Influence of Cellulose Charge on Bacteria Adhesion and Viability to PVAm/CNF/PVAm-Modified Cellulose Model Surfaces

Abstract

A contact-active antibacterial approach based on the physical adsorption of a cationic polyelectrolyte onto the surface of a cellulose material is today regarded as an environment-friendly way of creating antibacterial surfaces and materials. In this approach, the electrostatic charge of the treated surfaces is considered to be an important factor for the level of bacteria adsorption and deactivation/killing of the bacteria. In order to clarify the influence of surface charge density of the cellulose on bacteria adsorption as well as on their viability, bacteria were adsorbed onto cellulose model surfaces, which were modified by physically adsorbed cationic polyelectrolytes to create surfaces with different positive charge densities. The surface charge was altered by the layer-by-layer (LbL) assembly of cationic polyvinylamine (PVAm)/anionic cellulose nanofibril/PVAm onto the initially differently charged cellulose model surfaces. After exposing the LbL-treated surfaces to Escherichia coli in aqueous media, a positive correlation was found between the adsorption of bacteria as well as the ratio of nonviable/viable bacteria and the surface charge of the LbL-modified cellulose. By careful colloidal probe atomic force microscopy measurements, it was estimated, due to the difference in surface charges, that interaction forces at least 50 nN between the treated surfaces and a bacterium could be achieved for the surfaces with the highest surface charge, and it is suggested that these considerable interaction forces are sufficient to disrupt the bacterial cell wall and hence kill the bacteria.

The Use of Layer‐by‐Layer Self‐Assembly and Nanocellulose to Prepare Advanced Functional Materials

“…However, in a recent investigation the recharging of cellulose model surfaces, with different charge densities, by of cationic polyvinylamine (PVAm) and anionic CNF was carefully determined using colloidal probe atomic force microscopy (AFM) measurements. [ 23 ] By fitting the force curves from the AFM colloidal probe measurements to the Derjaguin−Landau−Verwey−Overbeek (DLVO) theory it was possible to determine the surface potential of both the untreated and the LbL‐treated surfaces under different ionic strengths. From these potentials, it was also possible to calculate the surface charge using the Gouy–Chapman model.…”

“…For the highest charged surface, a surface potential of 110 mV could be obtained corresponding to a surface charge of 47 mC m −2 . [ 23 ] In order to quantify the colloidal properties of LbL‐treated surfaces it is important to publish these types of quantitative data.…”

“…Conversely, the antibacterial effects of (PVAm/CNF)‐multilayers on cellulose model surfaces were found to be correlated to a higher surface charge of the cellulose model surface and hence an increased PVAm adsorbtion. [ 23 ,61] By comparing different types of cellulose materials it was found that a close packing of the CNFs in the nanosheets limits the adsorption of bacteria. By creating a porous 3D‐structure of CNFs in the form of wet‐stable aerogels it was possible to preserve the high specific surface area of the CNFs to a large extent.…”

Layer-by-Layer Nanocoating of Antiviral Polysaccharides on Surfaces to Prevent Coronavirus Infections

“…To date, the GAGs and other polysaccharides have not been employed widely in LbL nanocoating to specifically produce antiviral surfaces as is the case for antibacterial or antifungal coatings. Numerous publications have reported on the antibacterial surface application of polysaccharides via an LbL approach [ 85 , 86 , 87 , 88 , 89 , 90 ]. Table 1 lists some commonly utilized polysaccharides that have been employed in LbL nanocoatings and a non-exhaustive list of recent applications.…”

In Situ Monitoring of Alkanethiol Self‐Assembly onto Zinc Selenide: The Role of Substrate Pretreatment and Its Implication in Bacterial Attachment

“…[17,[45][46][47] LGG cells appeared green after the staining, which suggested the integrity of their membrane, despite the presence of positive charges known as potential bactericides. [48,49] Possibly, this effect was attributed to the fact that LGG, like other Gram-positive bacteria, possess a thick peptidoglycan-rich layer on their cell wall that could act as a protective layer against detrimental electrostatic forces. [49,50]…”