[BNC-all] Nano Seminar: Dr. Samir Iqbal, Purdue, Thurs., 2/22/07, @ 10:30 AM, BRK 1001 (On the Cross Roads of Biology and Nanotechnology ­ Selective DNA Nanopore Sensors

[Deborah Starewich]

Late announced seminar . . . Didn't make the Monday memo so I am sending an
additional e-mail

³On the Cross Roads of Biology and Nanotechnology ­ Selective DNA
Nanopore Sensors²


Thursday, February 22, 2007
Birck Nanotechnology Building, Room 1001
10:30 AM


Dr. Samir Iqbal
Purdue University


The ability to manipulate and identify the properties of single
biological molecules with the potential of characterizing biological
processes at the most fundamental levels can significantly facilitate
rapid diagnostics and therapeutics.  Fabrication of solid-state
devices investigating bacteria, viruses, proteins and even at such
smaller sizes as of DNA can create a large arsenal of highly specific
and ultra-sensitive biosensors and systems.  From a long list of nano-
scale solid- state biological sensors pursued in our lab, two
important silicon based electrical frameworks will be discussed.
These novel systems have been used to characterize DNA molecules.
First, a method employing metal nano-electrodes with nanometer scale
spacing will be presented.  These nano-electrodes were used to
measure the effects of the GC-content of the DNA on its DC
conductivity.  A dramatic decrease in conductance was seen on heating
the DNA devices, analogous to an electrical fuse, attributable to
complete or partial denaturing of the ds-DNA molecules that bridged
the nanogaps.  These findings have applications in non-optical
detection of extremely low concentrations, biophysical studies of
charge transport, and control of DNA-modified materials.  Second,
solid-state nanopores, progenitors of rapid and cheap next-generation
DNA sequencing ³machines², selective to important DNA sequences will
be described.  To date, this work is the first evidence of
engineering selectivity in solid-state nanopores.  Distinctly
different translocation signatures and event frequencies were
discovered for important DNA targets.

The selective solid-state nanopores realized in an array format can
open avenues to novel devices for sequencing, detection of single
nucleotide polymorphism, expression analysis, etc. as well as
detection of specific proteins using specific ligand-receptor systems
from very few copies of the analytes. Such selectivity can be
electrically measured and can be used for direct label-free
sequencing and detection of nucleic acids.  These devices can
potentially mimic the exquisite selectivity found in natural
biological channels in cell or nuclear membranes, and help unravel
the physics of selective and facilitated transport of bio-molecules
in nanoscale channels.

Dr. Samir Iqbal is working in the Laboratory of Integrated Bio-Nano
Applications (LIBNA) in Birck Nanotechnology Center.  He received his
undergraduate degree in Electrical Engineering from NED University of
Engineering and Technology, Karachi, Pakistan.  He worked in various
technical and management positions in academia, military, industry
and nonprofits for five years before joining the School of Electrical
and Computer Engineering at Purdue University in direct Ph.D.
program.  In graduate school, he received a number of awards and
distinctions, most notably the Magoon Award for Excellence in
Teaching from the College of Engineering and an NSF fellowship to
attend summer school at Northwestern University, Illinois, USA.  He
received his doctoral degree under the supervision of Professor
Rashid Bashir in February 2007.

SPONSORED BY:
Birck Nanotechnology Center, Bindley Bioscience Center, Discovery
Park, The NASA Institute for Nanoelectronics and Computing, The
Network for Computational Nanotechnology, VEECO, NCN Student
Leadership Council, Department of Chemistry, Department of Physics,
School of Chemical Engineering, School of Electrical and Computer
Engineering, School of Mechanical Engineering

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