靶向巨噬细胞的纳米抗体PET分子探针⁶⁸Ga-NOTA-Nb119的制备方法

Objective: To prepare positron emission computed tomography (PET) molecular probes targeting macrophages using Nb119 and BCⅡ10 labeled with ⁶⁸Ga nuclide. Methods: To explore the labeling conditions of nanobodies with ⁶⁸Ga nuclides, first, the anti-Vsig4 nanobody Nb119 and isotype control antibody BCⅡ10 were incubated with NOTA and then purified to obtain the chelating agent-modified NOTA-Nb119 and NOTA-BCⅡ10. The NOTA-Nb119 and NOTA-BCⅡ10 were further incubated with ⁶⁸Ga. Finally, NOTA-Nb119 was identified by SDS-PAGE and MALDI-TOF methods, and the radiochemical purity was detected by radio-HPLC. Results: The results of SDS-PAGE showed that the lanes of the successfully labeled NOTA-Nb119 had apparent hysteresis than the unlabeled nanobody band, which proved that the molecular weight of the labeled product was increased and NOTA successfully modified the nanobody. Subsequently, ⁶⁸Ga nuclides could successfully label Nb119 and BC Ⅱ10. According to radio-HPLC detection, the radiochemical purity of NOTA-Nb119 and NOTA-BCⅡ10 labeled with ⁶⁸Ga was greater than 90% and remained stable. Conclusion: ⁶⁸Ga-labeled nanobodies have high radiochemical purity and high stability, indicating that this study can be applied to other nanobodies for modification and labeling and provides a practical and feasible method for the preparation of PET using nanobodies.