Methods for Making Particles Having Long Spin-Lattice Relaxation Times

摘要

Methods for making collections of small particles having spin-lattice relaxation times greater than about 5 minutes are described. The long-T₁ particles are useful as imaging agents for nuclear magnetic resonance imaging. In one embodiment, bulk silicon wafers are reduced to particles in a machining process, and the particles processed to obtain a collection of particles having an average size of about 300 nanometers and a T₁ relaxation time of about 15 minutes. The particles can be subjected to post-fabrication processing to alter their surface composition or the chemical functionality of their surface. In certain embodiments, porous particles produced by the inventive methods can be loaded with pharmaceutical drugs and used to track and evaluate delivery and effectiveness of drugs.