Large-area surface-enhanced raman spectroscopy imaging of brain ischemia by gold nanoparticles grown on random nanoarrays of transparent boehmite

Shogo Yamazoe, Masayuki Naya, Megumi Shiota, Takayuki Morikawa, Akiko Kubo, Takeharu Tani, Takako Hishiki, Tadashi Horiuchi, Makoto Suematsu, Mayumi Kajimura

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Although SERS spectroscopy, which is sensitive to molecular vibration states, offers label-free visualization of molecules, identification of molecules and their reliable large-area imaging remains to be developed. Limitation comes from difficulties in fabricating a SERS-active substrate with homogeneity over a large area. Here, we overcome this hurdle by utilizing a self-assembled nanostructure of boehmite that is easily achieved by a hydrothermal preparation of aluminum as a template for subsequent gold (Au) deposition. This approach brought about random arrays of Au-nanostructures with a diameter of ∼125 nm and a spacing of <10 nm, ideal for the hot-spots formation. The substrate, which we named gold nanocoral (GNC) after its coral reef-like shape, exhibited a small variability of signal intensities (coefficient value <11.2%) in detecting rhodamine 6G molecule when 121 spots were measured over an area of 10 × 10 mm2, confirming high uniformity. The transparent nature of boehmite enabled us to conduct the measurement from the back-side of the substrate as efficiently as that from the front-side. We then conducted tissue imaging using the mouse ischemic brain adhered on the GNC substrate. Through nontargeted construction of two-dimensional-Raman-intensity map using differential bands from two metabolically distinct regions, that is, ischemic core and contralateral-control areas, we found that mapping using the adenine ring vibration band at 736 cm-1 clearly demarcated ischemic core where high-energy adenine phosphonucleotides were degraded as judged by imaging mass spectrometry. Such a detection capability makes the GNC-based SERS technology especially promising for revealing acute energy derangement of tissues.

Original languageEnglish
Pages (from-to)5622-5632
Number of pages11
JournalACS Nano
Volume8
Issue number6
DOIs
Publication statusPublished - 2014 Jun 24

Keywords

  • 3D-FDTD
  • back-side detection
  • biosensor
  • emission pattern
  • gold nanocoral
  • ischemia detection
  • template-guided self-assembly

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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