SiO2 Coated Up-Conversion Nanomaterial Doped with Ag Nanoparticles for Micro-CT Imaging

Abstract

In this study, a new method for synthesizing Ag-NaYF4:Yb3+/Er3+ @ SiO2 nanocomposites was introduced. Using a hydrothermal method, the synthesized Yb3+- and Er3+-codoped NaYF4 up-conversion luminescent materials and Ag nanoparticles were doped into up-conversion nanomaterials and coated with SiO2 up-conversion nanomaterials. This material is known as Ag-UCNPs@SiO2, it improves both the luminous intensity because of the doped Ag nanoparticles and has low cytotoxicity because of the SiO2 coating. The morphology of UCNPs was observed using scanning electron microscopy (SEM), and the mapping confirmed the successful doping of Ag nanoparticles. Successful coating of SiO2 was confirmed using transmission electron microscopy (TEM). Fluorescence spectra were used to compare changes in luminescence intensity before and after doping Ag nanoparticles. The reason for the increase in luminescence intensity after doping with Ag nanoparticles was simulated using first-principles calculations. The cytotoxicity of Ag-UCNPs@SiO2 was tested via the cell counting kit-8 (CCK-8) method, and its imaging ability was characterized using the micro-CT method.

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

“…Given the potential attractiveness of high atomic number elements for the design of CT contrast agents, Bi ( Z = 83) 1100 or Yb ( Z = 70) 1101–1103 -based NPs have been adopted for in vivo CT imaging. Also, a silica shell was used to improve the biocompatibility of inorganic NPs and further functionalize them for use in multimodal applications.…”

Lanthanide-Doped Upconversion Luminescent Nanoparticles—Evolving Role in Bioimaging, Biosensing, and Drug Delivery

“…In this method, a chemical reaction occurs when positive ions and negative ions are exposed to temperatures and pressures above their critical points in polar liquids, resulting in the formation of UCNPs. Zhang et al used the hydrothermal method for the synthesis of Yb 3+ and Er 3+ co-doped NaYF 4 upconversion luminescent materials and Ag nanoparticles coated with SiO 2 , which enhances the luminous intensity and has low cytotoxicity because of the SiO 2 coating [ 38 ]. Nampi et al synthesized single-crystalline, stable, aqueous Yb 3+ /Er 3+ doped BaYF 5 UCNPs with polyethyleneimine (PEI) via hydrothermal route.…”

Photodynamic Therapy and Multi-Modality Imaging of Up-Conversion Nanomaterial Doped with AuNPs

“…Many scholars have proposed doping Mo 3+ , Cu 2+ [3,4], and other metal ions in the NaYF 4 :Yb 3+ /Er 3+ unit cell to increase the luminous intensity [5,6], but the effect is not significant. Others have offered sliver doping [7], which has a large impact as well; however, sliver is poisonous to cells, may cause cell death without targeting, and cannot be employed in biology. Many scholars have proposed constructing core-shell structures such as NaYF 4 :Yb 3+ /Er 3+ @NaGdF 4 :Yb 3+ and NaYF 4 :Yb 3+ /Er 3+ @NaNdF 4 :Yb 3+ /Tm 3+ @NaGdF 4 :Yb 3+ [8][9][10].…”

“…Unfortunately, when these materials meet the biological requirements, they will inevitably reduce their luminous intensity, so that imaging cannot be performed to obtain a clear image [19,20]. Considering the high desire to develop UCNPs nanomaterials with highly effective imaging capability as well as high biocompatibility to prevent apoptosis or biological organ failure, UCNPs doped with Au nanoparticles (AuNPs) are an ideal candidate because they are easy to fabricate, have enhanced luminescence, and are easy to surface modify [7,21]. More notably, following illumination, the UCNPs are harmless to normal tissues but cytotoxic to malignancies.…”