Carmichael’s Concise Review


remainder partially wrapped. A majority of cells were wrapped in as many as 7 layers of PFG. Tests confirmed that cells that were alive when they were wrapped. Wrapped and unwrapped cells were immobilized on silicon nitride windows and examined in the TEM for up to 20 minutes. TEM micrographs of the wrapped cells clearly showed the bacterial cell wall and intracellular structure, whereas micrographs of unwrapped cells had unrecognizable intracellular structure and evidence of charging that distorted the image (see Figure 1). Also, much of the water was retained within the wrapped cells, and there was no discernable volume change. Te unwrapped cells quickly shrank by 76 percent and were apparently dry aſter 20 minutes in the TEM. Berry’s group has developed yet another use for graphene


and its modifications, one that can be helpful to microscopists. Tis is reinforced by the supplemental material (such as videos of wrapped bacteria) that accompanied their article. Tey envision that encasing wet samples within graphenic chambers could enable real-time imaging of fluid dynamics, proteins, liquid suspension of nanoparticles, and the biochemical activity within living cells [2]!


References [1] N Mohanty, M Fahrenholtz, A Nagaraja, D Boyle, and V Berry, Nano Letters 11 (2011) 1270–75.


[2] Te authors gratefully acknowledge Dr. Vikas Berry for reviewing this article.


10


www.microscopy-today.com • 2011 July


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