Measurement of ionic concentration fluctuations due to 'live' process in a
micro-organism. The in-situ measurement of the change in the local extra-cellular
ionic content of the cells, as result of the biochemical activities initiated, due to
oxidative stress will lead to new insights towards cellular oxidative damage
coping mechanisms. For example, yeast cells, used as a model living organism,
can be immobilized on a gold electrode and ion dynamics in the EDL formed at
the metal-electrolyte interface can be probed by applying a small alternating
potential to the electrode.
"Nano-sieves" based on polyelectrolyte motion through tortuous path.
Separation of biological moieties is usually carried out on the basis of the size
and/or charge of the molecules e.g., column separations and gel electrophoresis.
However, separation techniques at single molecule level are still not fully
developed. Exploiting the sensitive measurement of the polyelectrolyte
accumulation at the metal electrode, after passing through a multi-layer film, we
can fabricate "nano-sieves" to detect analyte of interest based on the charge and
the chain conformation. The "sieve size" of the multi-layer film formed by self-
assembly of insulation nanoparticles can be tuned by varying the size and shape
of the nanoparticles.
Single electron effects on Nano-Electrodes. The quantized double layer charging
of gold nanoparticles immobilized on electrodes has been demonstrated in
literature. The optical signature of this phenomenon can be observed by our
differential interferometer provided the gold nanoparticles are sufficiently mono-dispersed in size. On immobilization of electro-active proteins to these
nanoparticles, the effect of single electron transfer to and from the protein can be
monitored by observing the ion charging at the electrodes.
'Direct Measurement of Ion Accumulation at Electrode Electrolyte interface
under Oscillatory Electric Field', Singh G., Saraf R.F., J PHYSICAL
CHEMISTRY B 110 (25): 12581-12587, 2006
'Optical Properties of an Immobilized DNA Monolayer from 255 to 700 nm',
Elhadj S., Singh G., Saraf F.F., LANGMUIR 20 (13): 5539-5543, 2004
'Solid-like Dynamics in Ultrathin Films of Polymeric Liquids', Singh G., Saraf
R.F., Martin Y., APPLIED PHYSICS LETTERS 83 (26): 5410-5412, 2003
'Mesoscale Thin Film Actuator for Promoting Fluid Motion in Microfluidic and
Nanofluidic Channels', Singh G., Sadler D., Zenhausern F., Saraf R.F., MRS
PROCEEDING, 741, 3-8, 2002
American Physical Society (APS), Materials Research Society (MRS)
Contact:
Department of Chemical &
Biomolecular Engineering 207 Othmer Hall
University of Nebraska-Lincoln
Lincoln, NE 68588-0643
Phone: (402) 472-2750
FAX: (402) 472-6989
E-mail: chembeng@unl.edu
