Multifunctional core-shell upconversion nanoparticles for targeted tumor cells induced by near-infrared light

Area of Science:

• Biomaterials Science
• Nanotechnology
• Photodynamic Therapy

Background:

• Developing targeted therapies for deep-seated cancers remains a challenge.
• Nanocomposite materials offer potential for enhanced drug delivery and therapeutic efficacy.

Purpose of the Study:

• To synthesize and characterize silica-coated NaYF4:Yb/Er nanocomposites functionalized with hypericin (UCNPs@SiO2@hypericin).
• To evaluate the efficacy of these nanocomposites in inducing cancer cell apoptosis under near-infrared (NIR) light irradiation.
• To assess the targeted cellular uptake and biocompatibility of the developed nanocomposites.

Main Methods:

• Synthesis of silica-coated NaYF4:Yb/Er upconversion nanoparticles (UCNPs) with covalently bound hypericin.
• Characterization of size, water dispersity, and biocompatibility.
• NIR light irradiation to trigger hypericin-mediated singlet oxygen generation.
• Flow cytometry, fluorescence microscopy (Annexin V-FITC/PI staining), and Western blotting (caspase-3) to assess apoptosis.
• Cell viability assays to evaluate cytotoxicity.
• Confocal microscopy to study cellular uptake in folate receptor (FR) positive and negative cell lines.

Main Results:

• Successfully synthesized UCNPs@SiO2@hypericin nanocomposites with controlled size, good water dispersity, and excellent biocompatibility.
• NIR irradiation of UCNPs@SiO2@hypericin induced efficient singlet oxygen generation, leading to apoptosis in Hela and HepG2 cells.
• Demonstrated minimal cytotoxicity and high selectivity for FR(+) cells (Hela) over FR(-) cells (293T) in cellular uptake studies.
• Short NIR irradiation times were sufficient for effective apoptosis induction.

Conclusions:

• UCNPs@SiO2@hypericin-FA nanocomposites are effective theranostic agents for photodynamic therapy.
• The targeted delivery and NIR-triggered activation show promise for treating deep-seated tumors.
• These nanocomposites exhibit potential for future applications in PDT and deep tissue disease treatment.