Preparation of dual-modal nanoprobe for fluorescent-magnetic imaging with manganese-doped car-bon quantum dots and imaging study in tumor bearing mice / 中华核医学与分子影像杂志

ABSTRACT

Objective To prepare manganese-doped carbon quantum dots ( Mn-CDs) dual-modal nanoprobe for fluorescent-magnetic imaging, and evaluate its characteristics and potential on fluorescence imaging and MRI. Methods Mn-CDs were synthesized at 150 ℃. The form, diameter, component, fluo-rescent capability, T1 relaxation rate, stability and cytotoxicity of Mn-CDs in vivo were verified. The fluores-cence imaging of HO-8910 tumor-bearing mice was performed on small animal imager, and the whole-body enhanced imaging was performed on 3.0 T MRI scanner. One-way analysis of variance was used to analyze the data. Results The Mn-CDs with the diameter of (4.64±0.85) nm showed a well-defined spherical morpholo-gy. The fluorescent spectra of Mn-CDs exhibited that the excitation maximum was at 360 nm and the emission maximum was at 440 nm. The T1 relaxation rate was (3.26±0.04) mmol·L-1·s-1. The Mn-CDs had good stability of fluorescent and magnetic imaging capability at 0, 0.25, 0.5, 0.75, 1.0 and 2 months at room tem-perature with no significant differences of fluorescent and magnetic signals ( F=1. 566 and 0. 987, both P>0. 05) . After injection of 200 μl Mn-CDs ( 15 g/L) , mice were all alive and had no viscera damage. The tumor could be observed obviously on fluorescence imaging at 5 min. Enhanced MRI showed that the tumor was unevenly enhanced and Mn-CDs were mainly cleared away through urinary system. Conclusion Mn-CDs are stable and have good potential on fluorescence imaging and MRI, which provides a promising multimodal im-aging method for tumor detection and monitoring.