Conflictsof interest: CS, NG and WFQS are founders of BIOND Solutions B.V. (BI/OND). AO is employee of BIOND Solutions B.V. AvdS is a full-time employee of Philips Molecular Pathway Dx.

Worldwide, the incidence of primary brain tumors is on the rise. Unfortunately, noninvasive drug therapy is hampered by poor access of most drugs to the brain due to the insurmountable blood-brain barrier (BBB). Nanotechnology holds great promise for noninvasive therapy of severe brain diseases. Furthermore, recent bioconjugation strategies have enabled the invasion of the BBB via tailored-designed bioconjugates either with targeting moieties or alterations in the physicochemical and/or the pharmacokinetic parameters of central nervous system (CNS) active pharmaceutical ingredients. Multifunctional systems and new entities are being developed to target brain cells and tumor cells to resist the progression of brain tumors. Direct conjugation of an FDA-approved drug with a targeting moiety, diagnostic moiety, or pharmacokinetic-modifying moiety represents another current approach in combating brain tumors and metastases. Finally, genetic engineering, stem cells, and vaccinations are innovative nontraditional approaches described in different patents for the management of brain tumors and metastases. This review summarizes the recent technologies and patent applications in the past five years for the noninvasive treatment of glioblastoma and other brain tumors. Till now, there has been no optimal strategy to deliver therapeutic agents to the CNS for the treatment of brain tumors and metastases. Intensive research efforts are ongoing to bring novel CNS delivery systems to potential clinical application.

Kidney organoids derived from human induced pluripotent stem cells (iPSCs) have proven to be a valuable tool to study kidney development and disease. However, the lack of vascularization of these organoids often leads to insufficient oxygen and nutrient supply. Vascularization has previously been achieved by implantation into animal models, however, the vasculature arises largely from animal host tissue. Our aim is to transition from an in vivo implantation model towards an in vitro model that fulfils the advantages of vascularization whilst being fully human-cell derived. Our chip system supported culturing of kidney organoids, which presented nephron structures. We also showed that organoids cultured on chip showed increased maturation of endothelial populations based on a colocalization analysis of endothelial markers. Moreover, we observed migration and proliferation of human umbilical vein endothelial cells (HUVECs) cultured in the channels of the chip inside the organoid tissue, where these HUVECs interconnected with endogenous endothelial cells and formed structures presenting an open lumen resembling vessels. Our results establish for the first-time vascularization of kidney organoids in HUVEC co-culture conditions using a microfluidic organ-on-chip. Our model therefore provides a useful insight into kidney organoid vascularization in vitro and presents a tool for further studies of kidney development and drug testing, both for research purposes and pre-clinical applications.