Figure 1. Magnetic iron oxide-containing hydrogels.
a, Human glioblastoma cells (lower arrow) treated with magnetic iron oxide (MIO)-containing hydrogel held at the air-medium interface by a magnet. The image was captured at 48 h of culture and depicts a ~1 mm spheroid. Scale bar, 5mm. b, Vial of a MIO-containing hydrogel (arrow) in water. c, Scheme of electrostatic interaction of nanoparticles (spheres) with phage (elongated structures). Gold (yellow sphere) and MIO (brown sphere) nanoparticles are depicted (not drawn to scale). d, MRI image (T2*-weighted) of purified hydrogel in solution: MIO-containing hydrogel (top panel), average T2* = 16 ms and MIO-free hydrogel control (bottom panel), average T2* = 46.2 ms. Scale bar, 2 mm.