Modelling, simulation, and experimental characterization of particle sedimentation inside a horizontal syringe

Area of Science:

• Microfluidics and Lab-on-Chip (LOC) Technology
• Biomedical Engineering
• Particle Dynamics

Background:

• Sedimentation of particles in liquid media poses challenges for prolonged sample handling in lab-on-chip (LOC) applications, such as 3D bioprinting and microfluidic cytometers.
• Existing mitigation strategies like mechanical agitation or buffer modification increase system complexity and cost.
• Understanding and predicting particle settling is crucial for reliable LOC experimental design.

Purpose of the Study:

• To develop a predictive model for particle sedimentation within horizontal syringes used in LOC devices.
• To identify key parameters influencing sedimentation rates, including syringe dimensions, particle properties, and flow conditions.
• To provide practical guidelines for designing LOC systems that minimize particle sedimentation.

Main Methods:

• Development of a mathematical model to describe particle sedimentation in a horizontal syringe.
• Numerical simulations to analyze model behavior and parameter influence.
• Experimental validation of the model using physical setups and biological particles.
• Derivation of a concentration half-life metric for assessing sedimentation impact.

Main Results:

• The model accurately predicts particle sedimentation, highlighting the critical roles of syringe radius, particle terminal velocity, outlet position, and flow rate.
• A concentration half-life parameter was established to quantify sedimentation effects over time.
• Experimental validation confirmed the model's applicability to both general particles and biological samples.
• The study generated design guidelines to effectively minimize particle sedimentation in LOC experiments.

Conclusions:

• The developed sedimentation model offers a valuable tool for optimizing LOC experimental design.
• By considering key parameters, researchers can mitigate sedimentation issues and improve assay reliability.
• The findings provide a foundation for developing more robust and efficient microfluidic systems.