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Vercruysse_Chem Preprint_pigment characterization with anti-oxidant properties.pdf (809.51 kB)
Synthesis of L-DOPA Based Melanins with Reproducible Physic-Chemical Properties
Preprints are manuscripts made publicly available before they have been submitted for formal peer review and publication. They might contain new research findings or data. Preprints can be a draft or final version of an author's research but must not have been accepted for publication at the time of submission.
This report expands our ongoing research efforts
into the non-enzymatic synthesis of melanins. We have explored four different
methods for the synthesis of L-DOPA based melanins and evaluated the
reproducibility of some of their physic-chemical properties. The melanins were
synthesized through the addition of NaOH, tyrosinate or Fe2+/H2O2.
Two different approaches for the reactions involving Fe2+ and H2O2
were tested: a) addition of H2O2 spread out over multiple
days or b) addition of H2O2 in one fraction at the start
of the reaction. The physic-chemical properties of the melanins explored involved:
1) retention on size exclusion chromatography column, 2) FT-IR spectroscopy, 3)
UV-Vis spectroscopy and 4) the capacity to reduce a redox dye,
dichlorophenolindophenol. Overall the results obtained indicated that 1) the
various synthesis methods lead to melanins with reproducible physic-chemical
properties, 2) that the melanins synthesized in the presence of Fe2+/H2O2
are distinctly different from the melanins synthesized in the presence of NaOH
or tyrosinate and 3) that no distinctly different melanins were generated when
comparing the two different synthesis approaches involving Fe2+/H2O2.
Only the melanins synthesized in the presence of Fe2+/H2O2
appeared to possess the capacity to reduce dichlorophenolindophenol.