Contents: (Adv. Sci. 7/2016)

Cyrille Boyer, May Lim, and co-workers highlight recent advances in upconversion nanoparticles (UCNPs) as NIR-initiated controlled drug delivery systems. Surface modification strategies are reviewed alongside with the influence of the laser power intensity and illumination time on the drug release pattern in article 1500437. NIRto-UV/visible UCNPs have emerged as potential remotecontrolled nanotransducers to generate in situ UV/visible light in order to activate the photoreaction of photoresponsive molecules for drug delivery applications. The cover design represents the mechanism of upconverting process by energy transfer between doped lanthanide ions in the upconversion nanoplatforms using NIR laser as excitation source and generation of UV/visible light.