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Nano-biosensors: A Custom-built Diagnosis
Published in Paula V. Messina, Luciano A. Benedini, Damián Placente, Tomorrow’s Healthcare by Nano-sized Approaches, 2020
Paula V. Messina, Luciano A. Benedini, Damián Placente
DNA damage can also cause epigenetic changes (Simmons 2008). A new kind of epigenetic modification, which plays key roles in DNA demethylation, genomic reprogramming, and the gene expression in mammals, is the DNA hydroxymethylation (5-hmC). Shixing Chen et al. (Chen et al. 2016) developed a novel multiplexing electrochemical (MEC) biosensor for 5-hmC detection based on the glycosylation modification of 5-hmC and enzymatic signal amplification. The limit of detection of the MEC biosensor is 20 times lower than that of commercial kits based on optical measurement with high detection specificity. Epigenetic changes, particularly in cancer suppressor genes, are also to be utilized as novel biomarkers for cancer diagnostics and therapeutics. Therefore, tumour DNA-specific mutation and methylation are promising biomarkers for non-invasive cancer assessment. Recently, nanoplasmonics has emerged as a platform for one-step dual detection with high sensitivity and specificity of circulating tumour DNA (ctDNA) behaviour (Nguyen et al. 2015, Nguyen and Sim 2015). Finally, yet importantly, we will mention the determination of binding kinetics and affinity of DNA hybridization and single-base mismatches that plays an essential role in systems biology, personalized and precision medicine. The standard tools are optical-based sensors that are hard to translate to low cost and miniaturize platforms for high-throughput quantification. Xu et al. (2009) constructed an integrated, miniaturized, all-electrical multiplexed, graphene-based DNA array that can reliably and sensitively measure the time- and concentration-dependence of DNA hybridization kinetics and affinity. The authors claimed that the system exhibited a detection limit of 10 pM for DNA and that can distinguish single-base mutations quantitatively in real time suggesting a promising future for cost-effective, high-throughput screening of drug candidates, genetic variations and disease biomarkers.
Benzo[a]pyrene osteotoxicity and the regulatory roles of genetic and epigenetic factors: A review
Published in Critical Reviews in Environmental Science and Technology, 2022
Jiezhang Mo, Doris Wai-Ting Au, Jiahua Guo, Christoph Winkler, Richard Yuen-Chong Kong, Frauke Seemann
DNA methylation, closely associated with transcriptional silencing, presents at the 5′ position of the cytosine ring within CpG dinucleotides of DNA. It is catalyzed by DNA methyltransferases (DNMTs) that include DNMT1, DNMT3A and DNMT3B (Chen & Zhang, 2020). Passive demethylation occurs via the suppression of DNA methylation maintenance during DNA replication, while active DNA demethylation is achieved by a methylcytosine-to-hydroxymethylcytosine conversion and a follow-up base excision repair, catalyzed by the ten eleven translocation (TET) gene family members (Guo et al., 2011).