title: Controllable synthesis and SERS characteristics of hollow sea-urchin gold nanoparticles.
abstract: Hollow sea-urchin gold nanoparticles (HSU-GNPs) were successfully prepared through a novel one-step galvanic replacement strategy, and their corresponding optical properties was studied in detail. During the synthesis process, the sizes of the interior hollows of the HSU-GNPs could be changed by adjusting the amount of silver nitrate added into hydrogen tetrachloroaurate trihydrate solution. The absorption spectra of the HSU-GNPs showed that the localized surface plasmon resonance (LSPR) peaks were red-shifted with increasing size of the interior hollows in the HSU-GNPs. When the added amount of silver nitrate was up to 6 μl, the LSPR peak of the synthesized HSU-GNP reached 726 nm as a maximum red-shift. Furthermore, the absorption spectra of the HSU-GNPs with different morphologies were theoretically simulated by the finite element method, which was consistent with the experimental results and explained the origin of the red-shift of the LSPR peaks. In addition, the surface-enhanced Raman scattering (SERS) of the sea urchin gold nanoparticles were also investigated using 4-mercaptobenzoic acid as a Raman reporter molecule. Both the experimental and calculated results showed that the HSU-GNPs had stronger SERS enhancement than the solid sea-urchin gold nanoparticles. In particular, the HSU-GNPs prepared by adding 6 μl silver nitrate exhibited a maximum SERS enhancement factor, EF = 1.1 × 10(9), due to the LSPR peak at 726 nm which is near to the excitation wavelength, 785 nm. This feature is significant for designing a biosensor with a super-high sensitivity based on the morphology of the HSU-GNPs.
authors.affiliation: Institute of Photonics, Faculty of Science, Ningbo University, Ningbo 315211, Zhejiang, China. zhoujun@nbu.edu.cn.
authors.forename: Junpeng
authors.initials: J
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Zhou
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.forename: Binbing
authors.initials: B
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Gu
authors.forename: Lucia
authors.initials: L
authors.lastname: Petti
authors.forename: Pasquale
authors.initials: P
authors.lastname: Mormile
mesh_terms: D001565:Benzoates / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D012835:Silver Nitrate / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013499:Surface Properties
chemical_list: D001565:Benzoates; D013438:Sulfhydryl Compounds; C013594:4-mercaptobenzoate; D006046:Gold; D012835:Silver Nitrate