Wound dressings based on chitosan and gelatin containing starch, sesame oil and banana peel powder for the treatment of skin burn wounds

Exploiting Polymeric Films as a Multipurpose Drug Delivery System: a Review

Polymeric films are drug delivery systems that maintain contact with the delivery tissue and sustain a controlled release of therapeutic molecules. These systems allow a longer time of drug contact with the target site in the case of topical treatments and allow the controlled administration of drugs. They can be manufactured by various methods such as solvent casting, hot melt extrusion, electrospinning, and 3D bioprinting. Furthermore, they can employ various polymers, for example PVP, PVA, cellulose derivatives, chitosan, gelling gum, pectin, and alginate. Its versatility is also applicable to different routes of administration, as it can be administered to the skin, oral mucosa, vaginal canal, and eyeballs. All these factors allow numerous combinations to obtain a better treatment. This review focuses on exploring some possible ways to develop them and some particularities and advantages/disadvantages in each case. It also aims to show the versatility of these systems and the advantages and disadvantages in each case, as they bring the opportunity to develop different medicines to facilitate therapies for the most diverse purposes .

Development of chitosan/tannic acid/corn starch multifunctional bilayer smart films as pH-responsive actuators and for fruit preservation

The design of intelligent films for pH-responsive actuators fully constructed from natural biopolymers remains challenging. This study used natural biopolymers to develop a new type of smart and multifunctional chitosan/tannic acid/corn starch (CHT/TA/CS) bilayer films, which can be used for pH-responsive actuators and fruit preservation. We studied the microstructural morphology, physicochemical, antioxidant, antimicrobial properties of the films. Compared with the CHT film, the water vapor permeability (WVP) values of the CHT/TA/CS bilayer films were reduced by 3.1 times, and the tensile strength was increased by 4.6 times. The CHT/TA/CS bilayer films also exhibited high 1,1-diphenyl-2-picrylhydrazyl (DPPH) (94.6%) and hydroxyl (OH) (97.5%) radical scavenging activity. The bilayer films had good antimicrobial activity. The CHT/TA/CS bilayer films exhibited different directional deformation behaviors in acid-base solutions and could be used as pH-responsive actuators. By changing the solution's pH, the bilayer films could grab and release heavy objects 21 times heavier than themselves. Furthermore, the CHT/TA/CS bilayer coating prolonged the bananas' storage time from three to six days, and its weight loss was reduced by 14%. The developed CHT/TA/CS bilayer films have potential application in degradable materials, soft robotics fields, and food packaging materials.

Pectin–Zeolite-Based Wound Dressings with Controlled Albumin Release

Hypoalbuminemia can lead to poor and delayed wound healing, while it is also associated with acute myocardial infarction, heart failure, malignancies, and COVID-19. In elective surgery, patients with low albumin have high risks of postoperative wound complications. Here, we propose a novel cost-effective wound dressing material based on low-methoxy pectin and NaA-zeolite particles with controlled albumin release properties. We focused on both albumin adsorption and release phenomena for wounds with excess exudate. Firstly, we investigated albumin dynamics and calculated electrostatic surfaces at experimental pH values in water by using molecular dynamics methods. Then, we studied in detail pectin–zeolite hydrogels with both adsorption and diffusion into membrane methods using different pH values and albumin concentrations. To understand if uploaded albumin molecules preserved their secondary conformation in different formulations, we monitored the effect of pH and albumin concentration on the conformational changes in albumin after it was released from the hydrogels by using CD-UV spectroscopy analyses. Our results indicate that at pH 6.4, BSA-containing films preserved the protein’s folded structure while the protein was being released to the external buffer solutions. In vitro wound healing assay indicated that albumin-loaded hydrogels showed no toxic effects on the fibroblast cells.

Starch Solutions Prepared under Different Conditions as Modifiers of Chitosan/Poly(aspartic acid)-Based Hydrogels

Recently, there has been great interest in the application of polysaccharides in the preparation of diverse biomaterials which result from their biocompatibility, biodegradability and biological activity. In this work, the investigations on chitosan/poly(aspartic acid)-based hydrogels modified with starch were described. Firstly, a series of hydrogel matrices was prepared and investigated to characterize their swelling properties, structure via FT-IR spectroscopy, elasticity and tensile strength using the Brookfield texture analyzer as well as their impact on simulated physiological liquids. Hydrogels consisting of chitosan and poly(aspartic acid) in a 2:1 volume ratio were elastic (9% elongation), did not degrade after 30-day incubation in simulated physiological liquids, exhibited a relative biocompatibility towards these liquids and similar swelling in each absorbed medium. This hydrogel matrix was modified with starch wherein two of its form were applied-a solution obtained at an elevated temperature and a suspension obtained at room temperature. Hydrogels modified with hot starch solution showed higher sorption that unmodified materials. This was probably due to the higher starch inclusion (i.e., a larger number of hydrophilic groups able to interact with the adsorbed liquid) when this polysaccharide was given in the form of a hot solution. Hydrogels modified with a cold starch suspension had visible heterogeneous inequalities on their surfaces and this modification led to the obtainment materials with unrepeatable structures which made the analysis of their properties difficult and may have led to misleading conclusions.

Bioactivity of Chitosan-Based Particles Loaded with Plant-Derived Extracts for Biomedical Applications: Emphasis on Antimicrobial Fiber-Based Systems

Marine-derived chitosan (CS) is a cationic polysaccharide widely studied for its bioactivity, which is mostly attached to its primary amine groups. CS is able to neutralize reactive oxygen species (ROS) from the microenvironments in which it is integrated, consequently reducing cell-induced oxidative stress. It also acts as a bacterial peripheral layer hindering nutrient intake and interacting with negatively charged outer cellular components, which lead to an increase in the cell permeability or to its lysis. Its biocompatibility, biodegradability, ease of processability (particularly in mild conditions), and chemical versatility has fueled CS study as a valuable matrix component of bioactive small-scaled organic drug-delivery systems, with current research also showcasing CS’s potential within tridimensional sponges, hydrogels and sutures, blended films, nanofiber sheets and fabric coatings. On the other hand, renewable plant-derived extracts are here emphasized, given their potential as eco-friendly radical scavengers, microbicidal agents, or alternatives to antibiotics, considering that most of the latter have induced bacterial resistance because of excessive and/or inappropriate use. Loading them into small-scaled particles potentiates a strong and sustained bioactivity, and a controlled release, using lower doses of bioactive compounds. A pH-triggered release, dependent on CS’s protonation/deprotonation of its amine groups, has been the most explored stimulus for that control. However, the use of CS derivatives, crosslinking agents, and/or additional stabilization processes is enabling slower release rates, following extract diffusion from the particle matrix, which can find major applicability in fiber-based systems within ROS-enriched microenvironments and/or spiked with microbes. Research on this is still in its infancy. Yet, the few published studies have already revealed that the composition, along with an adequate drug release rate, has an important role in controlling an existing infection, forming new tissue, and successfully closing a wound. A bioactive finishing of textiles has also been promoting high particle infiltration, superior washing durability, and biological response.