title: Improving impedimetric nucleic acid detection by using enzyme-decorated liposomes and nanostructured screen-printed electrodes.
abstract: Sensitive impedimetric detection of miR-222, a miRNA sequence found in many lung tumors, was investigated by using gold-nanostructured disposable carbon electrodes and enzyme-decorated liposomes. The proposed method was based on the immobilization of thiolated DNA capture probes onto gold-nanostructured carbon surfaces. Afterwards, the capture probes were allowed to hybridize to the target miRNAs. Finally, enzyme-decorated liposomes were used as labels to amplify the miRNA sensing, by their association with the probe-miRNA hybrids generated on the nanostructured transducer. By using this amplification route a limit of detection of 0.400 pM, a limit of quantification of 1.70 pM, and an assay range spanning three orders of magnitude (1.70-900 pM) were obtained (RSD % = 13). This limit of quantification was 20 times lower than that obtained using a simple enzyme conjugate for the detection. A comparison was also made with gold screen-printed transducers. In this case, a limit of quantification approximately 70 times lower was found by using the nanostructured transducers. Application of the optimized assay in serum samples was also demonstrated. Graphical abstract Alkaline Phosphatase-decorated liposomes and Au nanostructured screen-printed electrodes have been used for the impedimetric detection of miRNAs, via the bio-catalyzed precipitation of an insulating product onto the electrode surface.
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Via della Lastruccia 3, Sesto Fiorentino, 50019, Firenze, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Voccia
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Via della Lastruccia 3, Sesto Fiorentino, 50019, Firenze, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bettazzi
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Via della Lastruccia 3, Sesto Fiorentino, 50019, Firenze, Italy.|CSGI, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019, Firenze, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Fratini
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Via della Lastruccia 3, Sesto Fiorentino, 50019, Firenze, Italy.|CSGI, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019, Firenze, Italy.
authors.forename: Debora
authors.initials: D
authors.lastname: Berti
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Via della Lastruccia 3, Sesto Fiorentino, 50019, Firenze, Italy. ilaria.palchetti@unifi.it.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Palchetti
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D015342:DNA Probes / Q000737:chemistry; D058266:Dielectric Spectroscopy / Q000379:methods*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D061925:Immobilized Nucleic Acids / Q000737:chemistry; D057230:Limit of Detection; D008081:Liposomes / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D035683:MicroRNAs / Q000032:analysis / Q000097:blood*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D009693:Nucleic Acid Hybridization / Q000379:methods
chemical_list: D000469:Alkaline Phosphatase; D015342:DNA Probes; D004800:Enzymes, Immobilized; D006046:Gold; D061925:Immobilized Nucleic Acids; D008081:Liposomes; D035683:MicroRNAs; C525710:MIR222, human
keywords: Alkaline phosphatase; Electrochemical impedance spectroscopy; Gold nanoparticles; Liposome; Screen-printed electrodes