Quantifying Age-Related Skin Autofluorescence

For the detection and measurement of AGE-related autofluorescence (excitation 370 nm, emission 390–700 nm) in the human skin samples, a Flame miniature spectrometer (FLAME-S-VIS-NIR-ES, 350–1000 nm, Ocean Optics, Dunedin, FL, USA) coupled to an LSS-LED light source (365 nm, Ocean Optics) and a reflection probe (QR400-7-IS-BX, Ocean Optics) was used. For the AF measurements, first, the background signal was corrected, after which the skin samples were transferred to a black 96-well plate (SPL Lifesciences, Pochon, Republic of Korea), and fluorescence measurements were taken at a 90° angle. Each measurement was repeated three to five times. The intensity of the light source was manually set to an excitation peak with an intensity of approximately 60,000. The AF measurements were processed using the OceanView program (Ocean Optics, Largo, FL, USA), which was set to an average of 128 scans and an integration time of 10 ms. The AF values were calculated by dividing the mean light intensity emitted per nm for a range of 407–677 nm by the mean light intensity per nm for a range of 342–407 nm [35 (link),48 (link)].