To date, the need for biomaterials capable of improving the treatment of chronic skin wounds remains a clinical challenge. The aim of the present work is to formulate and characterize chitosan (Cs)/hydrolyzed collagen (HC) films as potential biomaterials with improved mechanical and hydration performances compared to single component formulations. Films were made by the solvent casting method, with or without glycerin and/or PEG1500 as plasticizers, resulting in a total of eight formulations. All films were characterized by their physico-chemical characteristics and their mechanical and hydration features. A full factorial design was also used to statistically assess the effect of HC concentration, type and concentration of plasticizers and their possible interactions on mechanical and swelling behaviors. Solid state characterization confirmed the hybrid nature of the films, with suggested electrostatic interactions between Cs and HC. Mechanical and swelling properties, along with the analysis of the experimental design, allowed the identification of formulations containing high HC concentration (2% w/v) and glycerin or glycerin/PEG1500 as more suitable candidates for skin wound treatment. Finally, viability assay of immortalized human keratinocytes (HaCaT) showed no statistical differences in cell survival compared to the complete culture medium, suggesting their potential as a promising tool for biomedical applications.

The healing process of chronic wounds continues to be a current clinical challenge, worsened by the risk of microbial infections and bacterial resistance to the most frequent antibiotics. In this work, non-antibiotic nanohybrids based on chlorhexidine dihydrochloride and clay minerals have been developed in order to design advanced therapeutic systems aimed to enhance wound healing in chronic lesions. To prepare the nanohybrids, two methodologies have been compared: the intercalation solution procedure and the spray-drying technique, the latter as a one-step process able to reduce preparation times. Nanohybrids were then fully studied by solid state characterization techniques. Computational calculations were also performed to assess the interactions between the drug and the clays at the molecular level. In vitro human fibroblast biocompatibility and antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa were assessed to check biocompatibility and potential microbicidal effects of the obtained nanomaterials. The results demonstrated the effective organic/inorganic character of the nanohybrids with homogeneous drug distribution into the clayey structures, which had been confirmed by classical mechanics calculations. Good biocompatibility and microbicidal effects were also observed, especially for the spray-dried nanohybrids. It was suggested that it could be due to a greater contact area with target cells and bacterial suspensions.

Chitosan-nanoclay nanocomposites (CNNCs) are attractive aqueous platforms for biorelevant manufacturing, yet the impact of clay morphology under identical preparation and testing conditions remains insufficiently resolved. In the present work, low-molecular-weight chitosan (CS) was combined with three nanoclays, bentonite (BEN, layered), halloysite (HAL, tubular) and sepiolite (SEP, fibrous), to prepare hybrid suspensions at pH 4.5 spanning defined CS/nanoclay ratios. BEN and SEP series were formulated from 15/85 to 75/25 (CS/nanoclay, w/w); HAL series ranged from 5/95 to 55/45. After 48 h aging and intermittent sonication, rheology was measured: all hybrids exhibited pronounced shear-thinning. For each clay type, the apparent viscosity increased steadily with higher chitosan content. This trend suggests that the flow behavior is mainly governed by the polymer, as protonated chitosan chains adsorb onto silicate surfaces and form bridges between particles, creating transient networks. Sepiolite-based hybrids showed the highest viscosities and the strongest shear-thinning, consistent with a network, fiber-driven architecture. Halloysite formulations displayed high viscosities with indications of a yield-like response, whereas bentonite afforded intermediate viscosities and smooth flow. The results indicate that nanoclay morphology plays a key role in determining network formation efficiency, enabling controlled modulation of rheological properties under fixed processing conditions. Complementary FTIR/XRPD and X-ray micro-computed tomography supported hybrid formation and uniform three-dimensional dispersion of the nanoclays. Collectively, these results provide clear design rules for programming CNNC rheology under mild, aqueous conditions, offering practical guidance for casting, molding and printing of bioactive formulations that require high shear injectability and structural integrity at rest. The materials palette provides a tunable basis for bioactive formulations and future device-oriented investigations.

Most of the therapeutic systems developed for managing chronic skin wounds lack adequate mechanical and hydration properties, primarily because they rely on a single component. This study addresses this issue by combining organic and inorganic materials to obtain hybrid films with enhanced mechanical behavior, adhesion, and fluid absorption properties. To that aim, chitosan/hydrolyzed collagen blends were mixed with halloysite/antimicrobial nanohybrids at 10% and 20% (w/w) using glycerin or glycerin/polyethylene glycol-1500 as plasticizers. The films were characterized through the use of Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and electron microscopy. The mechanical properties were evaluated macroscopically using tensile tests, and at a nanoscale through atomic force microscopy (AFM) and nanoindentation. Thermodynamic studies were conducted to assess their hydrophilic or hydrophobic character. Additionally, in vitro cytocompatibility tests were performed on human keratinocytes. Results from FTIR, TGA, AFM and electron microscopy confirmed the hybrid nature of the films. Both tensile tests and nanomechanical measurements postulated that the nanohybrids improved the films’ toughness and adhesion and optimized the nanoindentation properties. All nanohybrid-loaded films were hydrophilic and non-cytotoxic, showcasing their potential for skin wound applications given their enhanced performance at the macro- and nanoscale.