Probing viscosity of nanoliter droplets of butterfly saliva by magnetic rotational spectroscopy

Tokarev, Alexander; Kaufman, Bethany; Gu, Yu; Andrukh, Taras; Adler, Peter H.; Kornev, Konstantin G.

doi:10.1063/1.4788927

Cited by 38 publications

(60 citation statements)

References 23 publications

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“…Submitted to a rotating magnetic field with increasing angular frequency, the behavior of the wires immersed in viscous and in viscoelastic fluids is modeled. The rotational phase diagram exhibits a transition between a synchronous and an asynchronous regime, this second regime being characterized by a backand-forth motion [18,24,[26][27][28]. The instability resembles that observed on laboratory benches when a viscous solution is actuated with a magnetic bar.…”

Section: -Conclusionmentioning

confidence: 99%

“…In recent studies, the case of the Newton fluid was evaluated [18,24,[26][27][28]. It was shown that for frequency above the wire undergoes an hydrodynamic instability between two rotation regimes [32,33].…”

Section: -Theoretical Backgroundmentioning

confidence: 99%

“…Each of these methods provides the particle trajectory and orientation as a function of the time, an important outcome for the study of anisotropic or heterogeneous media. For driven motions, the transition between steady and hindered rotation of a micro-actuator above a critical frequency was successfully used to evaluate the viscosity of the fluid [18,24,[26][27][28]. In the later case, only Newton liquids were surveyed.…”

Section: -Introductionmentioning

confidence: 99%

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Magnetic wire-based sensors for the microrheology of complex fluids

et al. 2013

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Abstract:We propose a simple µ-rheology technique to evaluate the viscoelastic properties of complex fluids. The method is based on the use of magnetic wires of a few microns in length submitted to a rotational magnetic field. In this work, the method is implemented on a surfactant wormlike micellar solution that behaves as an ideal Maxwell fluid. With increasing frequency, the wires undergo a transition between a steady and a hindered rotation regime. The study shows that the average rotational velocity and the amplitudes of the oscillations obey scaling laws with well-defined exponents. From a comparison between model predictions and experiments, the rheological parameters of the fluid are determined. -IntroductionRheology is the study of flow and deformation of fluids when they are submitted to mechanical stresses. Conventional rheometers determine the relationship between strain and stress in steady or oscillating flow on samples of a few milliliters. µ-rheology in contrast studies the motion of micron-size probe particles that are thermally fluctuating via the interactions with a surrounding medium, or particles that are forced by an external field. In the first case, the µ-rheology is said to be passive, in the second active. In both cases, the motion of the probes is related by the mechanical properties of the medium. Fluids produced in small quantities, e.g. costly protein dispersion or fluids confined in small volumes down to 1 picoliter, such as living cells can only be examined by this technique. With the development of microfluidics systems in the last decade [1], rapid advances were made in the field of µ-rheology. Standard experimental protocols and data treatment softwares are now available and implemented on a regular and controlled basis [2][3][4][5][6][7]. The correspondence between µ-and macro-rheology is nowadays well established. In µ-rheology, the objective is to translate the motion of a probe particle into the relevant rheological

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Section: -Conclusionmentioning

confidence: 99%

Section: -Theoretical Backgroundmentioning

confidence: 99%

Section: -Introductionmentioning

confidence: 99%

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Magnetic wire-based sensors for the microrheology of complex fluids

et al. 2013

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“…For example, in 1950, Frances Crick monitored the rotational motion of micron sized aspherical particles in response to pulsed magnetic fields to measure the viscosity in chick fibroblasts [21]. Optical tracking of rotating magnetic particles was used to monitor changes in drag during growth of single bacteria on MagMOONs [22] to monitor changes in shape of single cancer stem cells [23], to measure the viscosity of butterfly saliva [24], and to detect bacteria based on changes in viscosity when bacteria excrete biofilm polymers [25]. In addition, particle rotation has been used to track intracellular transport [26, 27].…”

Section: Introductionmentioning

confidence: 99%

Detecting de-gelation through tissue using magnetically modulated optical nanoprobes (MagMOONs)

Nguyen

Anker

2014

Sensors and Actuators B: Chemical

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Alginate gels are widely used for drug delivery and implanted devices. The rate at which these gels break down is important for controlling drug release. Since the de-gelation may be different in vivo, monitoring this process in situ is essential. However, it is challenging to monitor the gel through tissue due to optical scattering and tissue autofluorescence. Herein we describe a method to detect through tissue the chemically-induced changes in viscosity and de-gelation process of alginate gels using magnetically modulated optical nanoprobes (MagMOONs). The MagMOONs are fluorescent magnetic microspheres coated with a thin layer of opaque metal on one hemisphere. The metal layer prevents excitation and emission light from passing through one side of the MagMOONs, which creates orientation-dependent fluorescence intensity. The magnetic particles also align in an external magnetic field and give blinking signals when they rotate to follow an external modulated magnetic field. The blinking signals from these MagMOONs are distinguished from background autofluorescence and can be tracked on a single particle level in the absence of tissue, or for an ensemble average of particles blinking through tissue. When these MagMOONs are dispersed in calcium alginate gel, they become sensors for detecting gel degradation upon addition of either ammonium ion or alginate lyase. Our results show MagMOONs start blinking approximately 10 minutes after 2 mg/mL alginate lyase addition and this blinking is clearly detected even through up to 4 mm chicken breast. This approach can potentially be employed to detect bacterial biofilm formation on medical implants by sensing specific proteases that either activate a related function or regulate biofilm formation. It can also be applied to other biosensors and drug delivery systems based on enzyme-catalyzed breakdown of gel components.

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“…5). In these calculations, the viscosities of sucrose solutions were measured by magnetic rotational spectroscopy (Tokarev et al, 2013) and the densities of the sucrose solutions were taken from published values (Asadi, 2005) (Table 2).…”

Section: Suction-pump Pressurementioning

confidence: 99%

Paradox of the drinking-straw model of the butterfly proboscis

Tsai

Monaenkova

beard

et al. 2014

Journal of Experimental Biology

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There was an error published in J. Exp. Biol. 217, 2130-2138. Eqns A12 and A13 in the Appendix were cropped. The online pdf and fulltext versions (but not the print version) of the article have been corrected. The correct versions of the equations also appear below.We apologise to the authors and readers for this error. ABSTRACT Fluid-feeding Lepidoptera use an elongated proboscis, conventionally modeled as a drinking straw, to feed from pools and films of liquid. Using the monarch butterfly, Danaus plexippus (Linnaeus), we show that the inherent structural features of the lepidopteran proboscis contradict the basic assumptions of the drinking-straw model. By experimentally characterizing permeability and flow in the proboscis, we show that tapering of the food canal in the drinking region increases resistance, significantly hindering the flow of fluid. The calculated pressure differential required for a suction pump to support flow along the entire proboscis is greater than 1 atm (~101 kPa) when the butterfly feeds from a pool of liquid. We suggest that behavioral strategies employed by butterflies and moths can resolve this paradoxical pressure anomaly. Butterflies can alter the taper, the interlegular spacing and the terminal opening of the food canal, thereby controlling fluid entry and flow, by splaying the galeal tips apart, sliding the galeae along one another, pulsing hemolymph into each galeal lumen, and pressing the proboscis against a substrate. Thus, although physical construction of the proboscis limits its mechanical capabilities, its functionality can be modified and enhanced by behavioral strategies.

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Probing viscosity of nanoliter droplets of butterfly saliva by magnetic rotational spectroscopy

Cited by 38 publications

References 23 publications

Magnetic wire-based sensors for the microrheology of complex fluids

Magnetic wire-based sensors for the microrheology of complex fluids

Detecting de-gelation through tissue using magnetically modulated optical nanoprobes (MagMOONs)

Paradox of the drinking-straw model of the butterfly proboscis

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