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Published on: October 21, 2013
Ridge-assisted micro positioning of cells in a channel
Adriana Payan-Medina1,2,3,4, Victor R Putaturo2,3,4, Sajad R Bazaz2,3,4
1Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts 02139, USA.
Science Advances
|July 17, 2026
Summary
Ridge-assisted micro positioning (RAMP) precisely controls cell streams in microchannels, independent of cell size or flow rate. This versatile method enables clog-free cell concentration and focusing in complex fluids like whole blood.
Area of Science:
- Biomedical Engineering
- Microfluidics
- Cellular Biology
Background:
- Precise control of cell streams in microchannels is crucial for applications like cell concentration, sorting, and sensing.
- Existing methods like inertial focusing have limitations regarding particle size and flow rate dependency.
Purpose of the Study:
- To develop a novel microfluidic method for deterministic and precise lateral positioning of focused cell streams.
- To overcome the limitations of existing cell focusing techniques, enabling applications in complex biological fluids.
Main Methods:
- Leveraging engineered microvortices generated by channel ridges and fluidic lift forces.
- Introducing ridge-assisted micro positioning (RAMP), a technique independent of particle size and flow rate.
- Demonstrating adjustable focusing positions via ridge placement and geometry modification.
Main Results:
- RAMP enables deterministic focusing of polydisperse particles to desired streamlines across a broad range of flow rates.
- Achieved micron-level lateral shifts in cell stream positions through controlled ridge design.
- Developed clog-free microfluidic cell concentrators capable of enriching single cells and clusters.
- Successfully focused particles in undiluted whole blood, showcasing applicability in complex biological samples.
Conclusions:
- RAMP offers a versatile and precise platform for cell positioning in microfluidic devices.
- The method's independence from particle size and flow rate expands its utility in various biomedical applications.
- RAMP facilitates clog-free cell concentration and focusing, even in challenging biological fluids like whole blood.
