Thermosensitive Biodegradable Copper Sulfide Nanoparticles for Real-Time Multispectral Optoacoustic Tomography.

Although multifunctional inorganic nanoparticles have been extensively explored for effective cancer diagnosis and therapy, their clinical translation has been greatly impeded because of significant uptake in the reticuloendothelial system and concerns about potential toxicity. In this study, we uncovered the thermosensitive biodegradability of CuS nanoparticles, which have classically been considered as stable in bulk state. Polyethylene glycol (PEG)-coated CuS nanoparticles (CuS-PEG) were well preserved at 4 ºC but were rapidly degraded at 37 ºC within 1 week in both in vitro and in vivo tests. Furthermore, real-time multispectral optoacoustic tomography, which is more convenient and accurate than traditional ex vivo analysis, was successfully employed to noninvasively demonstrate the biodegradability of CuS-PEG nanoparticles and dynamically monitor their tumor imaging capacity. The temperature-dependent controllable degradation profile and excellent tumor retention of CuS-PEG nanoparticles endows them with great potential for clinical applications since it ensures that the nanoparticles remain intact during production, transportation, and storage but degrade and clear from the body at physiological temperature after accomplishing sufficient diagnosis and therapeutic operations.