Dr Kevin Freedman

Research Interests: Nanopipettes, Nanopores, DNA sequencing, Protein Folding, FRET, Graphene Sensors

Project Topics

(1) Single Molecule Trapping and Sensing Using Nanopipettes, and (2) .

 The ability to sense and deliver single molecules using nanopipettes is an extremely powerful scientific tool.  Opposed to solid-state pores with a planar membrane, nanopipettes can be easily inserted into microfluidic channels or cells owing to their asymmetric geometry.  My project aims to integrate nanopipettes with optical systems for simultaneous optical and electrical measurement.  Towards this aim, as well as providing added functionality to the pipette, coatings and chemical modifications are being actively investigated for single molecule detection. 

Single Molecule FRET

Despite having single molecule sensing capability, nanopipettes having limited ability to sense small-scale structural changes within proteins.  In an effort to enhance the resolution of nanopipette sensing as well as obtain simultaneous electrical and optical signals to the same biophysical events, our protein analytes have been dual-labelled with fluorescent probes (i.e. donor and acceptor).  When the donor is excited by a fluorescent source, energy is transferred from the donor to the acceptor allowing the acceptor’s emission wavelength to be detected.  The extent of energy transfer (known as FRET) is a direct measure of the distance between the probes allowing for nanoscale fluctuations to be quantified.  Aside from nanopipettes, other nanostructures are also being fabricated to enhance FRET-sensing of DNA and proteins. 

Mini-Bio

• Postdoctoral Research Associate & Whitaker Fellow, Imperial College London, Department of Chemistry (Chemical Physics Section).  Supervisor: Dr. Joshua Edel.
• PhD in Chemical & Biological Engineering, Drexel University. Advisor: Prof. MinJun Kim.
• MSc in Chemical & Biological Engineering, Drexel University.  Advisor: Prof. MinJun Kim.
• MSc in Neuroengineering, Drexel University.  Advisor: Prof. Karen Moxon.
• BSc in Biomedical Engineering, Drexel University.

Selected Publications

1. K. Freedman, C.W. Ahn, M.J. Kim, "Detection of long and short DNA using nanopores with graphitic polyhedral edges," ACS Nano, 7(6), 5008-5016, 2013.
2. K. Freedman, S. R. Haq, J.B. Edel, P. Jemth, M.J. Kim, "Controlled unfolding and stretching of a protein domain inside a solid-state nanopore," Nature Scientific Reports, Vol. 3, 1638, 2013.
3. K. Freedman, A. Bastian, I. Chaiken, M.J. Kim, "Solid-state nanopore detection of antibody-antigen complexes: a HIV model study," Small, 9(5), 750-759, 2013.
4. K. Freedman, M. Jurgens, A. Prabhu, C.W. Ahn, P. Jemth, J. Edel, M.J. Kim, "Chemical, thermal, and electric field induced unfolding of single protein molecules studied using nanopores," Analytical Chemistry, Vol. 83, 5137-5144, 2011.

Selected Conference Proceedings:

Platform Speaker: American Chemical Society Spring Meeting (New Orleans, 2013), 56th Annual Biophysical Society Conference (San Diego, 2012), Nanopore Conference (Spain, 2012), Asia Nano Camp Meeting (S. Korea, 2011), IEEE SENSORS (Hawaii, 2010).