Major technological attempts are today being made to produce materials and engineer systems suitable for so-called Lab-on-a-chip. These are devices capable of performing selected biochemical reactions and accurate analyses on a single chip. The key challe nge here is to develop materials and technical processes that allow fast and reliable transpor-tation of molecules or reagents across the chip. This transportation can be performed us-ing tiny shuttles, e.g. paramagnetic colloidal particles that carry sin gle molecules, and can be manipulated with external magnetic fields. We propose a novel system for magnetic manipulation, which consists of a specially manufactured ferrite garnet film, Y2.5Bi0.5Fe5-qGaqO12 (q = 0.5-1), with sophisticated tunable magnetic domain structure. As molecular shuttle we propose to use super-paramagnetic functionalized Ugelstad spheres. The sys-tem can realize not only transportation, but also separation operations on a discrete space and time base. Thus, the system becomes a dev ice for digital molecular computation. The advantages of the proposed device include that (i) one does not need a complex channel network enabling transport as in most microfluidic chips, (ii) full flexibility in the trans-portation routes and the operati ons performed, since the domain pattern can be com-pletely rewritten, (iii) the possibility to follow the pattern dynamics and shuttle motion using a polarized light microscopy due to the large Faraday effect in ferrite garnets.