Abstract
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Objectives A gold/mesoporous silica hybrid nanoparticle (GoMe), which possesses the best of both conventional gold nanoparticles and mesoporous silica nanoparticles, such as excellent photothermal converting ability as well as high and versatile drug loading capacity, has been developed. The objective is to evaluate PET imaging of GoMe in lung cancer mouse model.
Methods The GoMe hybrid nanoparticles with built-in phthalocyanine photosensitizer Pc 4 were conjugated with or without DOTA and radiolabeled by Cu64 at 37 oC. The Cu64 radiolabeling was evaluated in phosphate buffer and mouse serum for up to 24 hours. The nanoparticles labeled with Cu64 were injected in mouse with clinically relevant spontaneous lung tumors induced by urethane. Gd-DTPA enhanced MRI was performed to confirm tumor occurrence. PET imaging were performed at 6h and 20h post-injection of Cu64 labeled nanoparticle.
Results The labeling yield was above 98%. Both Cu64 radiolabeling with or without DOTA showed excellent stability in phosphate buffer. For the stability in mouse serum, the Cu64 labeling with DOTA chelator was stable for up to 24 hours while that without DOTA was much less stable. While the nanoparticles showed highest uptake in liver, PET at both time points clearly detected all 3 tumors in lung that were in agreement with the MRI findings.
Conclusions Cu64-labeled GoMe can successfully detect the existence of clinically relevant spontaneous lung tumors in a urethane-induced lung cancer mouse model through PET imaging. Furthermore, GoMe can be utilized an effective theranostic platform for cancer therapy when loaded with therapeutic drugs.