Fabrication and formation studies on single-walled CA/NaCS-WSC microcapsules

Strategies for the Preparation of Chitosan Derivatives for Antimicrobial, Drug Delivery, and Agricultural Applications: A Review

Chitosan has received much attention for its role in designing and developing novel derivatives as well as its applications across a broad spectrum of biological and physiological activities, owing to its desirable characteristics such as being biodegradable, being a biopolymer, and its overall eco-friendliness. The main objective of this review is to explore the recent chemical modifications of chitosan that have been achieved through various synthetic methods. These chitosan derivatives are categorized based on their synthetic pathways or the presence of common functional groups, which include alkylated, acylated, Schiff base, quaternary ammonia, guanidine, and heterocyclic rings. We have also described the recent applications of chitosan and its derivatives, along with nanomaterials, their mechanisms, and prospective challenges, especially in areas such as antimicrobial activities, targeted drug delivery for various diseases, and plant agricultural domains. The accumulation of these recent findings has the potential to offer insight not only into innovative approaches for the preparation of chitosan derivatives but also into their diverse applications. These insights may spark novel ideas for drug development or drug carriers, particularly in the antimicrobial, medicinal, and plant agricultural fields.

Spherical Cellulose Micro and Nanoparticles: A Review of Recent Developments and Applications

Cellulose, the most abundant natural polymer, is a versatile polysaccharide that is being exploited to manufacture innovative blends, composites, and hybrid materials in the form of membranes, films, coatings, hydrogels, and foams, as well as particles at the micro and nano scales. The application fields of cellulose micro and nanoparticles run the gamut from medicine, biology, and environment to electronics and energy. In fact, the number of studies dealing with sphere-shaped micro and nanoparticles based exclusively on cellulose (or its derivatives) or cellulose in combination with other molecules and macromolecules has been steadily increasing in the last five years. Hence, there is a clear need for an up-to-date narrative that gathers the latest advances on this research topic. So, the aim of this review is to portray some of the most recent and relevant developments on the use of cellulose to produce spherical micro- and nano-sized particles. An attempt was made to illustrate the present state of affairs in terms of the go-to strategies (e.g., emulsification processes, nanoprecipitation, microfluidics, and other assembly approaches) for the generation of sphere-shaped particles of cellulose and derivatives thereof. A concise description of the application fields of these cellulose-based spherical micro and nanoparticles is also presented.

Preparation of chitosan-sodium alginate films through layer-by-layer assembly and ferulic acid crosslinking: Film properties, characterization, and formation mechanism

Chitosan-alginate films were prepared through layer-by-layer assembly combined with ferulic acid crosslinking. Their mechanical properties, opacity, and hydrophobicity were compared to films prepared by direct mixing, crosslinking alone, and LBL assembly alone. Thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy were used to characterize the films and analyze their formation mechanism. The results indicated that the layer-by-layer assembly and ferulic acid crosslinking combination increased the tensile strength and light-blocking ability of the films. In addition, the films had a lower water vapor transmission rate, swelling degree, and water solubility, as well as higher hydrophobicity. Scanning electron microscopy showed a good compatibility between the film components of the film prepared by the combination technique. The structural characterization results revealed some strong interactions among the amino, carboxyl, and hydroxyl groups of the ferulic acid, chitosan, and sodium alginate in the film. The driving force for film formation was the generation of non-covalent bonds among the film components rather than covalent bonds.