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SUMMARY:Microtechnologies for biomolecular complex analysis and cryo-micro
 scopy - Dr Thomas Burg\, Max Planck Institute for Biophysical Chemistry
DTSTART:20151118T150000Z
DTEND:20151118T160000Z
UID:TALK62234@talks.cam.ac.uk
CONTACT:Jerome Charmet
DESCRIPTION:Micro- and nanofluidic technologies provide exciting opportuni
 ties to study the structure and function of biological systems at the leve
 l of cells\, organelles\, and molecular machines.\n\nIn the first part of 
 this seminar\, I will describe the use of micromechanical resonators with 
 embedded fluidic channels of only 10 pL volume for the label-free\, mass-b
 ased measurement of protein aggregation kinetics. The sensitivity of the m
 ethod is greatly enhanced by a fluctuation analysis termed mass correlatio
 n spectroscopy (MCS). This technique has been used to monitor the formatio
 n of insulin amyloids from monomers to mature fibrils. While\, during MCS 
 measurements\, molecules are dispersed free in solution\, embedded channel
  resonators also can be used in a surface-based mode analogous to the quar
 tz crystal microbalance (QCM) and surface plasmon resonance (SPR). In this
  mode\, the devices are advantageous due to their low sample consumption\,
  wide dynamic range\, and reaction limited kinetic measurements. The benef
 its and limitations of nanomechanical mass measurements and other nanoflui
 dic techniques for the analysis of large biomolecular complexes will be di
 scussed.\n\nIn the second part of the talk\, I will focus on work of our g
 roup towards imaging dynamic cellular events by correlative microscopy usi
 ng microfluidic cryofixation. Recent years have seen enormous progress in 
 cellular imaging by fluorescence\, electron\, and X-ray microscopy\, but m
 any of these advanced imaging technologies cannot be readily combined. In 
 particular\, the correlation between live-cell imaging and electron micros
 copy (EM) remains challenging due to a lack of adequate fixation technolog
 y. Cryofixation is widely regarded as the gold standard in stabilizing bio
 logical samples for ultramicroscopy. Unfortunately\, all current methods o
 f cryofixation require samples to be removed from the light-microscope bef
 ore freezing. This transfer often results in a loss of spatial registratio
 n and strongly limits temporal resolution. We recently introduced and vali
 dated a new concept for the cryofixation of cells directly in the light mi
 croscope and with millisecond time resolution. Formation of crystalline ic
 e is suppressed by the high cooling rate (~10^4 K/s)\, which is enabled by
  placing the sample in a microfluidic channel embedded inside a thin polym
 er foil of low thermal mass. We expect that\, in the future\, this new con
 cept can help to bridge the gap between live-cell imaging and cryofixation
  for a wide class of applications in cell biology and other fields. In par
 ticular\, the method should enable precise temporal correlation of live-ce
 ll imaging and cell stimulation with post-fixation ultrastructural studies
  by means of optical nanoscopy\, electron microscopy\, or X-ray tomography
 .\n
LOCATION:Department of Chemistry\, Cambridge\, Wolfson Lecture Theatre
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