Despite profound advances in treatment approaches,
gliomas remain associated with very poor prognoses. The residual cells after incomplete resection often migrate and proliferate giving a seed for highly resistant
gliomas. The efficacy of chemotherapeutic drugs is often strongly limited by their poor selectivity and the blood brain barrier (BBB). Therefore, the development of therapeutic carrier systems for efficient transport across the BBB and selective delivery to
tumor cells remains one of the most complex problems facing molecular medicine and nano-biotechnology. To address this challenge, a stimuli sensitive
nanogel is synthesized using pre-
polymer approach for the effective delivery of nano-irradiation. The
nanogels are cross-linked via
matrix metalloproteinase (MMP-2,9) substrate and armed with Auger electron emitting
drug 5-[125 I]Iodo-4"-thio-2"-
deoxyuridine ([125 I]ITdU) which after release can be incorporated into the
DNA of
tumor cells. Functionalization with
diphtheria toxin receptor ligand allows
nanogel transcytosis across the BBB at
tumor site. Functionalized
nanogels efficiently and increasingly explore transcytosis via BBB co-cultured with
glioblastoma cells. The subsequent
nanogel degradation correlates with up-regulated MMP2/9. Released [125 I]ITdU follows the
thymidine salvage pathway ending in its incorporation into the
DNA of
tumor cells. With this concept, a highly efficient strategy for intracellular delivery of
radiopharmaceuticals across the challenging BBB is presented.