Multiscale vapor-mediateddendritic pattern formation and bacterial aggregation in complex respiratory biofluid...

Area of Science:

• Fluid Dynamics
• Biophysics
• Materials Science

Background:

• Biofluid droplets, such as respiratory droplets, form complex deposits upon evaporation.
• The composition and internal flow dynamics of these droplets dictate deposit patterns and bacterial aggregation.
• Current methods lack precise control over these nanoscale phenomena.

Purpose of the Study:

• To investigate spatio-temporal and topological regulation of respiratory fluid droplet deposits.
• To demonstrate control over bacterial aggregation within these droplets using non-contact methods.
• To explore the potential of vapor-mediated interactions for manipulating droplet evaporation and deposit formation.

Main Methods:

• Utilizing non-contact vapor-mediated interactions to influence flow within respiratory fluid droplets.
• Employing ethanol droplets to induce short and long-range interactions, controlling deposit morphology (dendrite size, orientation) and crystal formation.
• Observing the segregation and agglomeration of bacteria within the fluid without affecting viability or pathogenesis.

Main Results:

• Demonstrated precise control over deposit topology, including dendrite morphology and suppression of cruciform crystals.
• Achieved control over nucleation sites via preferential solute transfer, influencing crystal growth dynamics.
• Presented a proof-of-concept for non-contact control of live bacterial aggregation, a first in experimental studies.

Conclusions:

• Vapor-mediated interactions offer a novel, non-contact approach to regulate biofluid droplet evaporation and resultant deposit structures.
• This methodology allows for the controlled aggregation of active biological matter like bacteria.
• The findings have significant potential for biomedical applications, including enhanced disease detection and targeted bacterial segregation.