Atto Thio 12 as a promising dye for photo-CIDNP

Photo-CIDNP is one among different promising techniques to improve nuclear magnetic resonance (NMR) sensitivity. Being sensitive to particular amino acids makes it a promising candidate with respect to biological NMR. Our goal is to exploit new sensitizers and compare them to the present working horses flavin mononucleotide, bipyridyl, and the recently applied fluorescein. Among the investigated dyes, we found a new and very efficient one, Atto Thio 12, conveniently used in fluorescence microscopy with 2-3 fold enhanced polarization when compared to the established ones. We also show that diode lasers which are now available from near UV to IR can be efficiently used in photo-CIDNP. Results are obtained with the amino acids tyrosine and tryptophan.