Exploring the effect of surfactants on the interactions of manganese dioxide nanoparticles with biomolecules

Interactions of manganese dioxide nanoparticles (MnO₂ NPs) with vital biomolecules namely deoxyribonucleic acid (DNA) and serum albumin (BSA) have been studied in association with different surfactants by using fluorescence (steady state, synchronous and 3D), UV-visible, resonance light scattering (RLS), dynamic light scattering (DLS), and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The esterase activity of serum albumin was tested in associations with MnO₂ NPs and surfactants. The antioxidant potential of prepared NPs was also evaluated (DPPH method). Gel electrophoresis was carried out to analyze the effect of MnO₂ NPs and surfactants on DNA. Presence of CTAB, Tween 20, DTAB and Tween 80 enhanced nanoparticle-protein binding. Tween 20 based nanoparticle systems showed long-term stability and biocompatibility. The quenching of BSA fluorescence emission in presence of MnO₂ NPs alone and along with Tween 20 revealed stronger association of nanoparticles with proteins. Enhancement in the esterase activity (BSA) was observed in the presence of Tween 20. Furthermore, radical scavenging activity showed highest antioxidant potential in presence of Tween 20. The enthalpy and entropy assessment for protein-NPs association showed the predominance of Vander Waals interactions and hydrogen bonding. The synchronous fluorescence analysis highlighted the involvement of tryptophan (Trp) in the MnO₂ NPs-protein interactions. The study evaluates the influence of surfactant on the associations of MnO₂ NPs with the essential biomolecules. The findings can be crucially utilized in designing biocompatible MnO₂ formulations for long term applications.Communicated by Ramaswamy H. Sarma.