Viscosity Sensing With Lamb-Wave Microsensor: Dimethylsulfoxide Solution Viscosity as a Function of Temperature

Abstract

Recently, a new microsensor employing low-velocity ultrasonic Lamb waves was developed and demonstrated to be capable of measuring the viscosity of solutions in small volumes. The microsensor, when attached to a temperature-controlled stage, can measure viscosity as a function of temperature. In this investigation, the ultrasonic Lamb-wave oscillator is employed to experimentally measure the viscosity of dimethylsulfoxide (Me2SO) solutions as a function of temperature. The microsensor and the experimental procedure are described and results for 1M, 3M, and 5M Me2SO aqueous solutions are presented. Dimethylsulfoxide is a compound commonly employed as a cryoprotectant in cryopreservation, the low-temperature preservation of biological materials. The temperature dependence of viscosity obtained through this study can be used in determining the probability for ice nucleation in biological materials, a parameter of importance during cryopreservation.

Measurement and numerical analysis of freezing in solutions enclosed in a small container

“…A simple stereological analysis was performed using NIH™ image analysis software (NIH, Bethesda, MD) to estimate the initial radius of the ice crystals, R( ) 0 at the phase change temperature ( T ph0 ). We found that the initial radius of the ice crystals are ~2.7 ± 0.1 and ~3.7 ± 0.05 times smaller in the 5x and 10x PBS solution than in the 1x PBS 3 The viscosity (µ) model used in the present study predicts a ten fold increase in the value of µ between 0˚C and -40 ˚C which correlates reasonably well with the measured values [47]. Other viscosity models [48,49] also predict a similar increase over the temperature range of interest.…”

“…However, a decrease in viscosity (or an increase in diffusivity, D 2 ) with increasing solute is contrary to published literature [47][48][49]. Therefore, the decrease in ν 2 with increasing concentration of solutes must be due to the reduction in R (as suggested by cryomicroscopy images shown in Fig.…”

“…However, we find that an inordinately large decrease (by a factor of 10 -10 ) in the value of the diffusion coefficient is needed to occur between the temperature range of 0 ˚C and -20 ˚C for this 'shut-off' effect to occur at a temperature comparable to the experimental data (~-20 ˚C). For the solutions studied, such a large decrease in the diffusion coefficient (or a large increase in viscosity) is unsupported by any published literature [47][48][49]. Therefore, we account for this lowering in the diffusion coefficient (and the 'shut-off') by normalizing the model simulations to experimentally determined temperatures (~-14 to -22 ˚C, based on the cooling rate; as plotted in Fig.…”

Microfabricated acoustofluidic membrane acoustic waveguide actuator for highly localized in-droplet dynamic particle manipulation

“…[52][53][54] These processes can significantly benefit acoustofluidic lab-on-a-chip systems 55 due to their high degree of reproducibility, essential for consistent acoustic actuation, and low-cost batch fabrication. Thin-film transducers are compatible with most of the acoustophoretic methods deployed with their bulk piezoelectric counterparts, such as patterning, 56,57 sensing 44,58,59 and streaming generation. 44,[60][61][62] However, the thin films can be deposited onto microfabricated features, enabling new actuation methods that were previously impossible.…”