The technique of laser ablation in liquids is applied to produce of Boron-containing nanoparticles from ablation of a Fe$_2$B bulk target enriched in 10B isotope. Laser ablation of the target in liquid isopropanol results in partial disproportionation to free Fe and Boron while nanoparticles of Fe$_2$B are also presented. Nanoparticles are magnetic and can be collected using a permanent magnet. Average size of nanoparticles is of 15 nm. The content of 10B in generated nanoparticles amounts to 76,9 %. Nanoparticles are biocompatible and can be used in Boron Neutron Capture Therapy.