Multifunctional nanogel engineering with redox-responsive and AIEgen features for the targeted delivery of doxorubicin hydrochloride with enhanced antitumor efficiency and real-time intracellular imaging

Figures & data

Scheme 1. Synthesis of HA-ss-ATRA/TPENH₂ conjugates (A). Illustration of the self-assembly, accumulation at cancer cells, intracellular trafficking pathway of redox-sensitive AIE HNPs, and real-time intracellular imaging of AIE HNPs (B). Circulation of AIE HNPs within vessel (a); Accumulation of DOX-loaded HNPs within the tumor site through passive and active targeting effects (b); CD44 receptor-mediated cellular internalization (c, d); Endo/Lysosomal escape, and GSH-controllable release of DOX in cytoplasm (e, f); Released DOX into nucleus for apoptosis and cytotoxicity (g).

Figure 1. ¹H NMR spectra of HA (A), HA-ATRA conjugate (B) and HA-ss-ATRA conjugate (C).

Scheme 2. Synthetic scheme of TPENH₂ molecule.

Figure 2. UV-vis spectra of TPENH₂, HA-ss-ATRA and HA-ss-ATRA/TPENH₂ conjugates.

Figure 3. Representative SEM images (A) and TEM images (B) of HA-ss-ATRA/TPENH₂ HNPs. size distribution of HA-ss-ATRA/TPENH₂ HNPs (C).

Figure 4. GSH triggered DOX release from HA-ss-ATRA/TPENH₂ HNPs and HA-ATRA/TPENH₂ HNPs. The error bars in the graph represent standard deviations (n = 3).

Figure 5. Cell viability of HepG-2 cells treated with DOX-loaded HA-ss-ATRA/TPENH₂ HNPs and free DOX after 24 h (A). Cell viability of HepG-2 cells treated with DOX-loaded HA-ss-ATRA/TPENH₂ HNPs and free DOX after 24 h, 48 h and 72 h (B). Cytotoxicity of blank HA-ss-ATRA/TPENH₂ HNPs against HepG-2 cells and 293T cells (C). Cell viability of HepG-2 cells treated with DOX-loaded HA-ss-ATRA/TPENH₂ HNPs and DOX-loaded HA-ATRA/TPENH₂ HNPs (D). Cell survival fractions were assessed by MTT assay. Data represent mean ± SD (n = 5).

Table 1. IC50 of Free DOX and DOX-loaded HNPs for HepG-2 cells.

IC50(µg/ml)	24 h	48 h	72 h
Free DOX	8.030	0.5763	0.2032
DOX-loaded HNPs	30.86	0.1495	0.0309

Figure 6. Cell viability of HepG-2 and 293T cells treated with DOX-loaded HA-ss-ATRA/TPENH₂ HNPs after 48 h.

Figure 7. Fluorescence microscopy images of HepG-2 cells incubated with HA-ss-ATRA/TPENH₂ HNPs (A), free DOX (B) and DOX-loaded HA-ss-ATRA/TPENH₂ HNPs (C) for 8 h. For each panel, left to right show the UW, GW, bright and merge field images. Scale bars correspond to 10 μm in all the images.

Figure 8. Fluorescence microscopy images of HepG-2 cells incubated with HA-ss-ATRA/TPENH₂ HNPs for 4 h(A), 6 h(B), 8 h(C) and 10 h(D). Scale bars correspond to 10 μm in all the images.