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. 2011 Aug 4;6(8):e22802. doi: 10.1371/journal.pone.0022802

Figure 4. SERS spectra characteristic of the 3 differentiation stages of mES cells.

Figure 4

The dark-field microscopic image of undifferentiated single ES cells loaded with 100 nm GNPs (A), and the corresponding SERS spectrum from the particle encircled inside the ES cell (D). The bright-field microscopic image of EBs treated with 100 nm GNPs and gold nanoaggregates visible in the dark (B). The corresponding SERS spectrum measured from the encircled area of EB (E). The bright-field microscopic image of 12-d-grown cardiomyocyte tissues loaded with 100 nm GNPs appeared as aggregates in the circled area (C) and in the corresponding SERS spectrum (F). Images captured by a digital camera (Canon, Japan) after excitation with a He-Ne laser (632.8 nm) at a power of 130 µW using a ×100 objective lens. SERS spectra of both ES cells and EBs acquired with 30-s laser acquisitions. The SERS spectrum of the cardiomyocyte tissue samples was acquired with 1-s acquisitions.