A green, efficient, photoinduced synthesis of arylboronic esters and aryl sulfides has been developed. Bench stable arylazo sulfones were used as radical precursors for a photocatalyst- and additive-free carbon–heteroatom bond formation under visible light. The protocols are applicable to a wide range of substrates, providing products in good yields.

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.

Blood–Brain Barrier In article number 2100812 by Smriti Singh, Agnieszka Morgenroth, and co‐workers, Matrix metalloprotease (MMP) sensitive nanogels are synthesized for effective delivery of a radiopharmaceutical ([125I]ITdU) across the blood‐brain barrier (BBB). The nanogels show efficient transcytosis across the in vitro model of BBB co‐cultured with glioblastoma cells. Once transcytosed, nanogels degrade in an up‐regulated MMP2/9 environment of glioblastoma and release the radiopharmaceutical, which gets incorporated into the DNA of tumor cells by thymidine salvage pathway.