THEORETICAL STUDY OF MELANIN-ZN²⁺ COMPLEXES: INVESTIGATING IONIC CHELATION AND ACTIVATION INTERACTION WITH BACTERIAL LIPOPOLYSACCHARIDES

João Pedro Dionizio; Orisson Gomes; Paulo Noronha Lisboa Filho; Jean Valdir Uchôa Teixeira; Augusto Batagin Neto

Título do Trabalho

Autores

João Pedro Dionizio
Orisson Gomes
Paulo Noronha Lisboa Filho
Jean Valdir Uchôa Teixeira
Augusto Batagin Neto

Modalidade

Pôster - resumo

Área temática

Materiais e biomateriais

Data de Publicação

27/05/2026

País da Publicação

Brasil

Idioma da Publicação

pt-BR

Página do Trabalho

https://www.even3.com.br/anais/workshop-do-ineo-2026/1462587-theoretical-study-of-melanin-zn%3f-complexes--investigating-ionic-chelation-and-activation-interaction-with-bacte

ISBN

978-65-272-2467-9

Palavras-Chave

Melanin, Antibacterial, DFT, Electronic Structure, Zinc Chelation

Resumo

Melanin-like dopamine compounds are widely used for the design of biomaterials, presenting a huge potential for biomedical applications. It is mainly due its biocompatibility and presence of active functional groups which allows effective interactions with molecules, enzymes and/or ions. A relevant aspect is the melanin capacity of ion chelation, which allows the formation of a variety of bioactive complexes1. In particular, it has been reported the use of melanin+Zn+2 complexes as an effective antibacterial agent2. Despite the number of works in the literature, there is still a notable gap regarding the role of ion-melanin interactions for biological applications, mainly due to the difficulty of experimentally analyzing such systems. In this report, we use density functional theory (DFT) based calculations to evaluate melanin+Zn+2 (oligomeric) complexes, to better understand the influence of metal ion on the electronic properties of such materials, and underline possible relevant mechanisms that rule their biological activity. The calculations were performed using the hybrid B3LYP functional, as it is sufficient for this type of structural calculations, and the 6-31G(d,p) basis set, which is also well-established within our research group. The PCM model was also used for the solvation and the Empiric Dispersion Correction (GD3) as well. All fundamental melanin monomers with different oxidation states were fully optimized. The local reactivity, electrostatic potential map, and adsorption energy of these monomers with zinc ions were analyzed. These data were used alongside docking studies and previous research to construct the dimeric structures3. Similar analyses were performed for the possible dimers, both before and after the incorporation of the zinc ion, with the addition of Frontier Molecular Orbital (FMO) analysis. The results show that the presence of the metal center on the oligomers affects the structural properties and the local reactivity of the melanin-based systems, leading to an intense electric polarization, and activation of the metal (increase of its local reactivity), which play a relevant role in their interaction with typical lipopolysaccharides present in gram-negative bacterias. Our data are also compatible with other experimental spectroscopic results associated with such systems, allowing us to interpret additional effects of ion chelation on the electronic structure of the complexes. The authors gratefully acknowledge the FAPESP (process nº 2025/23809-7 and 2025/09784-1) for financial support and for the scholarship granted. The authors also acknowledge INEO for the organization of the event and for the logistical and financial support provided. This work was further supported by FAPESP (process nº 2025/27044-5) and CNPq (process nº 408449/2024-1). [1] ELIATO, Tahmineh Rahmani et al. Melanin Zinc Complex as a Biocompatible Agent for Clearing Bacteremia (Adv. Mater. Interfaces 5/2024). Advanced Materials Interfaces, v. 11, n. 5, 2024. [2]MEREDITH, Paul; SARNA, Tadeusz. The physical and chemical properties of eumelanin. Pigment cell research, v. 19, n. 6, p. 572-594, 2006. [3]ALVES, Gabriel GB et al. Reactivity of eumelanin building blocks: A DFT study of monomers and dimers. Journal of Molecular Graphics and Modelling, v. 98, p. 107609, 2020.

Título do Evento: Workshop do INEO 2026
Cidade do Evento: Nazaré Paulista
Título dos Anais do Evento: Anais do Workshop do INEO 2026
Nome da Editora: Even3
Meio de Divulgação: Meio Digital

Como citar

DIONIZIO, João Pedro et al.. THEORETICAL STUDY OF MELANIN-ZN²⁺ COMPLEXES: INVESTIGATING IONIC CHELATION AND ACTIVATION INTERACTION WITH BACTERIAL LIPOPOLYSACCHARIDES.. In: Anais do Workshop do INEO 2026. Anais...Nazaré Paulista(SP) Hotel Estância Atibainha, 2026. Disponível em: https//www.even3.com.br/anais/workshop-do-ineo-2026/1462587-THEORETICAL-STUDY-OF-MELANIN-ZN%3f-COMPLEXES--INVESTIGATING-IONIC-CHELATION-AND-ACTIVATION-INTERACTION-WITH-BACTE. Acesso em: 10/08/2026