Eric Betzig: Imaging Life at High Spatiotemporal Resolution
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- čas přidán 14. 03. 2015
- In this lecture, held on 3/9/15 at UC Berkeley, Nobel Laureate Eric Betzig, describes three areas focused on addressing the challenges of high resolution imaging: super-resolution microscopy; plane illumination microscopy using non-diffracting beams; and adaptive optics to recover optimal images from within optically heterogeneous specimens.
I started to watch for a few minutes. Here I am, the video is over, and still needing more of his talks.
I really love it when brilliant scientists cuss. Not sure why but it just hits differently.
0:00 Intro by Berkeley physics chair
4:42 Talk begins - what is super resolution? Why fluorescence?
7:34 Eric’s interesting history - near-field, Bell labs
10:09 Two inspired experiments - Moerner 1989, cryo temp spectral signature of single molecule; Harald Hess, probe switch, resolve by color
13:10 Frustration with near-field, hiatus, an idea struck, back to the family business
20:40 Searching for meaning, the GFP light bulb, building the microscope; Optical lattice, photoactivated fluorescent protein, PALM - Nobel Prize, the 4th dimension is time; La Jolla Lab, Jennifer Lippincott-Schwartz, 200nm to 20nm,
Howard Hughes
31:13 PALM at HHMI, 2-color, spatial segregation of core promoter (Tjian), actin dendritic spine
33:21 Sick of PALM, labeling density, dead fixed cells, overexpression, 10,000x brighter than natural light phototoxic, Stefan Hell STED
36:44 Structured illumination (SIM), beat frequency, Moire fringes doubles diffraction-limited resolution, faster, much less intensity, spatial resolution (pixel, exposure) temporal resolution light intensity, Gustaffson, live imaging
40:02 Improve SIM scope objective high 1.7 numerical aperture + TIRF -> 80nm, endocytosis, no photoswitching -> multicolor
42:52 Nonlinear SIM, higher harmonics by saturating fluorescence/photoswitch -> 60nm, early endosome, EM validation
45:05 Sacrificing spatial resolution for 4th dimension time resolution, challenges of 3D imaging: time resolution must improve at the same rate as space (or image will smear), most microscopies are focused on 2D resolution (scans a flat surface; z is poor), unlike nature, also harder to compromise intensity for signal in 3D (1 extra dimension); in short, live much harder than fixed, 3D much harder than 2D
48:43 3D currently just blasting cells with wide field or death star with confocal, most important innovation in microscopy: plane illumination (cylindrical lens from the side, thin sheet of light coincident with plane in focus and illuminate whole plane at once, like a camera), no bleaching, quick imaging; problem: 4 um sized light sheet too big to study cell; solution: diffraction free/Bessel beam illuminates objective with a ring creates tiny little pens of light, like the supermarket checkout scanner, doesn’t diffract/diverge, plane by plane buildup (1000 planes or several volumes/sec)
Another problem: in cross-section looks like a bullseye with concentric rings, as you sweep the light along side lobes create out of focus excitation; solution: 2-photon microscopy to excite just the focus
52:56 Another solution: step light discretely instead of continuously, creates grating pattern, with structured illumination use side lobe to create patterned excitation, poke beyond diffraction limit in 3D
More problem: took too long to step the beam to create pattern; solution: fan the beam into 7 to fix speed but also makes it less damaging to cell, instantaneous intensity much more important than total dose of light: plane > line > point; confocal is a deathray
More “problem:” More split side lobes get too close and interfere,
but separation magic: at certain splits all side lobes destructively interfere
with each other and solves the problem itself; old theory sees light ->
lattice light sheet microscopy, faster, very noninvasive (protein turnover
faster than photobleaching)
57:09 Lattice sheet so thin that it’s thinner than detection objective -> only focus plane excited -> fantastic signal to noise in thick sectioning; gets rid of dye labeling problem with PALM: -> PAINT (Hochstrasser): molecules moving so fast but when they bind to sample then they fix and localizes to spots (good reserve of fluorophore for density but hard to work with high SNR) -> works well with lattice sheet to provide the labeling density
59:45 Lattice sheet with 4D imaging: light sensitive cell division, etc.
1:03:59 Even more problem: scrambled signal due to optical aberration from sample/equipment; solution: adaptive optics -> flat distorted wave front AO system bounce off mirror pick a bit from sensor that determines the deformation and the computer changes the shape of mirror to correct distortion to create a flat wave front; doesn’t gain resolution, recover resolution and signal lost from scattering; historical connection between microscopy and astronomy in that astronomy innovation comes first; in astronomy: light from distant galaxy not very bright (not enough signal to measure error) laser excites sodium atoms to create artificial star by fluorescence -> bright enough and close enough for correction; transparent organism like zebrafish it’s applicable: zebrafish big enough and enough variation in the refractive index across the organism so you have to create many corrections with AO (200um); lattice sheet with both excitation and detection AO and PALM/SIM; Mouse brain scatters like tofu (like observing star through the clouds), but can do AO correction (Na Ji)
1:13:05 Problem with academia: people get too wound up in titles and prizes and papers; it’s subjective; the things that matter is the accomplishment/application/insight; most people won’t be professors, but there are other ways to contribute; tech transfer to ubiquitous use difficult -> solution: set up a center for collaborations with biologists, document the build, work with microscope company (can buy lattice sheet); Betzig lab only 3-5 people
1:19:30 Q&A
Thanks for organizing
My PhD project was about this tec. Thanks Dr Betzig!
Thank you for uploading the video here. It's been a pleasure to watch it and learn from this great person, developer, leader and physicist. Don't know if he ever going to read this, but Sir, I want to thank you for your message to us, the young people, I'm a Genomic Biotechnologist and entrepreneur from Mexico, your words really help me to continue fighting impact my society.
Cheers from Mexico!
this is a major breakthrough for regular scientists.... can you imagine having 10000 biologists, cooridinating on understanding quantum cellular communication using this tool..
I am truly mesmerized. you are amazing Sir Betzig. Hope to meet you one day.
this guy inspires me.
Standing ovations !
Saved the URL to this. Have to show this to my oldest niece ("the molecular mechanisms of diseases")
This should have more views.
I love this speech! Very inspirational and exciting!! - recent Duke BME grad and Harvard Med Student
I FUCKING love the FUCKING swearing. lol. this is amazing work.
loving the language lmao
the talk is fucking amaizing