Copper‐Based Nanostructured Coatings on Natural Cellulose: Nanocomposites Exhibiting Rapid and Efficient Inhibition of a Multi‐Drug Resistant Wound Pathogen, A. baumannii, and Mammalian Cell Biocompatibility In Vitro

Abstract

This paper describes a layer‐by‐layer (LBL) electrostatic self‐assembly process for fabricating highly efficient antimicrobial nanocoatings on a natural cellulose substrate. The composite materials comprise a chemically modified cotton substrate and a layer of sub‐5 nm copper‐based nanoparticles. The LBL process involves a chemical preconditioning step to impart high negative surface charge on the cotton substrate for chelation controlled binding of cupric ions (Cu2+), followed by chemical reduction to yield nanostructured coatings on cotton fibers. These model wound dressings exhibit rapid and efficient killing of a multidrug resistant bacterial wound pathogen, A. baumannii, where an 8‐log reduction in bacterial growth can be achieved in as little as 10 min of contact. Comparative silver‐based nanocoated wound dressings–a more conventional antimicrobial composite material–exhibit much lower antimicrobial efficiencies; a 5‐log reduction in A. baumannii growth is possible after 24 h exposure times to silver nanoparticle‐coated cotton substrates. The copper nanoparticle–cotton composites described herein also resist leaching of copper species in the presence of buffer, and exhibit an order of magnitude higher killing efficiency using 20 times less total metal when compared to tests using soluble Cu2+. Together these data suggest that copper‐based nanoparticle‐coated cotton materials have facile antimicrobial properties in the presence of A. baumannii through a process that may be associated with contact killing, and not simply due to enhanced release of metal ion. The biocompatibility of these copper‐cotton composites toward embryonic fibroblast stem cells in vitro suggests their potential as a new paradigm in metal‐based wound care and combating pathogenic bacterial infections.

Drying cellulose-based materials containing copper nanoparticles

“…). Similar phenomenon was reported by Cady et al (2011). After the sprayand freeze-drying process, the CMC-copper nanoparticles exhibited a yellow and green color, respectively.…”

Incorporation of copper nanoparticles into paper for point-of-use water purification

“…Lower peak intensities were observed in the ground CuNP paper samples and most peaks were in the same locations with the additional peak at 2θ at 36.4°, which corresponds to Cu 2 O (111) (JCPDS 77 – 0199). This indicates some minor oxide formation on the copper surface in the air, which is not unexpected, as other researchers have also observed the presence of copper oxides along with CuNPs following CuNP formation on fiber surfaces (Cady et al, 2011; Vainio et al, 2007). No peaks were observed for the untreated paper.…”

Metal–Organic Framework Polymer Coating Inhibits Staphylococcus aureus Attachment on Medical Circulation Tubing under Static and Dynamic Flow Conditions

“…CuBTTri contains copper centers both inside the framework and on the framework surface. Copper centers on the framework surface may be able to come into direct contact with bacterial membranes and induce oxidative damage to bacterial cells. ,, However, coating physiochemical properties, such as surface patterns and surface roughness, may also affect bacterial attachment . Patterning surfaces, such as sharklet, are known to influence the interaction between bacteria and material surfaces. , In this study, a regular micropatterning was not observed on the CuBTTri-coating surfaces (Figure ).…”