scholarly journals Antibacterial activity testing methods for hydrophobic patterned surfaces

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana Perez-Gavilan ◽  
Joana Vieira de Castro ◽  
Ainara Arana ◽  
Santos Merino ◽  
Aritz Retolaza ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Reference Method ◽  
Hydrophobic Surface ◽  
Patterned Surfaces ◽  
Testing Methods ◽  
Immersion Method ◽  
Horizon 2020 ◽  
Inoculation Method ◽  
Smooth Controls ◽  
Patterned Films

AbstractOne strategy to decrease the incidence of hospital-acquired infections is to avoid the survival of pathogens in the environment by the development of surfaces with antimicrobial activity. To study the antibacterial behaviour of active surfaces, different approaches have been developed of which ISO 22916 is the standard. To assess the performance of different testing methodologies to analyse the antibacterial activity of hydrophobic surface patterned plastics as part of a Horizon 2020 European research project. Four different testing methods were used to study the antibacterial activity of a patterned film, including the ISO 22916 standard, the immersion method, the touch-transfer inoculation method, and the swab inoculation method, this latter developed specifically for this project. The non-realistic test conditions of the ISO 22916 standard showed this method to be non-appropriate in the study of hydrophobic patterned surfaces. The immersion method also showed no differences between patterned films and smooth controls due to the lack of attachment of testing bacteria on both surfaces. The antibacterial activity of films could be demonstrated by the touch-transfer and the swab inoculation methods, that more precisely mimicked the way of high-touch surfaces contamination, and showed to be the best methodologies to test the antibacterial activity of patterned hydrophobic surfaces. A new ISO standard would be desirable as the reference method to study the antibacterial behaviour of patterned surfaces.

scholarly journals Antimicrobial Activity Testing Methods for Hydrophobic Patterned Surfaces

2020 ◽  
Author(s):  
Ana Perez-Gavilan ◽  
Joana Vieira de Castro ◽  
Ainara Arana ◽  
Santos Merino ◽  
Aritz Retolaza ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Hydrophobic Surface ◽  
Patterned Surfaces ◽  
Testing Methods ◽  
Immersion Method ◽  
Inoculation Methods ◽  
Horizon 2020 ◽  
Inoculation Method ◽  
Smooth Controls ◽  
Patterned Films

Abstract Background: One strategy to decrease the incidence of hospital-acquired infections is to avoid the survival of pathogens in the environment by the development of surfaces with antimicrobial activity. To study the antimicrobial behaviour of active surfaces, different approaches have been developed of which ISO 22916 is the standard. Aim: To assess the performance of different testing methodologies to analyse the antimicrobial activity of hydrophobic surface patterned plastics as part of a Horizon 2020 European research project (FLEXPOL: Antimicrobial FLEXible POLymers for its use in hospital environments No. 721062).Methods: Four different testing methods were used to study the antimicrobial activity of a patterned film, including the ISO 22916 standard, the immersion method, the touch-transfer inoculation method, and the swab inoculation method, this latter developed specifically for this project.Findings: The non-realistic test conditions of the ISO 22916 standard showed this method to be non-appropriate in the study of hydrophobic antimicrobial patterned surfaces. The immersion method also showed no differences between patterned films and smooth controls due to the lack of attachment of testing bacteria on both surfaces. The antimicrobial activity of films could be demonstrated by the touch-transfer and the swab inoculation methods that more precisely mimicked the way of high-touch surfaces contamination. Conclusion: The touch-transfer and the swab inoculation methods proved to be the best methodologies to test the antimicrobial activity of patterned hydrophobic surfaces. In our opinion, a new ISO standard should be developed on the basis of these tests to study the antimicrobial behaviour of patterned surfaces.

scholarly journals One-step deposition of antibacterial Ag@Pdop hybrid films on an NiTi alloy

RSC Advances ◽  
2019 ◽  
Vol 9 (50) ◽  
pp. 29263-29272 ◽  
Author(s):  
Yongkui Yin ◽  
Ying Li ◽  
Wei Cai ◽  
Jiehe Sui
Keyword(s):  
Antibacterial Activity ◽  
Niti Alloy ◽  
Hybrid Films ◽  
Immersion Method ◽  
One Step ◽  
Anticorrosion Performance

Ag@12Pdop modified NiTi was fabricated by one-step immersion method; it exhibited strong antibacterial activity, enhanced anticorrosion performance, and ideal cytocompatibility.

scholarly journals Comparison of noninvasive and invasive point-of-care testing methods with reference method for hemoglobin measurement

2017 ◽  
Vol 32 (3) ◽  
pp. e22309 ◽  
Author(s):  
Gamze Avcioglu ◽  
Cemil Nural ◽  
Fatma Meriç Yilmaz ◽  
Pervin Baran ◽  
Özcan Erel ◽  
...  
Keyword(s):  
Point Of Care ◽  
Reference Method ◽  
Point Of Care Testing ◽  
Testing Methods ◽  
Hemoglobin Measurement

Study of Microdroplet Growth on Homogeneous and Patterned Surfaces Using Lattice Boltzmann Modeling

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Nilesh D. Pawar ◽  
Sunil R. Kale ◽  
Supreet Singh Bahga ◽  
Hassan Farhat ◽  
Sasidhar Kondaraju
Keyword(s):  
Contact Angle ◽  
Contact Line ◽  
Lattice Boltzmann ◽  
Growth Dynamics ◽  
Hydrophobic Surface ◽  
Droplet Growth ◽  
Patterned Surfaces ◽  
Hydrophobic Region ◽  
Hydrophilic Region ◽  
Contact Line Pinning

We present droplet growth dynamics on homogeneous and patterned surfaces (surface with hydrophilic and hydrophobic region) using two-dimensional thermal lattice Boltzmann method (LBM). In the first part, we performed 2D simulations on homogeneous hydrophobic surfaces. The result shows that the droplet grows at higher rate on a surface with higher wettability which is attributed to low conduction resistance and high solid–liquid contact area. In the later part, we performed simulations on patterned surface and observed that droplet preferentially nucleates on the hydrophilic region due to lower energy barrier and grows in constant contact line (CCL) mode because of contact line pinning at the interface of hydrophilic–hydrophobic region. As the contact angle reaches the maximum value of hydrophobic surface, contact line depins and droplet shows constant contact angle (CCA) growth mode. We also discuss the effect of characteristic width of hydrophilic region on growth of droplet. We show that contact angle of the droplet increases rapidly and reaches the contact angle of hydrophobic region on a surface with a lower width of the hydrophilic surface.

scholarly journals Peptide/Peptoid Hybrid Oligomers: The Influence of Hydrophobicity and Relative Side-Chain Length on Antibacterial Activity and Cell Selectivity

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4429 ◽  
Author(s):  
Nicki Frederiksen ◽  
Paul R. Hansen ◽  
Fredrik Björkling ◽  
Henrik Franzyk
Keyword(s):  
Antibacterial Activity ◽  
Chain Length ◽  
Hydrophobic Surface ◽  
Structural Features ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
E Coli ◽  
Cell Selectivity ◽  
Wide Range

Previous optimisation studies of peptide/peptoid hybrids typically comprise comparison of structurally related analogues displaying different oligomer length and diverse side chains. The present work concerns a systematically constructed series of 16 closely related 12-mer oligomers with an alternating cationic/hydrophobic design, representing a wide range of hydrophobicity and differences in relative side-chain lengths. The aim was to explore and rationalise the structure–activity relationships within a subclass of oligomers displaying variation of three structural features: (i) cationic side-chain length, (ii) hydrophobic side-chain length, and (iii) type of residue that is of a flexible peptoid nature. Increased side-chain length of cationic residues led to reduced hydrophobicity till the side chains became more extended than the aromatic/hydrophobic side chains, at which point hydrophobicity increased slightly. Evaluation of antibacterial activity revealed that analogues with lowest hydrophobicity exhibited reduced activity against E. coli, while oligomers with the shortest cationic side chains were most potent against P. aeruginosa. Thus, membrane-disruptive interaction with P. aeruginosa appears to be promoted by a hydrophobic surface of the oligomers (comprised of the aromatic groups shielding the cationic side chains). Peptidomimetics with short cationic side chains exhibit increased hemolytic properties as well as give rise to decreased HepG2 (hepatoblastoma G2 cell line) cell viability. An optimal hydrophobicity window could be defined by a threshold of minimal hydrophobicity conferring activity toward E. coli and a threshold for maximal hydrophobicity, beyond which cell selectivity was lost.

Fabrication of Super-Hydrophobic Surface on Aluminum Alloy by a Simple Immersion Method

2010 ◽  
Vol 160-162 ◽  
pp. 379-383 ◽  
Author(s):  
Ruo Mei Wu ◽  
Shu Quan Liang ◽  
Zhi Qing Yuan ◽  
Hong Chen ◽  
Jing Deng
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Potassium Permanganate ◽  
Hydrophobic Surface ◽  
Solution Concentration ◽  
Immersion Method ◽  
Potassium Permanganate Solution ◽  
Corrosion Resistance Property ◽  
Aluminum Alloy Surface

In order to improve the corrosion resistance property of the aluminum alloy surface, a simple chemical immersion method was developed for fabricating the super-hydrophobic surface on aluminum alloy. After treating the chemical etched surface using low surface energy material stearic-acid, the aluminum alloy surface exhibits a super-hydrophobic property with water contact angle of 154° and contact angle hysteresis of 7°. The surface morphology was inspected with scanning electron microscope, and it was found that the surface was configured in a labyrinth structure with convexity and caves of micro-nanostructure; this hierarchical micro-nanostructure plays an important role in the formation of the super-hydrophobic surface. The effects of the etching time and the etchant (potassium permanganate solution) concentration on the super-hydrophobic surface were investigated, and the optimum technical conditions are that etching the aluminum alloy in 0.1mol/L potassium permanganate solution concentration for 3 h. At the same time, we also studied the wettability of the aluminum alloy super-hydrophobic surface. The results showed that the super-hydrophobic aluminum alloy has good stability, corrosion resistance property and self-cleaning.

scholarly journals OPTO-TECHNICAL MONITORING – A STANDARDIZED METHODOLOGY TO ASSESS THE TREATMENT OF HISTORICAL STONE SURFACES

2018 ◽  
Vol XLII-2 ◽  
pp. 945-952
Author(s):  
M. Rahrig ◽  
R. Drewello ◽  
A. Lazzeri
Keyword(s):  
Near Field ◽  
Three Dimensional ◽  
Non Destructive Testing ◽  
New Materials ◽  
Testing Methods ◽  
Destructive Testing ◽  
Monitoring Method ◽  
Horizon 2020 ◽  
Research And Innovation ◽  
Non Destructive

Monitoring is an essential requirement for the planning, assessment and evaluation of conservation measures. It should be based on a standardized and reproducible observation of the historical surface. For many areas and materials suitable methods for long-term monitoring already exist. But hardly any non-destructive testing methods have been used to test new materials for conservation of damaged stone surfaces. The Nano-Cathedral project, funded by the European Union's Horizon 2020 research and innovation program, is developing new materials and technologies for preserving damaged stone surfaces of built heritage. The prototypes developed are adjusted to the needs and problems of a total of six major cultural monuments in Europe. In addition to the testing of the materials under controlled laboratory conditions, the products have been applied to trial areas on the original stone surfaces. For a location-independent standardized assessment of surface changes of the entire trial areas a monitoring method based on opto-technical, non-contact and non-destructive testing methods has been developed. This method involves a three-dimensional measurement of the surface topography using Structured-Light-Scanning and the analysis of the surfaces in different light ranges using high resolution VIS photography, as well as UV-A-fluorescence photography and reflected near-field IR photography.<br> The paper will show the workflow of this methodology, including a detailed description of the equipment used data processing and the advantages for monitoring highly valuable stone surfaces. Alongside the theoretical discussion, the results of two measuring campaigns on trial areas of the Nano-Cathedral project will be shown.

scholarly journals Evaluation of Vitek®2 performance for colistin susceptibility testing for Gram-negative isolates

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Surbhi Khurana ◽  
Rajesh Malhotra ◽  
Purva Mathur
Keyword(s):  
Susceptibility Testing ◽  
Reference Method ◽  
Trauma Centre ◽  
Gram Negative Bacteria ◽  
Test Results ◽  
Major Error ◽  
Colistin Resistance ◽  
Testing Methods ◽  
Gram Negative ◽  
Unreliable Method

Abstract Background The emerging resistance to the last-resort antimicrobial colistin is being reported globally. Underestimation of the burden of colistin resistance and misinterpretation of colistin susceptibility test results, using suboptimal testing methods, may be causing unexplained treatment failures and even mortality among critically ill patients. Thus, this study was conducted at an apex trauma centre to assess the performance of Vitek®2 for colistin susceptibility testing. Methods A total of 910 clinical isolates of Gram-negative bacteria (GNB), including Enterobacterales, Acinetobacter baumannii and Pseudomonas aeruginosa, were tested and analysed for colistin resistance using Vitek®2. Broth microdilution (BMD) was taken as the reference method. The essential (EA) and categorical (CA) agreements and very major error (VME) and major error (ME) rates were calculated. An MIC correlation was taken to be positive with EA ≥ 90%, CA ≥ 90%, VME ≤ 1.5% and ME ≤ 3.0% rates. Spearman’s coefficient was calculated and P &lt; 0.05 was considered statistically significant. Results A total of 64% of isolates were MDR. Overall, 196 (21.5%) and 110 (12%) of isolates were resistant to colistin by BMD and Vitek®2, respectively. The automated Vitek®2 method failed to detect the resistance in up to 48.5% of GNB tested. When comparing Vitek®2 colistin interpretive results with reference BMD for all 910 isolates, the CA was 88% (798/910) with 10% (95/910) VMEs and 1% (9/910) MEs. Conclusions The Vitek®2 method for colistin susceptibility testing, still in use in some settings; is a suboptimal and unreliable method.

scholarly journals Influence of Serum on Antibacterial Activity of Disinfectants and Evaluation of Disinfectant Testing Methods

1978 ◽  
Vol 3 (4) ◽  
pp. 208-214
Author(s):  
SAEKO ANJO ◽  
TAKAKO SATO ◽  
MISAO KAGAMI ◽  
MACHIKO OKURA ◽  
MACHIKO KAMISHIMA ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Testing Methods

scholarly journals PERBANDINGAN PENGUJIAN AKTIVITAS ANTIBAKTERI STARTER YOGURT DENGAN METODE DIFUSI SUMURAN DAN METODE DIFUSI CAKRAM

2020 ◽  
Vol 1 (2) ◽  
pp. 41
Author(s):  
Lilih Siti Nurhayati ◽  
Nadhira Yahdiyani ◽  
Akhmad Hidayatulloh
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Activity ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Testing Methods ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Agar Diffusion ◽  
Agar Diffusion Method ◽  
Agar Well Diffusion Method

Antibacterial activity testing can be done using the agar diffusion method, including agar well difussion and disk diffusion agar methods. This study aims to compare two antibacterial testing methods to analyze the anti-bacterial activity of a yogurt starter against the bacteria Eschericia coli and Staphilococcus aureus. The study was conducted experimentally with 5 concentrations of yogurt starter, namely 2%, 4%, 6%, 8%, and 10%. Testing antibacterial activity using two methods ,disk diffusion agar and well difussion agar methods. The research showed that agar well diffusion method obtained antibacterial activity greater than the disk diffusion method for E. coli and S. aureus.

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