ABSTRACT
In this study, the control of magnetic fields to manipulate surface-functionalized Fe3O4 nanoparticles by urokinase coating is investigated for thrombolysis in a microfluidic channel. The urokinase-coated Fe3O4 nanoparticles are characterized using particle size distribution, zeta potential measurement and spectroscopic data. Thrombolytic ratio tests reveal that the efficiency for thrombus cleaning is significantly improved when using magnetically-controlled urokinase-coated Fe3O4 nanoparticles than pure urokinase solution. The average increase in the rate of thrombolysis with the use of urokinase-coated Fe3O4 nanoparticles is about 50%. In vitro thrombolysis test in a microfluidic channel using the coated nanoparticles shows nearly complete removal of thrombus, a result that can be attributed to the clot busting effect of the urokinase as it inhibits the possible formation of blood bolus during the magnetically-activated microablation process. The experiment further demonstrates that a thrombus mass of 10.32 mg in the microchannel is fully removed in about 180 s.
Subject(s)
Ferrosoferric Oxide/chemistry , Nanoparticles/chemistry , Thrombolytic Therapy/methods , Thrombosis/drug therapy , Urokinase-Type Plasminogen Activator/pharmacology , Coated Materials, Biocompatible/chemistry , Drug Delivery Systems , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/pharmacology , Humans , Microfluidics , Models, Theoretical , Particle Size , Urokinase-Type Plasminogen Activator/chemistryABSTRACT
Fe3O4 nanoparticles were controlled by an oscillating magnetic field to enable fast and non-contact ablation of microchannel occlusion. Scalable behaviour of their translational and rotational velocities was experimentally verified. Rotational flows created by such motions are fundamental for ablation as demonstrated by the removal of thrombi in occluded microchannels.
Subject(s)
Ferrosoferric Oxide/chemistry , Magnetite Nanoparticles/chemistry , Blood Coagulation/physiology , Humans , Magnetic Fields , Magnetite Nanoparticles/therapeutic use , Thrombosis/blood , Thrombosis/therapyABSTRACT
In this study, surface modification of iron (II, III) oxide Fe3O4 nanoparticles by oleic acid (OA) coating is investigated for the microablation of fat in a microchannel. The nanoparticles are synthesized by the co-precipitation method and then dispersed in organic solvent prior to mixing with the OA. The magnetization, agglomeration, and particle size distribution properties of the OA-coated Fe3O4 nanoparticles are characterized. The surface modification of the Fe3O4 nanoparticles reveals that upon injection into a microchannel, the lipophilicity of the OA coating influences the movement of the nanoparticles across an oil-phase barrier. The motion of the nanoparticles is controlled using an AC magnetic field to induce magnetic torque and a static gradient field to control linear translation. The fat microablation process in a microchannel is demonstrated using an oscillating driving field of less than 1200 Am-1.
