Environmentally Induced Changes of Commercial Carbon Nanotubes in Aqueous Suspensions. Adaptive Behavior of Bacteria in Biofilms

RODRÍGUEZ SARTORI, DAMIÁN; BERTUOLA, MARCOS; MIÑÁN, ALEJANDRO; GONIK, EDUARDO; GONZALEZ, MÓNICA C.; FERNÁNDEZ LORENZO DE MELE, MÓNICA

ACS Omega

ACS

Año: 2021

2470-1343

ABSTRACT: The effects of environmental factors such as sunlightirradiation and the presence of humic acid (HA) on the physicochemicalproperties of commercial multiwall carbon nanotubes (MWCNT)suspended in a simulated inorganic matrix (SIM) and their impacts onbacteria growing in biofilms were evaluated. Both solar irradiation and thepresence of HA lead to the dissolution of adsorbed metals on theMWCNT, which are residues of synthesis catalysts. Also, preferentialadsorption of certain HA components on the MWCNT induces importantmodifications in the aliphatic/aromatic relationship of HA components insolution and the generation and release of new moieties. Resultsdemonstrated that the variation of such physicochemical parametersstrongly affects the interactions of MWCNT with Pseudomonas aeruginosasessile bacteria. Thus, the number of attached bacteria increased, and stressresponses such as decrease in bacterial size were found in the presence ofsunlight-irradiated MWCNT with a particular distribution of extracellular polymeric substances (EPS) strands. A shielding effect was observed when HA was added. It was concluded that physicochemical alterations caused by environmental conditions (with/withoutirradiation, presence/absence of HA) on MWCNT-containing SIM trigger distinctive adaptive behavior of bacteria in biofilms. This information must be taken into account in the development of biologically assisted treatments for organic metal co-contamination ofMWCNT-containing media since MWCNT discharge alters the physicochemical properties and composition of the aqueous environment and the response of the biofilms that interact with it.