Visible-Light-Responsive Photocatalyst of Graphitic Carbon Nitride for Pathogenic Biofilm Control

Abstract

Pathogenic biofilms raise significant health and economic concerns, because these bacteria are persistent and can lead to long-term infections in vivo and surface contamination in healthcare and industrial facilities or devices. Compared with conventional antimicrobial strategies, photocatalysis holds promise for biofilm control because of its broad-spectrum effectiveness under ambient conditions, low cost, easy operation, and reduced maintenance. In this study, we investigated the performance and mechanism of Staphylococcus epidermidis biofilm control and eradication on the surface of an innovative photocatalyst, graphitic carbon nitride (g-C 3 N 4 ), under visible-light irradiation, which overcame the need for ultraviolet light for many current photocatalysts (e.g., titanium dioxide (TiO 2 )). Optical coherence tomography and confocal laser scanning microscopy (CLSM) suggested that g-C 3 N 4 coupons inhibited biofilm development and eradicated mature biofilms under the irradiation of white light-emitting diodes. Biofilm inactivation was observed occurring from the surface toward the center of the biofilms, suggesting that the diffusion of reactive species into the biofilms played a key role. By taking advantage of scanning electron microscopy, CLSM, and atomic force microscopy for biofilm morphology, composition, and mechanical property characterization, we demonstrated that photocatalysis destroyed the integrated and cohesive structure of biofilms and facilitated biofilm eradication by removing the extracellular polymeric substances. Moreover, reactive oxygen species generated during g-C 3 N 4 photocatalysis were quantified via reactions with radical probes and 1 O 2 was believed to be responsible for biofilm control and removal. Our work highlights the promise of using g-C 3 N 4 for a broad range of antimicrobial applications, especially for the eradication of persistent biofilms under visible-light irradiation, including photodynamic therapy, environmental remediation, food-industry applications, and self-cleaning surface development.

1,4,5,8-Naphthalene tetracarboxylate dianhydride/g-C3N4 van der Waals heterojunctions exhibit enhanced photochemical H2O2 production and antimicrobial activity

“…Initial reports illustrated the potential of CN to produce 1 O 2 (Δ g ), but required extended irradiation to achieve the desired effects. 11,12 Subsequent studies, conducted by both our group and others, have illustrated that CN-mediated ROS formation reduces microbial biofilm formation, but complete inhibition was generally not observed. 13,14 …”

Recent Innovations in Bacterial Infection Detection and Treatment

“…Responsvie drug delivery approaches can also utilize external triggers to release therapeutics on-demand. These may include infared, − visible, , and ultraviolet light; , temperature; and ultrasound . Implant and device coatings, ,, hydrogels, and NPs ,,,, have all been designed to respond to these types of external triggers for antibacterial applications.…”

Antimicrobial Biocomposites Fiber‐Welded with Lignocellulose Containing Silver Nanoparticles

“…[42] Due to the protection of EPS and unique cellular properties, bacteria within biofilms are much more resistant to conventional disinfection methods, for example, ultraviolet light in the field applications and antibiotics in human body, compared with their planktonic counterparts. [43,44] In general, the typical biofilm life cycle includes three stages, that is, attachment, maturation, and recolonization. [45] Biofilms start from the attachment of planktonic bacteria onto various surfaces.…”