The effect of Dunaliella salina extracts on the adhesion of Pseudomonas aeruginosa to 3D printed polyethylene terephthalate and polylactic acid.

Polyethylene terephthalate (PET) and polylactic acid (PLA) are among the polymers used in the food industry. In this study, crude extracts of Dunaliella salina were used to treat the surface of 3D printed materials studied, aiming to provide them with an anti-adhesive property against Pseudomonas aeruginosa. The hydrophobicity of treated and untreated surfaces was characterized using the contact angle method. Furthermore, the adhesive behavior of P. aeruginosa toward the substrata surfaces was also studied theoretically and experimentally. The results showed that the untreated PLA was hydrophobic, while the untreated PET was hydrophilic. It was also found that the treated materials became hydrophilic and electron-donating. The total energy of adhesion revealed that P. aeruginosa adhesion was theoretically favorable on untreated materials, while it was unfavorable on treated ones. Moreover, the experimental data proved that the adhesion to untreated substrata was obtained, while there was complete inhibition of adhesion to treated surfaces.

The effect of essential oils mixture on chitosan-based film surface energy and antiadhesion activity against foodborne bacteria.

In the food sector, the formation of biofilms as a result of microbial adherence on food-grade surfaces causes a major problem resulting in significant economic losses. Thereby, this work aimed to elaborate a biodegradable film using chitosan (CS-film) and reinforce its antiadhesion activity by incorporating pelargonium, clove, thyme, and cinnamon essential oils (EOs). Firstly, the antibacterial activity of these EOs alone and combined against four foodborne bacteria were analyzed by the microdilution method. Synergism was observed in the case of EOs combination. Secondly, the physicochemical characteristics and antiadhesion behavior of the CS-films were assessed by the contact angle method and ESEM, respectively. Results revealed that the EOs mixture treatment impacted considerably the physicochemical characteristics of the CS-film and reduced its qualitative and quantitative hydrophobicity. Moreover, the treated CS-film showed a strong antiadhesion behavior against Enterococcus hirae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus with percentages of non-covered surface equal to 97.65 ± 1.43%, 98.76 ± 0.32%, 99.68 ± 0.28%, and 95.63 ± 1.32% respectively. From all these results, the CS-film treated with the mixture of EOs presents a great potential for application as surface coating and food packaging preventing microbial adhesion and thus, avoiding food contamination and spoilage.

The theoretical adhesion of Staphylococcus aureus and Pseudomonas aeruginosa as nosocomial pathogens on 3D printing filament materials.

Microbial infections and nosocomial diseases associated with biomaterial have become a major problem of public health and largely lead to revision surgery, which is painful and quite expensive for patients. These infections are caused by formation of biofilm, which present a difficulty of treatment with conventional antibiotics. The aim of our study is to investigate the theoretical adhesion of Staphylococcus aureus and Pseudomonas aeruginosa on four 3-dimensional printing filament materials used in the manufacture of medical equipment. Thus, the physicochemical properties of these microorganisms and all filament materials were determined using the contact angle measurements. Our results indicated that bacterial surfaces were hydrophilic, strongly electron donating and weakly electron accepting. In contrast, nylon, acrylonitrile butadiene-styrene, polyethylene terephthalate, and polylactic acid surfaces were hydrophobic and more electron-donor than electron-acceptor. In addition, according to the values of total free interaction energy ΔGTotal, Staphylococcus aureus was found unable to adhere to the filament materials except polyethylene terephthalate surface. However, Pseudomonas aeruginosa showed adhesion capacity only for acrylonitrile butadiene-styrene and polyethylene terephthalate surfaces. These findings imply that the usage of these 3D printed materials in the medical area necessitates more research into enhancing their resistance to bacterial adherence.

Environmental Scanning Electron Microscopy characterization of the adhesion of conidia from Penicillium expansum to cedar wood substrata at different pH values.

Initial microbial adhesion to surfaces is a complicated process that is affected by a number of factors. An important property of a solution that may influence adhesion is pH. The surface properties of the cedar wood were characterized by the sessile drop technique. Moreover, the interfacial free energy of surface adhesion to the cedar wood was determined under pH values (2, 3, 5, 7, 9 and 11). The results showed that cedar wood examined at different pH levels could be considered hydrophobic ranged from Giwi = -13.1 mJ/m(2) to Giwi = -75 mJ/m(2). We noted that the electron-donor character of cedar wood was important at both basic and limit acidic conditions (pH 11 and pH 3) and it decreased at intermediate pH (pH 5). The cedar wood substratum presents a weak electron acceptor under various pH's. In addition, the adhesion of conidia from Penicilllium expansum to the cedar wood surfaces at different pH values (2, 3, 5, 7, 9 and 11) was investigated using Environmental Scanning Electron Microscopy and image analysis was assessed with the Mathlab(®) program. The data analysis showed that the conidia from P. expansum were strongly influenced by the pH. The maximum adhesion occurs in the pH 11 and pH 3 and decreased to 24% at pH 5.

Nitinol as a suitable anode material for electricity generation in microbial fuel cells.

Nitinols (Nickel-titanium alloys) have a good electrical conductivity and biocompatibility with human tissue and bacteria and, therefore, can be effectively used as an anode material in bioelectrochemical systems. This paper aimed to use nitinols (at different Ni/Ti ratios) as an anode material for microbial fuel cells (MFCs) in order to achieve higher power density. The maximum power densities of the MFCs using NiTi-1, NiTi-2, and NiTi-3 electrodes were 555 mW/m2, 811 mW/m2, and 652 mW/m2, respectively. More bacterial adhesion was observed on the NiTi-2 electrode. Electrochemical impedance spectroscopy (EIS) results showed low charge transfer resistance at MFCs fabricated with NiTi. The biofilm observations indicate that bacterial attachment is better with NiTi-2 as compared with that on NiTi-1 and NiTi-3. The resulting mesopore and macropore rich structure significantly promote microbial colonization, enabling formation of compact electroactive biofilms with additional benefit from the excellent biocompatibility and chemical stability of NiTi-2. Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) results indicated that five groups of bacteria were the dominant phyla in the MFCs: environmental samples, b-proteobacteria, g-proteobacteria, d-proteobacteria, and CFB group bacteria. The high biocompatibility, electrical conductivity and stability of nitinols make them a more attractive anode material for MFCs.

Salvia officinalis extract mitigates the microbiologically influenced corrosion of 304L stainless steel by Pseudomonas aeruginosa biofilm.

The mitigation of microbiologically influenced corrosion (MIC) of 304L stainless steel (SS) against Pseudomonas aeruginosa by a Salvia officinalis extract was investigated using electrochemical and surface analysis techniques. The extract was characterized by HPLC-Q-TOF-MS and its antibiofilm property was evaluated. The data revealed the presence of well-known antimicrobial and anticorrosion compounds in the extract. The S. officinalis extract was found effective in preventing biofilm formation and inhibiting mature biofilm. Electrochemical results indicated that P. aeruginosa accelerated the MIC of 304L SS, while the extract was found to prevent the MIC with an inhibition efficiency of 97.5 ±â€¯1.5%. This was attributed to the formation of a protective film by the adsorption of some compounds from the extract on the 304L SS surface.