Track-etched magnetic micropores for immunomagnetic isolation of pathogens
Melaku Muluneh1, Wu Shang, David Issadore
1Bioengineering, University of Pennsylvania, 210 South 33rd Street, Suite 240 Skirkanich Hall, Philadelphia, PA, 19104-6321, USA.
Abstract:
A microfluidic chip is developed to selectively isolate magnetically tagged cells from heterogeneous suspensions, the track-etched magnetic micropore (TEMPO) filter. The TEMPO consists of an ion track-etched polycarbonate membrane coated with soft magnetic film (Ni20 Fe80 ). In the presence of an applied field, provided by a small external magnet, the filter becomes magnetized and strong magnetic traps are created along the edges of the micro-pores. In contrast to conventional microfluidics, fluid flows vertically through the porous membrane allowing large flow rates while keeping the capture rate high and the chip compact. By utilizing track-etching instead of conventional semiconductor fabrication, TEMPOs can be fabricated with microscale pores over large areas A > 1 cm(2) at little cost (< 5 C| cm(-) (2) ). To demonstrate the utility of this platform, a TEMPO with 5 μm pore size is used to selectively and rapidly isolate immunomagnetically targeted Escherichia coli from heterogeneous suspensions, demonstrating enrichment of ζ > 500 at a flow rate of Φ = 5 mL h(-1) . Furthermore, the large density of micropores (ρ = 10(6) cm(-2) ) allows the TEMPO to sort E. coli from unprocessed environmental and clinical samples, as the blockage of a few pores does not significantly change the behavior of the device.
Insights
A novel microfluidic chip, the track-etched magnetic micropore (TEMPO) filter, efficiently isolates magnetically tagged cells. This cost-effective device enables rapid, high-purity cell separation from complex samples.
Area of Science:
- Biotechnology
- Microfluidics
- Materials Science
Background:
- Cell isolation from heterogeneous samples is crucial for diagnostics and research.
- Existing microfluidic devices face limitations in flow rate, capture efficiency, and cost.
- Developing advanced filtration systems is essential for efficient biological sample processing.
Purpose of the Study:
- To develop and characterize a novel microfluidic device for selective magnetic cell isolation.
- To demonstrate the high efficiency and cost-effectiveness of the track-etched magnetic micropore (TEMPO) filter.
- To showcase the TEMPO filter's capability in isolating specific bacteria from complex biological samples.
Main Methods:
- Fabrication of a microfluidic chip using ion track-etched polycarbonate membranes coated with a soft magnetic film (Ni20Fe80).
- Utilizing an external magnet to create magnetic traps along micro-pore edges for cell capture.
- Vertical fluid flow through the porous membrane to achieve high flow rates and capture efficiency.
- Demonstration using immunomagnetically targeted Escherichia coli with a 5 μm pore size TEMPO filter.
Main Results:
- The TEMPO filter demonstrated selective and rapid isolation of magnetically tagged Escherichia coli.
- Achieved high enrichment factors (ζ > 500) at a flow rate of 5 mL/h.
- The device exhibits robustness against pore blockage due to a high micropore density (10^6 cm^-2).
- Low fabrication cost (< 5 C/cm^2) and scalability for large areas (> 1 cm^2) were confirmed.
Conclusions:
- The TEMPO filter offers a cost-effective, high-performance solution for magnetic cell isolation in microfluidics.
- Its design enables high throughput and efficient capture, suitable for diverse biological applications.
- The technology is promising for processing unprocessed environmental and clinical samples, advancing cell sorting and diagnostics.
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