Reduction Of Bacterial Adhesion Research Articles

Construction of durable, multifunctional superhydrophobic wood surface via ɛ-polylysine/PDMS/wax treatment

In addressing the limitations of wood's susceptibility to water and moisture, this study explored the development of a durable, superhydrophobic surface through a novel ɛ-polylysine/polydimethylsiloxane (PDMS)/wax composite system. Leveraging the layer-by-layer (LBL) assembly, the incorporation of cationic ɛ-polylysine not only improved the adherence of PDMS and wax to the wood surface through electrostatic attraction but also facilitated a more uniform distribution, achieving optimal hydrophobicity at a ɛ-polylysine concentration of 2 g/L. The synergistic effect of the wood's natural rough structure and the deposition of these hydrophobic substances endowed the treated wood with superhydrophobic properties, showcasing exceptional self-cleaning capabilities by efficiently repelling a variety of liquid contaminants. Durability assessments through sandpaper abrasion, chemical exposure, and accelerated weathering tests confirmed the enhanced long-term stability of the treated wood surfaces. Furthermore, the incorporation of ε-polylysine provided nice antimicrobial properties, showing a substantial reduction in bacterial adhesion. The ε-polylysine/PDMS/wax composite system represents a significant advancement in the development of multifunctional wood surfaces, promising broader applications in sustainable building materials, furniture, and packaging solutions.

Enhancing antibacterial properties of titanium implants through a novel Ag-TiO2-OTS nanocomposite coating: a comprehensive study on resist-killing-disintegrate approach

Titanium (Ti) implants are widely used in orthopedic and dental applications due to their excellent biocompatibility and mechanical properties. However, bacterial adhesion and subsequent biofilm formation on implant surfaces pose a significant risk of postoperative infections and complications. Conventional surface modifications often lack long-lasting antibacterial efficacy, necessitating the development of novel coatings with enhanced antimicrobial properties. This study aims to develop a novel Ag-TiO2-OTS (Silver-Titanium dioxide-Octadecyltrichlorosilane, ATO) nanocomposite coating, through a chemical plating method. By employing a ‘resist-killing-disintegrate’ approach, the coating is designed to inhibit bacterial adhesion effectively, and facilitate pollutant removal with lasting effects. Characterization of the coatings was performed using spectroscopy, electron microscopy, and contact angle analysis. Antibacterial efficacy, quantitatively evaluated against E. coli and S. aureus over 168 h, showed a significant reduction in bacterial adhesion by 76.6% and 66.5% respectively, and bacterial removal rates were up to 83.8% and 73.3% in comparison to uncoated Ti-base material. Additionally, antibacterial assays indicated that the ratio of the Lifshitz-van der Waals apolar component to electron donor surface energy components significantly influences bacterial adhesion and removal, underscoring a tunable parameter for optimizing antibacterial surfaces. Biocompatibility assessments with the L929 cell line revealed that the ATO coatings exhibited excellent biocompatibility, with minimal cytotoxicity and no significant impact on cell proliferation or apoptosis. The ATO coatings provided a multi-functionality surface that not only resists bacterial colonization but also possesses self-cleaning capabilities, thereby marking a substantial advancement in the development of antibacterial coatings for medical implants.

Electrospun superhydrophobic polyvinyl chloride /polydimethylsiloxane-nanodiamond nanocomposite with enhanced antifouling and mechanical properties for fresh produce packaging

Food package films serve the important functions of preserving food quality, extending shelf life, and protecting against external contaminants while also providing a barrier to moisture and oxygen. In consideration of the increasing frequency of foodborne outbreaks, there is a growing demand for food packaging films with additional functionality to prevent cross-contamination and the attachment of pathogens, thereby enhancing bacterial safety. Herein, we report a one-step fabrication approach relying on electrospinning of a blend of polyvinyl chloride (PVC) and polydimethylsiloxane (PDMS) together with nanodiamond (ND) on a rotating drum collector for the formation of bacterially antifouling food package films. In this approach, by adjusting the concentrations of PVC, PDMS, and ND and the drum angular velocity, the nanofiber diameter could be tuned in the range of 0.4 μm to 2.0 μm. Furthermore, these process parameters could also be used to modulate the water contact angle on the resultant films, with a minimum contact angle of 136.2 ± 5.6° and a maximum of 159.5 ± 3.8°. The lowest water contact angles were observed for films with bare PVC fibers while the highest contact angles were seen for films with nanocomposite fibers containing ND and PVC/PDMS. Compared with the films with bare PVC, nanocomposite films with ND-PVC/PDMS achieved up to 99.8 % and 99.6 % reduction in bacterial adhesion against S. typhimurium LT2 and Listeria innocua, respectively. The tensile strength of nanofibrous PVC film can be increased from 1.2 ± 0.4 MPa to 4.4 ± 0.3 MPa by the inclusion of PDMS (1:1 wt.%) and further increased to 8.9 ± 0.3 MPa with the additional inclusion of ND (PVC/PDMS/ND 1:1:0.1 wt.%). Considering the notable antifouling properties against bacteria and the improved mechanical characteristics, these nanocomposite films represent a noteworthy step in the development of sustainable and active food packaging solutions for a safer and healthier food supply chain.

Laser surface texturing of Ti-cp and Ti6Al4V alloy for the improvement of fibroblast adhesion and alignment and the reduction of bacterial adhesion

Surface texturing is widely investigated for the modulation of the surface properties and biological response of implantable materials. Laser is a green technology for the obtainment of specific patterns without the employment of toxic chemicals. In the present research, a picosecond laser treatment was applied to commercially pure titanium and Ti6Al4V alloy for the obtainment of aligned grooves characterized by micrometric width and spacing but submicrometric depth to promote fibroblast alignment and discourage bacterial adhesion. Surface topography and roughness of laser-textured surfaces were characterized using confocal microscopy, contact profiler, and Scanning Electron Microscopy. Zeta potential titration curves and contact angle measurements were used for the investigation of surface charge and wettability, while X-Ray Diffraction was employed for crystallographic characterization. Finally, the biological response (fibroblast adhesion and alignment and bacterial adhesion) was assessed. Similar results were obtained on commercially pure Ti and Ti6Al4V. Grooves with the designed features were obtained (about 15 μm spaced and 0.2μ deep) and the treated surfaces had a complex micro- and nano-scale morphology which reduced wettability. No evident chemical modification occurred. The treated surfaces were biocompatible and grooves had a contact guidance effect on human fibroblasts. The obtained topography had anti-adhesive action on bacteria (Staphylococcus aureus).

Unveiling the synergistic potency of chlorhexidine and azithromycin in combined action.

The growing challenge of antibiotic resistance necessitates novel approaches for combating bacterial infections. This study explores the distinctive synergy between chlorhexidine, an antiseptic and disinfectant agent, and azithromycin, a macrolide antibiotic, in their impact on bacterial growth and virulence factors using Escherichia coli strain Crooks (ATCC 8739) as a model. Our findings reveal that the chlorhexidine and azithromycin combination demonstrates enhanced anti-bacterial effects compared to individual treatments. Intriguingly, the combination induced oxidative stress, decreased flagellin expression, impaired bacterial motility, and enhanced bacterial autoaggregation. Notably, the combined treatment also demonstrated a substantial reduction in bacterial adherence to colon epithelial cells and downregulated NF-κB in the epithelial cells. In conclusion, these results shed light on the potential of the chlorhexidine and azithromycin synergy as a compelling strategy to address the rising challenge of antibiotic resistance and may pave the way for innovative therapeutic interventions in tackling bacterial infections.

Oil-infused feed spacers for biofouling inhibition

A novel approach is investigated for preventing biofouling of spacer filaments, which are an essential part of spiral-wound modules used in membrane-based desalination. Biofouling, caused by the growth and multiplication of microorganisms on the membrane surface, can significantly impact the efficiency and cost-effectiveness of the desalination process. Herein, a method is proposed for fabricating modified feed spacers based on oil-infused slippery substrates made of polydimethylsiloxane (PDMS). These feed spacers, when infused with silicone oil, create a stable, extremely slippery interface that exhibits exceptionally low bacterial adhesion and prevents biofilm formation, especially under flow conditions. By examining the effect of the silicone oil's viscosity, we determined the optimal ratio of the curing agent for fabricating the oil-infused feed spacer. Results showed a substantial reduction of bacterial adhesion to the surface for all tested oil viscosities, particularly under dynamic conditions. Furthermore, even where bacterial adhesion occurred, primarily on samples infused with lower-viscosity oil, it could be easily removed by simple rinsing. Overall, the oil-infused feed spacer demonstrated exceptional biofilm inhibition, providing preliminary indication of the potential offered by this promising approach.

Analysis of Antibacterial Efficacy and Cellular Alignment Regulation on Plasma Nanotextured Chitosan Surfaces.

To address implant-related infections, antibacterial solutions specific to biomaterials are required to prevent bacterial proliferation. Traditional antibiotic usage has been found insufficient, motivating researchers to investigate alternative strategies such as surface modification and the application of antifouling or infection-resistant properties. A developing interest lies in designing surfaces that mimic natural antibacterial nanotopographies. In this study, we conducted a quantitative analysis of the outcomes from plasma nanotexturing, with particular emphasis on how the organization of topography influences antibacterial efficacy and the regulation of cell alignment. Plasma nanotexturing was applied to chitosan surfaces, which gradually transformed from nanopores to pillars and eventually into tilted pillars, as the plasma parameters (fluence and angle) increased. We used directed plasma nanosynthesis, a plasma-based technique that primarily induces topographical alterations on the surfaces. The surfaces were systematically characterized, incorporating methods such as scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). A comprehensive comparison of the nanotextures was executed by utilizing a trapezoidal method to calculate aspect ratios and assess texture orientation by examining the gaps in the nanostructures. We evaluated antibacterial properties against E. coli and S. aureus strains and assessed the survival and alignment of human bone marrow mesenchymal stem cells. Our findings reveal a significant reduction in bacterial adhesion (>80%) and growth on nanotextured surfaces, underscoring their potential for clinical applications. Moreover, we measured cell alignment, presenting the results in both a color-coded and numerical format to demonstrate the preferential alignment orientation induced specially by the tilted nanotexture. These insights highlight the profound impacts of plasma nanotexturing, indicating its potential for innovative biomedical applications such as advanced wound healing and tissue engineering.

Influence of passive layer fabrication method on physicochemical and antimicrobial properties of the Ta2O5 layer on NiTi alloy

The use of nickel-titanium (NiTi) alloy in implants, despite its good biocompatibility, is not entirely inert to the human body. To reduce nickel ions and improve the hemocompatibility of implants for blood contact, a thin layer of tantalum oxide (Ta2O5) was proposed. Although nitinol self-coats a thin layer of TiO2 titanium dioxide to protect against corrosion, many studies emphasized the need to enhance this protection. Therefore, in the first stage of this study, the alloy surface was prepared by four different methods, producing a passive interlayer. Then a Ta2O5 coating was applied, and the properties with and without the layer were investigated. The resulting coating was applied to the NiTi alloy in the initial state and passivated in water, and perhydrol showed a high adhesion to the substrate. However, the coating deteriorated resistance to pitting corrosion and increased surface wettability. For the initial condition and passivation in perhydrol, the coating affected the reduction of bacterial adhesion to the substrate. Surface preparation directly influenced the optimization of the deposition of this layer on implants in contact with blood. The results suggest that the properties studied were strongly correlated with the type of passive interlayer.

Effects of magnesium oxide and copper oxide nanoparticles on biofilm formation of Escherichia coli and Listeria monocytogenes

Biofilms formed in food-processing environments are of special importance as they have the potential to act as a persistent source of microbial contamination that may lead to food spoilage or transmission of diseases. The creation of microbial biofilms, which can be a source of food product contamination with food spoilage and foodborne pathogenic bacteria, is one of the most critical elements in the food industry. The goal of this study was to see how well magnesium oxide (MgO) and copper oxide (CuO) nanoparticles (NPs) inhibited growth and biofilm formation of two common foodborne bacterial pathogens. This study was completed in the year 2020. Resazurin reduction and micro-dilution procedures were used to assess the minimum inhibitory concentration (MIC) of magnesium oxide and copper oxide nanoparticles for Escherichia coli O157: H7 (ATCC 35 218) and Listeria monocytogenes (L. monocytogenes) (ATCC 19 118). The bacterial adhesion to hydrocarbon technique was used to determine the cell-surface hydrophobicity of the selected bacteria. The surface assay was also used to calculate the influence of the NPs coated surfaces on the biofilm formation of the selected bacteria. Magnesium oxide nanoparticles had MICs of 2 and 2 mg ml−1, while copper oxide nanoparticles had MICs of 0.16 and 1 mg ml−1 against E. coli and L. monocytogenes, respectively. At the MIC, the magnesium and copper nanoparticles inhibited biofilm formation of E. coli and L. monocytogenes by 89.9 and 96.6 percent and 93.6 and 98.7 percent, respectively. The hydrophobicity of E. coli and L. monocytogenes was determined to be 74% and 67%, respectively. The surface assay revealed a substantial reduction in bacterial adhesion and colonization on NPs-coated surfaces. Both compounds had inhibitory effects on E. coli and L. monocytogenes, according to our findings. Even at sub-MICs, NPs were found to be able to prevent biofilm development. The microbial count and production of microbial biofilms were reduced on surfaces coated with MgO and CuO nanoparticles. MgO and CuO nanoparticles can be utilized as a cleaning agent for surfaces to avoid the formation of foodborne bacterial biofilms, which is important for public health.

Highly Stable Hierarchically Structured All-Polymeric Lubricant-Infused Films Prevent Thrombosis and Repel Multidrug-Resistant Pathogens.

Thrombus formation and infections caused by bacterial adhesion are the most common causes of failure in blood-contacting medical devices. Reducing the interaction of pathogens using repellent surfaces has proven to be a successful strategy in preventing device failure. However, designing scale-up methodologies to create large-scale repellent surfaces remains challenging. To address this need, we have created an all-polymeric lubricant-infused system using an industrially viable swelling-coagulation solvent (S-C) method. This induces hierarchically structured micro/nano features onto the surface, enabling improved lubricant infusion. Poly(3,3,3-trifluoropropylmethylsiloxane) (PTFS) was used as the lubricant of choice, a previously unexplored omniphobic nonvolatile silicone oil. This resulted in all-polymeric liquid-infused surfaces that are transparent and flexible with long-term stability. Repellent properties have been demonstrated using human whole blood and methicillin-resistant Staphylococcus aureus (MRSA) bacteria matrices, with lubricated surfaces showing 93% reduction in blood stains and 96.7% reduction in bacterial adherence. The developed material has the potential to prevent blood and pathogenic contamination for a range biomedical devices within healthcare settings.

Helicobacter pylori employs a general protein glycosylation system for the modification of outer membrane adhesins

ABSTRACT Helicobacter pylori infection is associated with the development of several gastric diseases including gastric cancer. To reach a long-term colonization in the host stomach, H. pylori employs multiple outer membrane adhesins for binding to the gastric mucosa. However, due to the redundancy of adhesins that complement the adhesive function of bacteria, targeting each individual adhesin alone usually achieves nonideal outcomes for preventing bacterial adhesion. Here, we report that key adhesins AlpA/B and BabA/B in H. pylori are modified by glycans and display a two-step molecular weight upshift pattern from the cytoplasm to the inner membrane and from the inner membrane to the outer membrane. Nevertheless, this upshift pattern is missing when the expression of some enzymes related to lipopolysaccharide (LPS) biosynthesis, including the LPS O-antigen assembly and ligation enzymes WecA, Wzk, and WaaL, is disrupted, indicating that the underlying mechanisms and the involved enzymes for the adhesin glycosylation are partially shared with the LPS biosynthesis. Loss of the adhesin glycosylation not only reduces the protease resistance and the stability of the tested adhesins but also changes the adhesin-binding ability. In addition, mutations in the LPS biosynthesis cause a significant reduction in bacterial adhesion in the in vitro cell-line model. The current findings reveal that H. pylori employs a general protein glycosylation system related to LPS biosynthesis for adhesin modification and its biological significance. The enzymes required for adhesin glycosylation rather than the adhesins themselves are potentially better drug targets for preventing or treating H. pylori infection.

Bacteriophobic Zwitterionic/Dopamine Coatings for Medical Elastomers (Adv. Mater. Interfaces 30/2022)

Anti-Biofouling Coatings In article number 2201152, Robert Texidó, Pol Cabanach, Abdon Pena-Francesch, and colleagues use a coating strategy combining dopamine and zwitterionic polymers to prevent bacteria from adhering to soft and flexible materials commonly used in medical devices. The coatings exhibit superhydrophilic and anti-biofouling properties, leading to a >99% reduction in bacterial adhesion. This bacteriophobic coating is implemented in a commercial urinary catheter, reducing bacterial adhesion by 2 orders of magnitude, and avoiding bacterial colonization to prevent catheter-associated urinary tract infections.

Bacteriophobic Zwitterionic/Dopamine Coatings for Medical Elastomers

AbstractDespite modern advancements in sterilization and medical practices, bacterial infections remain a significant concern in the implantation of medical devices. There is currently an urgent need for long‐lasting and high‐stable strategies to avoid the adhesion of bacteria to the wide range of materials present in medical devices. Here, a versatile methodology to create anti‐biofouling coatings that prevent the adhesion of bacteria to silicone‐based materials used in healthcare is reported. These coatings consist of bifunctional ethylene glycol dimethacrylate as an anchor between a zwitterionic polymer (SBMA), which provides antifouling properties, and a polydopamine layer that operates as an interfacial binder, providing mechanical strength and strong adhesion to elastomeric substrates. The coatings exhibit superhydrophilic and anti‐biofouling properties, creating a strong “bacteriophobic effect” that leads to a >99% reduction in bacterial adhesion. This bacteriophobic coating is successfully implemented and validated in a commercial urinary catheter, reducing bacterial adhesion by 1–2 orders of magnitude and avoiding bacterial colonization to prevent catheter‐associated urinary tract infections. The results presented here demonstrate the versatility, durability, and scalability of the coating methodology for preventing bacterial adhesion in silicone elastomers, which can be easily applied to other elastomeric materials used in medical devices beyond urinary tract infection prevention.

Influence of Aesthetic Archwire Coatings on Bacterial Adhesion

Bacterial biofilm plays a key role in the development of complications in orthodontic treatment in the form of caries or periodontal disease. The coating of orthodontic archwires can affect their mechanical properties and their bactericidal properties. In connection with the growing interest in aesthetic archwires, it was examined whether aesthetic archwire coatings contribute to the reduction of bacterial adhesion. Based on the available literature, a review was conducted on the basis of the risk of bias (RoB) assessment and GRADE (Grading of Recommendations, Assessment, Development and Evaluations) analysis. The study took into account the results of research on different aesthetic archwire coatings. The analysis shows that there is a lack of homogeneity in the research results. The data on the different aesthetic coatings are inconclusive. On the basis of the data collected, it is impossible to determine whether aesthetic coatings reduce bacterial adhesion. Further studies, standardised in terms of research methods and statistical analysis, are needed to definitively establish whether aesthetic coatings influence bacterial adhesion.

Self-Patterned Nanoscale Topography of Thin Copolymer Films Prepared by Evaporative Assembly-Resist Early-Stage Bacterial Adhesion.

Biofilm formation on the surfaces of indwelling medical devices has become a growing health threat due to the development of antimicrobial resistance to infection-causing bacteria. For example, ventilator-associated pneumonia caused by Pseudomonas and Staphylococci species has become a significant concern in treatment of patients during COVID-19 pandemic. Nanostructured surfaces with antifouling activity are of interest as a promising strategy to prevent bacterial adhesion without triggering drug resistance. In this study, we report a facile evaporative approach to prepare block copolymer film coatings with nanoscale topography that resist bacterial adhesion. The initial attachment of the target bacterium Pseudomonas aeruginosa PAO1 to copolymer films as well as homopolymer films was evaluated by fluorescence microscopy. Significant reduction in bacterial adhesion (93-99% less) and area coverage (>92% less) on the copolymer films was observed compared with that on the control and homopolymer films [poly(methacrylic acid) (PMAA)─only 40 and 23% less, respectively]. The surfaces of poly(styrene)-PMAA copolymer films with patterned nanoscale topography that contains sharp peaks ranging from 20 to 80 nm spaced at 30-50 nm were confirmed by atomic force microscopy and the corresponding surface morphology analysis. Investigation of the surface wettability and surface potential of polymer films assists in understanding the effect of surface properties on the bacterial attachment. Comparison of bacterial growth studies in polymer solutions with the growth studies on coatings highlights the importance of physical nanostructure in resisting bacterial adhesion, as opposed to chemical characteristics of the copolymers. Such self-patterned antifouling surface coatings, produced with a straightforward and energy-efficient approach, could provide a convenient and effective method to resist bacterial fouling on the surface of medical devices and reduce device-associated infections.

Potassium Hydroxide Activated Titanium Dioxide Nanoparticles Diminishes Streptococcus mutans Biofilm Formation

Dental caries represents one of the most common oral diseases. Streptococcus mutans is an oral bacterium involved in the process of caries development, forming a biofilm to promote bacterial adherence to the tooth surface and to other bacteria. Photocatalytically activated titanium dioxide (TiO2) has been shown to have antimicrobial properties on oral pathogens as well as on biofilm formation.We aimed to evaluate the effect of potassium‐incorporated TiO2 (KTiOx) nanostructures, a high performance photocatalyst, on biofilm formation by S. mutans.S.mutans was cultured in the presence of KTiOx 1M and 10M nanoparticles, as well as a elemental Ti control. Biofilm formation was assessed using a crystal violet biofilm formation after 24, 48, and 72 hours.A decrease in biofilm formation was observed in a dose response manner after 48 hours incubation with 32, 64, and 128 ug/mL of KTiOx.Our findings show that KTiOx nanoparticles have anti‐biofilm properties which may be applied to combat biofilm containing S.mutans, This novel approach may be a promising therapeutic alternative in caries prevention, though reduction of bacterial adhesion to dental surfaces.

Long-Term Reduction of Bacterial Adhesion on Polyurethane by an Ultra-Thin Surface Modifier.

Indwelling urinary catheters are employed widely to relieve urinary retention in patients. A common side effect of the use of these catheters is the formation of urinary tract infections (UTIs), which can lead not only to severe medical complications, but even to death. A number of approaches have been used to attempt reduction in the rate of UTI development in catheterized patients, which include the application of antibiotics and modification of the device surface by coatings. Many of these coatings have not seen use on catheters in medical settings due to either the high cost of their implementation, their long-term stability, or their safety. In previous work, it has been established that the simple, stable, and easily applicable sterilization surface coating 2-(3-trichlorosilylpropyloxy)-ethyl hydroxide (MEG-OH) can be applied to polyurethane plastic, where it greatly reduces microbial fouling from a variety of species for a 1-day time period. In the present work, we establish that this coating is able to remain stable and provide a similarly large reduction in fouling against Escherichia coli and Staphylococcus aureus for time periods in an excess of 30 days. This non-specific coating functioned against both Gram-positive and Gram-negative bacteria, providing a log 1.1 to log 1.9 reduction, depending on the species and day. This stability and continued efficacy greatly suggest that MEG-OH may be capable of providing a solution to the UTI issue which occurs with urinary catheters.

Polyphenols as Inhibitors of Antibiotic Resistant Bacteria-Mechanisms Underlying Rutin Interference with Bacterial Virulence.

The rising incidence of antibiotic resistant microorganisms urges novel antimicrobials development with polyphenols as appealing potential therapeutics. We aimed to reveal the most promising polyphenols among hesperetin, hesperidin, naringenin, naringin, taxifolin, rutin, isoquercitrin, morin, chlorogenic acid, ferulic acid, p-coumaric acid, and gallic acid based on antimicrobial capacity, antibiofilm potential, and lack of cytotoxicity towards HaCaT, and to further test its antivirulence mechanisms. Although the majority of studied polyphenols were able to inhibit bacterial growth and biofilm formation, the most promising activities were observed for rutin. Further investigation proved rutin’s ability to prevent/eradicate Pseudomonas aeruginosa and MRSA urinary catheter biofilms. Besides reduction of biofilm biomass, rutin antibiofilm mechanisms included reduction of cell viability, exopolysaccharide, and extracellular DNA levels. Moderate reduction of bacterial adhesion to human keratinocytes upon treatment was observed. Rutin antivirulence mechanisms included an impact on P. aeruginosa protease, pyocyanin, rhamnolipid, and elastase production and the downregulation of the lasI, lasR, rhlI, rhlR, pqsA and mvfR genes. Rutin also interfered with membrane permeability. Polyphenols could repress antibiotic resistant bacteria. Rutin has shown wide antimicrobial and antibiofilm capacity employing a range of mechanisms that might be used for the development of novel antimicrobials.

Transparent and Highly Flexible Hierarchically Structured Polydimethylsiloxane Surfaces Suppress Bacterial Attachment and Thrombosis Under Static and Dynamic Conditions.

The surface fouling of biomedical devices has been an ongoing issue in healthcare. Bacterial and blood adhesion in particular, severely impede the performance of such tools, leading to poor patient outcomes. Various structural and chemical modifications have been shown to reduce fouling, but all existing strategies lack the combination of physical, chemical, and economic traits necessary for widespread use. Herein, a lubricant infused, hierarchically micro- and nanostructured polydimethylsiloxane surface is presented. The surface is easy to produce and exhibits the high flexibility and optical transparency necessary for incorporation into various biomedical tools. Tests involving two clinically relevant, priority pathogens show up to a 98.5% reduction in the biofilm formation of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. With blood, the surface reduces staining by 95% and suppresses thrombin generation to background levels. Furthermore, the surface shows applicability within applications such as catheters, extracorporeal circuits, and microfluidic devices, through its effectiveness in dynamic conditions. The perfusion of bacterial media shows up to 96.5% reduction in bacterial adhesion. Similarly, a 95.8% reduction in fibrin networks is observed following whole blood perfusion. This substrate stands to hold high applicability within biomedical systems as a means to prevent fouling, thus improving performance.

Electrochemical modification of high contact stainless steel 304 surfaces for antimicrobial applications

High-contact or high-touch surfaces are usually associated with higher risk of microbial contamination and subsequent infection, especially during global pandemics. Previous studies have shown that changing the surface roughness or topography at the micro or even nano-scale to enrich antimicrobial properties on the high-contact surfaces has been widely considered. In this work, we have used electrochemical techniques to modify the surface of metals that are commonly used in high contact situations such as stainless steel 304 (SS304). The aim of this study was to systematically elucidate the optimal electrochemical parameters such as anodizing current density and electrolyte composition needed for different types of metals. Surface morphology and topography profiles were observed by scanning electron microscopy and atomic force microscopy. Fabricated surface nanostructures were studied to evaluate the effect it has on the antimicrobial properties. The colony forming units with Escherichia coli were investigated. The results indicated that SS304 anodized at 3.5 V for 20 mins resulted in the fabrication of nanostructures up to 556 nm in size and was the optimized candidate due to its highest surface roughness (Ra) of 262.28 nm and 52.6% reduction of bacterial adhesion after 24 h incubation.