Method of preparing macrophage-targeting nanobody 68Ga-NOTA-Nb119 as PET molecular probe / 西安交通大学学报(医学版)

ABSTRACT

【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 BCⅡ10. 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.