Wire‐Active Microrheology to Differentiate Viscoelastic Liquids from Soft Solids

Loosli, Frédéric; Najm, M. Abou; Chan, Raymond C. K.; Oikonomou, Evdokia K.; Grados, Arnaud; Receveur, Mathieu; Berret, Jean‐François

doi:10.1002/cphc.201601037

Cited by 15 publications

(74 citation statements)

References 62 publications

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“…57,58 Note that in the H ( / G )-representation, the continuous line in the figure is obtained with no adjustable parameter. 45,57 In conclusion to this part, it is found that Curosurf® loaded with silica behaves as a Newtonian fluid at all concentrations studied and that the dispersions are characterized by a single rheological parameter, the static shear viscosity . A similar type of behavior can be observed for Curosurf® mixed with alumina at concentrations lower than 31 = 0.1 g L -1 .…”

Section: Ii2 -Nanoparticle Loaded Surfactant Showing a Viscous Fluidmentioning

confidence: 78%

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Effect of Nanoparticles on the Bulk Shear Viscosity of a Lung Surfactant Fluid

et al. 2019

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Inhaled nanoparticles (< 100 nm) reaching the deep lung region first interact with the pulmonary surfactant, a thin lipid film lining the alveolar epithelium. To date, most biophysical studies have focused on particle induced modifications of the film interfacial properties. In comparison, there is less work on the surfactant bulk properties, and on their changes upon particle exposure. Here we study the viscoelastic properties of a biomimetic pulmonary surfactant in the presence of various engineered nanoparticles. The microrheology technique used is based on the remote actuation of micron-sized wires via the application of a rotating magnetic field and on timelapse optical microscopy. It is found that particles strongly interacting with lipid vesicles, such as cationic silica (SiO2, 42 nm) and alumina (Al2O3, 40 nm) induce profound modifications of the surfactant flow properties, even at low concentrations. In particular, we find that silica causes fluidification, while alumina induces a liquid-to-soft solid transition. Both phenomena are described quantitatively and accounted for in the context of colloidal physics models. It is finally suggested that the structure and viscosity changes could impair the fluid reorganization and recirculation occurring during breathing.

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Section: Ii2 -Nanoparticle Loaded Surfactant Showing a Viscous Fluidmentioning

confidence: 78%

“…b, c) H,abc ( * ) for Curosurf® dispersions loaded with alumina particles at 31 = 0.19 and 0.49 g L -1 respectively, * being the reduced wire length defined in the text. The thick red line indicates the 1/ * , -behavior expected from the soft solid model 45. The orange areas denote the range over which the 1/ * , -prefactor varies in these experiments.…”

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confidence: 92%

Effect of Nanoparticles on the Bulk Shear Viscosity of a Lung Surfactant Fluid

et al. 2019

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“…The magnetic wire microrheology technique has been described in previous accounts [41][42][43]. For reviews on microrheology techniques and data analysis, especially those using anisotropic probes, we refer to Refs [30,31,33,44].…”

Section: Ii8 -Active Microrheologymentioning

confidence: 99%

“…The images show that after a counter-clockwise rotation in the first 3 panels (between 20.5 and 23.0 s after the field inception), the wire comes back rapidly by 40 degrees in a clockwise motion, indicating that the wire does not follow the field in this time interval. The angular frequency at which the transition occurs reads [41,43] :…”

Section: F) the Microscopy Images On The Right-hand Side Show That Afmentioning

confidence: 99%

On the rheology of pulmonary surfactant: Effects of concentration and consequences for the surfactant replacement therapy

Thai

Mousseau

Oikonomou

et al. 2019

Colloids and Surfaces B: Biointerfaces

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The role of pulmonary surfactant is to reduce the surface tension in the lungs and to facilitate breathing. Surfactant replacement therapy (SRT) aims at bringing a substitute by instillation into the airways, a technique that has proven to be efficient and lifesaving for preterm infants. Adapting this therapy to adults requires to scale the administered dose to the patient body weight and to increase the lipid concentration, whilst maintaining its surface and flow properties similar. Here, we exploit a magnetic wire-based microrheology technique to measure the viscosity of the exogenous pulmonary surfactant Curosurf® in various experimental conditions. The Curosurf® viscosity is found to increase exponentially with lipid concentration following the Krieger-Dougherty law of colloids. The Krieger-Dougherty behavior also predicts a divergence of the viscosity at the liquid-to-gel transition. For Curosurf® the transition concentration is found close to the concentration at which it is formulated (117 g L -1 versus 80 g L -1 ). This outcome suggests that for SRT the surfactant rheological properties need to be monitored and kept within a certain range. The results found here could help in producing suspensions for respiratory distress syndrome adapted to adults. The present work also demonstrates the potential of the magnetic wire microrheology technique as an accurate tool to explore biological soft matter dynamics.

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“…The optical cell equipped with the environment control circuit is fit under the Olympus BX51 upright microscope. We illustrate robustness of this stage by studying viscous properties of liquids with a high-speed rheological technique based on Magnetic Rotational Spectroscopy [4,36,54,55], using magnetic nano-and microrods as the probes.…”

Section: Introductionmentioning

confidence: 99%

Magnetic stage with environmental control for optical microscopy and high-speed nano- and microrheology

et al. 2017

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A novel design of a low-field magnetic stage for optical microscopy of droplets and films within a controlled environment is described. The stage consists of five magnetic coils with a 3D magnetic sensor in a feedback control loop, which allows one to manipulate magnetic nano and microprobes with microTesla fields. A locally uniform time-dependent field within the focal plane of the microscope objective enables one to rotate the probes in a precisely set manner and observe their motion. The probe tracking protocol was developed to follow the probe rotation in real time and relate it with the viscosity of the host liquid. Using this magnetic stage, a method for measuring mPa•s-level viscosity of nanoliter droplets and micron thick films in a 10-20 second timeframe is presented and validated. The viscosity of a rapidly changing liquid can be tracked by using only a few visible probes rotating simultaneously. Vapor pressure and temperature around the sample can be controlled to directly measure viscosity as a function of equilibrium vapor pressure; this addresses a significant challenge in characterization of volatile nanodroplets and thin films. Thin films of surfactant solutions undergoing phase transitions upon solvent evaporation were studied and their rheological properties were related to morphological changes in the material.

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Wire‐Active Microrheology to Differentiate Viscoelastic Liquids from Soft Solids

Cited by 15 publications

References 62 publications

Effect of Nanoparticles on the Bulk Shear Viscosity of a Lung Surfactant Fluid

Effect of Nanoparticles on the Bulk Shear Viscosity of a Lung Surfactant Fluid

On the rheology of pulmonary surfactant: Effects of concentration and consequences for the surfactant replacement therapy

Magnetic stage with environmental control for optical microscopy and high-speed nano- and microrheology

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