Antimicrobial resistance (AMR) is one of the most significant global health threats of the 21st century, driving the urgent search for alternatives to conventional antibiotics. Copper nanoparticles (CuNPs) have gained attention due to their broad antimicrobial spectrum, cost-effectiveness, and versatile applications in medicine, agriculture, and the food industry. This review provides a systematic overview of the advances in CuNP synthesis, mechanisms of antimicrobial action, biomedical and industrial applications, and associated toxicity issues. A comprehensive literature review was conducted, covering chemical, physical, and biological synthesis strategies; mechanistic studies on microbial inhibition; and experimental reports on biomedical and environmental applications. A comparative analysis revealed opportunities, limitations, and knowledge gaps, with particular emphasis on cytotoxic and ecotoxicological aspects. CuNPs show strong antimicrobial activity against bacteria, fungi, viruses, and multidrug-resistant strains through mechanisms such as reactive oxygen species (ROS) generation, membrane disruption, and DNA/protein interactions. Their use in medical devices, wound dressings, textiles, and packaging materials underlines their application potential. However, cytotoxicity to mammalian cells, ecological risks, and the lack of standardized safety protocols remain critical challenges. Particle size, morphology, and surface chemistry strongly influence both efficacy and toxicity, underlining the importance of controlled synthesis and functionalization. Overall, CuNPs represent a promising strategy to tackle the AMR crisis. Future research should focus on environmentally friendly and surface-modified synthesis approaches, standardized toxicity assessments, and robust regulatory frameworks. By balancing antimicrobial efficacy with biosafety and sustainability, CuNPs could become a transformative platform for clinical, industrial, and environmental applications.

Copper and its alloys are structural materials used in industries and engineering applications due to their excellent thermal and electrical conductivity and chemical stability. Integrating graphene, known for its exceptional electrical conductivity, into the copper matrix is a promising strategy to enhance mechanical properties without sacrificing electrical conductivity. The Accumulative Roll Bonding (ARB) process can effectively and homogeneously introduce graphene into the metal matrix and is adaptable to an industrial scale. This study investigates the impact of varying graphene concentrations and two heat treatment protocols (without a controlled atmosphere) on the mechanical and electrical properties of ARBed copper/graphene composites. Optical microscopy revealed minimal voids and graphene clumps, and the energy dispersive spectroscopy analysis revealed the absence of copper oxide in some samples. The conductivity test showed little influence of the graphene content and stress relief heat treatment temperature on electrical conductivity (~86% of the International Annealed Copper Standard) within a limited number of ARB cycles. The tensile tests did not reveal a significant influence of the graphene content and stress relief heat treatment temperature on the ultimate tensile strength (220–420 MPa) and elongation (~2%).

The present study evaluated the influences of different temperatures during heat treatment on the microstructure and mechanical properties of the manganese bronze alloy. During heating, there was a decrease of stored energy in the form of crystal defects due to the mechanisms of rearrangement and the annihilation of dislocations, followed by nucleation and grain growth. Initially, the samples were drawn using 34% cold work. Then, the specimens were heat-treated for one hour with different temperatures ranging from 200 to 750 °C, increasing by 50 °C for each sample. The chemical composition characterization was determined by X-ray fluorescence spectrometry (XRF). The mechanical property characterization involved the Vickers hardness, tensile strength, yield strength, and elongation. For the microstructural analysis of the samples, optical microscopy and scanning electron microscopy were used. The results showed an increase of elongation and decrease of the Vickers hardness and tensile and yield strengths with the increasing annealing temperature. The Hollomon model was used to investigate the strain-hardening behavior in all specimens. The (n) strain-hardening coefficient and the (K) strength coefficient were calculated, and the correlation with the increase of temperature occurred with the increase of n and variation of K after the recrystallization temperature.

The use of copper as an antimicrobial agent has a long history and has gained renewed interest in the context of the COVID-19 pandemic. In this study, the authors investigated the antimicrobial properties of an alloy composed of copper with a small percentage of silver (Cu-0.03% wt.Ag). The alloy was tested against various pathogens, including Escherichia coli, Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa, and the H1N1 virus, using contact exposure tests. Results showed that the alloy was capable of inactivating these pathogens in two hours or less, indicating its strong antimicrobial activity. Electrochemical measurements were also performed, revealing that the small addition of silver to copper promoted a higher resistance to corrosion and shifted the formation of copper ions to higher potentials. This shift led to a slow but continuous release of Cu²⁺ ions, which have high biocidal activity. These findings show that the addition of small amounts of silver to copper can enhance its biocidal properties and improve its effectiveness as an antimicrobial material.

This study evaluated mixing methods for producing graphene oxide-reinforced copper matrix composites aiming for a better dispersion of graphene oxide in the composite, using powder metallurgy techniques. The compacted specimens were prepared by four different mixing processes that employed either a mechanical stirrer, rotary evaporator, tip ultrasound, or ultrasound process followed by mechanical stirring. Characterizations were performed using optical microscopy, scanning electron microscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, compression tests, Vickers microhardness, and electrical conductivity measurements. The results indicate that the combined method yields a more homogeneous microstructure and superior mechanical properties, while electrical conductivity was maintained at a level higher than that achieved by the other methods.

The Cu-24Zn-6Al-4Mn-3Fe alloy is mainly used for the manufacture of sliding bushings in the agricultural sector due to its high mechanical properties in the cast state. Understanding how the casting thermal parameters affect the microstructure and impact the properties of alloys is fundamental to optimizing manufacturing processes and improving performance during their application. In this study, the Cu-24Zn-6Al-4Mn-3Fe alloy was unidirectionally solidified under non-steady heat flow conditions using a water-cooled graphite base for heat exchange. Seven points were monitored along the longitudinal region of this ingot, and the data to obtain the solidification variables were extracted using an acquisition system. The cooling rates varied from 4.50 °C/s to 0.22 °C/s from the closest to the furthest position from the heat extraction point. The microstructure was analyzed via optical microscopy, scanning electron microscopy and X-ray diffraction in order to characterize the phases and intermetallic elements present in the material. The mechanical properties were evaluated through hardness and microhardness tests throughout longitudinal extension of the solidified part. The results showed an increase in hardness and microhardness with a decrease in the cooling rate, which may be related to the increase in size and the κ phase fraction with a decrease in the cooling rate, as analyzed via optical microscopy and scanning electron microscopy. Furthermore, in all positions, there was no significant change in the amount of the α phase retained, with the matrix being mainly composed of the β phase and a small content of approximately 2% of the α phase.