Chitosan/Phenolic Compounds Scaffolds for Connective Tissue Regeneration

3D Printing of Alginate/Chitosan-Based Scaffold Empowered by Tyrosol-Loaded Niosome for Wound Healing Applications: In Vitro and In Vivo Performances

This study introduces a tyrosol-loaded niosome integrated into a chitosan-alginate scaffold (Nio-Tyro@CS-AL), employing advanced electrospinning and 3D printing techniques for wound healing applications. The niosomes, measuring 185.40 ± 6.40 nm with a polydispersity index of 0.168 ± 0.012, encapsulated tyrosol with an efficiency of 77.54 ± 1.25%. The scaffold's microsized porous structure (600-900 μm) enhances water absorption, promoting cell adhesion, migration, and proliferation. Mechanical property assessments revealed the scaffold's enhanced resilience, with niosomes increasing the compressive strength, modulus, and strain to failure, indicative of its suitability for wound healing. Controlled tyrosol release was demonstrated in vitro, essential for therapeutic efficacy. The scaffold exhibited significant antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus, with substantial biofilm inhibition and downregulation of bacterial genes (ndvb and icab). A wound healing assay highlighted a notable increase in MMP-2 and MMP-9 mRNA expression and the wound closure area (69.35 ± 2.21%) in HFF cells treated with Nio-Tyro@CS-AL. In vivo studies in mice confirmed the scaffold's biocompatibility, showing no significant inflammatory response, hypertrophic scarring, or foreign body reaction. Histological evaluations revealed increased fibroblast and macrophage activity, enhanced re-epithelialization, and angiogenesis in wounds treated with Nio-Tyro@CS-AL, indicating effective tissue integration and repair. Overall, the Nio-Tyro@CS-AL scaffold presents a significant advancement in wound-healing materials, combining antibacterial properties with enhanced tissue regeneration, and holds promising potential for clinical applications in wound management.

Biodegradability Study of Modified Chitosan Films with Cinnamic Acid and Ellagic Acid in Soil

Currently, natural polymer materials with bactericidal properties are extremely popular. Unfortunately, although the biopolymer material itself is biodegradable, its enrichment with bactericidal compounds may affect the efficiency of biodegradation by natural soil microflora. Therefore, the primary objective of this study was to evaluate the utility of fungi belonging to the genus Trichoderma in facilitating the degradation of chitosan film modified with cinnamic acid and ellagic acid in the soil environment. Only two strains (T.07 and T.14) used chitosan films as a source of carbon and nitrogen. However, their respiratory activity decreased with the addition of tested phenolic acids, especially cinnamic acid. Addition of Trichoderma isolates to the soil increased oxygen consumption during the biodegradation process compared with native microorganisms, especially after application of the T.07 and T.14 consortium. Isolates T.07 and T.14 showed high lipolytic (55.78 U/h and 62.21 U/h) and chitinase (43.03 U/h and 41.27 U/h) activities. Chitinase activity after incorporation of the materials into the soil was higher for samples enriched with T.07, T.14 and the consortium. The isolates were classified as Trichoderma sp. and Trichoderma koningii. Considering the outcomes derived from our findings, it is our contention that the application of Trichoderma isolates holds promise for expediting the degradation process of chitosan materials containing bactericidal compounds.

Cold plasma treatment of tannic acid as a green technology for the fabrication of advanced cross-linkers for bioactive collagen/gelatin hydrogels

Tannic acid (TA) is a natural compound studied as the cross-linker for biopolymers due to its ability to form hydrogen bonds. There are different methods to improve its reactivity and effectiveness to be used as a modifier for biopolymeric materials. This work employed plasma to modify tannic acid TA, which was then used as a cross-linker for fabricating collagen/gelatin scaffolds. Plasma treatment did not cause any significant changes in the structure of TA, and the resulting oxidized TA showed a higher antioxidant activity than that without treatment. Adding TA to collagen/gelatin scaffolds improved their mechanical properties and stability. Moreover, the obtained plasma-treated TA-containing scaffolds showed antibacterial properties and were non-hemolytic, with improved cytocompatibility towards human dermal fibroblasts. These results suggest the suitability of plasma treatment as a green technology for the modification of TA towards the development of advanced TA-crosslinked hydrogels for various biomedical applications.

Chitosan bioactive glass scaffolds for in vivo subcutaneous implantation, toxicity assessment, and diabetic wound healing upon animal model

This study aims to develop chitosan-bioactive glass (BG) scaffolds for diabetic wound healing, toxicity valuation, and subcutaneous implantation in animals for biocompatibility assessment. The scaffolds were prepared by lyophilization technique. In specific BG without sodium (Na), composited with chitosan for better biological activities. The equipped scaffolds were studied for their physiochemical, biological, in vitro and in vivo performances. The chitosan and chitosan-BG (Na free) scaffolds show reliable biocompatibility, cytocompatibility, anti-oxidant, and tissue regeneration. The biocompatibility, toxicity assessments, and diabetic skin wound healing experiments were examined through in vivo studies using Sprague Dawley rats. The extracted tissue samples were analyzed using hematoxylin-eosin- (H and E) and Masson's trichrome staining. Further, tissue excised after scaffold implantation declared non-toxic, non-allergic, and anti-inflammatory nature of chitosan scaffolds. Moreover, the total ribonucleic acid (RNA) expression levels were measured using reverse transcription-polymerase chain reaction (RT-PCR) for the scaffolds against vascular endothelial growth factor (VEGF), and collagen type one (Col-1) primers. Admirably, the scaffolds achieved the best level of skin wound healing via tissue regeneration by increasing epithetical cell formation and collagen deposition. Thus, the biocompatibility, non-toxicity, anti-inflammatory, and wound healing efficiency proved that the chitosan-BG (Na free) scaffold can be readily substantial for wound healing.

Application Potential of Trichoderma in the Degradation of Phenolic Acid-Modified Chitosan

The aim of the study was to determine the potential use of fungi of the genus Trichoderma for the degradation of phenolic acid-modified chitosan in compost. At the same time, the enzymatic activity in the compost was checked after the application of a preparation containing a suspension of the fungi Trichoderma (spores concentration 105/mL). The Trichoderma strains were characterized by high lipase and aminopeptidase activity, chitinase, and β-1,3-glucanases. T. atroviride TN1 and T. citrinoviride TN3 metabolized the modified chitosan films best. Biodegradation of modified chitosan films by native microorganisms in the compost was significantly less effective than after the application of a formulation composed of Trichoderma TN1 and TN3. Bioaugmentation with a Trichoderma preparation had a significant effect on the activity of all enzymes in the compost. The highest oxygen consumption in the presence of chitosan with tannic acid film was found after the application of the consortium of these strains (861 mg O2/kg after 21 days of incubation). Similarly, chitosan with gallic acid and chitosan with ferulic acid were found after the application of the consortium of these strains (849 mgO2/kg and 725 mg O2/kg after 21 days of incubation). The use of the Trichoderma consortium significantly increased the chitinase activity. The application of Trichoderma also offers many possibilities in sustainable agriculture. Trichoderma can not only degrade chitosan films, but also protect plants against fungal pathogens by synthesizing chitinases and β-1,3 glucanases with antifungal properties.

Engineering Antioxidant Surfaces for Titanium-Based Metallic Biomaterials

Prolonged inflammation induced by orthopedic metallic implants can critically affect the success rates, which can even lead to aseptic loosening and consequent implant failure. In the case of adverse clinical conditions involving osteoporosis, orthopedic trauma and implant corrosion-wear in peri-implant region, the reactive oxygen species (ROS) activity is enhanced which leads to increased oxidative stress. Metallic implant materials (such as titanium and its alloys) can induce increased amount of ROS, thereby critically influencing the healing process. This will consequently affect the bone remodeling process and increase healing time. The current review explores the ROS generation aspects associated with Ti-based metallic biomaterials and the various surface modification strategies developed specifically to improve antioxidant aspects of Ti surfaces. The initial part of this review explores the ROS generation associated with Ti implant materials and the associated ROS metabolism resulting in the formation of superoxide anion, hydroxyl radical and hydrogen peroxide radicals. This is followed by a comprehensive overview of various organic and inorganic coatings/materials for effective antioxidant surfaces and outlook in this research direction. Overall, this review highlights the critical need to consider the aspects of ROS generation as well as oxidative stress while designing an implant material and its effective surface engineering.