We previously have developed the
photoresponsive tetra-gel and
nanoparticles for controlling the function of the encapsulated substance
by UV irradiation. However, the penetration ability of the UV is not
high enough. Here, we developed a radiation-responsive tetra-gel and
nanoparticle based on γ-ray-responsive X-shaped polyethylene
glycol (PEG) linker with a disulfide bond. The nanoparticle could
retain small molecules and biomacromolecules. γ-Rays were used
as a trigger signal because of their higher penetrating ability. This
allowed a spatiotemporal release and control of the encapsulated substances
from the nanoparticle in the deeper region, which is impossible by
using light exposure (ultraviolet, visible, and near-infrared).