Graphene oxide nanohybrids for electron transfer-mediated antimicrobial activity

Area of Science:

• Materials Science
• Nanotechnology
• Microbiology

Background:

• Antibiotic resistance is a growing global health crisis, necessitating novel antimicrobial strategies.
• Graphene oxide (GO) and phthalocyanine derivatives show intrinsic antibacterial properties.
• Combining these materials into nanohybrids could enhance their efficacy.

Purpose of the Study:

• To synthesize and characterize graphene oxide incorporated zinc phthalocyanine (ZnPc-GO) nanohybrids.
• To evaluate the bactericidal activity of these nanohybrids against Gram-negative Escherichia coli (E. coli).
• To investigate the underlying mechanisms of bacterial inactivation.

Main Methods:

• Facile synthesis of ZnPc-GO nanohybrids via in situ deposition on indium tin oxide (ITO) substrates.
• Utilized two distinct ZnPc phases: α-phase ZnPc(A) and β-phase ZnPc(B).
• Employed characterization techniques to study interactions and electron transfer.
• Investigated bacterial adherence and cell death kinetics using surface potential mapping and Kelvin probe force microscopy (KPFM).

Main Results:

• ZnPc(B)-GO nanocomposites exhibited stronger π-π interactions and more efficient electron transfer compared to ZnPc(A)-GO.
• E. coli cells showed significant adherence to the electron-withdrawing ZnPc(B)-GO surface.
• Direct contact with ZnPc(B)-GO induced bacterial cell deformation and membrane leakage, attributed to a charge-transfer mechanism.

Conclusions:

• ZnPc-GO nanohybrids possess significant, light-independent bactericidal activity against E. coli.
• The β-phase ZnPc(B)-GO variant is particularly effective due to enhanced interfacial properties.
• Findings suggest potential for developing novel ZnPc-GO-based antimicrobial materials and surface coatings.