Graphene-enabled electron microscopy and correlated super-resolution microscopy of wet cells

Wojcik, Michal; Hauser, Margaret; Li, Wan; Moon, Seonah; Xu, Ke

doi:10.1038/ncomms8384

Cited by 123 publications

(101 citation statements)

References 36 publications

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“…As the glass substrate is insulating and unsuitable for SEM, we relied on the conductivity of graphene itself. 27 The SEM images (Figures 2e, S3, S4) are in agreement with IRM results but afford significantly lower contrast and SNR. Whereas bilayers and the more prominent wrinkles and cracks are visible (solid arrows), the thinner wrinkles and cracks, which are clearly resolved in IRM, are hardly observable in SEM (dashed green and blue arrows).…”

supporting

confidence: 89%

Direct Optical Visualization of Graphene and Its Nanoscale Defects on Transparent Substrates

Moon

Wojcik

et al. 2016

Nano Lett.

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The discovery and rise of graphene were historically enabled by its ∼10% optical contrast on specialized substrates like oxide-capped silicon. However, substantially lower contrast is obtained on transparent substrates. Moreover, it remains difficult to visualize nanoscale defects in graphene, including voids, cracks, wrinkles, and multilayers, on most device substrates. We report the use of interference reflection microscopy (IRM), a facile, label-free optical microscopy method originated in cell biology, to directly visualize graphene on transparent inorganic and polymer substrates at 30-40% image contrast per graphene layer. Our noninvasive approach overcomes typical challenges associated with transparent substrates, including insulating and rough surfaces, enables unambiguous identification of local graphene layer numbers and reveals nanoscale structures and defects with outstanding contrast and throughput. We thus demonstrate in situ monitoring of nanoscale defects in graphene, including the generation of nanocracks under uniaxial strain, at up to 4× video rate.

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supporting

confidence: 89%

Direct Optical Visualization of Graphene and Its Nanoscale Defects on Transparent Substrates

Moon

Wojcik

et al. 2016

Nano Lett.

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“…3D-STORM (Huang et al, 2008; Rust et al, 2006) was carried out on a homebuilt setup, as reported previously(Wojcik et al, 2015). Typical localization accuracies (SDs), as determined by repeatedly localizing the same single clusters in the samples in this study, were ~12 nm in plane ( xy ) and ~20 nm in depth ( z ), corresponding to full width at half maximum (FWHM) values of 28 and 47 nm, respectively.…”

Section: Methodsmentioning

confidence: 99%

Asymmetrically Positioned Flagellar Control Units Regulate Human Sperm Rotation

et al. 2018

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SUMMARY Ion channels control sperm navigation within the female reproductive tract and, thus, are critical for their ability to find and fertilize an egg. The flagellar calcium channel CatSper controls sperm hyperactivated motility and is dependent on an alkaline cytoplasmic pH. The latter is accomplished by either proton transporters or, in human sperm, via the voltage-gated proton channel Hv1. To provide concerted regulation, ion channels and their regulatory proteins must be compartmentalized. Here, we describe flagellar regulatory nanodomains comprised of Hv1, CatSper, and its regulatory protein ABHD2. Super-resolution microscopy revealed that Hv1 is distributed asymmetrically within bilateral longitudinal lines and that inhibition of this channel leads to a decrease in sperm rotation along the long axis. We suggest that specific distribution of flagellar nanodomains provides a structural basis for the selective activation of CatSper and subsequent flagellar rotation. The latter, together with hyperactivated motility, enhances the fertility of sperm.

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“…A related technique for imaging wet tissue in SEM has recently been described by Wojcik et al . [15]. This method covers tissue specimens with a monolayer of graphene.…”

Section: Discussionmentioning

confidence: 99%

A modified ‘NanoSuit®’ preserves wet samples in high vacuum: direct observations on cells and tissues in field-emission scanning electron microscopy

et al. 2017

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Although field-emission scanning electron microscopy (FE-SEM) has proven very useful in biomedical research, the high vacuum required (10−3 to 10−7 Pa) precludes direct observations of living cells and tissues at high resolution and often produces unwanted structural changes. We have previously described a method that allows the investigator to keep a variety of insect larvae alive in the high vacuum environment of the electron microscope by encasing the organisms in a thin, vacuum-proof suit, the ‘NanoSuit®'. However, it was impossible to protect wet tissues freshly excised from intact organisms or cultured cells. Here we describe an improved ‘NanoSuit' technique to overcome this limitation. We protected the specimens with a surface shield enhancer (SSE) solution that consists of glycerine and electrolytes and found that the fine structure of the SSE-treated specimens is superior to that of conventionally prepared specimens. The SSE-based NanoSuit affords a much stronger barrier to gas and/or liquid loss than the previous NanoSuit did and, since it allows more detailed images, it could significantly help to elucidate the ‘real' organization of cells and their functions.

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Graphene-enabled electron microscopy and correlated super-resolution microscopy of wet cells

Cited by 123 publications

References 36 publications

Direct Optical Visualization of Graphene and Its Nanoscale Defects on Transparent Substrates

Direct Optical Visualization of Graphene and Its Nanoscale Defects on Transparent Substrates

Asymmetrically Positioned Flagellar Control Units Regulate Human Sperm Rotation

A modified ‘NanoSuit®’ preserves wet samples in high vacuum: direct observations on cells and tissues in field-emission scanning electron microscopy

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