Reduced Concentration Limit of Nucleic Acid Biosensor by Utilizing Long DNA

Abstract

We previously described a simple, PCR-free, low cost device for sequence-specific nucleic acid detection which coupled target nucleic acids to a bead and measured the blockade of a large pore by the bead, achieving a 10 pM concentration detection limit of 20-mer DNA oligomers. Here, we describe function of our device for detection of longer DNA fragments. We prepared four different DNA fragments containing a specific target sequence 110, 235, 419, and 1613 nucleotides in length, and four different control fragments not containing the target sequence 125, 184, 309, and 1503 nucleotides in length. We examined detection of the target DNA oligomers at concentrations of 1pM - 1fM, finding that as target DNA length increased, lower concentrations were detectable, with a 10 fM detection limit for the 419 and 1613 nucleotide DNA oligomers.L. Esfandiari et al., J. Am. Chem. Soc., vol. 134, no. 38, pp. 15880-15886, 2012.