Antibacterial Properties of a Honeycomb-like Pattern with Cellulose Acetate and Silver Nanoparticles

Abstract

This study involved the preparation and characterization of structures with a honeycomb-like pattern (HCP) formed using the phase separation method using a solution mixture of chloroform and methanol together with cellulose acetate. Fluorinated ethylene propylene modified by plasma treatment was used as a suitable substrate for the formation of the HCP structures. Further, we modified the HCP structures using silver sputtering (discontinuous Ag nanoparticles) or by adding Ag nanoparticles in PEG into the cellulose acetate solution. The material morphology was then determined using atomic force microscopy (AFM) and scanning electron microscopy (SEM), while the material surface chemistry was studied using energy dispersive spectroscopy (EDS) and wettability was analyzed with goniometry. The AFM and SEM results revealed that the surface morphology of pristine HCP with hexagonal pores changed after additional sample modification with Ag, both via the addition of nanoparticles and sputtering, accompanied with an increase in the roughness of the PEG-doped samples, which was caused by the high molecular weight of PEG and its gel-like structure. The highest amount (approx. 25 at %) of fluorine was detected using the EDS method on the sample with an HCP-like structure, while the lowest amount (0.08%) was measured on the PEG + Ag sample, which revealed the covering of the substrate with biopolymer (the greater fluorine extent means more of the fluorinated substrate is exposed). As expected, the thickness of the Ag layer on the HCP surface depended on the length of sputtering (either 150 s or 500 s). The sputtering times for Ag (150 s and 500 s) corresponded to layers with heights of about 8 nm (3.9 at % of Ag) and 22 nm (10.8 at % of Ag), respectively. In addition, we evaluated the antibacterial potential of the prepared substrate using two bacterial strains, one Gram-positive of S. epidermidis and one Gram-negative of E. coli. The most effective method for the construction of antibacterial surfaces was determined to be sputtering (150 s) of a silver nanolayer onto a HCP-like cellulose structure, which proved to have excellent antibacterial properties against both G+ and G− bacterial strains.

Antibacterial Properties of Silver Nanoclusters with Carbon Support on Flexible Polymer

“…The changes in the chemical composition of the surface were studied using the XPS method, which under normal conditions measures only to a depth of 10 nm [ 37 ]. As an alternative elemental analysis, we have applied the EDS method to acquire elemental composition data from a larger depth, since EDS analysis enables the determination up to a depth of several hundreds of nanometers [ 38 ]. Figure 4 shows the XPS spectrum of a sample deposited with an Ag layer at 20 mA for 200 s and a table with the atomic concentration of Ag for samples sputtered at a current of 20 mA at different deposition times.…”

Cytocompatibility of Polymethyl Methacrylate Honeycomb-like Pattern on Perfluorinated Polymer

“…However, the latest new theory confirms that hexagonal structures are formed due to highly elastic wax, elevated temperature, and surface tension, transforming circular shapes into hexagonal [12][13][14]. Based on this study, honeycomb-like patterns (HCP) have been identified as unique surfaces due to thousands of interconnected and oriented pores with high mechanical strength [15,16]. Based on the pore size and porosity, three-dimensional (3D) scaffolds resembling the in vivo shape and conditions can be created.…”

“…Short exposure of a polymer to the plasma treatment creates nanometric structures while changing the polymer surface into a porous form for a longer time [47]. Based on previous research [16,25], the plasma treatment parameters for creating the suitable surface of HCP structures were selected: duration 240 s at the power of 8 W. The changes on the prepared HCP structures' surface morphology were analyzed by two different methods, AFM and SEM. Figure 1 represents the scans of the prepared samples acquired by the SEM analysis.…”

“…The method is based on a tertiary system: solvent (chloroform)-polymer-"no" solvent (methanol), in the correct volume ratio. To achieve the preparation of HCP structures is necessary to immerse the substrate in the prepared solution and then, spontaneously evaporate it in the air [16,[35][36][37]. The advantage of this method, except for the humid environment and other active substances, is the exact ratio of solvents [8].…”

Antibacterial Activity of Polyaniline Coated in the Patterned Film Depending on the Surface Morphology and Acidic Dopant

“…The BF method is a simple and convenient method to fabricate highly ordered honeycomb-patterned (HCP) porous films with specific surface topography and chemical distribution, first reported by Widawski et al [ 37 ]. Many researchers have reported the antibacterial and antifouling activity of HCP films by incorporating antibacterial and antibiofilm moieties such as TiO 2 [ 24 ], silver NPs [ 38 , 39 ], silicone oil [ 40 ], etc. However, the antibacterial activity of PANI-coated HCP films has not been reported yet.…”