Smart packaging with biodegradable polymers has emerged as a response to food challenges in a modern society, in terms of environmental impact, innovation, quality and safety. For that reason, it is important to design and understand smart materials that may have high potential for application in food science. In this work, films based on potato starch reinforced with six different levels of content of silver nanoparticles (AgNp) were produced by casting with the aim of evaluating its potential use as a material for smart packaging. The films were evaluated in terms of shape memory stimulated by temperature, antibacterial activity (against Salmonella typhimurium) , thermo-mechanical and physicochemical tests. Addition of AgNp in potato starch films modified the assembly of polymer chains, with changes observed in superficial water affinity, thickness, and shape memory. Nanocomposites films showed antibacterial activity against Salmonella typhimurium , and they were efficient at blocking ultraviolet light and extending this protection to visible light, unlike control samples without nanoparticles. AgNp mechanically reinforced potato starch films, showing an increase in the elastic modulus greater than 200%. Furthermore, the film intermediate content of AgNp exhibited higher thermal stability than the control potato starch film, increasing its thermal degradation temperature by 15 °C. Additionally, an enhanced shape memory response of potato starch films is observed at an activation temperature of 80 °C for the formulation with the lowest AgNp content. Therefore, establishing the amounts of AgNp in potato starch allows us to modulate the properties of the nanocomposite, depending on the requirements of smart packaging.
Rare earth metal oxide nanoparticles possess unique physicochemical properties that enable diverse technological applications. Among these, europium oxide (Eu 2 O 3 ), characterized by a wide band gap energy (~ 4.4 eV) and advantageous dielectric properties, has attracted significant research interest. This review comprehensively covers recent progress in the synthesis of Eu 2 O 3 and Eu 2 O 3 -functionalized heterostructures via diverse chemical routes, including precipitation, hydrothermal, solvothermal, sonochemical, sol-gel, and reflux methods. Particular emphasis is placed on the influence of key operational parameters, such as reaction temperature, time, and capping agents, on particle morphology and structural evolution. Furthermore, the functional performance and underlying mechanisms of these heterostructures across photocatalysis, luminescence, chemical sensing, and biological domain applications are critically evaluated, highlighting current challenges and prospects for sustainable utilization.
Intercalation of gases and metal species beneath graphene supported on transition-metal substrates has emerged as a powerful strategy for tuning graphene–substrate interactions and tailoring its electronic, chemical, and mechanical properties. Numerous studies have investigated these phenomena using surface-sensitive techniques, including X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and low-energy electron diffraction (LEED). This review examines the intercalation of oxygen, carbon monoxide, and hydrogen, with particular emphasis on graphene grown on Ir(111). Oxygen intercalation proceeds under ultrahigh-vacuum conditions through atomic oxygen formation on bare Ir terraces and requires elevated temperatures (~355 K), whereas hydrogen intercalation occurs at much lower temperatures (~140 K). CO intercalation takes place near room temperature but requires millibar-range pressures. In all cases, substrate step edges and graphene flake boundaries serve as critical pathways for intercalant penetration. These structural features have been consistently identified as key entry points for intercalant diffusion. Intercalation provides an additional degree of freedom for controlling the properties of 2D materials, enabling modulation of electrical conductivity, thermoelectric response, and catalytic activity. The process significantly modifies the electronic, chemical, and mechanical characteristics of the graphene layer, while also partially decoupling it from the underlying substrate. Given these effects, gas intercalation beneath graphene represents a promising strategy for applications in catalysis, sensing, and energy storage. Intercalation can also be used to partially separate the graphene overlayer from the underlying metal, leading to considerable enhancement of electronic, chemical and mechanical properties. This review highlights the fundamental mechanisms and technological potential of gas (O 2 , H 2 , and CO) intercalation beneath graphene for applications in catalysis, sensing, energy storage, and next-generation graphene-based devices.
Curcumin (CUR) has limited aqueous solubility, motivating the development of dispersed formulations for its delivery. Although clove-oil nanoemulsions (CONE) have been reported, the influence of emulsifier choice on the properties of CUR-loaded clove-oil nanoemulsions (CONEs) has received limited direct comparison. This study aimed to prepare CUR-loaded CONEs stabilized with Tween 20 (T20) or whey protein concentrate (WPC 80) and compared their physicochemical characteristics, interactions with bovine serum albumin (BSA), and in vitro release behavior. The optimized CUR-loaded T20 and WPC 80 formulations had hydrodynamic diameters of 16 ± 1 and 225 ± 5 nm, respectively, and CUR entrapment efficiencies of 92.77 ± 1.43% and 95.42 ± 1.72%. Neither formulation showed visible phase separation over 30 days. Spectroscopic measurements indicated interactions between BSA and the CUR-loaded nanoemulsion systems, although the contributions of individual formulation components could not be resolved. Release varied with formulation and pH: after 12 h at pH 5.5, cumulative CUR release was 84.42 ± 0.88% from the T20 formulation and 45.78 ± 0.81% from the WPC 80 formulation. The CUR-loaded WPC 80 NE showed 91.0 ± 0.58% radical-scavenging activity in the ABTS assay and a 15.0 ± 0.28 mm inhibition zone against Klebsiella pneumoniae under the tested conditions. DNA electrophoresis and SDS-PAGE provided preliminary information on interactions with the tested biomolecular models but did not establish overall biocompatibility. These findings show that emulsifier choice influences the measured physicochemical properties and in vitro performance of CUR-loaded CONEs, highlighting the potential of emulsifier-tailored CONEs as delivery systems while supporting the need for further evaluation of their safety and delivery performance.
Herein, we report the phytogenic, single-step synthesis of silver/reduced graphene oxide (Ag/rGO) nanocomposites utilizing Citrus macroptera peel extract as a sustainable, dual reducing and stabilizing agent. Spectroscopic and diffractometric analyses (UV–vis, FTIR, Raman, EDX, and XRD) confirmed the synchronized bio-reduction of graphene oxide (GO) and silver ions (Ag + ), yielding highly crystalline metallic ‘Ag’ anchored on an exfoliated reduced graphene oxide (rGO) matrix. Electron microscopy (SEM and TEM) analyses established the homogeneous immobilization of ultrafine, spherical silver nanoparticles (AgNPs) in the tens-of-nanometers scale across wrinkled, semi-transparent, and exfoliated rGO nanosheets. Benefiting from a synergistic interfacial electron-transfer mechanism, the Ag/rGO nanocomposite demonstrated vastly superior catalytic efficiency for 4-nitrophenol reduction (9 min, 97.5 s −1 g −1 ) compared to pristine AgNPs (18 min, 87.2 s −1 g −1 ) and their corresponding physical mixtures (AgNPs & rGO synthesized using same extract). Furthermore, the hybrid material exhibited potent, broad-spectrum antibacterial activity against critical pathogens, including Escherichia coli , Staphylococcus aureus , Vibrio cholerae , and Salmonella typhi . This study establishes a green, waste-to-wealth fabrication strategy for multifunctional nano-architectures, offering potential solutions for environmental remediation and biomedical applications.
