Probing the Molecular Interactions of Chitosan Films in Acidic Solutions with Different Salt Ions

Effect of gelatin and salicylic acid incorporated in chitosan coatings on strawberry preservation

Strawberries are highly prone to rapid post-harvest deterioration due to their high nutritional content and lack of protective peel, demanding the development of alternative preservation methods. This study evaluates chitosan (CH) edible coatings enhanced with gelatin (GE) and salicylic acid (SA) for extending shelf life while maintaining fruit quality. Through atomic force microscopy, it was demonstrated that GE and SA showed increased surface roughness, besides improved the ultraviolet barrier properties and reduced water vapor permeability. Over 14 days of storage (3.0 ± 1.0 °C), all coatings minimized weight loss, firmness reduction, and color changes while delaying total soluble solids and pH increases. The effectiveness of the CH (0.8 %) with GE (0.2 %) and SA (2 mM) coating was mainly determined by the reduction of the development of natural disease development (84.30 ± 3.62 %), whereas the physicochemical properties tend to be similar in the assessed formulations. Principal Component Analysis (PCA) was used to investigate the effects of the treatments on strawberry shelf life and to determine the correlations between the responses studied. Considering the variability of the dimensions of the responses, correlation coefficients were used to form the matrix and extract the eigenvalue. PCA showed that the properties of the strawberries change continuously regardless of the treatments and indicated that four principal components accounted for 82.7 % of data variability. This study demonstrates that coatings, combined with cold storage, offer an effective solution for extending the shelf life of strawberries while preserving their quality throughout storage.

Investigation of Chlorhexidine and Chitosan Gel-Based Coatings for the Prevention of Intravascular Catheter-Associated Infections Following Quality by Design Approach

Intravascular catheter-associated infections pose a significant threat to the health of patients because of biofilm formation. Hence, it is imperative to exploit cost-effective approaches to improve patient compliance. With this aim, our present study reported the potential of an antimicrobial polymeric gel coating of chitosan (CS) and chlorhexidine (CHX) on the marketed urinary catheters to minimize the risk of biofilm formation. The study involved the implementation of the Quality by Design (QbD) approach by identifying the critical parameters that can affect the coating of the catheter's surface in any possible way. Later, design of experiments (DoE) analysis affirmed the lack of linearity in the model for the studied responses in a holistic manner. Moreover, in vitro studies were conducted for the evaluation of various parameters followed by the antibiofilm study. The coating exhibited promising release of CHX in the artificial urinary media together with retention of the coating on the catheter's surface. Therefore, this study aims to emphasize the importance of a systematic and quality-focused approach by contributing to the development of a safe, effective, and reliable catheter coating to enhance intravascular catheter safety.

Polysaccharide-Protein Multilayers Based on Chitosan-Fibrinogen Assemblies for Cardiac Cell Engineering

The cell and tissue culture substrates play a pivotal role in the regulation of cell-matrix and cell-cell interactions. The surface properties of the materials control a wide variety of cell functions. Amongst various methods, layer-by-layer (LbL) assembly is a versatile surface coating technique for creating controllable bio-coatings. Here, polysaccharide/protein multilayers are proposed, which are fabricated by immersive LbL assembly and based on the chitosan/fibrinogen pair for improving the adhesion and spreading of cardiomyocytes. Two approaches in LbL assembly are employed for clarifying the effect of the bilayers order and their concentration on cardiomyocytes viability and morphology. Fourier transform infrared spectroscopy (FTIR) measurements show that the adsorption of the biopolymers is enhanced during the LbL deposition in a synergistic manner. Contact angle measurements indicate that the multilayers are alternating from less to more hydrophilic behavior depending on the biopolymer that is added last. Confocal microscopy with immunostained fibrinogen reveals that the amount of the protein is higher when the concentration of the immersion solution is increased, however, for low solution concentration it is speculated that interdigitation between the separate biopolymer layers takes place. This work motivates the use of fibrinogen in polysaccharide/protein multilayers for enhanced cytocompatibility in cardiac tissue engineering.