Fluorescence ratio thermometry in a microfluidic dual-beam laser trap

Ebert, Susanne; Travis, Kort; Lincoln, Bryan; Guck, Jochen

doi:10.1364/oe.15.015493

Cited by 103 publications

(120 citation statements)

References 27 publications

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“…This magnitude of heating is in agreement with experimentally observed laser-induced heating of vesicles by infrared optical tweezers (Liu et al, 1995), of DNA in an infrared optical trap (Braun and Libchaber, 2002), of micron-sized silica and polystyrene beads in a optical traps (Peterman et al, 2003), and temperature sensitive dyes in buffer suspension in an infrared dual-beam laser trap (Ebert et al, 2007). We find that for spot sizes with w s = 1-2 m, we have d hm = 32.7 m, which is comparable to the diameter of a neuronal growth cone.…”

Section: D Temperature Field For a Stationary Laser Spotsupporting

confidence: 90%

“…Previous estimates of this effect in the optical neuronal guidance experiments suggested a negligible temperature increase (Albrecht-Buehler, 1991;Carnegie et al, 2008Carnegie et al, , 2009Ehrlicher et al, 2002;Graves et al, 2009;Higuchi et al, 2005Higuchi et al, , 2007Mohanty et al, 2005;Stevenson et al, 2006;Mathew et al, 2010;Koch et al, 2004), but our more detailed simulations show a temperature increase of the order 1 • C/100 mW of laser power, which is in agreement with experimental results and modelling from the field of optical trapping (Schönle and Hell, 1998;Braun and Libchaber, 2002;Peterman et al, 2003;Ebert et al, 2007). Furthermore, we find a temperature gradient of the order 1 • C/typical neuronal growth cone-radius.…”

Section: Introductionsupporting

confidence: 91%

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Analysis of laser-induced heating in optical neuronal guidance

Ebbesen

Bruus

2012

Journal of Neuroscience Methods

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a b s t r a c tRecently, it has been shown that it is possible to control the growth direction of neuronal growth cones by stimulation with weak laser light; an effect dubbed optical neuronal guidance. The effect exists for a broad range of laser wavelengths, spot sizes, spot intensities, optical intensity profiles and beam modulations, but it is unknown which biophysical mechanisms govern it. Based on thermodynamic modeling and simulation using published experimental parameters as input, we argue that the guidance is linked to heating. Until now, temperature effects due to laser-induced heating of the guided neuron have been neglected in the optical neuronal guidance literature. The results of our finite-element-method simulations show the relevance of the temperature field in optical guidance experiments and are consistent with published experimental results and modeling in the field of optical traps. Furthermore, we propose two experiments designed to test this hypotheses experimentally. For one of these experiments, we have designed a microfluidic platform, to be made using standard microfabrication techniques, for incubation of neurons in temperature gradients on micrometer lengthscales.

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Section: D Temperature Field For a Stationary Laser Spotsupporting

confidence: 90%

Section: Introductionsupporting

confidence: 91%

Analysis of laser-induced heating in optical neuronal guidance

Ebbesen

Bruus

2012

Journal of Neuroscience Methods

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“…Owing to the fact that the OS, operated at a wavelength of 1064 nm, might introduce additional heating effects that can impact cell rheology (34,38,39), we employed a MMM to confirm the impact of changes to suspended cell mechanical properties free from heating artifacts (see Materials and Methods). In this setup, cells were advected sequentially through a long microchannel with many constrictions smaller than the cell diameter using driving pressures within physiological range (50 mbar) (Fig.…”

Section: Cell Stiffening Correlates With Longer Advection Time Througmentioning

confidence: 99%

Myosin II Activity Softens Cells in Suspension

Chan

Ekpenyong

Golfier

et al. 2015

Biophysical Journal

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103

105

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The cellular cytoskeleton is crucial for many cellular functions such as cell motility and wound healing, as well as other processes that require shape change or force generation. Actin is one cytoskeleton component that regulates cell mechanics. Important properties driving this regulation include the amount of actin, its level of cross-linking, and its coordination with the activity of specific molecular motors like myosin. While studies investigating the contribution of myosin activity to cell mechanics have been performed on cells attached to a substrate, we investigated mechanical properties of cells in suspension.To do this, we used multiple probes for cell mechanics including a microfluidic optical stretcher, a microfluidic microcirculation mimetic, and real-time deformability cytometry. We found that nonadherent blood cells, cells arrested in mitosis, and naturally adherent cells brought into suspension, stiffen and become more solidlike upon myosin inhibition across multiple timescales (milliseconds to minutes). Our results hold across several pharmacological and genetic perturbations targeting myosin. Our findings suggest that myosin II activity contributes to increased whole-cell compliance and fluidity. This finding is contrary to what has been reported for cells attached to a substrate, which stiffen via active myosin driven prestress. Our results establish the importance of myosin II as an active component in modulating suspended cell mechanics, with a functional role distinctly different from that for substrate-adhered cells.

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“…The obtained results on optical deformability showed a statistically significant difference (p < 10 −3 ) between all the five temperatures. As known from literature [10,21,22], laser power can induce a sudden increase of the cell temperature, making it difficult to compare the deformation values obtained at different optical power levels. As in our case the same optical power is applied to all OS measurements, we expect an increase of about 30°C in the irradiated region for all the samples, provided that absorption coefficient changes due to the different temperatures are negligible.…”

Section: Optical Deformation and Passage Through Constrictionsmentioning

confidence: 99%

Investigation of temperature effect on cell mechanics by optofluidic microchips

Yang

Nava

Minzioni

et al. 2015

Biomed. Opt. Express

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Abstract:Here we present the results of a study concerning the effect of temperature on cell mechanical properties. Two different optofluidic microchips with external temperature control are used to investigate the temperature-induced changes of highly metastatic human melanoma cells (A375MC2) in the range of ~0 -35 °C. By means of an integrated optical stretcher, we observe that cells' optical deformability is strongly enhanced by increasing cell and buffer-fluid temperature. This finding is supported by the results obtained from a second device, which probes the cells' ability to be squeezed through a constriction. Measured data demonstrate a marked dependence of cell mechanical properties on temperature, thus highlighting the importance of including a proper temperature-control system in the experimental apparatus. Qin, "Microfluidics separation reveals the stem-cell-like deformability of tumor-initiating cells," Proc. Natl.

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Fluorescence ratio thermometry in a microfluidic dual-beam laser trap

Cited by 103 publications

References 27 publications

Analysis of laser-induced heating in optical neuronal guidance

Analysis of laser-induced heating in optical neuronal guidance

Myosin II Activity Softens Cells in Suspension

Investigation of temperature effect on cell mechanics by optofluidic microchips

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