Fig 2: Schematic illustration of the ultra-sensitive detection platform for BDNF using Au@SiO2 and enzymatically synthesized QDs.

Fig 3: Confirmation of a QD formation around Au@SiO2 following BDNF detection via an elemental analysis. (a) TEM image showing BDNF detection in regard to Au@SiO2. ALP-conjugated antibodies specific to BDNF were attached, and QDs were formed through an enzymatic reaction on the nanoparticle surface. (b) An elemental ratio graph obtained from an EDS analysis showing the following weight percentages: Si 1.96%, S 10.72%, Cd 37.07%, and Au 50.25%. (c–f) Elemental distribution images showing the presence of (c) sulfur (S), (d) cadmium (Cd), (e) gold (Au), and (f) silicon (Si).

Fig 4: BDNF immunofluorescence staining in rat hippocampus. (A) Staining of nuclei with antibodies against BDNF and DAPI and their merge from every group (magnification, ×400). (B) Amount of positive reaction in each group. Scale Bars: 20 µm. The ratio of BDNF-positive neurons is shown as mean±SEM (n=4 per group); Triple asterisks (***) are significantly different compared with the non-treated control group (P<0.001). Triple hash (###) significantly different compared with METH-inhalation group (P<0.001)