Silica-Encapsulated Perovskite Nanocrystals for X-ray-Activated Singlet Oxygen Production and Radiotherapy Application

Abstract

Multicomponent systems consisting of lead halide perovskite nanocrystals (CsPbX 3 -NCs, X = Br, I) grown inside mesoporous silica nanospheres (NSs) with selectively sealed pores combine intense scintillation and strong interaction with ionizing radiation of CsPbX 3 NCs with the chemical robustness in aqueous environment of silica particles, offering potentially promising candidates for enhanced radiotherapy and radio-imaging strategies. We demonstrate that CsPbX 3 NCs boost the generation of singlet oxygen species ( 1 O 2 ) in water under X-ray irradiation and that the encapsulation into sealed SiO 2 NSs guarantees perfect preservation of the inner NCs after prolonged storage in harsh conditions. We find that the 1 O 2 production is triggered by the electromagnetic shower released by the CsPbX 3 NCs with a striking correlation with the halide composition (I 3 > I 3−x Br x > Br 3 ). This opens the possibility of designing multifunctional radio-sensitizers able to reduce the local delivered dose and the undesired collateral effects in the surrounding healthy tissues by improving a localized cytotoxic effect of therapeutic treatments and concomitantly enabling optical diagnostics by radio imaging.

Ultrafast and Radiation-Hard Lead Halide Perovskite Nanocomposite Scintillators

“…The detection of high-energy photons (X or γ), particles (α, β) and neutrons, commonly referred to as ionizing radiation, is at the heart of many strategic applications in both science and technology, including high-energy/particle physics, space exploration, medical diagnostics, − cargo screening, border security, and industrial and environmental monitoring. , Typically, ionizing radiation is detected using direct radiation-to-charge converters , or scintillator materials − which emit UV–visible photons upon interaction with ionizing radiation by physical processes dependent on the nature of the radiation itself, such as Coulomb collisions, Compton scattering, photoelectric effect, and carrier pair formation . The fundamental characteristics of a scintillator are the probability of interaction with ionizing radiation, which scales with the n th power of the average atomic number Z (where n = 1–5 depending on the type of interaction), , the scintillation efficiency or light yield (LY), expressed as the number of photons emitted per unit of absorbed energy, and the stability at high doses of absorbed radiation, also known as radiation hardness. − The scintillation rate is of paramount importance when radiation detection is performed in time-of-flight (TOF) mode, which assigns a precise time tag to each scintillation event .…”

Advances in Perovskite Nanocrystals and Nanocomposites for Scintillation Applications

“…The presence of a sintering agent, which promotes the collapse of the internal pores of the MSN template, ensured the sealing of the emissive PNCs inside the MSN (Figure e). The silica-coated PNCs have been successfully applied as biological markers for in vivo X-ray imaging and have been shown to dramatically enhance the production of radical oxygen species for radiotherapy applications . Similarly, an armor-like passivation strategy to synthesize highly efficient and stable CsPbBr 3 PNCs by the solvothermal method was presented by Yang et al .…”

Long live(d) CsPbBr3 superlattices: colloidal atomic layer deposition for structural stability

“…Metal halide perovskite nanocrystals (PNCs) are promising materials for many applications such as photovoltaics, 1 photodetectors, 2 photocatalysts, 3 and scintillators 4 due to their diverse and tunable optoelectronic properties governed by their composition and stabilized by a wide breadth of surface capping groups. 5–7 Ordered PNC self-assembly under slow solvent evaporation leads to superlattice (SL) formation where the individual PNCs can be considered “atoms” and the extended structure leads to micron-sized cubic supercrystals.…”