Hybrid tellurium-lignin nanoparticles with enhanced antibacterial properties

Abstract

The surge of antibiotic-resistant bacteria is leading to the loss of antibiotic treatment effectiveness, resulting in prolonged infections and even death. Against this healthcare threat, antimicrobial nanoparticles that hamper the evolve of resistance mechanisms are promising alternatives to antibiotics. Herein, we used Kraft lignin, a poorly valorized polymer derived from plant biomass, to develop novel hybrid tellurium-lignin nanoparticles (TeLigNPs) as alternative antimicrobial agents. The sonochemically synthesized TeLigNPs are comprised of a lignin matrix with embedded Te clusters, revealing the role of lignin as both reducing agent and structural component. The hybrid NPs showed strong bactericidal effect against the Gram-negative Escherichia coli and Pseudomonas aeruginosa, achieving more than 5 log bacteria reduction, while only slightly inhibited the growth of the Gram-positive Staphylococcus aureus. Exposure of TeLigNPs to human cells did not cause morphological changes or reduction in cell viability. Studies on the antimicrobial mechanism of action demonstrated that the novel TeLigNPs were able to disturb bacterial model membranes and generate reactive oxygen species (ROS) in Gram-negative bacteria.