Investigation of photoexcited states in porcine eumelanin through their transient radical products.
Time-resolved electron paramagnetic resonance was used to monitor the photochemistry of radical pairs from melanin in porcine retinal pigment epithelial cells on the sub-microsecond time scale. Two distinct signals were found: one of enhanced absorption/emission at early times and one mostly emissive at later times. The emissive character of the longer lived feature suggests participation of an excited triplet precursor, something not generally thought to exist in melanins. The radicals in the early time signal were separated by about 21 A and those in the later time signal were separated by about 22-24 A.
Wang
Alice
A
Department of Chemistry, University of Chicago, Chicago, Illinois 60637, USA.
Marino
Anthony R
AR
Gasyna
Elzbieta M
EM
Sarna
Tadeusz
T
Norris
James R
JR
D000818:Animals; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D008543:Melanins / Q000737:chemistry* / Q000378:metabolism; D055668:Photochemical Processes; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000378:metabolism; D013552:Swine; D013997:Time Factors
D005609:Free Radicals; D008543:Melanins; C041877:eumelanin