posted on 2024-02-09, 03:29authored byPeng Zhang, Yuran Wang, Xiaotong Liu, Lishan Yuan, Jianing Liu, Ranran Guo, Ye Tian
Real-time,
noninvasive, and nonradiative bone imaging can directly
visualize bone health but requires bone-targeted probes with high
specificity. Herein, we propose that carboxyl-rich fluorescent nanoprobes
are easily absorbed by macrophages in bone marrow during circulation,
enabling optical bone marrow imaging in vivo. We
used PbS/CdS core–shell quantum dots with NIR-IIb (1500–1700
nm) emission as substrates to prepare the carboxyl-rich nanoprobe. In vivo NIR-IIb fluorescence imaging with the nanoprobes
showed high resolution and penetration depth in bone tissues and allowed
for imaging-guided fracture diagnosis. Bone tissue slices showed substantial
accumulation of carboxyl nanoprobes in the bone marrow and strong
colocalization with macrophages. Similar results with CdSe quantum
dots and an organic nanofluorophore suggest that carboxyl surface
modification is effective to achieve bone marrow targeting, providing
a novel strategy for developing bone/bone marrow imaging probes.