Cellulose Acetate Modification Towards Antibiofilm Properties via Chemical Attachment of Quaternary Ammonium Compounds using Supercritical CO2

There is an urgency to develop novel materials capable of preventing the adherence of microorganisms to their surface. Such materials with antibiofilm properties are needed in hospitals and public places, animal farms and veterinary hospitals, and biofouling prevention. Biofouling is the phenomenon of adhesion and the growth of microorganisms on surfaces in contact with water. It poses a significant problem for filtration processes, water treatment units, bioreactors, and ships performance (marine biofouling). High-pressure techniques such as supercritical solvent impregnation and grafting in the supercritical phase allow for the modification of a solid matrix throughout the whole volume and production of materials of unique properties in an environmentally friendly way. Grafting involves the chemical attachment of an active compound to a solid matrix, ensuring its long-lasting properties. Grafting in supercritical carbon dioxide (scCO2) has been reported as an efficient tool in the production of materials with antibacterial1 , and recently also antibiofilm properties2 . This study aims to investigate the potential of cellulose acetate (CA) grafting with quaternary ammonium compounds (QAC) for acquiring antibiofilm properties. Two QAC were synthesized, and the grafting conditions were investigated. The grafting was performed via hexamethylene diisocyanate (HDI) as a linker1 . Obtained materials were analyzed using FTIR, SEM and Ion microscopy, DSC analyses, contact angle measurements, and standardized microbiological procedures to evaluate antibiofilm properties

Cellulose Acetate Membranes Modification by Aminosilane Grafting in Supercritical Carbon Dioxide towards Antibiofilm Properties

The study explores the grafting of cellulose acetate microfiltration membranes with an aminosilane to attain antibiofilm properties. The grafting reaction was performed in the supercritical carbon dioxide used as a transport and reaction medium. The FTIR analyses and dissolution tests confirmed the covalent bonding between the aminosilane and polymer. The membranes’ microstructure was investigated using a dual-beam SEM and ion microscopy, and no adverse effects of the processing were found. The modified membranes showed a more hydrophilic nature and larger water permeate flow rate than the neat cellulose acetate membranes. The tests in a cross-filtration unit showed that modified membranes were considerably less blocked after a week of exposure to Staphylococcus aureus and Escherichia coli than the original ones. Microbiological investigations revealed strong antibiofilm properties of the grafted membranes in experiments with Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella Enteritidis

The transformation of cellulose acetate into a new biocidal polymer by effluent-free grafting in supercritical carbon dioxide

The study reports an effluent-free, green process for the production of materials with favorable antibiofilm properties by cellulose acetate grafting with quaternary ammonium compounds in supercritical carbon dioxide. Two quaternary ammonium compounds, N-(2-Hydroxyethyl)-N,N-dimethylundecan-1-aminium Bromide and N-(11-Hydroxyundecanyl-N,N-dimethyltetradecan- 1-aminium Bromide, were synthesized and chemically attached to cellulose acetate via hexamethylene diisocyanate as a linker under the conditions of 30 MPa and 70 °C. The polymer modification occurred in its whole volume. The chemical conversion led to a decrease in the degree of crystallinity and the appearance of a rugged polymer surface. However, the cross-section imaging of the newly obtained materials revealed a compact polymer structure. The functionalized materials acquired hydrophobic properties. Microbiological tests showed the impossibility of Staphylococcus aureus ATCC 29213, Methicillin-resistant Staphylococcus aureus ATCC 43300, Escherichia coli ATCC 10536, and Salmonella Enteritidis ATCC 13076 attachment to the material obtained by the cellulose acetate grafting procedure with N-(11-Hydroxyundecanyl-N,N-dimethyltetradecan- 1-aminium Bromide