Acoustic levitation of gels: A proof-of-concept for thromboelastography

Abstract

Current thromboelastography in the clinic requires contact between the measurement apparatus and the blood being studied. An alternative technique employs levitation of a small droplet to limit contact with the blood sample to air alone. As has been demonstrated for Newtonian liquid drops, the measurement of static spatial location and sample deformation can be used to infer sample surface tension. In the current study, ultrasonic acoustic levitation was used to levitate viscoelastic samples. Gelatin was used as a stand-in for blood to establish the validity of the ultrasonic levitation technique on viscoelastic materials. Liquid data was first taken to benchmark the apparatus, then deformation/location studies were performed on set and setting gelatin gels. Relationships between gelling time, gel concentration, and gel firmness were demonstrated. The elastic modulus of gels was inferred from the data using an idealized model.

Differential and Variational Formalism for an Acoustically Levitating Drop

“…The acoustic levitation [1,2,3] has been developing from the 70-90's as a contactless technology in chemical and pharmaceutical industry [4,5] of ultra-pure materials. The technology facilitates preventing the liquid contamination and intensifying the chemical reactions.…”