Novel research results on application of multi-step surface functionalized mesoporous silica nanoparticles (MSNs) in targeted cancer therapy and MRI imaging aredemonstrated. The external surface of MSN is functionalized with Chlorotoxin which targets the most aggressive type of brain cancer-Glioblastoma multiforme (GBM). Entrapping drugs (e.g. Paclitaxel) and the FDAapproved MRI contrast agent Gadobutrol within the pores is achieved through binding of cyclodextrin to the pore entrances through an acidification-cleavable hydrazone linkage. This further enables pH-responsive drug or contrast agent release from the MSNs. The tests on cancer cells reveal the capabilities of the prepared materials to deliver drugs and kill cancer cells. On the other hand, the tests involving MRI measurements revealed the capabilities of real time tracking of the release of contrast agents by MRI, which evidences the promising potential for the development of MRI-based methodology for monitoring and tracking the release of therapeutic content