Figure 1. Isotope labeled glucose-d₇ is a tracer for de-novo lipogenesis.

(a). Scheme of glucose-derived de-novo lipid synthesis in mammalian cells. (b). Raman spectrum of 1.0 M glucose-d₇ aqueous solution. A broad and unique peak around 2120 cm⁻¹ from C–D bond vibration was observed. Inset: chemical structure of glucose-d₇. (c). Linear dependence of SRS signal on glucose-d₇ concentration. The detection limit of our SRS imaging is around 50 mM. Inset: SRS image of 1.0 M glucose-d₇ solution at the interface of solution and air.