ABSTRACT
The purpose of this paper is to study the effect of polypyrrole (PPy) on cellulose acetate (CA) membranes prepared by the electrospinning technique (controlled variables) in the recovery of gold complexes of aqueous solutions that are environmentally ecofriendly. CA-PPy membranes were characterized by SEM, EDS, FTIR spectroscopy, contact angle measurements, electrical conductivity, and mechanical tests. They were submerged in two aqueous solutions using two gold complexes, AuI2 - and AuBr4 -, at room temperature. The recovery percentage was evaluated for several hours using the atomic adsorption technique for both complexes. The main findings indicate that the percentage of recovery in the first hours of the test was very high (>80%). The adsorption efficiency maxima were similar for both complexes (91%). The Langmuir model suggests the formation of a monolayer on the surface. The electrical conductivity did not change over time, and the mechanical properties indicate reuse in several experiments. Furthermore, the theoretical analysis showed that the system is helpful at acidic pH, funding its minimum energy. It is shown in this study that the used CA-PPy membranes show adsorption, absorption, and reusable properties with the effective recovery of the complexes in the first hours. These membranes could substitute for materials that are not environmentally ecofriendly.
ABSTRACT
Wound healing treatment in diabetic patients worldwide represents around 2.1 trillion dollars to global health sectors. This is because of the complications presented in the wound healing process of skin ulcers, such as a lack of macrophage and fibroblast growth factors (TGF-ß1 and PDGF, respectively) that are both needed for extracellular matrix (ECM) synthesis. Therefore, there is a need for research on new and cost-effective materials to enable ECM synthesis. Such materials include co-electrospun nanofibers used as wound dressings, since they have a similar morphology to the ECM, and therefore, possess the advantage of using different materials to accelerate the wound healing process. Co-electrospun nanofibers have a unique structural configuration, formed by a core and a shell. This configuration allows the protection and gradual liberation of healing agent compounds, which could be included in the core. Some of the materials used in nanofibers are polymers, including natural compounds, such as chitosan (which has been proven to possess antimicrobial and therapeutic activity) and gelatin (for its cell growth, adhesion, and organisational capacity in the wound healing process). Synthetics such as polyvinyl-alcohol (PVA) (mainly as a co-spinning agent to chitosan) can also be used. Another bioactive compound that can be used to enhance the wound healing process is eugenol, a terpenoid present in different medicinal plant tissues that have scarring properties. Therefore, the present review analyses the potential use of co-electrospun nanofibers, with chitosan-PVA-eugenol in the core and gelatin in the shell as a wound dressing for diabetic skin ulcers.
