Researchers from the University of California and Harvard-MIT have developed a new type of biodegradable, non-toxic nanoparticle (NP) that break down readily and can be excreted via the kidneys after delivering a drug payload to the target site thereby avoiding a major drawback with some other nanoparticle delivery systems that may have limited biodegradability, toxicity issues or which are rejected immediately by the body’s immune system.

The novel NPs were formed by electrochemical etching of single-crystal silicon wafers followed by ultrasonication and filtration, yielding NPs with 5-10nm pore diameters. Silicon oxide grown onto the surfaces provides an intrinsic photoluminescence at 650-900nm which is a range where organs and tissues exhibit very low adsorption, thereby providing a mechanism for monitoring accumulation and degradation in-vivo.

In-vivo tests in a mouse model with the anti-cancer drug doxorubicin showed accumulation in a tumour followed by subsequent breakdown of the NPs, probably into soluble silicic acid, and elimination by renal clearance within 1-4 weeks of injection with no indications of toxicity.

Source: Nanowerk

Paper: Nature Materials