Drug and bioactive delivery

One of the reasons nanomedicine is such an exciting field is that it promises to revolutionize pharmacological therapies by drastically reducing side effects and dosages. Once this is possible, one can imagine that chemotherapy would be much more bearable, the number of potentially useful drugs identified by in vitro screens would be much larger, and biological therapeutics could be much less expensive. These ambitious goals can be accomplished by encapsulating drugs in nanoparticles engineered to deliver their cargo preferentially to the cells and tissues in which they’re needed.

While most in the field approach this by attaching molecules that bind to proteins on target cells, CNME investigators take other innovative approaches. Several labs are developing nanocarriers that allow external control over their location or release of encapsulated molecules, while others are exploiting the capabilities of biological materials.

Responsive nanocarriers

Externally controllable nanocarriers under development within CNME respond to a variety of stimuli, each of which offer distinct advantages. Magnetically responsive nanoparticles enable both guidance to particular locations and triggered release; the Sungho Jin lab has developed nanocapsules containing iron oxide that allow remotely switchable release of anticancer drugs. Alternatively, the Joseph Wang lab has employed magnetic fields to guide ultrasound-powered nanowire motors. Finally, because light provides the greatest spatial resolution of any external stimulus, Adah Almutairi’s lab is breaking ground with materials capable of responding to wavelengths that innocuously penetrate tissues to appreciable depths. As these would enable precise control over the activity of encapsulated molecules in intact organisms, they promise major impact on fundamental biological research.

Light-triggered release. Absorption of light triggers polymer degradation, causing the nanoparticle to dissolve and release its contents (blue).

Biological materials

Other CNME investigators are exploiting biologically derived materials to target particular tissue sites or alter the pharmacokinetics of nanocarriers. Liangfang Zhang’s group has introduced a simple, biomimetic solution to clearance of nanoparticles by phagocytes. Encasing polymeric nanoparticles in red blood cell membranes greatly increases their circulation time, and has led to novel uses of such materials, including toxin removal and delivery of toxoid vaccines.