Application of Magnetic Nanoparticles in Microfluidic Cell Separation

Date: 02/15/2012
Time: 10:45 am – 12:00 pm
Location: 306 Egan Research Center
Speaker: Brian Plouffe, Ph.D., MIT

Application of magnetic nanoparticles in microfluidic cell separation

As means to isolate rare cells from whole blood conventional magnetic activated cell separation (MACS) is carried out at the macroscale, with a large external magnet surrounding a flow channel. This technology uses labeling with antibody-coated magnetic microparticles and extraction by attractive magnetic forces in order to effectively isolate the cells of interest. In recent years, there has been tremendous interest in miniaturizing the MACS process to harness the traditional advantages of microfluidic systems, namely the ability to process microliter-size sample volumes economically and portably. However, recent device designs have typically required large permanent magnets or electromagnets. Also there remains a need to understand the magnetic tagging entities to optimize the separation process.

This talk first aims to describe efforts that have been taken to investigate the feasibility using magnetic nanoparticle as substitute for the microparticle and sub-micron tags currently used in MACS was conducted. Magnetite (Fe3O4) particles were synthesized using traditional thermal decomposition a methods, followed by a ligand exchange using the biocompatible surfactant dopamine. Through the exchange process an interesting increase in magnetic moment was observed. Additionally, whilst characterizing the synthesized nanoparticles’ particle diameter and distribution – a key parameter in magnet-based microfluidic cell separation – a novel quantitative evaluation model of the nanoparticle ensemble was outlined solely from temperature-dependent magnetization measurements. These new insights into the characteristics of nanoparticles may allow for better understanding of the synthesized ensembles for implantation in bio-nanotechnological applications.

The talk will then focus on the approach taken to directly engineer a prototype microfluidics MACS system that overcomes the current limitations on external magnetic field sources. Ultimately, it was shown that the designed microfluidic platform achieved throughputs better than the state of the art, and efficiencies and purity comparable or better than the standards in separation today.