Hongqi Chen

ALP-triggered UCNP@SiO₂-Bodipy@FFYp for tumor-targeted photodynamic therapy (PDT).

An upconversion luminescent ratiometric probe was developed for super-resolution imaging sensing of biothiols in living cells using single-particle localization and rendering method.

In this work, a single particle imaging method based on the total internal reflection (TIR) imaging platform for the sensing and cell imaging of nitrite (NO₂ ⁻) in the near-infrared region using cyanine dye-assembled composite upconversion nanoparticles (UCNPs) was developed. The NaYF₄:Yb,Tm@NaGdF₄ UCNPs were synthesized as energy donors, and the cyanine dye IR-798 was prepared as an energy acceptor. Since the absorption spectrum of the cyanine dye IR-798 and the luminescence spectrum of upconversion nanoparticles overlapped effectively, IR-798 quenched the luminescence of the UCNPs. When NO₂ ⁻ was added to the cyanine dye-assembled composite upconversion nanoparticle system, NO₂ ⁻ destroyed the conjugate structure of IR-798, so that the luminous intensity of UCNPs could be restored. Based on the mechanism, a quantitative image analysis with high sensitivity, low sample usage, and fast response time using the TIR single particle imaging platform was developed to determine the content of nitrite in human serum samples. In addition, the UCNPs-IR-798 probe was applied to image the exogenous NO₂ ⁻ content in HeLa living cells based on the single particle imaging platform.

Here, NaGdF₄,Yb,Er@NaGdF₄,Yb,Tm@NaYF₄ core@shell@shell three‐layer structure of upconversion nanoparticles (UCNPs) coated with Fe−Tetrakis (4‐carboxyphenyl) porphine (TCPP) metal‐organic frameworks (Fe‐MOFs) nanocomposite (UCNPs@MOFs) was designed and constructed for multimodal imaging and synergetic chemodynamic therapy (CDT)/photodynamic therapy (PDT) of tumors. The UCNPs@MOFs were successfully applied for tumor cells imaging in vitro and in vivo in near‐infrared (NIR) region. The doped Gd was used as contrast agent for the magnetic resonance imaging (MRI) of mouse tumors. The luminescence in the UV‐vis region was absorbed by the Fe‐MOFs to produce singlet oxygen (¹O₂) for PDT. The Fe³⁺ doped in the MOFs can catalyze H₂O₂ to produce oxygen and hydroxyl radical (⋅OH). Hydroxyl radical is used in CDT and cooperates with the ¹O₂ of PDT. Based on the CDT/PDT synergistic effects, the UCNPs@MOFs nanocomposite had obviously enhanced tumor inhibitory efficiency in vivo. These results described that the asprared UCNPs@MOFs nanocomposite have great potential in the effective multimodal imaging and treatment of tumors.