Poly(N-isopropylacrylamide)-graft-polypropylene membranes containing adsorbed antibody for cell separation.

Abstract We developed a novel selective cell-separation method based on using a poly( N- isopropylacrylamide)- graft -polypropylene (PNIPAAm- g -PP) membrane containing adsorbed monoclonal antibody specific to the target cell. This membrane was prepared by plasma-induced polymerization and soaking in an antibody solution at 37°C. Poly( N -isopropylacrylamide) has a thermoresponsive phase transition: at 32°C water-insoluble (hydrophobic) and water-soluble (hydrophilic) states interconvert. Adsorption of antibody onto PNIPAAm- g -PP membrane at 37°C and its desorption at 4°C was verified by fluorescence-microscopy of the PNIPAAm- g -PP membrane after soaking it in fluorescein-conjugated goat anti-mouse IgG in phosphate-buffered saline. PNIPAAm- g -PP membranes containing adsorbed anti-mouse CD80 monoclonal antibody preferentially captured mouse-CD80 transfected cells at 37°C compared with membranes lacking antibody or containing anti-mouse CD86 monoclonal antibody. Detachment of captured cells from PNIPAAm- g -PP membranes was facilitated by washing at 4°C because of the thermoresponsive phase transition of PNIPAAm. With this method, mouse CD80- or mouse CD86-transfected cells were enriched from a 1:1 cell suspension to 72% or 66%, simply and with high yield.