Optical Trapping and Manipulation of a Single Human Virus
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PDF6.16.2016 OSA Webinar Handout.pdf
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This year marks the 30th anniversary of the invention of optical tweezers by Ashkin and co-workers. Although Ashkin and Dziedzic first demonstrated optical trapping of individual tobacco mosaic viruses in solution as early as 1987, this pioneering work has not been followed up only until recently. Using human immunodeficiency virus type 1 (HIV-1) as a model virus, Dr. Wei Cheng from the University of Michigan has recently demonstrated that a single HIV-1 virion can be stabled trapped, manipulated and measured in physiological media with high precision. Join the OSA Optical Trapping and Manipulation in Molecular and Cellular Biology Technical Group for this live webinar with Dr. Cheng as he presents the first demonstration for optical trapping of a single animal virus. 


The capability to optically trap a single virion in solution offers new research opportunities. First, by examining the stiffness of an optical trap as a function of the trapped virion size, we can determine the refractive index of a single virus with high precision, which offers a label-free parameter that may be useful for characterization of these particles in solution. To the best of our knowledge, this is also the first experimental measurement of the refractive index for a single virus particle. Second, using the simultaneous two-photon fluorescence excitation coincident with optical trapping, we show that optical trapping of a single virion allows one to quantitate the heterogeneity among individual particles with single-molecule resolution. We have used this technique to study individual HIV virions and the results bear implications on mechanisms of HIV-1 infection.  Lastly, the capability to physically capture a single virion in solution allows us to deliver individual virions to a single cell, which may be useful for the study of virion-cell interactions.


What You Will Learn/Seminar Objectives:

  • The webinar will focus on a very interesting emerging area of optical trapping and micromanipulation, namely the direct manipulation and characterisation of single viruses.
  • The webinar will provide an understanding of the type of insights gained from performing optical force measurements on single trapped viruses and also how these measurements can be combined with complementary microscopy techniques to probe cell-virus interactions.


Who Should Attend:

  • The webinar will be of interest to individuals and researchers working in the field of optical trapping 
  • The webinar will also be of interest to researchers in affiliated areas working in optical microscopy and biosensing.



  • This talk will be pitched at a graduate level audience and the technical content will be at a level one would normally expect from an invited talk at an OSA biomedical optics conference.
Seminar Information
Seminar Date:
June 16, 2016