Engineering upconversion nanoparticles for biomedical imaging and therapy

Upconversion nanoparticle (UCNP) has been attracting growing interests in the last few years owing to their unique upconversion luminescence features. Although the size and morphology control of UCNP have been well-documented, engineering of ultrasmall-sized UCNP with excellent optical properties is still in its early stage. With increasing interests in using UCNP as deeper tissue imaging probe, some new strategies have been developed for enhancing the emission efficiency of red and near-infrared bands. Also, doping suitable ions into UCNP crystal lattices has been accepted as one of the most unique and efficient techniques for integrating nearly all clinical relevant imaging modalities together in one single UCNP. Cancer multimodal imaging (or therapy) with these lanthanide ions-doped UCNPs has become a new hot topic in this field. Here, we summarized the very recent advances in engineering of UCNP for biological imaging and therapy.