Fig. 6: Assessment of the intracellular GS-like activity of STPE-PMNSs.

Intracellular fluorescence signals were monitored at different time points (a) (Scale bar: up: 10 μm; down: 5 μm), followed by quantification of the respective fluorescent signals (****p < 0.0001) (b). Cells underwent treatment with STPE-PMNSs for 6 h, followed by PBS washing. Glu production was induced in SH-SY5Y cells using 4-AP for 4 h, and cells were washed with PBS again. Intracellular fluorescence signals were subsequently observed at different time points, with corresponding signal quantification. Changes in intracellular Gln content were recorded at various time points (c) (****p < 0.0001), along with the linear relationship between Gln content and fluorescence intensity (d). Intracellular Gln (e) (*p = 0.0515, ****p = 0.0002) and Glu (f) (*p = 0.0226, **p = 0.3465, ***p = 0.0011) levels in distinct treatment groups were assessed after 24 h. g Apoptosis levels in SH-SY5Y cells were evaluated after 24 h across different treatment groups. h, i Bcl-2 expression levels in SH-SY5Y cells were measured after 24 h for each treatment group. **p = 0.0051, ****p < 0.0001. j, k Bax expression levels in SH-SY5Y cells were also analyzed after 24 h across treatment groups. **p = 0.0065, ****p < 0.0001. Data points presented in (b, c, e, f) represent three (n = 3) biologically independent samples and are displayed as mean ± standard deviation. p values of (b, c, e, f, i, k) were determined by a two-sided t-test. The samples in (i, k) were derived from the same experiment and blots were processed in parallel. Experiments of (a, g) were repeated three times with similar results.