Dynamic microcontainers as microvacuums for collecting nanomaterials after clinical treatments

We present a feasible method to collect ferromagnetic nanomaterials (FNMs) after clinical utilization by employing ferromagnetic micro-containers (MCs). The cubic MCs with dimensions of 200 micrometers have gold-coated nickel frames and were tethered such a way that they are able to remove FNMs from cells with the use of an external magnetic field. The study has been conducted in two parts: 1) enhancement of the motion of MCs in glass-based microfluidic channels filled with viscous fluids by magnetically-driven spinning MCs, i.e., 'dynamic MCs'; 2) sweeping FNMs from the cells using magnetic attractive forces between FNMs and MCs through a 'microvacuum' process. Our study shows that spinning MCs can transport better than nonspinning MCs through viscous fluids. We found that approximately 70% of FNMs internalized with human embryonic cells (HEK-293) were removed from the cells by the spinning MCs. Such in-vitro experiments suggest the possibility of resolving the issue of removing FNMs used for clinical treatments from human body after treatments.