Selective and Sensitive Detection of Intracellular O₂^•– Using Au NPs/Cytochrome c as SERS Nanosensors

Abstract

A novel surface-enhanced Raman scattering (SERS) nanosensor was developed by modifying oxidized cytochrome c (Cyt c) on gold nanoparticles (Au NPs) for the sensitive and selective determination of intracellular superoxide anion radical (O2(•-)). On the basis of the differences in the SERS spectra between the oxidized and reduced form of Cyt c, this nanosensor could be employed to investigate O2(•-) concentration by measuring the SERS spectra of the reduced Cyt c. Using this SERS nanosensor, a detection limit of 1.0 × 10(-8) M for O2(•-) could be attained. Additionally, the selectivity of the SERS nanosensor for O2(•-) was examined, showing that other reactive oxygen species (ROS) and biologically relevant species did not influence the detection of O2(•-). More importantly, the nanosensor could be delivered to the living HeLa and normal human liver cells and permitted the concentration of O2(•-) to be monitored in real time and in a noninvasive manner, which indicates that this nanosensor will be suitable for the qualitative and quantitative analysis of O2(•-) in biosystems, thus leading to a greater understanding of oxidative-stress-related diseases at a cellular level.

Highly selective and sensitive surface enhanced Raman scattering nanosensors for detection of hydrogen peroxide in living cells

“…Redox potential SERS nanosensors have been developed by decorating a noble-metal nanoshell with redox-responsive small molecules (Auchinvole et al, 2012;Thomson et al, 2015). Also, we have fabricated a novel SERS nanosensor by functionalizing gold nanoparticles with oxidized cytochrome c for the selective and sensitive monitoring of intracellular superoxide anion radical (Qu et al, 2013). However, to the best of our knowledge, SERS nanosensors for selective and sensitive detection of the H 2 O 2 have not yet been reported.…”

Probing cytochrome c in living mitochondria with surface-enhanced Raman spectroscopy

“…Both reduced and oxidized cytochromes possess intensive SERS spectra and can be distinguished from one another. Previously this cytochrome feature was used for the development of O 2 -sensitive SERS-probe based on gold nanoparticles with the attached cytochrome c 25 . However, to the best of our knowledge, SERS has never been used to monitor redox states and conformation of cytochromes in their natural environment—in ETC of living mitochondria.…”

Bovine serum albumin template synthesis of fluorescent gold nanoclusters for nitric oxide detection in vitro

“…The formation of Au NCs in BSA solution might be owing to the combination between Au and functional groups in BSA, containing several cysteine residues, which could stabilise Au NCs by coordination action and tyrosinase, which could reduce Au (III) or Au (I) ions. 22,23 Selectivity and sensitivity of BSA-Au NCs to NO To verify the specificity of BSA-Au NCs for NO detection in vitro, the relationship between (I 0 2I)/I 0 and different types of reactive oxygen and nitrogen species was analysed, 24 where I 0 and I were PL intensities of BSA-Au NCs solutions before and after the addition of NO or reactive species (Fig. 3c).The addition of NO resulted in the decrease in PL intensity greatly, while other reactive species such as NaNO 2 , NaNO 3 , H 2 O 2 , NaClO and their mixture did not change corresponding PL intensities obviously.…”