1.
Nano-copper enhanced flexible device for simultaneous measurement of human respiratory and electro-cardiac activities.
Wang, L, Zhang, F, Lu, K, Abdulaziz, M, Li, C, Zhang, C, Chen, J, Li, Y
Journal of nanobiotechnology. 2020;(1):82
Abstract
BACKGROUND Dysfunction of human respiratory and electro-cardiac activities could affect the ability of the heart to pump blood and the lungs to inhale oxygen. Thus, a device could simultaneously measure electro-cardiac signal and respiratory pressure could provide vital signs for predicting early warning of cardio-pulmonary function-related chronic diseases such as cardiovascular disease, and respiratory system disease. RESULTS In this study, a flexible device integrated with piezo-resistive sensing element and voltage-sensing element was developed to simultaneously measure human respiration and electro-cardiac signal (including respiratory pressure, respiration frequency, and respiration rhythm; electro-cardio frequency, electro-cardio amplitude, and electro-cardio rhythm). When applied to the measurement of respiratory pressure, the piezo-resistive performance of the device was enhanced by nano-copper modification, which detection limitation of pressure can reduce to 100 Pa and the sensitivity of pressure can achieve to 0.053 ± 0.00079 kPa-1. In addition, the signal-to-noise ratio during bio-electrical measurement was increased to 10.7 ± 1.4, five times better than that of the non-modified device. CONCLUSION This paper presents a flexible device for the simultaneous detection of human respiration and cardiac electrical activity. To avoid interference between the two signals, the layout of the electrode and the strain sensor was optimized by FEA simulation analysis. To improve the piezo-resistive sensitivity and bio-electric capturing capability of the device, a feather-shaped nano-copper was modified onto the surface of carbon fiber. The operation simplicity, compact size, and portability of the device open up new possibilities for multi-parameter monitoring.
2.
A comprehensive study on the generation of reactive oxygen species in Cu-Aβ-catalyzed redox processes.
Huang, H, Lou, X, Hu, B, Zhou, Z, Chen, J, Tian, Y
Free radical biology & medicine. 2019;:125-131
Abstract
In the amyloid plaques, a signature of AD, abnormally high Cu2+ concentrations are found bound to Aβ. Most of previous studies reported that Cu-Aβ could contribute to oxidative stress, as H2O2 and •OH are catalytically generated by Cu-Aβ with the assistance of biological reductant, with only one recent report stated that free O2•- is also generated in the Cu-Aβ catalyzed processes, where an indirect technique was applied. To comprehensively investigate the free radicals produced during this Cu-Aβ-mediated process with a biological reductant, DNA-cleavage assay, an indirect method, and two direct methods including electron paramagnetic resonance (EPR) spectroscopy and transient absorption spectroscopy (TAS), both having qualitative and quantitative power, were employed in this work. All the experimental results obtained from the three methods demonstrated that Cu-Aβ in the biological reducing environment was not only able to catalyze the production of H2O2 and •OH, but also to generate free O2•-. The results further indicated that O2•- was the precursor of H2O2 and •OH. It is also important to note that the results obtained from EPR spectroscopy and TAS provided direct evidence for the presence of O2•- and •OH. By virtue of the direct techniques, we also found that the longest peptide fragments of Aβ16, Aβ40, and Aβ42 produced the least radicals with a lowest rate. More interestingly, the fibrillar forms of Aβ generated less O2•- and •OH compared with oligomeric and monomeric forms.