Acoustically manipulating internal structure of disk-in-sphere endoskeletal droplets

Abstract

Manipulation of micro/nano particles has been well studied and demonstrated by optical, electromagnetic, and acoustic approaches, or their combinations. Manipulation of internal structure of droplet/particle is rarely explored and remains challenging due to its complicated nature. Here we demonstrated the manipulation of internal structure of disk-in-sphere endoskeletal droplets using acoustic wave. We developed a model to investigate the physical mechanisms behind this interesting phenomenon. Theoretical analysis of the acoustic interactions indicated that these assembly dynamics arise from a balance of the primary and secondary radiation forces. Additionally, the disk orientation was found to change with acoustic driving frequency, which allowed on-demand, reversible adjustment of the disk orientations with respect to the substrate. This dynamic behavior leads to unique reversible arrangements of the endoskeletal droplets and their internal architecture, which may provide an avenue for directed assembly of novel hierarchical colloidal architectures and intracellular organelles or intra-organoid structures.

Advances in Finite Element Analysis of External Field‐Driven Micro/Nanorobots: A Review

“…Shakya et al proposed swarms consisting of monodisperse disk‐in‐sphere droplets driven by an acoustic field. [ 26 ] Droplets were suspended in an acoustic field, and droplets attracted each other to form swarms when they approached another droplet. The phenomenon indicated that there were interaction forces between the droplets.…”

Photoacoustic Vaporization of Endoskeletal Droplets Loaded with Zinc Naphthalocyanine

“…The droplet vaporization temperature can therefore be tuned by choosing an appropriate hydrocarbon melting temperature. 11,12 Shakya et al recently showed that droplet processing history can also have a significant effect on vaporization behavior. 13 While heating and hyperthermia can be used for many applications, there is an interest in formulating new endoskeletal droplets that vaporize without the need for direct heating, such as exposure to light or sound.…”

“…A novel class of droplets, known as vaporizable endoskeletal droplets, are complex emulsions containing a solid hydrocarbon phase in their inner core along with a volatile fluorocarbon as the outer liquid. , Melting of the solid hydrocarbon phase interrupts intermolecular cohesion within the liquid fluorocarbon, thereby lowering the spinodal temperature and triggering vaporization of the volatile fluorocarbon. The droplet vaporization temperature can therefore be tuned by choosing an appropriate hydrocarbon melting temperature. , Shakya et al recently showed that droplet processing history can also have a significant effect on vaporization behavior …”

Staged Assembly of Colloids Using DNA and Acoustofluidics

“…Typically, a particle with positive acoustic contrast factor will be directed to the acoustic potential minimum at a PN, while a particle with negative acoustic contrast factor will be directed to a AN. 37,38 The acoustic contrast factor is a function determined by the compressibility and density of both the particle and the medium, and is positive for most colloidal systems, including polystyrene beads used here. The acoustic contrast factor of DNACCs depends on the materials properties of both the colloids and DNA.…”

“…By actuating the two pairs of IDTs with resonance frequencies, a specific arrangement of pressure nodes (PNs) and pressure antinodes (ANs) is formed in between the IDTs, which act as acoustic potential wells to attract any surrounding particles by acoustic radiation force. Typically, a particle with positive acoustic contrast factor will be directed to the acoustic potential minimum at a PN, while a particle with negative acoustic contrast factor will be directed to a AN. , The acoustic contrast factor is a function determined by the compressibility and density of both the particle and the medium, and is positive for most colloidal systems, including polystyrene beads used here. The acoustic contrast factor of DNACCs depends on the materials properties of both the colloids and DNA.…”