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The interaction of cytochrome c (Cyt c) with cardiolipin (CL) is believed to play an important role in the initial events of apoptosis. Herein, we investigate the structural changes of CL-bound Fe 2+ Cyt c and the correlation with Cyt c release through surface-enhanced Raman spectroscopy (SERS) on nickel substrates. The SERS results together with molecular dynamics simulation reveal that Fe 2+ Cyt c undergoes autoxidation and a relatively larger conformational alteration after binding with CL, inducing higher peroxidase activity of Cyt c and higher permeability of the CL membrane compared with those induced by the Fe 3+ Cyt c. The proapoptotic activity and SERS effect of the Ni nanostructures allow the in situ study of the redox-state-dependent Cyt c release from isolated mitochondria, which reveals for the first time that the ferrous state of Cyt c most likely plays a more important role in triggering apoptosis., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Intrinsic properties of nickel have enabled its wide applications as an effective catalyst. In this study, nickel nanowires (Ni NWs) as electron donors for oxidized cytochrome c (Cyt c) are investigated, which are NW diameter, temperature, and pH value-dependent. The reductive and magnetic properties facilitate the Ni NWs to rapidly and conveniently reduce Cyt c in complicated biological samples. Moreover, we find that the Ni NWs combined with resonance Raman spectroscopy have specificity toward Cyt c detection in real biological samples, which is successfully used to distinguish the redox state of the released Cyt c from isolated mitochondria in apoptotic Hela cells. Moreover, rapid label-free Cyt c quantification can be achieved by surface-enhanced Raman spectroscopy with a limit of detection of 1 nM and long concentration linear range (1 nM-1 μM). The proposed Ni NWs-based reduction approach will significantly simplify the traditional biological methods and has great potential in the application of Cyt c-related apoptotic studies.

The interaction of cytochrome c (Cyt c) with cardiolipin (CL) is believed to play an important role in the initial events of apoptosis. Herein, we investigate the structural changes of CL‐bound Fe2+Cyt c and the correlation with Cyt c release through surface‐enhanced Raman spectroscopy (SERS) on nickel substrates. The SERS results together with molecular dynamics simulation reveal that Fe2+Cyt c undergoes autoxidation and a relatively larger conformational alteration after binding with CL, inducing higher peroxidase activity of Cyt c and higher permeability of the CL membrane compared with those induced by the Fe3+Cyt c. The proapoptotic activity and SERS effect of the Ni nanostructures allow the in situ study of the redox‐state‐dependent Cyt c release from isolated mitochondria, which reveals for the first time that the ferrous state of Cyt c most likely plays a more important role in triggering apoptosis. [ABSTRACT FROM AUTHOR]

Abstract Facile fabrication of high-performance catalyst based on low-cost metals for sustainable hydrogen evolution is still a matter of cardinal significance. However, synthetic approaches for electrocatalyst are usually complicated and the yields are often low. Herein, we report a one-step simple method for the large-scale synthesis of Co/Ni-MoO 2 composite as efficient and stable hydrogen evolution reaction (HER) electrocatalyst to drive 10 mA cm−2 current density with a low overpotential of 103 mV in basic media. Co-MoO 2 and Ni-MoO 2 were also prepared using this method with overpotential of 137 and 130 mV, respectively, to gain the same current density. These results indicate that this facile synthesis approach is of great practical importance as it can be easily used for large-scale preparation of electrocatalysts in industry. Highlights • A facile one-step method for synthesis of Co/Ni-MoO 2 composite was developed. • Co/Ni-MoO 2 supplies two kinds of active sites including Co/Ni specie and MoO 2 specie. • The catalyst exhibits excellent catalytic performance for HER. [ABSTRACT FROM AUTHOR]