Fig. 1.
Characterization of Mimo-AuNPs. (a) Graphical image showing the chemical structure of mimosine obtained from Pubchem (ID: 440473). (b) FTIR spectra of Mimo (black) and Mimo-AuNPs (olive) displaying their respective vibrations before and after functionalization. (c) DLS peak of Mimo-AuNPs depicting an average diameter of ~8–12 nm. (d) TEM images revealing the evenly sized (~6 nm) spherical Mimo-AuNPs (i) and the high-resolution data show a fringe spacing of 2.2, 2.3 and 2.4 Å confirming its polycrystalline nature (ii) and selected area electron diffraction pattern (SAED) for Mimo-AuNPs showing the Scherrer ring patterns indicating the (111), (200) (220) and (311) nanocrystalline nature of FCC gold (iii). (e & f) Histograms depicting that 10–200 μM Mimo-AuNPs following 24h exposure did not alter the viability of cortical cultured neurons as evaluated using MTT (e) and LDH (f) assays. (g & h) DLS analysis showing Mimo-AuNPs in the apical side (before assay) and basolateral side (after assay) (g) and a histogram showing the apparent permeability coefficient (Papp) values after incubation of AuNPs, mimosine and Mimo-AuNPs for 30min in the activated BBB kit (h). All data expressed as mean ± SEM were obtained from three to five separate experiments, each performed in triplicate. ND, not detected. **p < 0.01.