A single-particle mechanofluorescent sensor.

Area of Science:

• Biomedical Engineering
• Materials Science
• Microfluidics

Background:

• Monitoring mechanical stresses in microchannels is crucial but technically challenging.
• Existing methods lack the sensitivity and real-time capabilities required for complex fluidic environments.

Purpose of the Study:

• To develop a novel mechanofluorescence sensor system for real-time monitoring of mechanical stresses in microchannels.
• To utilize a single polydiacetylene (PDA) particle as a sensitive probe for fluid dynamics and molecular interactions within microfluidic devices.

Main Methods:

• Fabrication of a fluorogenic single polydiacetylene (PDA) particle using co-flow microfluidics.
• Construction of a stenotic vessel-mimicking capillary channel for controlled fluid flow experiments.
• Real-time monitoring of PDA particle fluorescence responses using fluorescent microscopy.

Main Results:

• The PDA particle exhibited significant nonlinear fluorescence emissions in response to fluid viscosity, nanoparticles, and biomolecules.
• The observed nonlinear fluorescence is attributed to torsion energy along the PDA's main chain backbone.
• Computational fluid dynamics simulations determined the energy threshold for the blue-to-red fluorescence transition (~307 μJ).

Conclusions:

• The developed mechanofluorescence sensor system offers a unique platform for in vitro simulation of mechanical stresses in biological systems.
• This technology has potential applications in studying difficult-to-access regions of the human body and advancing microfluidic sensing.
• The study highlights the sensitivity of PDA particles to mechanical forces and fluid properties in microscale environments.