China
Africa
Explore chapters and articles related to this topic
MOF-based Electrochemical Sensors for Viruses/Bacteria
Published in Ram K. Gupta, Tahir Rasheed, Tuan Anh Nguyen, Muhammad Bilal, Metal-Organic Frameworks-Based Hybrid Materials for Environmental Sensing and Monitoring, 2022
Hessamaddin Sohrabi, Mir Reza Majidi, Ahad Mokhtarzadeh, Karim Asadpour-Zeynali
Zhang et al. [47] initiated an ultrasensitive switchable electrochemiluminescence (ECL) RNA sensing platform based on MOF and metal-organic gel (MOG) as nanotag and electrode matrix, respectively. In-situ loading of graphite-like carbon nitride (g-C3N4) and assembly of Au nanoparticles (AuNPs) within Zr based MOG (AuNPs&g-C3N4@Zr-MOG) has been used for the preparation of the second one, which represents greatly effective solid-state ECL (Figure 30.13). Fe-MIL-88 MOFs have metal active centers to consume co-reactant and can serve as an ECL acceptor in ECL resonance energy transfer system which initiates a double quenching effect on the ECL of AuNPs&g-C3N4@Zr-MOG. Subsequently, a DNA probe which is composed of an apyrimidinic/apurinic (AP) site was capable of connecting both, which leads to a turn-off signal. In the existence of the target RNA, since the AP site of the DNA probe has been triggered to be circularly cleaved by endonuclease IV, the ECL has been turned on. The ECL platform represented a wide detection range of 0.3 nM–3 μM using Zika virus (ZIKV) RNA as a model analyte, where the ultralow LOD was equal to 0.1 nM.
Using Laser-Driven Ion Sources to Study Fast Radiobiological Processes
Published in Paul R. Bolton, Katia Parodi, Jörg Schreiber, Applications of Laser-Driven Particle Acceleration, 2018
Naoya Shikazono, Kengo Moribayashi, Paul R. Bolton
Significant progress has been made in recent years demonstrating that not only DSB but non–DSB clustered DNA damage is correlated to the biological effectiveness of the radiation. The lack of a simple yet sensitive method to detect base lesions and AP sites that are spatially in close proximity has long impeded a detailed study of non–DSB clustered DNA damage induced by ionizing radiation. During the end of 1990s and the beginning of 2000s, the use of DNA glycosylases and AP endonucleases, whose major substrates are oxidized purines/pyrimidines and AP sites, respectively, was established and has significantly impacted the detection of clustered damage [Hada 2008, Shikazono 2009]. As DNA glycosylases and AP endonucleases recognize base lesions and AP sites to create a SSB at the site of the damage through their AP lyase/endonuclease activity, clustered DNA damage in which there is one or more base lesion or AP site on each strand can be detected as a DSB after enzymatic treatment. The technique, in principle, transforms non–DSB clustered damage into a DSB, using a DNA repair enzyme as the probe (Figure 10.2). In cells, the amount of non–DSB clustered damage revealed by the treatments of different repair enzymes is at least 3–4 times larger than that of DSB after exposure to low LET radiation [Gulston 2002, Sutherland 2000, Sutherland 2002]. However, the enzymatic assay revealed that non–DSB clustered damage displays intrinsic limitations; one of which is that the capacity of repair enzymes to cleave at a lesion within a cluster could be reduced such that the damaged cluster does not lead to DSBs. Another limitation of the enzymatic assay is that detectable clustered DNA damage has the configuration with individual lesions on two strands (bi-stranded lesions). In other words, tandem damage (Figure 10.1), which is a clustered DNA damage of which lesions are only on one strand, would not be detected distinctively. These limitations can greatly hamper the accurate estimation of the yield of clustered lesions. Recently, an alternative method based on fluorescent resonance energy transfer (FRET), which enables the detection of clustered DNA damage without the use of DNA repair enzymes, has been developed [Akamatsu 2013]. FRET is a mechanism in which a donor fluorophore, initially in its electronic excited state, transfers energy to an acceptor fluorophore through non-radiative dipole–dipole coupling [Lakowicz 2006]. A fluorophore is a chemical compound which re-emits light upon light excitation (fluorescence). Since FRET usually occurs between fluorophores that are less than 10 nm apart, the clustered fraction of AP sites labelled with fluorescent dyes could be measured. Extensive clustering of AP sites was found due to carbon ion irradiation (with an LET of 760 keV/μm) [Akamatsu 2015].
Genotoxicity of quinone: An insight on DNA adducts and its LC-MS-based detection
Published in Critical Reviews in Environmental Science and Technology, 2022
Yue Xiong, Han Yeong Kaw, Lizhong Zhu, Wei Wang
The hydrolysis of chemically modified DNA is fundamental for LC-MS detection, among which acid hydrolysis and enzymatic hydrolysis that based on different mechanisms are the widely used methods. Acid hydrolysis is a commonly known technique which can induce DNA depurination and the formation of AP site. Leung et al. revealed that heating the carcinogen-modified DNA samples at 70 °C in the presence of 0.05% HCl for an extended period of 4 to 6 h can induce DNA depurination, hence releasing modified nucleobases for LC-MS analysis (Leung et al., 2016). Tang et al. justified the good consistency of acid hydrolysis and enzymatic hydrolysis in releasing aristolochic acids-DNA adducts prior to instrumental analysis (Tang et al., 2019).