Fe3O4@Au nanoparticles-based magnetoplatform for the HMGA maize endogenous gene electrochemical genosensing

This work addresses a technological advance applied to the construction of a magnetogenoassay with electrochemical transduction for the maize taxon-specific (HMGA gene) detection using gold-coated magnetic nanoparticles as nanosized platform. Superparamagnetic core-shell Fe₃O₄@Au nanoparticles (10.4 ± 1.7 nm) were used to assemble the genoassay through the covalent immobilization of HMGA DNA probes onto carboxylated self-assembled monolayers at the nanoparticles surface. A hybridization reaction using sandwich format was selected to prevent inefficient hybridization connected with stable secondary DNA structures using also fluorescein isothiocyanate as DNA signaling tag. The labelling of the hybridization reaction with enzymes allowed the chronoamperometric measurement of the peroxidase activity linked to the nanoplatform located on gold surface. Using this electrochemical magnetogenoassay a linear concentration range from 0.5 to 5 nM and a LOD of 90 pM with a RSD <1.2% was calculated. Certified maize was evaluated without further purification after PCR amplification. This work highlights the efficacy of the electrochemical magnetogenoassay for the HMGA detection, showing its potential as alternative procedure for the verification of the compliance of the legislation.

Nucleic acid-based electrochemical biosensors

Colorectal cancer, breast cancer, oxidative DNA damage, and viral infections are all significant and major health threats to human health, presenting substantial challenges in early diagnosis. In this regard, a wide range of nucleic acid-based electrochemical platforms have been widely employed as point-of-care diagnostics in health care and biosensing technologies. This review focuses on biosensor design strategies, underlying principles involved in the development of advanced electrochemical genosensing devices, approaches for immobilizing DNA on electrode surfaces, as well as their utility in early disease diagnosis, with a particular emphasis on cancer, leukaemia, oxidative DNA damage, and viral pathogen detection. Notably, the role of biorecognition elements and nanointerfaces employed in the design and development of advanced electrochemical genosensors for recognizing biomarkers related to colorectal cancer, breast cancer, leukaemia, oxidative DNA damage, and viral pathogens has been extensively reviewed. Finally, challenges associated with the fabrication of nucleic acid-based biosensors to achieve high sensitivity, selectivity, a wide detection range, and a low detection limit have been addressed. We believe that this review will provide valuable information for scientists and bioengineers interested in gaining a deeper understanding of the fabrication and functionality of nucleic acid-based electrochemical biosensors for biomedical diagnostic applications.