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ACS Nano. 2014 Jun 24;8(6):5622-32. doi: 10.1021/nn4065692. Epub 2014 Jun 2.

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

Author information

1
Frontier Core-Technology Laboratories, R & D Management Headquarters, FUJIFILM Corporation , 577, Ushijima, Kaisei-machi, Ashigarakami-gun, Kanagawa 258-8577, Japan.

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 mm(2), 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.

PMID:
24865176
DOI:
10.1021/nn4065692
[Indexed for MEDLINE]

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