Films of conducting polymers can be oxidized and reduced in a reversible way. Any intermediate oxidation state determines an electrochemical equilibrium. Chemical or physical variables acting on the film may modify the equilibrium potential, so that the film acts as a sensor of the variable. The working potential of polypyrrole/DBSA (Dodecylbenzenesulfonic acid) films, oxidized or reduced under constant currents, changes as a function of the working conditions: electrolyte concentration, temperature or mechanical stress. During oxidation, the reactive material is a sensor of the ambient, the consumed electrical energy being the sensing magnitude. Devices based on any of the electrochemical properties of conducting polymers must act simultaneously as sensors of the working conditions. Artificial muscles, as electrochemical actuators constituted by reactive materials, respond to the ambient conditions during actuation. In this way, they can be used as actuators, sensing the surrounding conditions during actuation. Actuating and sensing signals are simultaneously included by the same two connecting wires.

The role of the oral microbiome and its effect on dental diseases is gaining interest. Therefore, it has been sought to decrease the bacterial load to fight oral cavity diseases. In this study, composite materials based on chitosan, chitosan crosslinked with glutaraldehyde, chitosan with zinc oxide particles, and chitosan with copper nanoparticles were prepared in the form of thin films, to evaluate a new alternative with a more significant impact on the oral cavity bacteria. The chemical structures and physical properties of the films were characterized using by Fourier transform infrared spectroscopy (FTIR,) Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), elemental analysis (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and contact angle measurements. Subsequently, the antimicrobial activity of each material was evaluated by agar diffusion tests. No differences were found in the hydrophilicity of the films with the incorporation of ZnO or copper particles. Antimicrobial activity was found against S. aureus in the chitosan film crosslinked with glutaraldehyde, but not in the other compositions. In contrast antimicrobial activity against S. typhimurium was found in all films. Based on the data of present investigation, chitosan composite films could be an option for the control of microorganisms with potential applications in various fields, such as medical and food industry.

This review provides an overview of recent developments in Citrus aurantium L. (sour or bitter orange), focusing on its bioactive compounds, innovative extraction techniques, and technological applications. C. aurantium is rich in bioactive compounds such as flavonoids (naringin, hesperidin, kaempferol, quercetin), essential oils (β-pinene, limonene), and vitamin C, which represents significant biological activities including antioxidant, antimicrobial, anti-inflammatory, and anticancer effects. The review discusses traditional extraction methods, such as solvent extraction and hydrodistillation, alongside newer, eco-friendly approaches like ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, and natural deep eutectic solvents. It also highlights cutting-edge techniques, including molecular imprinting polymer-based extraction, which enable the more efficient enrichment and purification of specific compounds like synephrine. Finally, the review examines the diverse industrial applications of these bioactive compounds in sectors such as foods, pharmaceuticals, and cosmetics, while emphasizing the growing need for sustainable and efficient extraction technologies.