Integration of collagen into chitosan blend film composites: physicochemical property aspects for pharmaceutical materials

Synthesis and Evaluation of a Chitosan-Based Cationic Hydrogel with Strong Antifungal and Antibiofilm Activities Against Clinical Isolates of Candida auris

Background: Candida auris is a significant global health concern, due to its rapid transmission, high mortality rate, and resistance to commonly available antifungal drugs. Methodology: During the current study, a cationic polymeric hydrogel was developed using chitosan (CS), polyethylene glycol (PEG), and methacrylic acid (MAA). The respective solutions were mixed in a volumetric ratio of 2:1:1. After characterization, the hydrogel was assessed using antifungal, antibiofilm, and hemocompatibility assays. Results: The hydrodynamic radius of 554.7 ± 90.1 nm and zeta potential of 15.6 ± 1.09 mV indicate the ideal size and charge for topical applications and in vivo studies, respectively. The formulation exhibited improved thermal stability, enhanced swelling, and a drug release profile for non-Fickian diffusion. The hydrogel effectively inhibited fungal growth in agar plates (42 ± 7.31 mm zone of inhibition), with a mean IC50 of 15.17 ± 4.01 μg/mL and MIC of 29.30 ± 11.72 μg/mL. Calcofluor white (CFW) staining showed diffuse irregular yeast cells, suggesting increased membrane permeability, eventually leading to cell death. The hemocompatibility assay revealed no visible agglutination or hemolysis at the MIC value. The formulation exhibited significantly reduced biofilm formation compared to the growth control (p < 0.05). Additionally, in silico analysis revealed that MAA showed superior oral bioavailability, no inhibitory activity on cytochrome P450 enzymes, and low potential for toxicity through nuclear receptor signaling pathways. Conclusions: Cationic hydrogels show promise as potential antifungal treatments. The development of cost-effective and improved therapeutic methods is crucial to combat this deadly pathogen and to improve patient outcomes.

Comparative characterization of leather from different tanning processes as a contribution for a sustainable development of the leather industry

Leather is a fully biobased material (100% biodegradable organic material, with collagen as the main constituent), derived from food industry byproducts (animal skin from butchery), which represents an excellence for the Italian industry (in the last years the production value reached 4.6 billion euros and an export of 3.2 billion euros) and a highly sustainable material. However, its production is still strongly handicraft, traditional and unfortunately based on the employment of toxic chemicals, such as chromium and glutaraldehyde. A deep knowledge of the tanning process and of the specific features of leather coming from different processing routes is crucial for the design and development of innovation in the field for a more sustainable and knowledge-based production. In this contest, the impact of tanning process on the surface reactivity of leather plays a crucial role. In the present research well established characterizations (optical microscopy, shrinkage temperature, wettability, metal content, infrared spectroscopy and X-ray diffraction) and new and unconventional methods for the leather field (surface topography, instrumented indentation and zeta potential electrokinetic measurements) were applied and optimized for the characterization of leather samples from traditional (e.g. Chrome and Glutaraldehyde) and innovative (e.g. vegetable, carbamoyl sulphate, starch, aluminum, zeolite, triazine and Olive Mill Wastewaters -OMW) tanning processes. The suitability of the characterization protocol for the in-depth investigation and comparison of leather samples from different processing has been demonstrated highlighting its applicability for a knowledge-based innovation in the leather field.

Magnetically induced anisotropic structure in an injectable hydrogel for skeletal muscle regeneration

Skeletal muscle integrity and its intrinsic aligned architecture are crucial for locomotion, postural support, and respiration functions, impacting overall quality of life. However, volumetric muscle loss (VML) can exceed intrinsic regenerative potential, leading to fibrosis and impairments. Autologous muscle grafting, the current gold standard, is constrained by tissue availability and success rates. Therefore, innovative strategies like cell-based therapies and scaffold-based approaches are needed. Our minimally invasive approach involves a tunable injectable hydrogel capable of achieving an aligned architecture post-injection via a low-intensity static magnetic field (SMF). Our hydrogel formulation uses gellan gum as the backbone polymer, enriched with essential extracellular matrix components such as hyaluronic acid and collagen type I, enhancing bio-functionality. To achieve an aligned architectural biomimicry, collagen type I is coupled with iron oxide magnetic nanoparticles, creating magnetic collagen bundles (MagC) that align within the hydrogel when exposed to a SMF. An extensive study was performed to characterize MagC and assess the hydrogel's stability, mechanical properties, and biological response in vitro and in vivo. The proposed system, fully composed of natural polymers, exhibited mechanical properties similar to human skeletal muscle and demonstrated effective biological performances, supporting its potential as a safe and patient-friendly treatment for VML.

Improving the processability and mechanical strength of self-hardening robocasted hydroxyapatite scaffolds with silane coupling agents

Bone cements are the subject of intensive research, primarily due to their versatility and the increasing importance for personalized medicine. In this study, novel hybrid self-setting scaffolds, based on calcium phosphates and natural polymers, were fabricated using the robocasting technique. Additionally, the influence of two different silane coupling agents, tetraethyl orthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS), on the physicochemical and biological properties of the obtained materials was thoroughly investigated. The chemical and phase compositions (XRF, XRD, FTIR), setting process, rheological properties, mechanical strength, microstructure (SEM), and chemical stability in vitro were comprehensively examined. The use of silane coupling agents improved compressive strength of the scaffolds from 5.20 to 9.26 MPa. The incorporation of citrus pectin into the liquid phase of the materials, along with the use of a hybrid hydroxyapatite-chitosan powder, not only facilitated the development of printable pastes suitable for robocasting but also enhanced the physicochemical properties of the robocasted scaffolds. The results presented in this study underscore the beneficial influence of silane coupling agents on the characteristics of calcium phosphate-based bone scaffolds. Developed robocasted scaffolds hold great potential for applications in the field of bone tissue engineering and personalized medicine. Further in vitro and in vivo studies are necessary to validate their suitability for clinical applications.

Methacrylated chitosan/jellyfish collagen membranes as cell instructive platforms for liver tissue engineering

Although the multidisciplinary area of liver tissue engineering is in continuous progress, research in this field is still focused on developing an ideal liver tissue template. Innovative strategies are required to improve membrane stability and bioactivity. In our study, sustainable biomimetic membranes were developed by blending methacrylated chitosan (CSMA) with jellyfish collagen (jCol) for liver tissue engineering applications. The in vitro biological behaviour demonstrated the capability of the developed membranes to create a suitable milieu to enable hepatocyte growth and differentiation. The functionalization of chitosan together with the biocompatibility of marine collagen and the intrinsic membrane properties offered the ideal biochemical, topographical, and mechanical cues to the cells. Thanks to the enhanced CSMA/jCol membranes' characteristics, hepatocytes on such biomaterials exhibited improved growth, viability, and active liver-specific functions when compared to the cell fate achieved on CSMA membranes. Our study provides new insights about the influence of membrane properties on liver cells behaviour for the design of novel instructive biomaterials. The enrichment of functionalized chitosan with marine collagen represents a promising and innovative approach for the development of an appropriate platform for hepatic tissue engineering.

The Properties of Thin Films Based on Chitosan/Konjac Glucomannan Blends

In this work, blend films were prepared by blending 2% chitosan (CS) and 0.5% konjac glucomannan (KGM) solutions. Five ratios of the blend mixture were implemented (95:5, 80:20, 50:50, 20:80, and 5:95), and a pure CS film and a pure KGM film were also obtained. All the polymeric films were evaluated using FTIR spectroscopy, mechanical testing, SEM and AFM imaging, thermogravimetric analyses, swelling and degradation analyses, and contact angle measurements. The CS/KGM blends were assessed for their miscibility. Additionally, the blend films' properties were evaluated after six months of storage. The proposed blends had good miscibility in a full range of composition proportions. The blend samples, compared to the pure CS film, indicated better structural integrity. The surface structure of the blend films was rather uniform and smooth. The sample CS/KGM 20:80 had the highest roughness value (Rq = 12.60 nm). The KGM addition increased the thermal stability of films. The blend sample CS/KGM 5:95 exhibited the greatest swelling ability, reaching a swelling degree of 946% in the first fifteen minutes of the analysis. Furthermore, the addition of KGM to CS improved the wettability of the film samples. As a result of their good mechanical properties, surface characteristics, and miscibility, the proposed CS/KGM blends are promising materials for topical biomedical and cosmetic applications.

Properties of Skin Collagen from Southern Catfish (Silurus meridionalis) Fed with Raw and Cooked Food

The southern catfish (Silurus meridionalis) is an economically important carnivorous freshwater fish in China. In this study, we compared the properties of skin collagen from southern catfish fed with raw food (RF) and cooked food (CF). The skin collagen yield in the RF group (8.66 ± 0.11%) was significantly higher than that of the CF group (8.00 ± 0.27%). SDS-PAGE, circular dichroism spectroscopy, and FTIR analyses revealed that the collagen extracted from southern catfish skin in both groups was type I collagen, with a unique triple helix structure and high purity. The thermal denaturation temperature of collagen in the RF group (35.20 ± 0.11 °C) was significantly higher than that of the CF group (34.51 ± 0.25 °C). The DPPH free radical scavenging rates were 68.30 ± 2.41% in the RF collagen and 61.78 ± 3.91% in the CF collagen, which was higher than that found in most fish collagen. Both the RF and CF groups had high ability to form fibrils in vitro. Under the same conditions, the CF group exhibited faster fibril formation and a thicker fibril diameter (p < 0.05). In addition, the RF group exhibited significantly higher expression of col1a1 compared to the CF group. These results indicated that feeding southern catfish raw food contributed to collagen production, and the collagen from these fish may have potential in biomaterial applications.

Development of films based on chitosan, gelatin and collagen extracted from bocachico scales (Prochilodus magdalenae)

Biodegradable biopolymers from species of the animal kingdom or their byproducts are sustainable as ecological materials due to their abundant supply and compatibility with the environment. The research aims to obtain a biodegradable active material from chitosan, gelatin, and collagen from bocachico scales (Prochilodus magdalenae). Regarding the methodology, films were developed from gelatin, chitosan, and collagen from bocachico scales (Prochilodus magdalenae) at different concentrations using glycerol as a plasticizer and citric acid as a cross-linker. The films were obtained with the hydrated mass processed by compression molding and characterized according to humidity, water solubility, contact angle, mechanical properties, and structural properties. The results of the films showed a hydrophobic characteristic. First, the chitosan-collagen (CS/CO) films showed a yellowish color, while the gelatin-collagen (Gel/CO) films were transparent and less soluble than the gelatin-collagen (Gel/CO) films. Concerning mechanical properties, gelatin films showed higher stiffness and tensile strength than chitosan films. Furthermore, in the morphological analysis, more homogeneous chitosan films were obtained by increasing the concentration of citric acid. In general, chitosan, gelatin, and collagen extracted from the scales of the bocachico (Prochilodus magdalenae) are an alternative in the application of films in the food industry.

Adhesive and biodegradable membranes made of sustainable catechol-functionalized marine collagen and chitosan

We describe bioadhesive membranes developed from marine renewable biomaterials, namely chitosan and collagen extracted from fish skins. Collagen was functionalized with catechol groups (Coll-Cat) to provide the membranes with superior adhesive properties in a wet environment and blended with chitosan to improve the mechanical properties. The blended membranes were compared to chitosan and chitosan blended with unmodified collagen in terms of surface morphology, wettability, weight loss, water uptake, mechanical and adhesive properties. The metabolic activity, the viability and the morphology of L929 fibroblastic cells seeded on these membranes were also assessed. Our results show that the functionalization with catechol groups improves the adhesive and mechanical properties of the membranes and enhances cell attachment and proliferation. These data suggest that the developed marine origin-raw membranes present a potential towards the restoration of the structural and functional properties of damaged soft tissues.

Preparation of chitosan/hydrolyzed collagen/hyaluronic acid based hydrogel composite with caffeic acid addition

In this work, biopolymer hydrogels were synthesized by mixing hyaluronic acid, hydrolyzed collagen, and chitosan through a solvent evaporation method and incorporating them with caffeic acid as an antioxidant agent. The obtained caffeic acid-loaded chitosan/hydrolyzed collagen/hyaluronic acid hydrogels were characterized by X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis. No significant change on structural and thermal properties was observed. Furthermore, scanning electron microscope reported that the surface morphology of the hydrogels was smooth, and no significant change in porosity was observed after the addition of hyaluronic acid. With high amount of hyaluronic acid, the swelling behaviour was superiority. The hydrogels showed an initial burst release of caffeic acid (~70%) within 60 min, followed by a gradual release of up to 80% by 480 min. The release was slightly higher with the presence of hyaluronic acid. In addition, DPPH, ABTS⁺, and FRAP assays revealed that the caffeic acid-loaded hyaluronic acid/hydrolyzed collagen/chitosan hydrogels exhibited antioxidant activity. Thus, these composites could potentially be used as dressing materials with antioxidant activity.