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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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