Publication

DNA biosensor using fluorescence microscopy and impedance spectroscopy

Martinus Gijs, Daniel Berdat
2006
Journal Articles

Abstract

Two types of DNA biosensors are presented. Both sensing principles are demonstrated using synthetic oligomer single-stranded DNA (ssDNA) with concentrations in the micromolar range. A first sensor type is based on the detection of fluorescently labeled ssDNA to a complementary probe that is bound to a silicon substrate by a disuccinimidyl terephtalate and aminosilane immobilization procedure. An enhanced fluorescent response is obtained using constructive interference effects in a fused silica layer deposited before immobilization onto the silicon substrate. The selectivity of different DNA probes towards complementary and non-complementary DNA targets is tested. A second type of DNA sensor is based on the impedimetric response of a solution of unlabeled 20-mer ssDNA in de-ionized water. Interdigitated microelectrodes that are 5 μm wide and separated by 5 μm gaps are microfabricated on glass substrates and the complex impedance of the system in the 100 Hz–100 MHz frequency range is investigated. The proportionality between the measured solution resistance and ssDNA concentration is demonstrated.

Official source

https://infoscience.epfl.ch/entities/publication/9b71c78e-d66c-4121-b221-5cea6eebcc2c

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Martinus Gijs, Daniel Berdat
2006
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/9b71c78e-d66c-4121-b221-5cea6eebcc2c

About this result

Related concepts (32)

Hybridization probe

In molecular biology, a hybridization probe (HP) is a fragment of DNA or RNA of usually 15–10000 nucleotide long which can be radioactively or fluorescently labeled. HP can be used to detect the presence of nucleotide sequences in analyzed RNA or DNA that are complementary to the sequence in the probe. The labeled probe is first denatured (by heating or under alkaline conditions such as exposure to sodium hydroxide) into single stranded DNA (ssDNA) and then hybridized to the target ssDNA (Southern blotting) or RNA (northern blotting) immobilized on a membrane or in situ.

Complementary DNA

In genetics, complementary DNA (cDNA) is DNA synthesized from a single-stranded RNA (e.g., messenger RNA (mRNA) or microRNA (miRNA)) template in a reaction catalyzed by the enzyme reverse transcriptase. cDNA is often used to express a specific protein in a cell that does not normally express that protein (i.e., heterologous expression), or to sequence or quantify mRNA molecules using DNA based methods (qPCR, RNA-seq). cDNA that codes for a specific protein can be transferred to a recipient cell for expression, often bacterial or yeast expression systems.

DNA sequencing

DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. The advent of rapid DNA sequencing methods has greatly accelerated biological and medical research and discovery. Knowledge of DNA sequences has become indispensable for basic biological research, DNA Genographic Projects and in numerous applied fields such as medical diagnosis, biotechnology, forensic biology, virology and biological systematics.

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