title: Rapid, sensitive, and label-free impedimetric detection of a single-nucleotide polymorphism correlated to kidney disease.
abstract: We present a protocol for the very rapid and sensitive detection of a specific mutation of the COL4A5 gene (exon 29, A-C mismatch) which was found in people affected by Alport syndrome (AS) and their families. Disposable electrochemically printed electrodes were used to immobilize a single-stranded oligonucleotide probe that was complementary to the AS-correlated gene. The detection principle is based on changes in the impedance spectra of the redox probe ferro/ferricyanide after hybridization with synthetic target DNA. Detection was performed either for mutated or for healthy (wild-type) gene copies. The high sensitivity obtained with this protocol (LOD in the picomolar range) was additionally enhanced to the femtomolar range by performing the detection in the presence of Ca(2+). In fact, the specific binding of the metal ions in the presence of an A-C nucleotide mismatch induced a further impedance change, thus improving the discrimination between the mutated and healthy gene, as the signal amplification is achieved only for the former.
authors.affiliation: International Center for Materials Nanoarchitectonics (MANA)/Biomaterials Center, National Institute for Material Science (NIMS), Ibaraki, Japan.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bonanni
authors.forename: Martin
authors.initials: M
authors.lastname: Pumera
authors.forename: Yuji
authors.initials: Y
authors.lastname: Miyahara
mesh_terms: D024141:Collagen Type IV / Q000235:genetics*; D006801:Humans; D007674:Kidney Diseases / Q000235:genetics*; D057230:Limit of Detection; D009394:Nephritis, Hereditary / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D013997:Time Factors
chemical_list: C478159:COL4A5 protein, human; D024141:Collagen Type IV