Figure 1 Schematic illustration demonstrating the photodynamic therapy and upconversion mechanism of pH-responsive FA-PEAH-UCNPs-Pha.
Figure 2 Synthesis of (A) polymer modified UCNPs (FA-PEAH-UCNPs), (B) ketonized Pha (Pha-HB), and (C) FA-PEAH-UCNPs-Pha.
Figure 3 (A) 1H NMR spectra of FA-PEAH-UCNPs-Pha; (B) UV-visible absorption spectra of (a) FA-PEAH-UCNPs and (b) FA-PEAH-UCNPs-Pha; and (C) EDS spectra of free UCNPs; (D) EDS spectra of FA-PEAH-UCNPs).
Figure 4 TEM images of (A) free UCNPs, (B) FA-PEAH-UCNPs, and (C) FA-PEAH-UCNPs-Pha; (D) Typical size distributions of UCNPs, (a) Free UCNPs, (b) FA-PEAH-UCNPs (b), FA-PEAH-UCNPs-Pha; (E) SAED pattern of NaYF4:Yb/Er UCNPs synthesized by a hydrothermal method.
Figure 5 XRD patterns of (A) hexagonal-phase NaYF4:Yb/Er UCNPs, and (B) copolymer-modified hexagonal-phase NaYF4:Yb/Er UCNPs (FA-PEAH-UCNPs), Bottom line patterns are the hexagonal-phase (JCPDS 16-0334) and PEG 4000 (JCPDS 49-2095).
Figure 6 Fluorescence emission spectra of copolymer-modified UCNPs (FA-PEAH-UCNPs) in water under 980-nm laser excitation; inset shows the green fluorescence emission from UCNPs and FA-PEAH-UCNPs upon 980 nm laser excitation.
Figure 7 Confocal images of free Pha and FA/CH3-PEAH-UCNPs-Pha against MCF7 cells (DAPI [blue color], F-actin [green color], Pha [red color)]); (A) control, (B) free Pha, (C) CH3-PEAH-UCNPs-Pha, and (D) FA/CH3-PEAH-UCNPs-Pha. Scale bars represent 20 μm.
Figure 8 In vitro cytotoxicity test using free Pha and FA/CH3 -PEAH-UCNPs-Pha against MCF7 cells, (A) phototoxicity depending on the Pha concentration; (B) phototoxicity depending on laser exposure time.