The Effect of Glycerin Content in Sodium Alginate/Poly(vinyl alcohol)-Based Hydrogels for Wound Dressing Application

Physical and mechanical properties of ocular thin films: a systematic review and meta-analysis

The ocular thin film presents a potential solution for addressing challenges to ocular drug delivery. In this review, we summarise the findings of a comprehensive review analysing 336 formulations from 68 studies. We investigated the physical and mechanical properties of ocular thin films, categorised into natural polymer-based, synthetic polymer-based, and combined polymer films. The results showed that the type of polymers used impacted mucoadhesion force, moisture absorption:moisture loss ratio, pH, swelling index, and elongation percentage. Significant relationships were found between these properties within each subgroup. The results also highlighted the influence of plasticisers on elongation percentage, mucoadhesion force, swelling index, and moisture absorption:moisture loss ratio. These findings have implications for designing and optimising ocular drug formulations and selecting appropriate plasticisers to achieve formulations with the desired properties.

Biodegradable suture development-based albumin composites for tissue engineering applications

Recent advancements in the field of biomedical engineering have underscored the pivotal role of biodegradable materials in addressing the challenges associated with tissue regeneration therapies. The spectrum of biodegradable materials presently encompasses ceramics, polymers, metals, and composites, each offering distinct advantages for the replacement or repair of compromised human tissues. Despite their utility, these biomaterials are not devoid of limitations, with issues such as suboptimal tissue integration, potential cytotoxicity, and mechanical mismatch (stress shielding) emerging as significant concerns. To mitigate these drawbacks, our research collective has embarked on the development of protein-based composite materials, showcasing enhanced biodegradability and biocompatibility. This study is dedicated to the elaboration and characterization of an innovative suture fabricated from human serum albumin through an extrusion methodology. Employing a suite of analytical techniques-namely tensile testing, scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA)-we endeavored to elucidate the physicochemical attributes of the engineered suture. Additionally, the investigation extends to assessing the influence of integrating biodegradable organic modifiers on the suture's mechanical performance. Preliminary tensile testing has delineated the mechanical profile of the Filament Suture (FS), delineating tensile strengths spanning 1.3 to 9.616 MPa and elongation at break percentages ranging from 11.5 to 146.64%. These findings illuminate the mechanical versatility of the suture, hinting at its applicability across a broad spectrum of medical interventions. Subsequent analyses via SEM and TGA are anticipated to further delineate the suture's morphological features and thermal resilience, thereby enriching our comprehension of its overall performance characteristics. Moreover, the investigation delves into the ramifications of incorporating biodegradable organic constituents on the suture's mechanical integrity. Collectively, the study not only sheds light on the mechanical and thermal dynamics of a novel suture material derived from human serum albumin but also explores the prospective enhancements afforded by the amalgamation of biodegradable organic compounds, thereby broadening the horizon for future biomedical applications.

The efficient role of sodium alginate-based biodegradable dressings for skin wound healing application: a systematic review

Injuries and damage to the skin can be caused by different reasons throughout human life. The use of sodium alginate in tissue dressing has been highly studied due to its intrinsic properties, including its degradation rate and biocompatibility, and the capacity of supporting tissue proliferation. The aim of this paper is to demonstrate evidences, through a systematic review method, to support the application of sodium alginate as a curative and as a potential accelerator in the healing of skin wounds. Four databases were used to develop this systematic review: Science Direct, PubMed, Scielo and Scopus. The time interval established for the search was from January 2016 to October 2023. After applying the exclusion and inclusion criteria, each selected article was evaluated and it was observed that the improvement of the mechanical properties of sodium alginate when correctly processed and crosslinked were evident. However, the increase of crosslinking affects as the wettability and the swelling of the biomaterials can cause limitations in mechanical properties and hidrophilic behavior. To achieve the ideal dressing, it is necessary to apply the optimal concentration of crosslinking and other substances, which can damage its hidrophilic characteristic. Thus, it was concluded that sodium alginate has every caracteristic desirable to develop an effective and safe dressing.

Preparation and comparison of two medical dressings made from the collagens from fish and bovine

Collagen is used in medical dressings because of its high hydrophilicity, low immunogenicity, excellent biocompatibility, and degradability. These features can promote cell proliferation and platelet agglomeration. Herein, we studied the preparation of gel dressing by using silver carp skin collagen and bovine collagen as raw materials. Their properties and the application effects of collagen gel dressing were evaluated and compared. The centrifugal stability, rheology, and water-loss rate of silver carp skin collagen gel (SCG) and bovine tendon collagen gel (CTG) were determined. Results showed that the two gels were stable, and SCG had better rheology and ductility than CTG. However, the denaturation temperature and water-retention rate of SCG were slightly lower than those of CTG. Two collagen gels were used in the burn-repair experiment of KM mice. Results showed that the SCG and CTG were consistent with the wound-repair effect of commercially available products for shallow II-degree scald and deep II-degree scald. In the superficial shallow II scald experiment, SCG had a faster healing rate in the first 8 days and a shorter recovery time than CTG. In the deep II-degree scald experiment, the wound-healing rate of SCG on the 14th day reached 94.24%, which was 2 days faster than the recovery time of CTG. Moreover, the skin after wound healing was shallower than the scar produced after CTG treatment. Therefore, SCG had the potential to be used as the medical dressing.

Synthesis, characterization and application of oligomeric proanthocyanidin-rich dual network hydrogels

A structurally dense hydrogel, with strong hydrogen bonding networks, was formed from poly(vinyl alcohol), sodium alginate, and oligomeric proanthocyanidins, using a combination of freeze-thaw cycles and calcium ion cross-linking. The structure of the hydrogel was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. Mechanical testing and thermogravimetric analysis showed that incorporation of proanthocyanidins enhanced both the mechanical properties and the thermal stability of the hydrogel. The hydrogel was also demonstrated to have excellent ultraviolet resistance and antioxidant properties. The hydrogel was further shown that this hydrogel is also capable of generating electrochemical reactions, which strongly suggests that this hydrogel has exciting potential in many fields.

Can an Alginate-based Wound Dressing Modified with Garden Cress Substitute for COE-PAK as a Wound Dressing? An In Vitro Study

AIM

The aim of the current study was to prepare a natural oral wound dressing from alginate modified with garden cress (GC), a rich source of antibacterial phytochemical compounds essential for wound healing.

MATERIALS AND METHODS

Sodium alginate (SA) dressing (negative control group), was prepared and modified with GC seeds extracts (25 µg/mL and 50 µg/mL) as the intervention groups, and COE-PAK was the positive control group. Cytotoxicity was measured using WST-1 assay (n = 15) after 24 and 48 hours. The in vitro wound healing assay (n = 15) was assessed in terms of wound width, and cell migration rate (0, 24, 48, and 72 hours). Agar diffusion test was performed to investigate the antibacterial action (n = 15) of the groups against Streptococcus mutans and Lactobacillus casei strains. Results were significant at p ≤ 0.05.

RESULTS

There was no statistically significant difference in cytotoxicity in all groups (p = 0.24 at 24 hours and 0.1 at 48 hours). Garden cress-containing groups revealed the lowest mean value of wound width (0.27 mm ± 0.01 and 0.23 mm ± 0.01 for 25 µg/mL and 50 µg/mL, respectively at 48 hours) and the highest mean value of cell migration rate (0.013 mm/hour ± 0.004 and 0.014 mm/hour ± 0.004 for 25 µg/mL and 50 µg/mL, respectively at 48 hours), in addition to the highest antibacterial action (1.49 mm ± 0.05 and 2.14 mm ± 0.09 for 25 µg/mL and 50 µg/mL, respectively against S. mutans, 1.43 mm ± 0.07 and 2.55 mm ± 0.09 for 25 µg/mL and 50 µg/mL, respectively against L. casei).

CONCLUSION

Alginate wound dressing modified with GC extract could be considered a promising wound dressing material in terms of wound healing and antibacterial action.

CLINICAL SIGNIFICANCE

Ready-to-use alginate-based wound dressing modified with GC extract may represent a promising natural alternative to the most commonly used oral wound dressing (COE-PAK).

Development of Natural Active Agent-Containing Porous Hydrogel Sheets with High Water Content for Wound Dressings

This work was concerned with the fabrication of a porous hydrogel system suitable for medium to heavy-exudating wounds where traditional hydrogels cannot be used. The hydrogels were based on 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPs). In order to produce the porous structure, additional components were added (acid, blowing agent, foam stabilizer). Manuka honey (MH) was also incorporated at concentrations of 1 and 10% w/w. The hydrogel samples were characterized for morphology via scanning electron microscopy, mechanical rheology, swelling using a gravimetric method, surface absorption, and cell cytotoxicity. The results confirmed the formation of porous hydrogels (PH) with pore sizes ranging from ~50-110 µm. The swelling performance showed that the non-porous hydrogel (NPH) swelled to ~2000%, while PH weight increased ~5000%. Additionally, the use of a surface absorption technique showed that the PH absorbed 10 μL in <3000 ms, and NPH absorbed <1 μL over the same time. Incorporating MH the enhanced gel appearance and mechanical properties, including smaller pores and linear swelling. In summary, the PH produced in this study had excellent swelling performance with rapid absorption of surface liquid. Therefore, these materials have the potential to expand the applicability of hydrogels to a range of wound types, as they can both donate and absorb fluid.

A review on the synthesis and development of alginate hydrogels for wound therapy

Convenient and low-cost dressings can reduce the difficulty of wound treatment. Alginate gel dressings have the advantages of low cost and safe usage, and they have obvious potential for development in biomedical materials. Alginate gel dressings are currently a research area of great interest owing to their versatility, intelligent, and their application attempts in treating complex wounds. We present a detailed summary of the preparation of alginate hydrogels and a study of their performance improvement. Herein, we summarize the various applications of alginate hydrogels. The research focuses in this area mainly include designing multifunctional dressings for the treatment of various wounds and fabricating specialized dressings to assist physicians in the treatment of complex wounds (TOC). This review gives an outlook for future directions in the field of alginate hydrogel dressings. We hope to attract more research interest and studies in alginate hydrogel dressings, thus contributing to the creation of low-cost and highly effective wound treatment materials.

Preparation and optimization of tetraethyl orthosilicate cross-linked chitosan-guar gum-poly(vinyl alcohol) composites reinforced with montmorillonite for sustained release of sitagliptin

Development of efficient drug carriers has become an integral part of advanced drug delivery systems. This work aims at developing composites by adopting an economically viable method for sustained release of anti-diabetic drug sitagliptin - a potent and selective dipeptidyl peptidase-IV inhibitor. To combat the harsh environment of gastrointestinal tract, the composite (F13) was prepared using biodegradable polymers namely chitosan, guar gum and poly(vinyl alcohol) with montmorillonite clay as nano-filler and tetraethyl orthosilicate as the cross linker. The composites were characterized using FT-IR, XRD, DSC and SEM techniques. Physical properties such as thickness, swelling capacity, folding endurance and water solubility were studied. In vitro analysis of composites (F17, F19 and F20) in simulated gastric medium showed <14 % cumulative release in 2 h while a sustained release was observed in simulated intestinal medium. Drug release kinetics was investigated using five mathematical models namely zero order, first order, Higuchi, Hixon-Crowell and Korsemeyer-Peppas wherein the latter was the best fit model (R², 0.969). Antimicrobial studies of drug free composite (F13) revealed good activity against bacteria as well as fungi. The results implied that the composites were pH sensitive and could serve as a potential choice for sustained release of drugs.

Bio-Hybrid Hydrogels Incorporated into a System of Salicylic Acid-pH/Thermosensitive Nanocarriers Intended for Cutaneous Wound-Healing Processes

In this paper, the preparation method of bio-hybrid hydrogels incorporated into a system of salicylic acid-pH/thermosensitive nanocarriers to speed up the wound-healing process was developed. This combination creates a dual drug delivery system, which releases the model hydrophobic active substance—salicylic acid—in a gradual and controlled manner for an extended time. Our research team has determined the various properties of bio-hybrid hydrogels based on their physicochemical (swelling degree, and degradation), structural (FT-IR), morphological (SEM), and mechanical (elongation tests) traits. Moreover, empty pH/thermosensitive nanocarriers and their salicylic acid-containing systems were characterized using the following methods: DLS, TG/DTG, and DSC. Additionally, salicylic acid release profiles directly from thermosensitive nanocarriers were compared to the bio-hybrid matrix. These studies were conducted in PBS (pH = 7.4) for 7 days using the USP4 method. To evaluate the antibacterial properties of the obtained materials, the inhibition of growth of Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus niger—as the main microorganisms responsible for human infections—were tested. The obtained results indicated that the pH/thermosensitive nanocarrier–salicylic acid system and bio-hybrid hydrogels are characterized by antibacterial activity against both S. aureus and E. coli.