Antibacterial Fe-xCu biomedical alloys are designed to have a satisfactory biodegradation rate compared with pure iron. Fe-xCu (x ¼ 0, 1.5, 2.3, 7.8, and 10.1 wt%) alloys are produced by selective laser melting (SLM). Alloying with Cu has a significant influence on the grain size, hardness, biodegradation rate, and antibacterial performance of SLMed Fe-xCu alloys. Increasing Cu content decreases the grain size and increases the hardness. SLMed Fe-1.5Cu, Fe-2.3Cu, and Fe-10.1Cu have degradation rates similar to that of pure iron, while the degradation rate of SLMed Fe-7.8Cu is almost 2.5 times faster. The SLMed Fe-2.3Cu, Fe-7.8Cu, and Fe-10.1Cu produce strong antibacterial performance. The mechanisms of degradation behavior and antibacterial performance are clarified. SLMed Fe-7.8Cu had appropriate mechanical properties, satisfactory degradation rates, strong antibacterial performance, and good cytocompatibility, and therefore is a novel type of antibacterial biomedical alloy with good potential for clinical application.
This research produced a porous Fe-8 wt.% Cu alloy by microwave sintering in order to achieve (i) an increased biodegradation rate, and (ii) an antibacterial function. The Fe-8Cu alloy had higher density, hardness and degradation rate (about 2 times higher) but smaller and fewer surface pores, compared to the pure Fe. The Fe-8Cu alloy had a strong antibacterial function (the antibacterial rates against E. coli were up to 99.9%) and good biocompatibility. This work provides a novel approach of alloy design and processing to develop novel antibacterial Fe-based alloys.
The aging process of human beings is accompanied by the decline of learning and memory ability and progressive decline of brain function, which induces Alzheimer’s Disease (AD) in serious cases and seriously affects the quality of patient’s life. In recent years, more and more studies have found that natural plant antioxidants can help to improve the learning and memory impairment, reduce oxidative stress injury and aging lesions in tissues. This study aimed to investigate the effect of Monarda didymaL. essential oil and its main component thymol on learning and memory impairment in D-galactose-induced aging mice and its molecular mechanism. The composition of Monarda didymaL. essential oil was analyzed by Gas Chromatography-Mass Spectrometer (GC-MS). A mouse aging model was established by the subcutaneous injection of D-galactose in mice. The behavior changes of the mice were observed by feeding the model mice with essential oil, thymol and donepezil, and the histopathological changes of the hippocampus were observed by HE staining. And the changes of acetylcholinesterase (AchE), superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities, and the content of malondialdehyde (MDA) in hippocampal tissues were detected by corresponding kits. The expression of mitogen activated protein kinase (MAPK) and nuclear factor E2 related factor 2 (Nrf2) pathways related proteins were detected by western blot. Animal experimental results showed that compared with model group, the above indexes in Monarda didymaL. essential oil and thymol groups improved significantly in a dose-dependent manner. Monarda didymaL. essential oil and its main active component thymol can improve the learning and memory impairment of aging mice to some extent, and Nrf2 and MAPK pathways may be involved in its action process.
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