Collective Activation of MRI Agents via Encapsulation and Disease-Triggered Release Mathieu L. Viger Jagadis Sankaranarayanan Caroline de Gracia Lux Minnie Chan Adah Almutairi 10.1021/ja403167p.s001 https://acs.figshare.com/articles/journal_contribution/Collective_Activation_of_MRI_Agents_via_Encapsulation_and_Disease_Triggered_Release/2410945 An activation mechanism based on encapsulated ultrasmall gadolinium oxide nanoparticles (Gd oxide NPs) in bioresponsive polymer capsules capable of triggered release in response to chemical markers of disease (i.e., acidic pH, H<sub>2</sub>O<sub>2</sub>) is presented. Inside the hydrophobic polymeric matrices, the Gd oxide NPs are shielded from the aqueous environment, silencing their ability to enhance water proton relaxation. Upon disassembly of the polymeric particles, activation of multiple contrast agents generates a strong positive contrast enhancement of >1 order of magnitude. 2013-05-29 00:00:00 contrast enhancement bioresponsive polymer capsules H 2O water proton relaxation contrast agents encapsulated ultrasmall gadolinium oxide nanoparticles Gd oxide NPs activation Collective Activation MRI Agents chemical markers