A Study of the Binding of Organic Compounds to Melanins

Tyona Lumbria Caldwell, Tennessee State University


Melanins (MNs) constitute a ubiquitous class of dark-colored pigments which can be found in all kingdoms of life. Despite many decades of intense research and computer modeling, there is no consensus on the precise chemical structure of these biomolecules, nor a precise explanation for their dark color, exhibited by their broad-range, monotonic absorbance profile over the entire ultraviolet and visible region of the electromagnetic spectrum. In this project, we study the binding of organic compounds to MNs synthesized from different precursors (catechol, pyrogallol, dopamine or L-DOPA) and co-precipitated on CaCO3 or Ca3(PO4)2. The MN-coated CaCO3 or Ca3(PO4)2 materials are washed, dried by freeze drying and characterized by FT-IR spectroscopy. The affinity of various organic compounds (acetaminophen, hydrocortisone, caffeine, theophylline, vanillin, carvone and others) have been evaluated using RP-HPLC analyses to determine the percent (%) binding of the compounds onto the MN-coated CaCO3 or Ca2(PO4)3 minerals. Preliminary results indicate that L-DOPA or dopamine based MNs bind organic compounds more strongly compared to catechol or pyrogallol based MNs. In addition, when given enough time (up to 48h) significant binding levels (> 80%) by select organic compounds onto dopamine or L-DOPA based MNs can be achieved.

Subject Area


Recommended Citation

Tyona Lumbria Caldwell, "A Study of the Binding of Organic Compounds to Melanins" (2021). ETD Collection for Tennessee State University. Paper AAI28646391.