Albumin‐coated monodisperse magnetic poly(glycidyl methacrylate) microspheres with immobilized antibodies: Application to the capture of epithelial cancer cells

Abstract

Monodisperse (4 μm) macroporous crosslinked poly(glycidyl methacrylate) (PGMA) microspheres for use in microfluidic immunomagnetic cell sorting, with a specific application to the capture of circulating tumor cells (CTCs), were prepared by multistep swelling polymerization in the presence of cyclohexyl acetate porogen and hydrolyzed and ammonolyzed. Iron oxide was then precipitated in the microspheres to render them magnetic. Repeated precipitation made possible to raise the iron oxide content to more than 30 wt %. To minimize nonspecific adsorption of the microspheres in a microchannel and of cells on the microspheres, they were coated with albumin crosslinked with glutaraldehyde. Antibodies of epithelial cell adhesion molecule (anti-EpCAM) were then immobilized on the albumin-coated magnetic microspheres using the carbodiimide method. Capture of breast cancer MCF7 cells as a model of CTCs by the microspheres with immobilized anti-EpCAM IgG was performed in a batch experiment. Finally, MCF7 cells were captured by the anti-EpCAM-immobilized albumin-coated magnetic microspheres in an Ephesia chip. A very good rejection of lymphocytes was achieved. Thus, albumin-coated monodisperse magnetic PGMA microspheres with immobilized anti-EpCAM seem to be promising for capture of CTCs in a microfluidic device.

Magnetic microparticles post-synthetically coated by hyaluronic acid as an enhanced carrier for microfluidic bioanalysis

“…One method for preparing such highly magnetized particles is that of multistep swelling and polymerization followed by repeated precipitation of iron oxides inside the pores [24]. In this case, however, the iron ions are easily accessible on the surface of particles and they may be responsible for undesired interference reactions, such as decrease or even absolute loss of bioactivity as a result of redox reaction.…”

Circulating tumor-cell detection and capture using microfluidic devices

“…The superparamagnetic beads were antibody (anti-EpCAM)-coated for CTC capture [72]. Under a moderate external magnetic field, dipole-dipole interactions between the magnetic bead particles formed chains aligned along the electric field direction forming nanopillar-like structures [73]. The principle of this technology is depicted in Fig.…”

Dot-ELISA Affinity Test: An Easy, Low-Cost Method to Estimate Binding Activity of Monoclonal Antibodies

“…The captured cells were subsequently observed and counted in a Bürker's chamber using a Nikon Eclipse 80i microscope (Tokyo, Japan) equipped with Nikon Plan Fluor 10×, 20×, 40× and 60× objective lenses and a Nikon digital sight DS-MS camera. The images were acquired and processed using NIS-Elements AR Analysis 3.2 software (Nikon, Tokyo, Japan) and a procedure described by Horak et al [14]. The MCF7 cells used in immunomagnetic separation experiments (expressing EpCAM molecules) were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal calf serum, 1% penicillin-streptomycin antibiotics and 0.01 mg/ml insulin at 37°C in a humidified 5% CO 2 atmosphere.…”