Abstract
We prepared an ultrathin porous silica shell-coated Au-Ag alloy nanoparticle (AuAg@p-SiO 2 NP) and developed it as a novel alkyne-based surface-enhanced Raman scattering (SERS) nanoprobe for the ratiometric Raman imaging of exogenous and endogenous H 2 O 2 in live cells. The AuAg@p-SiO 2 NPs functionalized with 4-mercaptophenylboronic acid (MPBA) and 4-mercaptophenylacetylene (MPAE, 1986 cm −1 ) as internal standard were first incubated with dopamine (DA) to incorporate the bridging molecules through the formation of borate bond between DA and MPBA on the surface of nanoparticle. Then, the signaling alkyne molecules of 3-(4-(phenylethynyl) benzylthio) propanoic acid (PEB, 2214 cm −1 ) were conjugated to the surface of nanoparticle through the formation of amide bond between the carboxyl group on the PEB and the amino group on the DA, forming the ratiometric SERS nanoprobe. In the presence of H 2 O 2 , the alkynyl on the PEB is released from the surface of the Au-Ag alloy nanoparticle due to the boronate-to-phenol switch, decreasing the Raman signal at 2214 cm −1 significantly. Since the Raman signal of MPAE at 1986 cm −1 remains unchanged, quantitative analysis of H 2 O 2 concentration can be achieved based on the ratiometric value of I 1986 /I 2214 . Under the optimized conditions, the plot of the ratiometric value of I 1986 /I 2214 versus the H 2 O 2 concentration in the range from 0.12 to 8 μM revealed a good linear response with a detection limit of 52 nM based on a signal-to-noise ratio of S/N = 3. The porous SiO 2 -coated Au-Ag alloy nanoparticle provides a novel SERS substrate with excellent biocompatibility, high stability, and effective anti-interference ability. Together with the alkynyl derivatives as internal standard, the SERS nanoprobe reported here allows the ratiometric detection of H 2 O 2 in live cells and can be further applied to quantify many other biomolecules by using different signaling agents.
Original language | English |
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Pages (from-to) | 1-10 |
Number of pages | 10 |
Journal | Analytica Chimica Acta |
Volume | 1057 |
DOIs | |
State | Published - May 30 2019 |
Externally published | Yes |
Funding
This work was supported by the National Natural Science Foundation of China ( 21475036 , 21775035 , 21527810 ), and Hunan Provincial Natural Science Foundation ( 2016JJ1005 ). The authors also thank Professor Chuanbo Gao at Xi'An Jiaotong University for his helpful suggestions in the synthesis of AuAg@p-SiO 2 NPs.
Keywords
- Alkyne
- Cell imaging
- Hydrogen peroxide
- Porous SiO -Coated Au-Ag alloy nanoparticle
- SERS