26, April 2011
What is Nano DNA Sequencing?
DNA strand is threaded through a nano-pore and its sequence is identified from fluctuations in ionic current. (9)
Trick is to figure out how to slow the strands movement through the opening so the base pairs A,T,C ,& G can be read. (1)
Example: graduate Brown student attached DNA strand to a bead using an electric field to drive the DNA to the pore. The DNA was too large for the pore, so, the bead was stuck in the hole with the attached DNA strand suspended on the other side of the membrane. Then they used magnets “magnetic tweezers” to draw the iron-oxide bead away from the pore. The bead moves towards the magnets, the DNA strand move through the pore- slowly enough so that the base pairs can be read. (1)
Fabricate devices with pores the scale of individual nucleotides (2)
To investigate a novel single molecule DNA sequencing nanotechnology protocol; gene sequencer, that has potential to sequence a molecule of genomic dimensions in hours without expensive and fault sensitive DNA copying steps and chemical reactions. The gene sequencer is based on the electrical characterization of individual nucleobases, while DNA passes through a nanopore with integrated nanotube side electrodes. (7)
“$1000 per genome” low cost sequencing for the entire human genome by 2014 (8)
Cost $3 billion to sequence 3 billion, now less than $100,000 per human genome, future $1000 Genome (6)
First convert the DNA to an expanded, digitized form by systematically substituting each and every base in the DNA sequence with a specific ordered pair of concatenated oligonucleotides. To detect the sequence, nanopores are then used to sequentially unzip the beacons. With each unzipping event a new fluorophore is un-quenched, giving rise to a series of photon flashes in two colors. The unzipping process slows down the translocation of the DNA through the pore in a voltage-dependent manner. allows parallel processing of millions
References: 1) http://www.foresight.org/nanodot/?p=3014 2) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2556950/ 3) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1965446/ 4) http://arxiv.org/pdf/cond-mat/0411317 5) http://www.nature.com/nnano/journal/v6/n3/full/nnano.2010.283.html 6) http://www.nature.com/nnano/journal/v5/n4/full/nnano.2010.72.html 7) http://nanodnasequencing.org/ 8) http://www.bu.edu/meller/research.html 9) http://www.ele.uri.edu/courses/ele482/S09/Matt_1.pdf Figure 3