title: Preparation of PEG-grafted immunomagnetoliposomes entrapping citrate stabilized magnetite particles and their application in CD34+ cell sorting.
abstract: Immunomagnetic systems have been used for positive selection of a cell fraction from a mixture using appropriate surface markers with satisfactory results, as haematopoietic CD34+ cells. This work reports on the development of poly(ethylene glycol)-grafted (PEG) immunoliposomes loaded with citrate-magnetite stabilized particles as the separation vehicles for immunomagnetic separations. The magnetic ferrofluid was encapsulated into PEG-liposomes by the DRV methodology. The magnetoliposomes had a liposomal size of approximately 450 nm and a Fe/lipid molar ratio of 1.52+/-0.26, and were retained in the magnetic field created by the MiniMACS system. Anti-CD34 immunomagnetoliposomes with 100 mAb/vesicle were prepared by coupling the My10 mAb and bound specifically for CD34+ KG-1a cells in culture and in mixtures with CD34-cells (CHO or Jurkat). The magnetic cell sorting was carried out in cell mixtures KG-1a/CHO or KG-1a/Jurkat with different initial% of CD34+ Kg-1a cells. For 10(6) positive cells and 100 microM of immunomagnetoliposomes, the capture efficiency was > 85% and independent of the starting percentage of CD34+ cells. The decrease of the final purity, when the starting percentage of CD34+ cells decreases and, dependent of the CD34- cell line used, point to the degree of non-specific cell binding of My10-immunomagnetoliposomes as being crucial, among of the methodological aspects as the number of starting CD34+ cells. The CD34+ cells isolated retained the viability with an estimated recovery of 45-50%.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Chemistry, University of Barcelona, Martí i Franqués, Spain. domingo@sun.bq.ub.es
authors.forename: J C
authors.initials: JC
authors.lastname: Domingo
authors.forename: M
authors.initials: M
authors.lastname: Mercadal
authors.forename: J
authors.initials: J
authors.lastname: Petriz
authors.forename: M A
authors.initials: MA
authors.lastname: De Madariaga
mesh_terms: D000465:Algorithms; D018952:Antigens, CD34 / Q000276:immunology*; D002460:Cell Line; D002951:Citrates; D052203:Ferrosoferric Oxide; D005434:Flow Cytometry; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods*; D007501:Iron / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010592:Pharmaceutic Aids; D011092:Polyethylene Glycols / Q000737:chemistry*
chemical_list: D018952:Antigens, CD34; D002951:Citrates; D008081:Liposomes; D010087:Oxides; D010592:Pharmaceutic Aids; D011092:Polyethylene Glycols; D007501:Iron; D052203:Ferrosoferric Oxide