Interaction mechanism of chitosan oligomers in pure water with cell membrane models studied by SFG vibrational spectroscopy

Autor(es)

Rimoli, Caio Vaz ; Pedro, Rafael de Oliveira ; Miranda, Paulo B.

• Tipo de documento: Artigo Científico
• Fonte: COLLOIDS AND SURFACES B-BIOINTERFACES; v. 219, p. 12-pg., 2022-09-02.

Resumo

Chitosan is a versatile and biocompatible cationic antimicrobial polymer obtained from sustainable sources that is effective against a wide range of microorganisms. Although it is soluble only at low pH, chitosan oligomers (ChitO) are soluble in pure water and thus more appropriate for antibacterial applications. Although there is a vast literature on chitosan's antimicrobial activity, the molecular details of its interaction with biomembranes remain unclear. Here we investigate these molecular interactions by resorting to phospholipid Langmuir films (zwitterionic DPPC and anionic DPPG) as simplified membrane models (for mammalian and bacterial mem-branes, respectively), and using SFG vibrational spectroscopy to probe lipid tail conformation, headgroup dy-namics and interfacial water orientation. For comparison, we also investigate the interactions of another simple cationic antimicrobial polyelectrolyte, poly(allylamine) hydrochloride - PAH. By forming the lipid films over the polyelectrolyte solutions, we found that both have only a very small interaction with DPPC, but PAH adsorption is able to invert the interfacial water orientation (membrane potential). This might explain why ChitO is compatible with mammalian cells, while PAH is toxic. In contrast, their interaction with DPPG films is much stronger, even more so for ChitO, with both insertion within the lipid film and interaction with the oppositely charged headgroups. Again, PAH adsorption inverts the membrane potential, while ChitO does not. Finally, ChitO interaction with DPPG is weaker if the antimicrobial is injected underneath a pre-assembled Langmuir film, and its interaction mode depends on the time interval between end of film compression and ChitO injection. These differences between ChitO and PAH effects on the model membranes highlight the importance of mo-lecular structure and intermolecular interactions for their bioactivity, and therefore this study may provide in-sights for the rational design of more effective antimicrobial molecules. (AU)

• Processo FAPESP: 18/02819-0 - Interação de quitosanas e surfactantes com modelos de membrana celular investigada por espectroscopia vibracional não linear
• Beneficiário: Paulo Barbeitas Miranda
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/23100-0 - Investigando o mecanismo molecular de ação de polieletrólitos antimicrobianos em filmes de Langmuir biomiméticos usando espectroscopia SFG
• Beneficiário: Caio Vaz Rimoli
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 14/01595-0 - Estudo de interfaces em dispositivos optoeletrônicos poliméricos por espectroscopia SFG
• Beneficiário: Roberto Mendonça Faria
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/03503-4 - Interação molecular entre quitosanas e modelos de membrana celular investigada por espectroscopia vibracional não linear
• Beneficiário: Rafael de Oliveira Pedro
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado