Enhancement of Light and X-ray Charging in Persistent Luminescence Nanoparticle Scintillators Zn₂SiO₄:Mn²⁺, Yb³⁺, Li⁺

Abstract

Persistent luminescence nanoparticle scintillators (PLNS) have been attempted for X-ray-induced photodynamic therapy (X-PDT) because persistent luminescence after ceasing radiation can make PLNS use less cumulative irradiation time and dose to generate the same amount of reactive oxygen species (ROS) compared with conventional scintillators to combat cancer cells. However, excessive surface defects in PLNS reduce the luminescence efficiency and quench the persistent luminescence, which is fatal to the efficacy of X-PDT. Herein, the PLNS of SiO 2 @Zn 2 SiO 4 :Mn 2+ , Yb 3+ , Li + was designed by the energy trap engineering and synthesized by a simple template method, which has excellent Xray and UV-excited persistent luminescence and continuously tunable emission spectra from 520 to 550 nm. Its luminescence intensity and afterglow time are more than 7 times that of the reported Zn 2 SiO 4 :Mn 2+ used for X-PDT. By loading a Rose Bengal (RB) photosensitizer, an effective persistent energy transfer from the PLNS to photosensitizer is observed even after the removal of X-ray irradiation. The X-ray dose of nanoplatform SiO 2 @ Zn 2 SiO 4 :Mn 2+ , Yb 3+ , Li + @RB in X-PDT of HeLa cancer cells was reduced to 0.18 Gy compared to the X-ray dose of 1.0 Gy for Zn 2 SiO 4 :Mn for X-PDT. This indicates that the Zn 2 SiO 4 :Mn 2+ , Yb 3+ , Li + PLNS have great potential for X-PDT applications.

Nanomaterials for light-mediated therapeutics in deep tissue

“…Recently, Han et al reported that Li + and Yb 3+ co-doping in Zn 2 SIO 4 :Mn 2+ ,Yb 3+ could enhance luminescence by shifting the crystal to the favourable phase. 210 A coexistence of α phase (410) and β phases (023) is present in Zn 2 SiO 4 , where the nanocrystals exhibit the most optimal afterglow time and luminescence intensity with an α / β ratio of 2.76 (Fig. 19c).…”

“…209 To improve the X-ray excited afterglow of the nanosystem, other Zn-based nanosystems were developed, namely, zinc gallate (ZnGa 2 O 4 ), zinc silicate (ZnSi 2 O 4 ), or variations of zinc gallogermanate. 210 X-ray-activated ZnGa 2 O 4 :Cr 3+ was first discovered in 2017 by Hao's group. 211 They reported ZnGa 2 O 4 :Cr 3+ , which exhibited 6 hours of persistent luminescence at 700 nm after the cessation of the soft X-ray excitation source with low excitation power (45 kVp, 0.5 mA), due to the characteristic electron transition of Cr 3+ from 2 E to 4 A 2 (Fig.…”

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

“…Similarly, RB was also introduced to couple with SiO 2 @Zn 2 SiO 4 :Mn 2+ , Yb 3+ , Li + for effective persistent energy transfer and HeLa cancer cell killing by Han's group. 1252 Considering that the body needs NPs that can break down into non-toxic or low-toxic ions and be eliminated quickly without posing a long-term toxicity risk, Chen et al described a nanosystem with a silica layer loaded with merocyanine 540 (MC 540) and SrAl 2 O 4 :Eu 2+ (SAO). 1253 SAO with XEOL feature could induce MC 540 to produce ROS for X-PDT.…”

Current Developments in Emerging Lanthanide‐Doped Persistent Luminescent Scintillators and Their Applications

“…Additional results show that the intensity of X‐ray‐induced NaYF 4 : 3 %Er PersL in the hexagonal phase was more than ten times that in the cubic phase. Very recently, Jiang et al [161] . reported a Zn 2 SiO 4 : Mn 2+ , Yb 3+ , Li + PersL nanoscintillators with coexistence of α‐ and β‐phases.…”