Fig. 1: Integration of flexible electronics onto a vascularized 3D tumor model.

a Flexible interdigitated electrodes and the scheme of the tip. b Steps of the development of the in ovo model of glioblastoma. c Spheroid of U87 cells obtained by 3D cell culture observed under the microscope. d Shell-less culture of a quail embryo with a zoom on the grafted spheroid. e–g pictures of vascularized spheroids observed by fluorescence microscopy. On e and f, vasculature was visualized by injecting Texas Red dextran into the circulation. On (g) in addition to the intravascular injection of Texas Red dextran in the circulatory system (red), spheroid was labeled intravitally with a viability marker (green). h Flexible interdigitated electrodes placed on the in ovo model of glioblastoma, observed by fluorescence microscopy with the same markers than (g). Scale bars: a 2 mm, c 100 µm, d left: 1 cm, right: 200 µm, e–h 400 µm.