Progress of Monodispersed Nano-Hydroxyapatite-Based Biological Tracing

Abstract

Nano-hydroxyapatite (nHAp)-based dual-/multi-modal bioimaging systems have received significant attention due to their excellent bioactivity and biocompatibility. However, it is difficult to obtain highly sensitive imaging results. On the one side, the high surface energy of nHAp tends to enable the agglomerations of nHAp, which could further limit the clinical applications. On the other side, the main strategy for the construction of co-doped nHAp nanocrystals depends on high temperature and techniques of post-modification, resulting in inevitable nHAp crystal polymerization and increased particle size. In order to overcome the current shortcomings of nonmonodispersed nHAp, such as uneven distribution and easy aggregation, the construction of monodispersed nHAp is expected to ensure the imaging performance of traceable nHAp by reducing the aggregation of nHAp in vivo and improving the imaging sensitivity. Thus, in this review, the approaches of monodispersed nHAp based on hydrothermal, biomimetic and microwave synthesis methods are summarized. Furthermore, the development of single/multi-mode traceable monodispersed nHAp for biological imaging applications is also discussed.