Visualization of magnetic microcapsules in liquid by optical coherent tomography and control of their arrangement via external magnetic field

Optical coherence tomography (OCT) is a new, non-invasive, noncontact in vivo imaging technology. We demonstrated that the OCT can be used as a sufficient technique for nanocomposite microcapsule visualization in a liquid medium. As a model system we choose a water/glycerol mixture with viscosity in a variable range from 1.01 to 1.41×103 mPa s, including viscosity of a blood plasma. We have found that tomography spatial resolution is enough to visualize capsules and their aggregates in liquids and to estimate their concentration via two-dimensional (2D) tomography scan analysis. In our experimental conditions microcapsule concentration measured by OCT was 3.9×107 cm-3 and this value correlated well with the concentration measured in a counting chamber (1.9×107 cm-3). We also demonstrated the possibility to control capsule spatial distribution in glycerol solutions by external magnetic field and determined the dependence of capsule sedimentation time on the liquid medium viscosity.