**4. Conclusions**

Our present study provided a facile approach for the synthesis of size-controlled SeNPs by using PSP as a stabilizer in the redox system of sodium selenite and ascorbic acid. The synthesized PSP-SeNPs presented a monodisperse spherical structure with zero-valent Se. The interaction between the hydroxyl groups of PSP chains and the surface of SeNPs contributed to the stable structure of PSP-SeNPs. Furthermore, PSP-SeNPs exhibited stronger free radical scavenging ability and a higher protective effect against H2O2-induced PC-12 cell death than SeNPs. Our findings not only provide the foundations for the utilization of PSP in the development of stable SeNPs but also emphasize the potential application of PSP-SeNPs as an antioxidant in food additives, dietary supplements, and nutraceuticals.

**Author Contributions:** Conceptualization, W.C. and H.C.; methodology, W.C.; software, W.C.; validation, W.C.; formal analysis, W.C. and H.C.; investigation, W.C.; resources, W.X.; data curation, H.C.; writing—original draft preparation, W.C.; writing—review and editing, H.C.; visualization, W.X.; supervision, W.X.; project administration, W.C. and H.C.; funding acquisition, W.C. and H.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the China Postdoctoral Science Foundation (Grant No. 2021M691288) and the National Natural Science Foundation of China (Grant No. 32101939).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available in this manuscript.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

