority and a preferred option over dealing with poor prognosis and high-cost treatments. Micron-thin sol-gel films have been noted for a continuous and effective local delivery system. This study aimed to perform a comprehensive in vitro evaluation of a novel hybrid organic-inorganic sol-gel coating developed from a mixture of organopolysiloxanes and organophosphite and loaded with different concentrations of linezolid and/or cefoxitin. The kinetics of degradation and antibiotics release from the coatings were measured. The inhibition of biofilm formation of the coatings against Staphylococcus aureus, S. epidermidis, and Escherichia coli strains was studied, as well as the cell viability and proliferation of MC3T3-E1 osteoblasts. The microbiological assays demonstrated that sol-gel coatings inhibited the biofilm formation of the evaluated Staphylococcus species; however, no inhibition of the E. coli strain was achieved. A synergistic effect of the coating loaded with both antibiotics was observed against S. aureus. The cell studies showed that the sol-gels did not compromise cell viability and proliferation. In conclusion, these coatings represent an innovative therapeutic strategy with potential clinical use to prevent staphylococcal OPRI.

Polysaccharide-Based Multifunctional Hydrogel Bio-Adhesives for Wound Healing: A Review

Wound healing is a long-term and complex biological process that involves multiple hemostasis, inflammation, proliferation, and remodeling stages. In order to realize comprehensive and systematic wound management, appropriate wound treatment bio-adhesives are urgently needed. Hydrogel bio-adhesives have excellent properties and show unique and remarkable advantages in the field of wound management. This review begins with a detailed description of the design criteria and functionalities of ideal hydrogel bio-adhesives for wound healing. Then, recent advances in polysaccharide-based multifunctional hydrogel bio-adhesives, which involve chitosan, hyaluronic acid, alginate, cellulose, dextran, konjac glucomannan, chondroitin sulfate, and other polysaccharides, are comprehensively discussed. Finally, the current challenges and future research directions of polysaccharide-based hydrogel bio-adhesives for wound healing are proposed to stimulate further exploration by researchers.

A Comprehensive Review on Bio-Based Materials for Chronic Diabetic Wounds

Globally, millions of people suffer from poor wound healing, which is associated with higher mortality rates and higher healthcare costs. There are several factors that can complicate the healing process of wounds, including inadequate conditions for cell migration, proliferation, and angiogenesis, microbial infections, and prolonged inflammatory responses. Current therapeutic methods have not yet been able to resolve several primary problems; therefore, their effectiveness is limited. As a result of their remarkable properties, bio-based materials have been demonstrated to have a significant impact on wound healing in recent years. In the wound microenvironment, bio-based materials can stimulate numerous cellular and molecular processes that may enhance healing by inhibiting the growth of pathogens, preventing inflammation, and stimulating angiogenesis, potentially converting a non-healing environment to an appropriately healing one. The aim of this present review article is to provide an overview of the mechanisms underlying wound healing and its pathophysiology. The development of bio-based nanomaterials for chronic diabetic wounds as well as novel methodologies for stimulating wound healing mechanisms are also discussed.

A comprehensive review on the applications of carbon-based nanostructures in wound healing: from antibacterial aspects to cell growth stimulation

A wound is defined as damage to the integrity of biological tissue, including skin, mucous membranes, and organ tissues. The treatment of these injuries is an important challenge for medical researchers. Various materials have been used for wound healing and dressing applications among which carbon nanomaterials have attracted significant attention due to their remarkable properties. In the present review, the latest studies on the application of carbon nanomaterials including graphene oxide (GO), reduced graphene oxide (rGO), carbon dots (CDs), carbon quantum dots (CQDs), carbon nanotubes (CNTs), carbon nanofibers (CNFs), and nanodiamonds (NDs) in wound dressing applications are evaluated. Also, a variety of carbon-based nanocomposites with advantages such as biocompatibility, hemocompatibility, reduced wound healing time, antibacterial properties, cell-adhesion, enhanced mechanical properties, and enhanced permeability to oxygen has been reported for the treatment of various wounds.

Bio-functional hydrogel with antibacterial and anti-inflammatory dual properties to combat with burn wound infection

Burn infection delays wound healing and increases the burn patient mortality. Consequently, a new dressing with antibacterial and anti-inflammatory dual properties is urgently required for wound healing. In this study, we propose a combination of methacrylate gelatin (GelMA) hydrogel system with silver nanoparticles embed in γ-cyclodextrin metal-organic frameworks (Ag@MOF) and hyaluronic acid-epigallocatechin gallate (HA-E) for the burn wound infection treatment. Ag@MOF is used as an antibacterial agent and epigallocatechin gallate (EGCG) has exhibited biological properties of anti-inflammation and antibacterial. The GelMA/HA-E/Ag@MOF hydrogel enjoys suitable physical properties and sustained release of Ag⁺. Meanwhile, the hydrogel has excellent biocompatibility and could promote macrophage polarization from M1 to M2. In vivo wound healing evaluations further demonstrate that the GelMA/HA-E/Ag@MOF hydrogel reduces the number of the bacterium efficiently, accelerates wound healing, promotes early angiogenesis, and regulates immune reaction. A further evaluation indicates that the noncanonical Wnt signal pathway is significantly activated in the GelMA/HA-E/Ag@MOF hydrogel treated group. In conclusion, the GelMA/HA-E/Ag@MOF hydrogel could serve as a promising multifunctional dressing for the burn wound healing.

Application of nanotechnology in management and treatment of diabetic wounds

Diabetic wounds are one of the most common health problems worldwide, enhancing the demand for new management strategies. Nanotechnology, as a developing subject in diabetic wound healing, is proving to be a promising and effective tool in treatment and care. It is, therefore, necessary to ascertain the available and distinct nanosystems and evaluate their performance when topically applied to the injury site, especially in diabetic wound healing. Several active ingredients, including bioactive ingredients, growth factors, mesenchymal stem cells, nucleic acids, and drugs, benefit from improved properties when loaded into nanosystems. Given the risk of problems associated with systemic administration, the topical application should be considered, provided stability and efficacy are assured. After nanoencapsulation, active ingredients-loaded nanosystems have been showing remarkable features of biocompatibility, healing process hastening, angiogenesis, and extracellular matrix compounds synthesis stimulation, contributing to a decrease in wound inflammation. Despite limitations, nanotechnology has attracted widespread attention in the scientific community and seems to be a valuable technological ally in the treatment and dressing of diabetic wounds. The use of nanotechnology in topical applications enables efficient delivery of the active ingredients to the specific skin site, increasing their bioavailability, stability, and half-life time, without compromising their safety.

Dendrimer as a momentous tool in tissue engineering and regenerative medicine

Dendrimers have been comprehensively used for cargo delivery, nucleic acid delivery (genes, miRNA/siRNAs), delivery of macromolecules, and other various biomedical applications. Dendrimers are highly versatile in function and can be engineered as multifunctional biomacromolecules by modifying the surface for fulfilling different applications. Dendrimers are being used for crosslinking of existing synthetic and natural polymeric scaffolds to regulate their binding efficiency, stiffness, biocompatibility, transfection, and many other properties to mimic the in vivo extracellular matrix in tissue engineering and regenerative medicine (TERM). Dendritic inter-cellular linkers can enhance the linkages between cells and result in scaffold-independent tissue constructs. Effectively engineered dendrimers are the ideal molecules for delivering bioactive molecules such as cytokines, chemokines, growth factors, etc., and other metabolites for efficaciously regulating cell behavior. Dendrimeric nanostructures have shown tremendous results in various TERM fields like stem cells survival, osteogenesis, increased crosslinking for eye and corneal repair, and proliferation in cartilage. This review highlights the role and various aspects of dendritic polymers for TERM in general and with respect to specific tissues. This review also covers novel explorations and insights into the use of dendrimers in TERM, focusing on the developments in the past decade and perspective of the future.

Functionalization and Antibacterial Applications of Cellulose-Based Composite Hydrogels

Pathogens, especially drug-resistant pathogens caused by the abuse of antibiotics, have become a major threat to human health and public health safety. The exploitation and application of new antibacterial agents is extremely urgent. As a natural biopolymer, cellulose has recently attracted much attention due to its excellent hydrophilicity, economy, biocompatibility, and biodegradability. In particular, the preparation of cellulose-based hydrogels with excellent structure and properties from cellulose and its derivatives has received increasing attention thanks to the existence of abundant hydrophilic functional groups (such as hydroxyl, carboxy, and aldehyde groups) within cellulose and its derivatives. The cellulose-based hydrogels have broad application prospects in antibacterial-related biomedical fields. The latest advances of preparation and antibacterial application of cellulose-based hydrogels has been reviewed, with a focus on the antibacterial applications of composite hydrogels formed from cellulose and metal nanoparticles; metal oxide nanoparticles; antibiotics; polymers; and plant extracts. In addition, the antibacterial mechanism and antibacterial characteristics of different cellulose-based antibacterial hydrogels were also summarized. Furthermore, the prospects and challenges of cellulose-based antibacterial hydrogels in biomedical applications were also discussed.

Cellulose: A Fascinating Biopolymer for Hydrogel Synthesis

The growing environmental concerns and increasing demands for eco-friendly materials have obliged researchers worldwide to explore naturally occurring biopolymers for various applications. Cellulose is a non-exhaustible polysaccharide biopolymer available almost...

Synthesis and characterization of levan hydrogels and their use for resveratrol release

Considering the need for systematic studies on levan based hydrogels to widen their use in drug delivery systems and biomedical applications, this study is mainly focused on the synthesis and comprehensive characterization as well as drug release properties of hydrogels based on Halomonas levan (HL) and its chemical derivatives. For this, hydrolyzed and phosphonated HL derivatives were chemically synthesized and then cross-linked with 1,4-Butanediol diglycidyl ether (BDDE) and the obtained hydrogels were characterized in terms of their swelling, adhesivity, and rheological properties. Both native and phosphonated HL hydrogels retained their rigid gel like structure with increasing shear stress levels and tack test analysis showed superior adhesive properties of the phosphonated HL hydrogels. Moreover, hydrogels were loaded with resveratrol and entrapment and release studies as well as cell culture studies with human keratinocytes were performed. Biocompatible and adhesive features of the hydrogels confirmed their suitability for tissue engineering and drug delivery applications.

Stimuli-responsive biphenyl-tripeptide supramolecular hydrogels as biomimetic extracellular matrix scaffolds for cartilage tissue engineering

Supramolecular hydrogel composed of aromatic short peptide gelator was an attractive biomaterial owing to its simple and convenient synthetic route, nano-fibrillar microstructure resembling natural collagen fibers and intelligent response to external stimulus. Herein, stimuli-responsive biphenyl-tripeptide supramolecular hydrogels was prepared to simulate extracellular matrix scaffolds by temperature switch, ion induction and pH switch. The amino acid arrangement substantially affected gelation behavior, only BPAA-βAFF and BPAA-FFβA could form nanostructured supramolecular hydrogels with 8-10 nm nanotubes or nanofibers by potential intermolecular hydrogen bond interactions and π-π stacking. The minimum gelation concentration (MGC) and maximum storage modulus were 0.4 mM (0.023 wt%) and around 8.2 KPa. The two supramolecular hydrogels could support adhesion and proliferation of L929 cells. Moreover, the BPAA-βAFF hydrogel promoted proliferation and ECM secretion of chondrocytes in vitro, and facilitate the phenotype maintenance of hyaline cartilage. All the results demonstrated that BPAA-βAFF hydrogel hold great potential application prospects in cartilage tissue engineering. STATEMENT OF SIGNIFICANCE: Diphenylalanine was served as a core segment conjugating with 4-biphenylacetic acid (BPAA) to produce biphenyl-tripeptide compounds with transforming amino sequence, and multiple external stimuli was applied to study the gelation properties of the aromatic short peptide gelators. "FF" brick (phenylalanine-phenylalanine) was crucial for formation of fibrous supramolecular hydrogels. Meanwhile, the sequence of amino acids arrangement also had an essential effect on the gelation behavior. Optimal BPAA-βAFF with ultra-low minimum gelation concentration (0.4 mM, about 0.023 wt%) and similar microstructure to extracellular matrix (ECM) of nature cartilage tissue could promote the proliferation and ECM secretion of chondrocytes in vitro, and facilitate the formation of hyaline cartilage.

Synthesis of Poly(ε-caprolactone) Diacrylate for Micelle-Cross-Linked Sodium AMPS Hydrogel for Use as Controlled Drug Delivery Wound Dressing

This study focuses on the synthesis of poly(ε-caprolactone) diacrylate (PCLDA) for the fabrication of micelle-cross-linked sodium AMPS wound dressing hydrogels. The novel synthetic approach of PCLDA is functionalizing a PCL diol with acrylic acid. The influences of varying the PCL diol/AA molar ratio and temperature on the suitable conditions for the synthesis of PCLDA are discussed. The hydrogel was synthesized through micellar copolymerization of sodium 2-acrylamido-2-methylpropane sulfonate (Na-AMPS) as a basic monomer and PCLDA as a hydrophobic association monomer. In this study, an attempt was made to develop new hydrogel wound dressings meant for the release of antibacterial drugs (ciprofloxacin and silver sulfadiazine). The chemical structures, morphology, porosity, and water interaction of the hydrogels were characterized. The hydrogels' swelling ratio and water vapor transmission rate (WVTR) showed a high swelling capacity (4688-10753%) and good WVTR (approximately 2000 g·m^-2·day^-1), which can be controlled through variation of the PCLDA concentration. The mechanical property results confirmed that PCLDA improved the mechanical properties of the hydrogel; the stress increased from 37 to 68 kPa, and the strain increased from 198 to 360% with increasing PCLDA (0-30% wt of Na-AMPS). These hydrogels presented no cytotoxicity based on over 70% cell viability responses (L929 fibroblasts) using an in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Additionally, the drug release mechanism, kinetic models, and antibacterial activity were determined. The results demonstrated that antibiotics were released from the hydrogel with a Fickian diffusion mechanism and antibacterial activity against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus). Based on the results obtained, and bearing in mind that further progress still needs to be made, the fabricated hydrogels show considerable potential for meeting the stringent property requirements of hydrogel wound dressings.

Degradation-Dependent Protein Release from Enzyme Sensitive Injectable Glycol Chitosan Hydrogel

Glycol chitosan (GC) is a hydrophilic chitosan derivative, known for its aqueous solubility. Previously, we have demonstrated the feasibility of preparing injectable, enzymatically crosslinked hydrogels from HPP [3-(4-Hydroxyphenyl)-propionic acid (98%)]-modified GC. However, HPP-GC gels showed very slow degradation, which presents challenges as an in vivo protein delivery vehicle. This study reports the potential of acetylated HPP-GC hydrogels as a biodegradable hydrogel platform for sustained protein delivery. Enzymatic crosslinking was used to prepare injectable, biodegradable hydrogels from HPP-GC with various degrees of acetylation (DA). The acetylated polymers were characterized using Fourier transform infrared and nuclear magnetic resonance spectroscopy. Rheological methods were used to characterize the mechanical behavior of the hydrogels. In vitro degradation and protein release were performed in the presence and absence of lysozyme. In vivo degradation was studied using a mouse subcutaneous implantation model. Finally, two hydrogel formulations with distinct in vitro/in vivo degradation and in vitro protein release were evaluated in 477-SKH1-Elite mice using live animal imaging to understand in vivo protein release profiles. The lysozyme-mediated degradation of the gels was demonstrated in vitro and the degradation rate was found to be dependent on the DA of the polymers. In vivo degradation study further confirmed that gels formed from polymers with higher DA degraded faster. In vitro protein release demonstrated the feasibility to achieve lysozyme-mediated protein release from the gels and that the rate of protein release can be modulated by varying the DA. In vivo protein release study further confirmed the feasibility to achieve differential protein release by varying the DA. The feasibility to develop degradable enzymatically crosslinked GC hydrogels is demonstrated. Gels with a wide spectrum of degradation time ranging from less than a week and more than 6 weeks can be developed using this approach. The study also showed the feasibility to fine tune in vivo protein release by modulating HPP-GC acetylation. The hydrogel platform therefore holds significant promise as a protein delivery vehicle for various biomedical and regenerative engineering applications. Impact statement The study describes the feasibility to develop a novel enzyme sensitive biodegradable and injectable hydrogel, where in the in vivo degradation rate and protein release profile can be modulated over a wide range. The described hydrogel platform has the potential to develop into a clinically relevant injectable and tunable protein delivery vehicle for a wide range of biomedical applications.

TMPyP-bound guanosine-borate supramolecular hydrogel as smart hemoperfusion device with real-time visualized/electrochemical bi-modal monitoring for selective blood lead elimination

Blood lead poisoning is a universal and severe health problem that greatly threatens human health in various industries. Elimination of blood lead relying on chelating agents and combination with hemoperfusion adsorbents has achieved considerable progress, but it is still suffering from the compromised selectivity of adsorbents as well as in absence of real time monitoring during treatment. Herein, we proposed a selective blood lead adsorbent integrated with real-time visualized/electrochemical bi-modal monitoring based on TMPyP-bound guanosine-borate (GB) supramolecular hydrogel as potential smart hemoperfusion device. The GB hydrogel possessed stability in physiological environment, self-healing ability resistant to fluid shear, blood compatibility, selective adsorption of lead ions superior to conventional adsorbents, anti-fouling performance to blood components and renewability. Benefiting from binding with TMPyP and the intrinsic conductivity, GB hydrogel was endowed with the ability to qualitatively diagnose the presence of blood lead via simple color change and quantitatively reflect the amount of adsorbed lead from blood accurately through electrochemical technique. This work puts forward an integrated treatment/monitoring hemoperfusion device with high selectivity, simple fabrication and low-cost, providing a paradigm for next generation design of intelligent, monitorable theranostic hemopurification system, which is also an extensible platform for the other research fields such as environmental monitoring and remediation.

Antimicrobial 3D Printed Objects in the Fight Against Pandemics

The uncharted nature of the COVID-19 pandemic has caused uncertainty globally, resulting in many health care professionals and key-workers being left with supply shortages in medical consumables and personal protective equipment, exacerbated by supply line issues and in some cases delays resulting from governmental policies. 3D printing (3DP) has played an important role in providing essential items to hospitals and the wider communities, such as visors, face masks, and ventilator components. This short-review article covers the potential of antimicrobial materials in the manufacturing of 3DP essential products, as an approach for added protection against pandemics.

Chitosan and Cellulose-Based Hydrogels for Wound Management

Wound management remains a challenge worldwide, although there are several developed wound dressing materials for the management of acute and chronic wounds. The wound dressings that are currently used include hydrogels, films, wafers, nanofibers, foams, topical formulations, transdermal patches, sponges, and bandages. Hydrogels exhibit unique features which make them suitable wound dressings such as providing a moist environment for wound healing, exhibiting high moisture content, or creating a barrier against bacterial infections, and are suitable for the management of exuding and granulating wounds. Biopolymers have been utilized for their development due to their non-toxic, biodegradable, and biocompatible properties. Hydrogels have been prepared from biopolymers such as cellulose and chitosan by crosslinking with selected synthetic polymers resulting in improved mechanical, biological, and physicochemical properties. They were useful by accelerating wound re-epithelialization and also mimic skin structure, inducing skin regeneration. Loading antibacterial agents into them prevented bacterial invasion of wounds. This review article is focused on hydrogels formulated from two biopolymers-chitosan and cellulose-for improved wound management.

From Cellulose to Cellulose Nanofibrils-A Comprehensive Review of the Preparation and Modification of Cellulose Nanofibrils

This review summarizes the preparation methods of cellulose nanofibrils (CNFs) and the progress in the research pertaining to their surface modification. Moreover, the preparation and surface modification of nanocellulose were comprehensively introduced based on the existing literature. The review focuses on the mechanical treatment of cellulose, the surface modification of fibrillated fibers during pretreatment, the surface modification of nanocellulose and the modification of CNFs and their functional application. In the past five years, research on cellulose nanofibrils has progressed with developments in nanomaterials research technology. The number of papers on nanocellulose alone has increased by six times. However, owing to its high energy consumption, high cost and challenging industrial production, the applications of nanocellulose remain limited. In addition, although nanofibrils exhibit strong biocompatibility and barrier and mechanical properties, their high hydrophilicity limits their practical application. Current research on cellulose nanofibrils has mainly focused on the industrial production of CNFs, their pretreatment and functional modification and their compatibility with other biomass materials. In the future, with the rapid development of modern science and technology, the demand for biodegradable biomass materials will continue to increase. Furthermore, research on bio-based nanomaterials is expected to advance in the direction of functionalization and popularization.

Sustained Release of Linezolid from Prepared Hydrogels with Polyvinyl Alcohol and Aliphatic Dicarboxylic Acids of Variable Chain Lengths

A series of hydrogels with a specific release profile of linezolid was successfully synthesized. The hydrogels were synthesized by cross-linking polyvinyl alcohol (PVA) and aliphatic dicarboxylic acids, which include succinic acid (SA), glutaric acid (GA), and adipic acid (AA). The three crosslinked hydrogels were prepared by esterification and characterized by equilibrium swelling ratio, infrared spectroscopy, thermogravimetric analysis, mechanical properties, and scanning electron microscopy. The release kinetics studies of the linezolid from prepared hydrogels were investigated by cumulative drug release and quantified by chromatographic techniques. Mathematical models were carried out to understand the behavior of the linezolid release. These data revealed that the sustained release of linezolid depends on the aliphatic dicarboxylic acid chain length, their polarity, as well as the hydrogel crosslinking degree and mechanical properties. The in vitro antibacterial assay of hydrogel formulations was assessed in an Enterococcus faecium bacterial strain, showing a significant activity over time. The antibacterial results were consistent with cumulative release assays. Thus, these results demonstrated that the aliphatic dicarboxylic acids used as crosslinkers in the PVA hydrogels were a determining factor in the antibiotic release profile.

Data of preparation and evaluation of supramolecular hydrogel based on cellulose for sustained release of therapeutic substances with antimicrobial and wound healing properties

The data article refers to the paper “supramolecular hydrogel based on cellulose for sustained release of therapeutic substances with antimicrobial and wound healing properties”[1]. The dataset includes the synthesis and characterization of (E)-1,3-bis(4-(allyloxy)phenyl)prop‑2-en-1-one (3) (crosslinking agent). Moreover, the multiwall carbon nanotubes (MWCNTs) synthesis and functionalization (MWCNTs-COOH) are described. The formulation obtained by adding multiwalled carbon nanotubes-COOH with the crosslinked cellulose-chalcone hydrogel is abbreviated as MWCNTsCCH, and the same formulation loaded with therapeutic substances (TS) is named MWCNTsCCH-TS. The MWCNTsCCH database such as components and their amounts, swelling degree, thermogravimetric analysis, and cytotoxicity evaluation are depicted. Finally, to elucidate the mechanism of therapeutic substances release, the obtained averages of the release profiles were fitted through mathematical models.