Research On The Stability And Cell Imaging Of CsPbBr₃@SiO₂ Nanoparticles

As one of the emerging photoelectric materials,CsPbBr₃ nanocrystals?NCs?have been predicted promising in various optoelectronic fields.However,it remains a significant challenge for CsPbBr₃ NCs to keep stable against aqueous environment.The vulnerable characteristics result in great difficulty for them to be used in most biomedical fields,e.g.tumor cell detection and diagnosis.To unlock the potential of CsPbBr₃ NCs in tumor imaging,it is an urgent demand to come up with a smart method to tightly encapsulate CsPbBr₃ NCs into nano-sized and biocompatible shells.And our research addresses this critical challenge.We developed a nature inspired“stress-response”method.When perceiving circumstantial life threats,many of living creature tend to protect themselves by rapidly growing a secondary outer shell,namely as“stress response”.Accordingly,we simply added an–NH₂ ended oxosilane,?3-aminopropyl?triethoxysilane?APTES?,as a new-type capping ligand.Our experimental results showed that the APTES molecules act as both the inductor to perceive the existence of moisture,and the Si O₂ precursor to fast form tight Si O₂ nano-shells at the surface of CsPbBr₃ NCs,resulting in a highly improved waterproof feature of CsPbBr₃@Si O₂ nanoparticles,allowing us to apply the CsPbBr₃@Si O₂ nanoparticles as the fluorescent probes for tumor cell imaging.We incubated CT26 tumor cells with CsPbBr₃@Si O₂ nanoparticles capped with human serum albumin?HSA?.Uptake of CsPbBr₃@Si O₂@HSA nanoparticles can be clearly observed from the robust and highly stable optical signals from the live cells.To the best of our knowledge,our work is the first report that lead halide perovskite?LHP?NCs were used in the biomedical field.Our study showed a simple ligand engineering approach to protect LHP NCs,and their high potential of biomedical applications.More specifically the key points of our study are:1.The CsPbBr₃ nanocrystals were prepared by the hot injection method,and then their morphology and fluorescence properties were studied through a series of characterizations:the CsPbBr₃ nanocrystals prepared by the hot injection method were found to be the cubic phases with uniform distribution and the size was 11.0±1.2 nm.The optical performance shows that the fluorescence emission peak is around 516 nm and the absorption peak is around 507 nm and the full width at half maximum?FWHM?is only 20 nm,showing its superior fluorescence performance.2.The simple nature inspired method was used to fast form tight Si O₂ nano-shells within lower than 30 minutes.And it shows the high water resistance of CsPbBr₃@Si O₂nanoparticles for over 48 hours.3.Our work was the successful demonstration of CsPbBr₃@Si O₂ nanoparticles with advantageous feature of high water stability,biocompatibility,and ignorable cytotoxicity during the complex and long-term operation of tumor within 24 hour test,showing their high potential in early cancer diagnosis.