Nonstoichiometric Nanocubes with a Controllable Morphology and Persistent Luminescence for Autofluorescence-Free Biosensing

Persistent luminescence nanoparticles (PLNPs) have shownspecialadvantages in areas such as bioimaging, cancer therapy, stress sensing,and photo-biocatalysis. However, the lack of methods for controllablesynthesis of PLNPs with uniform morphologies and strong persistentluminescence has seriously hindered the applications of PLNPs. Herein,we reported that modifying the electronic structures of zinc gallogermanate(ZGGO) PLNPs by nonstoichiometric reactions can produce highly uniformnanocubes with controllable size and persistent luminescence. By nonstoichiometricincrease of the Ge/Ga ratio in ZGGO, the ZGGO PLNPs were transformedfrom a mixture of nanocubes and small nanospheres into highly symmetricaland uniform large nanocubes, accompanied by the enhancement of persistentluminescence intensity by about 3.7 times. Moreover, we found thatZGGO PLNPs were responsive to reactive oxygen species (ROS), thatis, the persistent luminescence of ZGGO can be quenched by ROS. Autofluorescence-freeserum ROS detection was achieved with the developed PLNPs. Further,a biosensing assay for glucose oxidase (GOx) was designed based onthe responsiveness of ZGGO PLNPs to H2O2. Thisstudy may pave a new way for better control of PLNPs' size,morphology, and persistent luminescence, and it can further promotethe applications of PLNPs in areas ranging from theranostics to solarenergy utilization.