β-Galactosidase-guided self-assembled ⁶⁸Ga nanofibers probe for micro-PET tumor imaging

β-galactosidase (β-gal) has high activity in various malignancies, which is suitable for targeted positron emission tomography (PET) imaging. Meanwhile, β-gal can successfully guide the formation of nanofibers, which enhances the intensity of imaging and extends the imaging time. Herein, we designed a β-galactosidase-guided self-assembled PET imaging probe [⁶⁸Ga]Nap-NOTA-1Gal. We envisage that β-gal could recognize and cleave the target site, bringing about self-assembling to form nanofibers, thereby enhancing the PET imaging effect. The targeting specificity of [⁶⁸Ga]Nap-NOTA-1Gal for detecting β-gal activity was examined using the control probe [⁶⁸Ga]Nap-NOTA-1. Micro-PET imaging showed that tumor regions of [⁶⁸Ga]Nap-NOTA-1Gal were visible after injection. And the tumor uptake of [⁶⁸Ga]Nap-NOTA-1Gal was higher than [⁶⁸Ga]Nap-NOTA-1 at all-time points. Our results demonstrated that the [⁶⁸Ga]Nap-NOTA-1Gal can be used for the purpose of a new promising PET probe for helping diagnose cancer with high levels of β-gal activity.