Abstract: Liquid gallium (Ga) spontaneously alloys with metal (e.g. Ag, Co, Pt) thin films at near or even below room temperature resulting in rapid self-assembly of nanostructures (e.g. Ag2Ga needles, CoGa3 rods, and Ga6Pt plates). The Ag2Ga needles orient nearly vertical to the interface which suggests that an individual needle can be directed to grow in a desired direction by drawing a silver- coated surface from the Ga droplet. Very flexible and rugged Ag2Ga nanoneedles of constant diameter (sub 100 nm diameter, 7-70 microns long) can be securely grown onto AFM tips at room temperature. These nanoneedles are electrically conductive and have stiffness well matched to viscoelastic properties of complex fluids and biological materials. We are in the process of using this technology as platform to enable a combined intracellular electrochemical plus viscoelastic cell-to- electronics interface for real-time biological sensing of the cell, biofilms and their microenvironment. This talk specifically presents progress towards such platform by demonstrating the abilities of the needles to (1) make precise AFM measurements of surface tension, contact angle, evaporation rate, and shear viscosity of polymeric liquids, (2) draw polymer nanofibers of controlled lengths and widths as a combined function of surface tension, viscosity and evaporation rate, (3) measure complex viscoelastic properties of cell membranes and organelles of blood and endothelial cells, (4) capture and be surrounded by single live endothelial cells within a few seconds, (5) polymerize and detect the growth of long fibrin nanofibers polymerizing on the end of a 100 nm diameter needle.
Biography: Mehdi M. Yazdanpanah is the CEO-Founder of NaugaNeedles LLC and Entrepreneurial Fellow of Kauffman foundation. He holds a PhD degree in electrical engineering from the University of Louisville (2006), where he studied room temperature self-assembly of metal alloy nanostructures. During his doctoral studies, Mehdi co-invented a procedure to selectively grow nanoneedles on AFM tips. This invention became the basis to establish NaugaNeedles in 2007. He also holds a BS degree in physics from Sharif University of Technology (1998) and MS degree in physics from Beheshti University (2001), where he designed and fabricated a scanning tunneling microscope (STM).
Mehdi is the author of more than twenty peer-reviewed journal and conference proceeding papers and the co-inventor of three pending US patents. He received the 2008 Vogt Innovation Award and was chosen as one of 13 entrepreneurial fellow of Kauffman Foundation in 2009. Under Mehdi's leadership, NaugaNeedles has achieved tremendous milestones including: wining SBIR and STTR from NSF and NIH and establishing the NaugaNeedles' manufacturing facility. NaugaNeedles has already sold its products to more than 75 customers worldwide, and expect to expand its customer base significantly in near future.