High resolution and rapid separation of bacteria from blood using elasto-inertial microfluidics

Area of Science:

• Biomedical Engineering
• Microfluidics
• Separation Science

Background:

• Sepsis diagnosis requires rapid and efficient sample preparation for timely treatment.
• Current methods for bacteria isolation from blood can be time-consuming, delaying critical patient care.

Purpose of the Study:

• To develop and demonstrate a rapid, label-free method for bacteria separation from diluted blood using microfluidic devices.
• To investigate the elasto-inertial focusing behavior of blood cells and bacteria in viscoelastic flow for efficient separation.

Main Methods:

• Utilized elasto-inertial microfluidics in a spiral channel to separate microparticles and bacteria from blood.
• Investigated particle focusing and migration in viscoelastic fluids based on size differences.
• Optimized blood dilution and flow rates for efficient separation of *Escherichia coli* from diluted blood.

Main Results:

• Demonstrated size-dependent particle separation with 1 μm resolution at a throughput of 1 mL/min.
• Achieved continuous separation of *Escherichia coli* from diluted blood with 82-90% efficiency.
• Processed 1 mL of blood in 40 minutes with 82% separation efficiency using a single spiral device.

Conclusions:

• Elasto-inertial focusing offers a promising approach for rapid, label-free bacteria isolation from blood.
• This method significantly reduces sample preparation time, potentially accelerating sepsis test turnaround.
• The developed technique has broad applicability for speeding up downstream diagnostic analyses in clinical microbiology.