Figure 5.

Emission spectroscopy of an upconverting liposome gel through layers of chicken breast or pork fillet. Emission spectra of gellified L12 liposomes through layers of meat at room temperature as a function of: chicken breast thickness (a); or pork fillet thickness (c). Upconversion intensity (I_UC, at 474 nm), phosphorescence intensity of compound 1 (I_p) and the ratio of I_UC and I_p as a function of: chicken breast thickness (b) or pork fillet thickness (d). Conditions: 20 µL sample in a 25 µm × 25 mm diameter disk of L12 liposomes ([DLPC] = 10 mM) in 0.5% wt % agarose gel, 5 mM l-Asc, and 5 mM GSH in PBS at room temperature, irradiated with 30 mW (3 mm spot, 0.57 W/cm²) 630 nm light through a variable number of meat slices. The spectra are cut off between 575 nm and 675 nm to omit the large excitation scatter peak.