Drugs have main and adverse effects. Drugs have adverse effects because they spread to unaffected areas. To reduce such adverse effects, drugs should be concentrated in affected areas. This involves the use of a drug delivery system (DDS). Our research unit is developing new treatments for various diseases using nanoparticles and nanostructures as DDSs.

Nanoparticles to deliver drugs only to affected areas

Nanoparticles and nanostructures are used for different purposes. For example, nanoparticles are used to deliver drugs only to affected areas by injection into the blood. In general, the pH is lower in affected than in unaffected areas. Using this property, we prepared very small particles (nanoparticles) that only degrade at a low pH to eliminate active oxygen. The nanoparticles are administered into the body to exert effects only in affected areas, minimizing their effects in unaffected areas (Figure 1). In fact, nanoparticles have been administered to experimental animals with cerebral infarction, markedly improving the symptoms.

Figure 1 : Applied research on targeted DDS nanoparticles

Nanostructures that deliver drugs only to affected areas and maintain constant drug concentrations

Constant drug concentrations should be maintained for a long time in affected areas. Thus, for example, nanostructures are incorporated into biological materials to deliver drugs only to surgical sites and maintain constant drug concentrations. We developed a technique to coat (nanostructure) the surface of a biological material (e.g., artificial bone) to be implanted, in which a drug has been incorporated. This facilitates sustained drug release, exerting effects only in the affected area (Figure 2). Biological materials prepared using this technique have been effective in animal experiments, and should be applied to human treatments within this fiscal year.
Many research institutions have gathered in The Tsukuba Science City. Taking advantage of this, the Faculty of Medicine, University of Tsukuba will collaborate with them to develop various nanoparticles and nanostructures and apply nanostructure DDSs to medical practice in order to develop new Tsukuba drugs (nanomedicines).

Figure 2 : Cell control using nanostructures

(Interviewed on July 24, 2013)