Dielectrophoresis of spermatozoa in viscoelastic medium

Abstract

Knowledge of spermatozoa motility is important in selecting suitable spermatozoa for assisted reproduction procedures. By considering the internal sliding force within an active filament, its shape in a viscoelastic Oldroyd-B fluid subjected to nonuniform electric field is presented. The resulting velocity is a function of the beating pattern and DEP force, which is dependent on the spermatozoon's morphology as well as the gradient of the mean square electric field. Finally, the velocities of the X- and Y-spermatozoa are compared under various conditions of nonuniform electric field and viscoelasticity of the medium. The presence of DEP force alters their velocities to different extents, giving an 84% level of confidence for selecting spermatozoon that contains the chromosome leading to a female. Therefore, a nonuniform electric field can be used not only to sort and select spermatozoa of desired morphology, but also for gender selection. Moreover, we found that sorting in a viscoelastic fluid medium is more effective as the effect of DEP on the spermatozoa velocity is enhanced by an order of magnitude.

Supervised Learning to Predict Sperm Sorting by Magnetophoresis

“…We also consider the use of machine learning in investigating the sorting of sperm by dielectrophoresis, where the force is modelled as F DEP = C 0 Γi [57,58] and where Γ is the shape factor [59] rather than volume. The conclusions drawn are similar to those above-consistent predictions with little variance are obtained when a training size of 10,000 is used-but the results are always a couple of percentage points higher than results obtained from the full computation for 10 5 samples.…”

Theoretical modeling in microscale locomotion

“…Artificial swimmers have thereafter been used to demonstrate experimentally that reciprocal motion is possible in a polymeric fluid (Keim et al 2012). Therefore, models ought to incorporate the nonlinearity of fluid behavior if the object of study resides in a non-Newtonian environment (Koh and Marcos 2015a). In this section, we shall explore the extent to which the kinematic behavior of swimmers vary under different fluid medium, and determine if the various studies provide a common relation which may then be used as a correcting factor.…”

Manipulation of micro‐ and nanoparticles in viscoelastic fluid flows within microfluid systems

“…The DEP force and Clausius–Mossotti (CM) factor are defined, respectively, in the following equations: where r p is the particle radius, E is the electric field, ε 0 is the permittivity of the free space, and ε and ɛ p are fluid and particle permittivity, respectively. To date, a few works considered DEP through VEFs (Koh, ). For the first time, Lu, DuBose, Joo, Qian, and Xuan () and Lu et al () used a DEP method for particle manipulation utilizing viscoelastic PEO solution.…”

“…Lu et al () concluded that the constriction‐induced DEP is not an appropriate method for focusing of particles in VEFs. However, the modeling results of Koh and Marcos (Koh, ) predicted that in suitable electric field strength, the DEP force could separate spermatozoa containing the desired chromosome in a VEF flow with low concentration. Furthermore, Zhou et al () developed a numerical model to study DEP‐based particle manipulation in VEFs through a converging‐diverging microchannel.…”

“…In passive methods, no external force is utilized other than hydrodynamic forces, including lift and drag forces (D'Avino et al ; Lu et al, ; Yuan et al, ). However, in the active techniques, external force fields, for example, magnetic (Del Giudice et al, ), acoustic (Kiyasatfar & Nama, ), or electric (Koh, ) are used to exert a controlled force on particles (e.g., magnetophoretic (Del Giudice et al, ), acoustophoretic (Kiyasatfar & Nama, ), or dielectrophoretic (Koh, ) forces). Both active and passive methods have their own advantages and drawbacks.…”