1 research outputs found
Plasmonic Hydroxyl Radical-Driven Epoxidation of Fatty Acid Double Bonds in Nanoseconds for On-Tissue Mass-Spectrometric Analysis and Bioimaging
Lipids represent a large family of compounds with highly
diverse
structures that are involved in complex biological processes. A photocatalytic
technique of on-tissue epoxidation of C=C double bonds has been developed
for in situ mass spectrometric identification and spatial imaging
of positional isomers of lipids. It is based on the plasmonic hot-electron
transfer from irradiated gold nanowires to redox-active organic matrix
compounds that undergo bond cleavages and generate hydroxyl radicals
in nanoseconds. Intermediate radical anions and negative fragment
ions have been unambiguously identified. Under the irradiation of
a pulsed laser of the third harmonic of Nd3+:YAG (355 nm),
the hydroxyl radical-driven epoxidation of unsaturated lipids with
different numbers of C=C bonds can be completed in nanoseconds with
high yields of up to 95%. Locations of C=C bonds were recognized with
diagnostic fragment ions that were produced by either collision with
an inert gas or auto-fragmentation resulting from the impact of energetic
hot electrons and vibrational excitation. This technique has been
applied to the analysis of breast cancer tissues of mice models without
extensive sample processes. It was experimentally demonstrated that
C=C bonds may be formed at different positions of not only regular
mono- or poly-unsaturated fatty acids but also other odd-numbered
long-chain fatty acids