As a mental disease in modern society, depression shows an increasing occurrence, with low cure rate and high recurrence rate. It has become the most disabling disease in the world. At present, the treatment of depression is mainly based on drug therapy combined with psychological therapy, physical therapy, and other adjuvant therapy methods. Antidepressants are primarily administered peripherally (oral and intravenous) and have a slow onset of action. Antidepressant active ingredients, such as neuropeptides, natural active ingredients, and some chemical agents, are limited by factors such as the blood–brain barrier (BBB), first-pass metabolism, and extensive adverse effects caused by systemic administration. The potential anatomical link between the non-invasive nose–brain pathway and the lesion site of depression may provide a more attractive option for the delivery of antidepressant active ingredients. The purpose of this article is to describe the specific link between intranasal administration and depression, the challenges of intranasal administration, as well as studies of intranasal administration of antidepressant active ingredients.

Green-synthesized metal nanoparticles show promise in nanomedicine and material engineering. In this study, the polysaccharide of Zingiber officinale (ZOP) was used as a raw material. Through single-factor experiments and a response surface methodology, the optimum synthesis protocol of Zingiber officinale polysaccharide silver nanoparticles (ZOP-NPs-AgNPs) was determined as follows: V(AgNO₃):V(ZOP) = 2.98:1, 59.79 °C, 3 h, pH 9, and 20 mL NaCl, achieving a 92.51% silver chelation rate. Structure analysis revealed that ZOP-NPs-AgNPs were spherical or quasi-spherical, with a particle size < 20 nm and a face-centered cubic crystal structure, which has good thermal stability. Subsequent studies explored the antibacterial and immunomodulatory effects of ZOP-NPs-AgNPs. The minimum inhibitory concentration (MIC) of ZOP-NPs-AgNPs against Escherichia coli and Staphylococcus aureus was determined to be 0.5000 mg/mL and 0.0310 mg/mL, respectively, while the minimum bactericidal concentration (MBC) was 0.5000 mg/mL and 0.0310 mg/mL, respectively. Additionally, ZOP-NPs-AgNPs significantly enhance RAW264.7 cell proliferation and phagocytosis and boost IL−1β, IL−6, NO, and TNF-α production. This confirms that ZOP can act as a green reductant and stabilizer, offering a new method for green nano-silver synthesis. This provides a sustainable way to produce antibacterial products and functional foods, and offers useful references for eco-friendly nano-silver applications.