Mass Measurements of Individual Proteins using Nano-Electromechanical Systems

Selim Hanay, Roukes Group, California Institute of Technology (CALTECH), Pasadena, CA

Abstract: Several Nanoelectromechanical Systems (NEMS) offer a new paradigm for mass sensing. Especially exciting for biological applications is the ability to identify individual molecules landing on a NEMS detector, thus enabling a new kind of mass spectrometer that can directly measure the mass (instead of the mass-to-charge ratio) of the analytes. These detectors have a large dynamic range for mass measurements and are naturally integrable with microfluidics pre-processing system like on-chip liquid chromatography and on-chip electrospray ionization.

In this talk, I will describe our current experiment to measure the masses of individual protein molecules landing on a NEMS beam. The protein ions (66 kDa - 450 kDa) are created by electrospray ionization and transferred to the NEMS through an ion optical guide. The resulting changes in NEMS frequency are measured using phase-locked loop based detection. The natural resonance frequency of NEMS is 450 MHz and an Allan Deviation of 10-7 is attained, giving a mass noise floor of ~ 15 kDa. I will present our preliminary results and discuss the implications.

About the speaker: Mehmet Selim Hanay received the BS degree in Microelectronics Engineering from the Sabanci University, Istanbul, Turkey in 2003. He is currently working toward his PhD degree in Physics in the Nanoscale Systems Group of Prof. Michael L. Roukes at the California Institute of Technology (Caltech) in Pasadena, where his research interest is in mass detection of biomolecules using nano-scale mechanical resonators.

Selim Hanay was the recipient of a Gold Medal in the 31st International Chemistry Olympiad, Bangkok, Thailand in 1999. Later he received an honors scholarship both from the Sabanci University and the Turkish Scientific and Technological Research Council for his undergraduate studies at Sabanci University, between 1999-2003.