Lipid Bilayer-Enabled Synthesis of Waxberry-like Core–Fluidic Satellite Nanoparticles: Toward Ultrasensitive Surface-Enhanced Raman Scattering Tags for Bioimaging

Herein, we presented waxberry-like core–satellite (C–S) nanoparticles (NPs) prepared by an in situ growth of satellite gold NPs on spherical phospholipid bilayer-coated gold cores. The fluidic lipid bilayer cross-linker was reported for the first time, which imparted several novel morphological and optical properties to the C–S NPs. First, it regulated the anisotropic growth of the satellite NPs into vertically oriented nanorods on the core NP surface. Thus, an interesting waxberry-like nanostructure could be obtained, which was different from the conventional raspberry-like C–S structures decorated with spherical satellite NPs. Second, the satellite NPs were “soft-landed” on the lipid bilayer and could move on the core NP surface under certain conditions. The movement induced tunable plasmonic features in the C–S NPs. Furthermore, the fluidic lipid bilayer was capable of not only holding an abundance of reporter molecules but also delivering them to the hotspots at the junctions between the core and satellite NPs, which made the C–S NPs an excellent candidate for preparing ultrasensitive surface-enhanced Raman scattering (SERS) tags. The bioimaging capabilities of the C–S NP-based SERS tags were successfully demonstrated in living cells and mice. The developed SERS tags hold great potential for bioanalysis and medical diagnostics

Pharmacokinetic parameters of 24R-epimer and 24S-epimer in rat plasma after oral administration and intravenous administration of 24R-epimer or 24S-epimer, respectively.

<p>(n = 5 per group).</p><p>iv, intravenous group; BA, bioavailability.</p

Effects of 24R-epimer and 24S-epimer on the transport of P-gp substrate digoxin across Caco-2 cell monolayers.

<p>Cells were preincubated for 1-epimer (1 and 10 µM) or 24S-epimer (1 and 10 µM), and followed by co-incubation for 2 h in the presence of 5 µM digoxin. Data are the mean ± S.E. of three independent experiments. ^*<i>p</i><0.01 versus control, ^#<i>p</i><0.01 between groups.</p

Analytical conditions in LC-MS/MS analysis of 24R-epimer, 24S-epimer and digoxin.

<p>CID, collision induced decomposition voltage; IS, internal standard.</p

Effects of 24R-epimer and 24S-epimer on the accumulation of rhodamine 123 in Caco-2 cells.

<p>Cells were preincubated for 1-epimer or 24S-epimer at concentrations of 1, 5 and 10 µM, respectively; and followed by co-incubation for 2 h in the presence of 5 µM rhodamine 123. Data are the mean ± S.E. of three independent experiments. ^*<i>p</i><0.05 versus control; ^**<i>p</i><0.01 versus control.</p

Effects of 24R-epimer and 24S-epimer on P-gp expression levels in Caco-2 cells.

<p>Cells were exposed to 24R-epimer or 24S-epimer at concentrations of 1 µM (A) and 10 µM (B), and 1% of DMSO as a solvent control for 48 and 72 h. The bar graphs show the P-gp protein band intensity corrected by that of β-actin.</p

The effect of 24R-epimer and 24S-epimer on Caco-2 cell viability.

<p>Cells were incubated with 24R-epimer or 24S-epimer for 48 h at the concentration range of 1–100 µM, respectively; and the cell viability was measured by MTT assay. Data are the mean ± S.E. of three independent experiments.</p

Plasma concentration-time profiles of 24R-epimer and 24S-epimer in rats.

<p>The intragastric administration groups were administered 24R-epimer (A) or 24S-epimer (B) at doses of 5, 10 and 20 mg/kg, respectively. The intravenous groups were presented in smaller figure administered 1 mg/kg of 24R-epimer or 24S-epimer, respectively. n = 5 per group.</p

The uptake concentration-time profiles of 24R-epimer and 24S-epimer in Caco-2 cells.

<p>24R-epimer and 24S-epimer concentrations: 1, 5 and 20 µM, respectively. Data are the mean ± S.E. of three independent experiments.</p

Proposed possible metabolism pathway of ginsenoside Rg3 and its deglycosylated metabolites.

<p>Proposed possible metabolism pathway of ginsenoside Rg3 and its deglycosylated metabolites.</p