Structural analysis and spectroscopic characterization of melanin-alginate films

In this work, we present the spectroscopic and structural analysis of synthetic melanin incorporated within alginate films. We propose a synthesis methodology for alginate films with different concentrations of melanin. For this, Ca2${}^{+}$-crosslinked alginate films plasticized with glycerol (30% w/w) are used as a matrix to support melanin in a non-disolved state. The structural and morphological characteristics of the alginate-melanin films are evaluated. Furthermore, we analyze the structural and morphological characteristics of the obtained films and analyze their spectroscopic characteristics from the ultraviolet to the terahertz bands of the electromagnetic spectrum. This work demonstrates that alginate films are a viable option as a matrix for the analysis and characterization of non-dissolved melanin. Moreover, we determine the dependence of the analyzed physical and optical properties of the alginate-melanin films with respect to the melanin concentration and discuss the relevance of the observed changes. The analysis suggests the potential use of melanin-alginate films for further examination of non-dissolved melanin.