Department of Chemistry Biochemistry


Associate Professor
Ph.D., Ecole Polytechnique Federal de Lausanne, 2000

  Office: PSD-119  Lab: D18, D20
  Phone: (480)965-5323  
  Fax: (480) 965-2747

 Dr. ALEXANDRA ROS's Lab or Group Website

Research and Teaching Interests

The research in my group focuses on the chemical and physical basis of migration mechanisms for biopolymers and colloids as model systems. Tailored micro- and nanofluidic devices are developed wherein migration processes of biomolecules (e.g. DNA, proteins) are studied by optical single molecule as well as ensemble techniques. A second focus lies on the development of micro- and nanofluidic devices as platforms for novel single cell analysis tools. The ultimate goal consists in elucidating novel bioanalytical and biotechnological tools as well as efficient lab-on-a-chip systems for proteom research and systems nanobiology.

Migration mechanisms of biomolecules are studied via fluorescence video microscopy with subsequent particle tracking and on-chip separation experiments. A major interest lies in the dielectrophoretic behaviour of biomolecules which can be advantageously used in separation experiments. A very important part of our work is dedicated to adequate surface design, providing not only for the control of electrokinetic properties in the micro-and nanodevices but also as an additional design tool for novel migration mechanisms. Soft lithography serves as a primary fabrication method for tailored microdevices, whereas other appropriate micro- and nanofabrication methods find application for specific structuring problems. Our single cell studies focus on biologically relevant questions in organisms such as insect cells and bacteria. Single cell manipulation is developed for reproducible and parallel cell positioning. Our work also includes the integration of ultra sensitive detection methods in the microfluidic chip such as laser induced fluorescence as well as off-chip coupling to sensitive state of the art detection methods.

Selected Publications

"Combined single cell AFM manipulation and TIRFM for probing the molecular stability of multilayer fibrinogen matrices," W. Christenson, I. Yermolenko, B. Plochberger, F. Camacho-Alanis, A. Ros, T.P. Ugarova, R. Ros, Ultramicroscopy 136 211-215 (2014)

"Selective trapping of single mammalian breast cancer cells by insulator-based dielectrophoresis," S. Bhattacharya, T.-C. Chao, N. Ariyasinghe, Y. Ruiz, D. Lake, R. Ros, A. Ros, Analytical and Bioanalytical Chemistry 406 1855–1865 (2014)

"Insulator-based dielectrophoresis of mitochondria," J. Luo, B. G. Abdallah, G. G. Wolken, E. A. Arriaga, A. Ros, Biomicrofluidics 8 021801 (2014)

"Temporal and Spatial Temperature Measurement in Insulator-based Dielectrophoretic Devices," A. Nakano, J. Luo, A. Ros, Analytical Chemistry 86 6516−6524 (2014)

"Dielectrophoresis of DNA using 3D Carbon Electrodes," R. Martinez-Duarte, F. Camacho-Alanis, P. Renaud, A. Ros, Electrophoresis 34 1113-1122 (2013)

"Protein identification and quantification for single cell analysis by coupling a microfluidic platform with MALDI-TOF," M. Yang, T.-C. Chao, R. Nelson, A. Ros, 17th µTAS Proceedings 1039-1041 (2013)

"Mighty small: Observing and Modeling Individual Microbes Becomes Big Science," J.-U. Kreft, C. M. Plugge, V. Grimm, C. Prats, J. H. J. Leveau, T. Banitz, S. Baines, J. Clark, A. Ros, I. Klapper, C. J. Topping, A. J. Field, A. Schuler, E. Litchman, F. L. Hellweger, PNAS 110 18027–18028 (2013)

"Six Helix Bundle and Triangle DNA Origami Insulator- Based Dielectrophoresis," L. Gan, T.-C. Chao, F. Camacho-Alanis, A. Ros, Analytical Chemistry 85 11427-11434 (2013)

"Dielectrophoretic Sorting of Membrane Protein Nanocrystals," B.G. Abdallah, T.-C. Chao, C. Kupitz, P. Fromme, A. Ros, ACS Nano 7 10534–10543 (2013)

"Crystallization of the Large Membrane Protein Complex Photosystem I in a Microfluidic Channel," B. G. Abdallah, C. Kupitz, P. Fromme, A. Ros, ACS Nano 7 9129-9137 (2013)

"Direct Detection of Peptides and Proteins on a Microfluidic Platform with MALDI Mass Spectrometry," M. Yang, T.-C. Chao R. Nelson, A. Ros, Analytical and Bioanalytical Chemistry 404 1681–1689 (2012)

"Dielectrophoretic Focusing for Femtosecond Nanocrystallography of Membrane Proteins," B. Abdallah, T. C. Chao, P. Fromme, A. Ros, 16th µTAS Proceedings 458-460 (2012)

"Tuning Streaming Dielectrophoresis of Proteins," A. Nakano, F. Camacho-Alanis, T.-C. Chao, A. Ros, Biomicrofluidics 6 034108 (2012)

"Microscopic Linear Liquid Streams in Vacuum: Injection of Solvated Biological Samples into X-Ray Free Electron Lasers," R. B. Doak, D. P. De Ponte, G. Nelson, F. Camacho-Alanis, A. Ros, J .C. H. Spence, U. Weierstall, AIP Conf. Proc. 1501 1314-1323 (2012)

"Microfluidic Gel Electrophoresis in the Undergraduate Laboratory Applied to Food Analysis," T.-C. Chao, S. Bhattacharya, A. Ros, Journal of Chemical Education 89 125-129 (2012)

"Transitioning Streaming to Trapping in DC Insulator-based Dielectrophoresis for Biomolecules," F. Camacho-Alanis, L. Gan, A. Ros, Sensors and Actuators B 173 668-675 (2012)

"Immunoglobulin G and Bovine Serum Albumin Streaming Dielectrophoresis in a Microfluidic Device," A. Nakano F. Camacho-Alanis T.-C. Chao A. Ros , Electrophoresis 32 2314-2322 (2011)

"Insulator-Based Dielectrophoretic Single Particle and Single Cancer Cell Trapping," S. Bhattacharya T.-C. Chao A. Ros, Electrophoresis 32 2550-2558 (2011)

"Dielectrophoretic Trapping and Polarizability of DNA: The Role of Spatial Conformation," J. Regtmeier R. Eichhorn L. Bogunovic A. Ros D. Anselmetti, Analytical Chemistry 82 7141-7149 (2010)

"Microfluidic Single Cell Analysis of Intracellular Compounds," T.-C. Chao, A. Ros, J. Royal Society Interface 5 S139-S150 (2008)

"Dielectrophoretic manipulation of DNA: Separation and polarizability," J. Regtmeier, T. T. Duong, R. Eichhorn, D. Anselmetti, A. Ros, Analytical Chemistry 79 3925-3932 (2007)

"Bioanalysis in Structured Microfluidic Systems," A. Ros, W. Hellmich, J. Regtmeier, T. T. Duong, D. Anselmetti, Electrophoresis 27 2651-2658 (2006)

"Paradoxical Brownian Motion: Absolute Negative Particle Mobility," A. Ros, R. Eichhorn, J. Regtmeier, T. Duong, P. Reimann, D. Anselmetti, Nature 436 928 (2005)

"Single Cell Manipulation, Analytics and Label-free Protein Detection in Microfluidic Devices for NanoSystems Biology," W. Hellmich, C. Pelargus, K. Leffhalm, A. Ros, D. Anselmetti, Electrophoresis 26 3689-3696 (2005)

"Poly(oxyethylene) Based Surface Coatings for Poly(dimethylsiloxane) Microchannels," W. Hellmich, J. Regtmeier, T. Duong, R. Ros, D. Anselmetti, A. Ros, Langmuir 21 7551-7557 (2005)