Photothermal Antibacterial and Antibiofilm Activity of Black Phosphorus/Gold Nanocomposites against Pathogenic Bacteria

Abstract

Black phosphorus (BP) as a layered two-dimensional (2D) semiconductor material with a tunable band gap has attracted growing attention for promising applications in diverse fields including biotechnology owing to its excellent physical and chemical properties. In this study, BP crystals were synthesized using a chemical vapor transport method and exfoliated into BP nanosheets in deoxygenated water or hexane. Next, monodisperse Au nanoparticles that were synthesized using a surfactant-assisted chemical reduction method were assembled on exfoliated BP nanosheets hexane to yield BP/Au nanocomposites. The photothermal antibacterial and antibiofilm activities of BP nanosheets and BP/Au nanocomposites were investigated against Enterococcus faecalis, a pathogenic biofilm-forming bacterium, by studying the photothermal effect and bacterial growth curve and using colony counting and live/dead fluorescence staining methods under near-infrared (NIR) light irradiation. Thanks to the higher photothermal conversion efficiency of BP/Au nanocomposites than that of bare BP nanosheets under NIR light irradiation, they destructed the bacterial cell membrane more efficiently than bare BP with the biofilm inhibition rate of 58%. It should be noted that this is the first study on the antibacterial and antibiofilm activity of BP/Au nanocomposites via a photothermal process under NIR light irradiation. This work shows the potential of BP/Au nanocomposites in fighting against pathogenic bacteria and paves the way for the exploration of antibacterial platforms based on the biocompatible 2D semiconductor BP.

Emerging Trends in Nanomaterials for Antibacterial Applications

“…The membrane damage was due to BP/AuNPs disrupting bacterial membranes due to the sharp edges of the BP nanosheets through simple contact. 223

Figure 25 Design of BP/Au nanocomposite and its photothermal killing of bacteria. Reprinted with permission from Aksoy I, Kucukkececi H, Sevgi F, et al Photothermal antibacterial and antibiofilm activity of black phosphorus/gold nanocomposites against pathogenic bacteria.

…”

“…The membrane damage was due to BP/AuNPs disrupting bacterial membranes due to the sharp edges of the BP nanosheets through simple contact. 223 Amino-conjugated GO (AGO) nanosheets were fabricated by Bo-Yao Lu and co-authors to simultaneously exploit three properties: the natural power of AGO to cut bacteria, positive charges for bacterium targeting, and effective photothermal performance. [224][225][226] With this synthesized nanoantibiotic, the antibacterial effect was investigated on S. mutans, the main cause of dental caries.…”

Green Carbon Dots (GCDs) for Photocatalytic Hydrogen Evolution and Antibacterial Applications

“…[30d] Our previous study has also showed that NIR light irradiation could enhance ROS generation of Black phosphorus/Gold nanocomposite (BP/Au) to inhibit bacterial growth of Enterococcus faecalis. [45] In this study, GCDs were synthesized from Aloe vera leaves by using microwave synthesis technique. In the morphological characterizations of GCDs and GCDs/TiO 2 photocatalysts, transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), scanning electron microscopy analysis (SEM) techniques were used.…”

“…Finally, Chu and co‐workers have designed NIR CD‐based platform for photothermal/photodynamic synergetic sterilization of E. coli and S. aureus through ROS generation and hyperthermia [30d] . Our previous study has also showed that NIR light irradiation could enhance ROS generation of Black phosphorus/Gold nanocomposite (BP/Au) to inhibit bacterial growth of Enterococcus faecalis [45] …”

An N-Halamine/Graphene Oxide-Functionalized Electrospun Polymer Membrane That Inactivates Bacteria on Contact and by Releasing Active Chlorine

“…Vasan’s group found that a ZnO/Ag hybrid showed higher antibacterial activity against Gram-positive and Gram-negative bacteria than its individual components (i.e., ZnO and Ag) [ 24 ]. In Patir’s report, the excellent photothermal antibacterial and antibiofilm capabilities of BP/Au nanocomposites destroyed the bacterial cell membrane more efficiently than pristine BP [ 25 ]. Owing to its ease of operation and low cost, broad-spectrum effectiveness, the electrospinning technique has gained a great achievement on the combination of two or more active antibacterial agents for fighting pathogens [ 26 ].…”