Detection of PCR-Amplified Tuberculosis DNA Fragments with Polyelectrolyte-Modified Field-Effect Sensors

作者：Bronder Thomas S; Jessing Max P; Poghossian Arshak; Keusgen Michael; Schoening Michael J

来源：Analytical Chemistry, 2018, 90(12): 7747-7753.

DOI：10.1021/acs.analchem.8b01807

Field-effect-based electrolyte-insulator-semiconductor (EIS) sensors were modified with a bilayer of positively charged weak polyelectrolyte (poly(allylamine hydrochloride) (PAH)) and probe single-stranded DNA (ssDNA) and are used for the detection of complementary single-stranded target DNA (cDNA) in different test solutions. The sensing mechanism is based on the detection of the intrinsic molecular charge of target cDNA molecules after the hybridization event between cDNA and immobilized probe ssDNA. The test solutions contain synthetic cDNA oligonucleotides (with a sequence of tuberculosis mycobacteria genome) or PCR-amplified DNA (which origins from a template DNA strand that has been extracted from Mycobacterium avium paratuberculosis-spiked human sputum samples), respectively. Sensor responses up to 41 mV have been measured for the test solutions with DNA, while only small signals of similar to 5 mV were detected for solutions without DNA. The lower detection limit of the EIS sensors was similar to 0.3 nM, and the sensitivity was similar to 7.2 mV/decade. Fluorescence experiments using SybrGreen I fluorescence dye support the electrochemical results.

• 出版日期2018-6-19