br Fig Cell viability of HeLa cells treated by di
Fig. 6. Cell viability of HeLa Conessine treated by diﬀerent concentration of DOX-loaded HA-NB-SC with/without UV light irradiation for 0.5 h (A) or 1 h (B).
Fig. 7. Fluorescence microscopy images of HeLa cells exposed to DOX-loaded HA-NB-SC nanomicelles (200 μg/mL). The scale bar was 20 μm.
Fig. 8. CLSM images of HeLa cells exposed to FDA-loaded HA-NB-SC nanomicelles (200 μg/mL) without (A) or with (B) UV light irradiation for 1 h. The scale bar was 50 μm.
Fig. 9. Fluorescence micropy images of HeLa cells exposed to DOX-loaded HA-NB-SC nanomicelles in the absence of HA (A) and in the presence of HA (1 mg/mL) (B). The scale bar was 20 μm.
resulting some FDA molecules were leaked to light up cells even without UV irradiation. But, under UV irradiation condition, more FDA molecules were quickly-released intracellularly than that without UV irradiation.
3.5. Competition inhibition assay
To ulteriorly validate whether the DOX loaded HA-NB-SC nanomi-celles were taken up by cells via HA-specific receptor, CD44, mediated endocytosis, a competitive inhibition experiment was conducted by adding free HA (1 mg/mL) in the incubating media to block CD44 re-ceptors on the surface of HeLa cells. Before the experiment, the cyto-toxicity of diﬀerent concentrations of HA on Hela cells was conducted by MTT assay. There was no obvious cell death observed (Fig. S9). As shown in Fig. 9, image of cells exposed to DOX-loaded HA-NB-SC na-nomicelles without free HA was much brighter than cells exposed to DOX-loaded HA-NB-SC nanomicelles with free HA blocking CD44 re-ceptors. Results above support the role of receptor mediated en-docytosis in eﬃcient internalization of HA-NB-SC nanomicelles into HeLa cells.
In this paper, we have synthesized a light-labile HA-NB-SC amphi-phile by connecting stearyl chains and HA via a o-nitrobenzyl ester linkage for the first time, in which HA serves as a tumor-targeting li-gand for CD44 receptors. Based on the specific cell recognition by HA moiety, combination therapy by DOX and UV light-produced
nitrobenzaldehyde derivative, DOX-loaded HA-NB-SC nanomicelles not only significantly inhibited the proliferation of HeLa cells, but also in-creased the cellular uptake and controlled release drugs in cells under UV irradiation. The results acquired in this study exhibited future di-rections for synthesis and fabrication of light-responsive nanomicelles.
Conflict of interest
We declare that we have no conflict of interest.
The authors are thankful to Life Science Research Core Services (LSRCS), Northwest A&F University for support of TEM and CLSM. This work was supported by the National Natural Science Foundation of China (NSFC) (31570799, 31870799) and the Fundamental Research Funds for the Central Universities (2452017026).
Appendix A. Supplementary data
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