bhavik 1002
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IBTIBT--10021002
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Published in journal Nature Nanotecnology on 20th
december, 2009
Biomedical engineers had developed a me
thod
to makefuture genome sequencing faster and less expensive
A team led by Boston University Biomedical Engineering
Professor Dr. Amit Meller working for detecting DNA
molecules as they pass through silicon nanopores
It can detect much smaller amount of DNA sample than
previously reported" said Dr. Meller
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Nanotechnology is the creation ofFUNCTIONAL MATERIALS
and SYSTEMS through MANIPULATION of matter on the
NANOSCALE and exploitation of novel phenomena
IMPACT OF NANOTECHu
Computing and Data Storage
Materials and Manufacturing
Health and Medicine
Energy
Environmen
t
Transportation
National Security
Space exploration
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In traditional method DNA applification (PCR) stage is
used to make DNA larger enough to be sequenced
They like photocopies of photocopies
come outless than perfect
Very expensive,Time consuming and
Prone to errors
The new method devloped which requires very less
amount of DNA, Thus PCR step is removed
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AgCl
AgCl Voltage Amplifier
KClKCl
Nanopore
Chip
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Detecting DNA molecules as they pass
through silicon nanopores
Uses electrical fields to pass DNA through
pore.
Strands of DNA passing through four-nanometer-pores,
like threading a needle.
The longerthe DNA strand, the more
quickly it found the pore opening
Detection of long DNA strands --
Thousands basepairs, or even more can
be sequenced in single swipe
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High intensity electron beam of aTransmission Electron Microscope (TEM)
for the fabrication of uniform nanopore
arrays in Si-membranes
The chip uses layered electrodes tocontrol the movement of DNA molecules
called nanopore sequencing
Allows DNA to be passed through a
sensor that would rapidly read off itsgenetic code
It could read long DNA without the
Radio/ Fluorescent labels or
Amplifying enzymes
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The system that used to identify DNA bases is a tunnel-like
protein embedded in a membrane very similarto the flow of
ions across the membrane in biological cells
Current that can be measured using an electrode similarto
those used to study neurons in the lab
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When there is no DNA translocation,
there is a background ionic current
When DNA goes through the pore,
there is a drop in the background
signal
Correlation and changes ofthe
drops in the signal uses to distinguish
between individual nucleotides
DNA translocation event
Source: Viktor Stolc
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The researchers reduced the number of DNA molecules
required By a factor of10,000
From 1 billion sample molecules to 100,000
Less expensive
Faster
Accurate
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The rate ofthe movement ofthe DNA from nanopore, DNAtemplete floating around a nanopore
The DNA goes through the pore too fastDue to electric current
Meller and his team had optimize the effect by adding Salt
Gradients around the pores
They used salt gradients to alterthe electrical field around the
pores, which increased the rate of DNA captured and
Shortened the lag time between molecules, thus reducing the
quantity of DNA needed foraccurate measurements.
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oo NextNext--generation sequencing technology will offergeneration sequencing technology will offernovel, rapidnovel, rapid
ways forways for::--
Personal genomics with detailed analysis of individualPersonal genomics with detailed analysis of individual
genesgenes
MetagenomicsMetagenomics,,
Genome characterisation,Genome characterisation,
Profiling of mRNAs,Profiling of mRNAs,
Small RNAs,Small RNAs,
Transcription factor regions,Transcription factor regions,
Chromatin structures andChromatin structures and
DNADNA methylationmethylation patterns etc. . .patterns etc. . .
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