With the rapid development of nanotechnology, the unique rare earth lanthanide-doped upconversion nanocrystals (UCNs), which can convert tissue-penetrable near-infrared (NIR) photonic irradiation into ultraviolet, visible and NIR emissions, have found significant potential in bioimaging, diagnosis, therapy, as well as photovoltaics and optical data storage. Despite the promising achievements made in the past decade, critical challenges associated with low upconversion efficiencies and overheating effect induced by NIR laser-irradiation remain in the biomedical fields. More well-defined material design and unique structural modification are highly demanded that are capable of solving these technical concerns and promoting such promising NIR light mediated upconversion nanocrystals for their further practice in medical sciences. Recent advances in upconversion nanomaterials have witnessed the tremendous development towards enhancing the photon converted efficiency, which provides great opportunities in expanding the UCNs potential in bioimaging diagnosis and anticancer therapy. Hence, this review is mainly focusing on summarizing the fundamental principles and strategies to improve the upconversion luminescence and the approaches to reduce the local thermal effect on the basis of rational design of UCNs. In addition, the future perspectives in the development of UCNs for biomedical applications are also proposed.
- Linna Lyu
- Haolun Cheong
- Bengang Xing
