Magnetic liposomes and entrapping : time-resolved neutron scattering TR-SANS and electron microscopy

Abstract

Magnetic liposomes were prepared by a novel method from stabilized iron-complex solutions and biogenic phospholipids using a pH-jump procedure. During preparation Boron was entrapped inside the liposomes. This enables the later application in Neutron capture cancer therapy, a local radiation therapy, as well as rheological experiments with magnetic tweezers. The formation of the liposomes and the internal iron oxide structure was observed by time-resolved neutron scattering TR-SANS and electron microscopy using a stopped-flow mixing device. The liposome size was estimated by dynamic light scattering (DLS) also. Under selected conditions, the iron oxide was obtained as shell located at the inner surface of the lipid layer. Thus the internal volume was free for entrapping of other material, e.g. the Boron compounds for Neutron capture or drug targetting applications. The magnetic shell liposomes revealed a typical size of 100–400 nm, as required for applications in vivo.