Professor and Chair

PhD Princeton University (1989)

Research Group

Biological Physics

Research Interest

Biological physics with emphasis on gene regulatory networks, bacterial signaling, communication, and information processing.

Selected Publications

Entropy-driven motility of Sinorhizobium meliloti on a semi-solid surface, G. Dilanji, M. Teplitski, and S.J. Hagen, Proceedings of the Royal Society B-Biological Sciences, 281 (1784), 20132575 (2014). [PMID: 24741008]

Quorum activation at a distance: spatiotemporal patterns of gene regulation from diffusion of an autoinducer signal, G.E. Dilanji, J.B. Langebrake, P. De Leenheer, and S.J. Hagen, Journal of the American Chemical Society 134 (12), 5618 (2012). [PMID: 22372494]

Microfluidic study of competence regulation in Streptococcus mutans: environmental inputs modulate bimodal and unimodal expression of com, M. Son, S.J. Ahn, Q. Guo, R.A. Burne, and S.J. Hagen, Molecular Microbiology 86 (2), 258 (2012). [PMID: 22845615]

Heterogeneous response to a quorum-sensing signal in the luminescence of individual Vibrio fischeri, P. Delfino Perez and S.J. Hagen, PLoS One 5 (11), e15473 (2010). [PMID: 21103327]

Solvent viscosity and friction in protein folding dynamics, S.J. Hagen, Current Protein and Peptide Science 11 (5), 385 (2010). [PMID: 20426733]

Do protein molecules unfold in a simple shear flow, J. Jaspe and S.J. Hagen, Biophysical Journal 91 (9), 3415 (2006). [PMID: 16891374]

Trp zipper folding kinetics by molecular dynamics and temperature-jump spectroscopy, C.D. Snow, L.L. Qiu, D.G. Du, F. Gai, S.J. Hagen, and V.S. Pande, Proceedings of the National Academy of Sciences of the USA, 101 (12), 4077 (2004). [PMID: 15020773 ]

Internal friction controls the speed of protein folding from a compact configuration, S.A. Pabit, H. Roder, and S.J. Hagen, Biochemistry 43 (39), 12532 (2004). [PMID: 15449942]

Fast chain contraction during protein folding: foldability and collapse dynamics, L.L. Qiu, C. Zachariah, and S.J. Hagen, Physical Review Letters 90 (16), 168103 (2003). [PMID: 12732017]

Smaller and faster: The 20-residue Trp-cage protein folds in 4 microseconds, L.L. Qiu, S.A. Pabit, A.E. Roitberg, and S.J. Hagen, Journal of the American Chemical Society, 124 (44), 12952 (2002). [PMID: 12405814]

Laminar-flow fluid mixer for fast fluorescence kinetics studies, S.A. Pabit and S.J. Hagen, Biophysical Journal 83 (5), 2872 (2002). [PMID: 12414719]