Lanthanide-doped upconversion nanoparticles (UCNPs), emerging as a new generation of luminescent nano-bioprobes, have attracted tremendous interest for their potential bioapplications. Various UCNPs coated with silica shells for loading photosensitizers have been designed for bioimaging and near-infrared (NIR)-triggered photodynamic therapy (PDT).

Currently, the bottleneck for the practical application of these nanoprobes lies in their low PDT efficacy, which is primarily ascribed to low loading capacity of photosensitizers and inefficient energy transfer from UCNPs to the photosensitizer. 

To overcome these concerns, a research group led by Prof. CHEN Xueyuan and HUANG Mingdong at Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, have recently developed a novel strategy to fabricate multifunctional sub-50 nm nanoprobes based on β-NaLuF4:Gd/Yb/Er core and porous organosilica shell.  

Rattle structure and aromatic framework have been smartly designed for loading photosensitizers with higher capacity, shortening distance between UCNPs and photosensitizers, and inhibiting the self-aggregation of photosensitizers, all of which are critical for improving PDT efficacy.  

Particularly, a novel photosensitizer, β-carboxyphthalocyanine zinc, was successfully loaded in the rattle-structured nanoprobes with a capacity up to 7.7 wt% and a record-high upconversion (UC) energy transfer efficiency (98%) was achieved. This led to much higher NIR-triggered PDT efficacy against human lung cancer cells as compared to those counterparts with conventional core-shell structure or with pure-silica shell. They also demonstrated the successful use of these nanoprobes in  X-ray computed tomography(CT)/UC dual-mode bioimaging and tumor-targeting, revealing the great potentials of these rattle-structured nanoprobes for cancer theranostics. 

This study entitled “Multifunctional Nano-Bioprobes Based on Rattle-Structured Upconverting Luminescent Nanoparticles” was published as a communication in Angew. Chem. Int. Ed. (Angew. Chem. Int. Ed. 2015, 54, 7915-7919).

This work was supported by the 973 program of MOST, Special Project of National Major Scientific Equipment Development of China, the NSFC, the CAS/SAFEA International Partnership Program for Creative Research Teams, Strategic  Priority Research Program of the CAS, and NSF of Fujian Province.

Illustration of multifunctional nano-bioprobes based on rattle-structured organosilica-shelled UCNPs. (Image by Prof. CHEN Xueyuan's group)

Contact:
Prof. CHEN Xueyuan
Key Laboratory of Optoelectronic Materials Chemistry and Physics
Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences
Fuzhou, Fujian 350002, China
E-mail: xchen@fjirsm.ac.cn