Development of silica-containing redox nanoparticles for medical applications.

Silica-containing redox nanoparticles (siRNP) are nanocomposites consisting of silica nanoparticles and amphiphilic block copolymers with nitroxide radicals as reactive oxygen species (ROS) scavengers. Electrostatic interactions between the cationic segment of a polymer in the core and the entrapped silica nanoparticles form a crosslinking structure that provides siRNP stability in vivo, even under harsh conditions in the gastrointestinal tract. Due to the adsorption character of silica nanoparticles in the nanocomposite, siRNP can be applied not only for adsorbents of body wastes but also for drug carriers with high loading capacity. The ROS-scavenging character of siRNP significantly improves their performance for medical applications. Here, we describe the development of siRNP and provide two examples of their medical applications as (1) novel nano-sized adsorbents for peritoneal dialysis, and (2) orally administrable drug carriers for the treatment of gastrointestinal inflammation.