Fabrication and bioconjugation of BIII and CrIII co-doped ZnGa2O4 persistent luminescent nanoparticles for dual-targeted cancer bioimaging
Persistent luminescent nanoparticles (PLNPs) show great potential in realizing precision imaging due to the absence of in situ excitation and no background interference. However, the current PLNP-based tumour imaging is usually achieved by single targeting or passive targeting strategies, and thus it lacks high specificity and affinity for efficient persistent luminescence imaging in vivo. Herein we report the bioconjugation of multiple targeting ligands on the surface of PLNPs for dual-targeted bioimaging to improve the specificity and affinity of the PLNP nanoprobe for in vitro and in vivo bioimaging. The PLNPs were prepared by co-doping CrIII and BIII into ZnGa2O4via a hydrothermal–calcination method. While CrIII doped ZnGa2O4 PLNPs possess excellent near-infrared luminescence along with long afterglow and red light renewable near-infrared luminescence, doping of BIII into the PLNPs further improves the persistent luminescence. Conjugation of two targeting ligands, hyaluronic acid and folic acid, which have specificity toward the cluster determinant 44 receptor and folic acid receptor in tumour cells, respectively, provides synergistic targeting effects to enhance the specificity and affinity toward tumour cells. This work provides a dual-targeting strategy for fabricating PLNP-based nanoprobes to realize precision tumour-targeted bioimaging.