Optimization of Nanoparticle Assemblies for Amperometric Biosensing and Electrochemical Energy Storage

Timothy S. Fisher
Purdue University, Birck Nanotechnology Center and
School of Mechanical Engineering, West Lafayette, IN USA

Hybridization of nanoscale metals and carbon nanotubes into composite nanomaterials has shown promise in electrochemical biosensing—providing some of the most sensitive sensors to date [1-3].  The challenge remains to develop scalable nanofabrication protocols that are amenable to the development of sensors with broad sensing ranges. This talk considers the integration of these materials and will first introduce a heterogeneous nanostructure that contains vertical single-walled carbon nanotubes (SWCNTs) within an ordered nanoporous alumina template. The utility of this structure has been demonstrated recently in amperometric biosensing. These initial SWCNT/metal  nanoparticle  hybrid  sensors  provide  fascinating results—displaying  some  of  the  most  highly  sensitive glucose  sensing  to  date  [4];  however,  a  comprehensive  understanding  of  the  relationship  between  the nanofabrication/biofunctionalization protocols and biosensor performance is still lacking.  In an effort to elucidate the tradeoffs among kinetics, mass transport, and charge transport, the SWCNT/Pt nanosphere biosensors are computationally  modeled  in  an  enzymatic  biosensing  scenario.    The  results,  corroborated  experimentally, demonstrate how the Pt nanosphere density along the SWCNTs can dramatically alter the biosensor detection limit,  linear  sense  range,  and  sensitivity  [5].  The  talk  will  conclude  with  results  from  a  study  of  granular nanoparticle  assemblies  [6]  for  use  as  battery  electrodes.  The  results  indicate  that  columnar  ordering  of nanoplatelets  causes  a  catastrophic  loss  in  electrode  function,  and  a  mitigation  strategy  involving  the  dilute addition of inert nanoparticles is shown to frustrate this behavior.

Timothy  S.  Fisher  is  Professor  of  Mechanical  Engineering  at  Purdue  University.  He received Ph.D. and B.S. degrees in Mechanical Engineering from Cornell University in 1998 and 1991, respectively, and joined the Purdue’s School of Mechanical Engineering and Birck Nanotechnology Center in 2002 after several years at Vanderbilt University. In 2008 he was a Visiting Professor in the Chemistry and Physics of Materials Unit of the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR, Bangalore, India), and  he  now  holds  the  position  of  Adjunct  Professor  in  the  International  Centre  for Materials  Science  at  JNCASR  and  co-directs  the  JNCASR-Purdue  Joint  Networked Centre on Nanomaterials for Energy. From 2009 to 2011, he has served as a Research Scientist at the Air Force Research Laboratory’s newly formed Thermal Sciences and Materials Branch of the Materials and Manufacturing Directorate. Prior to his graduate studies,  he  was  employed  from  1991  to  1993  as  a  design  engineer  in  Motorola's Automotive  and  Industrial  Electronics  Group.  His  research  has  included  efforts  in simulation and measurement of nanoscale heat transfer, coupled electro-thermal effects in semiconductor and electron  emission  devices,  nanoscale  direct  energy  conversion,  molecular  electronics,  microfluidic  devices, hydrogen storage, and computational methods ranging from atomistic to continuum scales.