Daniel G. Cole Assistant Professor, Mechanical Engineering and Materials Science, BioEngineering


538-F Benedum Hall
Pittsburgh, PA



Keywords: Optical traps, magnetic traps, atomic force microscopy

    My research interests focus on three different instruments used in nanoscale science and engineering: atomic force microscopes (AFMs), optical traps, and magnetic traps.  For each instrument, the research focuses on the design of the instrument, applications, and  improvement of the instrument's performance using feedback control. 
   AFM research has focused on three sub-topics:  single-molecule force spectroscopy, cantilever calibration, and anodization lithography. For single-molecule experiments, the structural characteristics of biopolymers are determined by pulling on the molecules and monitoring force/deflection and bond failure rates.  Calibration techniques are being investigated that are consistent with nanoscale physics and that are useful and appropriate for use in water.  Research on AFMs for lithography uses anodization lithography to create silicon-oxide patterns that act as a resist in wet chemical etching.  These patterns are used for master molds in silicon for making micro-contact printing stamps.  

     Optical trap research is using traps for sensitive nanoscale measurements, and improves optical trap performance using feedback control.  This enables them to make highly sensitive measurements while controlling variables of interest for experimental protocols.  We have have demonstrated adaptive control of optical traps, and established analytical limits of performance for control  The adaptive efforts have focused on making optical traps more usable for biophysical measurements, including adaptive calibration. 
     Magnetic traps provide another technique for manipulating microscopic objects.  We have investigated how to automate the design of magnetic traps.  The research used adaptive control to account for changing instrument characteristics and to mitigate the effects of Brownian disturbances.  Current research is focused on using magnetic traps to measure the viscoelastic characteristics of cellular biopolymers.  For this, real time measurements of the stiffness and loss factor of the cytoskeleton in developing cells will be measured during various stages of development and under varying environmental conditions.