Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

Abstract

This study describes the development and testing of a magnetic microfluidic chip (MMC) for trapping and isolating cells tagged with superparamagnetic beads (SPBs) in a microfluidic environment for selective treatment and analysis. The trapping and isolation are done in two separate steps; first, the trapping of the tagged cells in a main channel is achieved by soft ferromagnetic disks and second, the transportation of the cells into side chambers for isolation is executed by tapered conductive paths made of Gold (Au). Numerical simulations were performed to analyze the magnetic flux and force distributions of the disks and conducting paths, for trapping and transporting SPBs. The MMC was fabricated using standard microfabrication processes. Experiments were performed with E. coli (K12 strand) tagged with 2.8 μm SPBs. The results showed that E. coli can be separated from a sample solution by trapping them at the disk sites, and then isolated into chambers by transporting them along the tapered conducting paths. Once the E. coli was trapped inside the side chambers, two selective treatments were performed. In one chamber, a solution with minimal nutrition content was added and, in another chamber, a solution with essential nutrition was added. The results showed that the growth of bacteria cultured in the second chamber containing nutrient was significantly higher, demonstrating that the E. coli was not affected by the magnetically driven transportation and the feasibility of performing different treatments on selectively isolated cells on a single microfluidic platform.

Tunable magnetic nanowires for biomedical and harsh environment applications

“…Fe NWs oxidize relatively quickly, depending on the environmental conditions, leading to iron oxide NWs with much poorer magnetic moment 5 . Iron oxide has proven to be a viable material for biomedical applications in the form of superparamagnetic beads 26 27 28 29 30 31 32 . Hence, combining Fe and Fe 3 O 4 to form core-shell NWs could present an attractive opportunity to tune their magnetic properties toward achieving long-term stability and a high degree of biocompatibility.…”

Magnetically Triggered Monodispersed Nanocomposite Fabricated by Microfluidic Approach for Drug Delivery

“…widely used for biological and chemical applications, exploiting a continuous flow or flow focusing to produce continuous streams of liquid or to generate droplets [32][33][34][35][36][37]. In order to synthetize the MTNs, we use a flow focusing method, generating a (water I and water II)-in-oil (( + )/ ) emulsion, in which two aqueous phases are mixed and encapsulated inside an oil stream.…”

Simultaneous diamagnetic and magnetic particle trapping in ferrofluid microflows via a single permanent magnet

“…Magnetic (either intrinsic or extrinsic) particles are pulled along magnetic field gradients toward the magnetic source in diamagnetic (e.g., water) or less magnetic media. 23,24 This positive magnetophoretic motion has been widely utilized to concentrate and isolate magnetically-tagged target cells (e.g., circulating tumor cells) from a heterogeneous mixture. [25][26][27] Diamagnetic particles must be re-suspended in magnetic media like ferrofluids [28][29][30][31][32][33] and paramagnetic solutions, 34,35 so that they experience negative magnetophoresis and are repelled away from the magnetic source.…”