Ultrasonic Deposition of Cellulose Nanocrystals on Substrates for Enhanced Eradication Activity on Multidrug-Resistant Pathogens

Amidst the pervasive threat of bacterial afflictions, the imperative for advanced antibiofilm surfaces with robust antimicrobial efficacy looms large. This study unveils a sophisticated ultrasonic synthesis method for cellulose nanocrystals (CNCs, 10-20 nm in diameter and 300-900 nm in length) and their subsequent application as coatings on flexible substrates, namely cotton (CC-1) and membrane (CM-1). The cellulose nanocrystals showed excellent water repellency with a water contact angle as high as 148° on the membrane. Noteworthy attributes of CNC-coated substrates include augmented reactive oxygen species (ROS) generation, heightened surface hydrophobicity, and comprehensive suppression of both drug-sensitive (<i>MDR E. coli</i> and <i>MRSA</i>) and susceptible (<i>E. coli</i> and <i>S. aureus</i>) planktonic and biofilm bacterial proliferation. In contrast, the uncoated substrates display 100% bacterial growth for the above bacteria. Empirical data corroborate the pronounced biofilm mass reduction capabilities of CNC-coated substrates across all tested bacterial strains. Elucidation of underlying mechanisms implicates ROS generation and electrostatic repulsion between CNCs and bacterial membranes in the disruption of mature biofilms. Hydroxyl radicals, superoxide, and hydrogen peroxide possess formidable reactivity, capable of disrupting essential biomolecules such as DNA, proteins, and lipids. The engineered CNC-coated substrates platform evinces considerable promise in the realm of infectious disease management, offering a cogent blueprint for the development of novel antimicrobial matrices adept at combating bacterial infections with efficacy and precision.