Label-Free, Fully Electronic Detection of DNA with a Field-Effect Transistor Array

Abstract

Massive parallel sequence analysis of nucleic acids and their use in genetics, medicine, and drug discovery has led to a broad interest in deoxyribonucleic acid (DNA) microarrays or DNA chips. For instance, nowadays many hundreds of diseases are diagnosable by the molecular analysis of DNA. Mainly the DNA hybridization reaction is used for the detection of unknown DNA, where the target (unknown single-stranded DNA; ssDNA) is identified, when it forms a double-stranded (dsDNA) helix structure with its complementary probe (known ssDNA). This biorecognition process is based on the affinity binding reaction between the base pairs, i.e., adenine-thymine (A-T) and cytosine-guanine (C-G). The hybridization reaction is known to be highly specific and is working in a sample solution with high background concentration of non-complementary probes. By labeling of either the target DNA or the probe DNA, the hybridization reaction can be detected by radiochemical, fluorescence, electrochemical, microgravimetric, enzymatic, and electroluminescence methods (Kricka 2002). However, the labeling approach is time consuming, cost intensive, and introduces