Antibiofilm Applications Research Articles

Surface charge switchable fluorinated small molecular micelles for enhanced photodynamic therapy for bacterial infections

Photodynamic therapy (PDT) employs reactive oxygen species (ROS) from a photosensitizer (PS) under light, inhibiting multi-drug resistance in bacteria. However, hypoxic conditions in infection sites and biofilms challenge PDT efficiency. We developed fluorinated small molecular micelles (PF-CBMs) as PS carriers to address this, relieving hypoxia and enhancing PS penetration into biofilms. Perfluorocarbons in PF-CBMs transport more oxygen due to their excellent oxygen-dissolving capability. Fluorination enhances loading capacity and serum stability, reduces premature release, and improves cellular uptake, to improve PDT efficacy. PF-CBMs, with acid-induced surface charge transformation, exhibit superior biofilm penetration, resulting in increased antibiofilm activity of PDT. Compared to fluorine-free micelles (PC-CBMs), PF-CBMs demonstrate better serum stability, higher drug loading, and reduced premature release, leading to significantly improved antibacterial efficacy in vitro and in vivo. In conclusion, fluorinated micelles with surface charge reversal enhance PDT for antibacterial and antibiofilm applications.

One-Pot Synthesis of Carbon Nanodots Retrieved from Motorcycle Exhaust: Antibacterial and Antibiofilm Applications

Carbon nanodots (CNDs) are nanoscale carbon-based materials with particle sizes typically less than 10 nm. They are characterized by their unique electronic, optical, and surface properties, as well as their bright and tunable fluorescence across the visible light spectrum. The process involved in synthesizing carbon nanodots is rather energy-consuming, expensive, and complicated. Motorcycle exhausts have been looked at as an environmental pollutant. In this paper, the bright side of motorcycle exhausts has been projected, whereby we have extracted carbon nanodots from motorcycle exhausts, using a simple and straightforward strategy. The nanomaterial was successfully isolated and characterized. The antimicrobial activity of the indigenously prepared nanomaterial was evaluated and coatings were prepared on glass and these nanocarbon coatings were demonstrated for their anti-biofilm activity. The results confirm the innovative and sustainable recovery of antibacterial carbon nanodots from environmental pollutants such as motorcycle exhaust.

Roles of Two-Dimensional Materials in Antibiofilm Applications: Recent Developments and Prospects.

Biofilm-associated infections pose a significant challenge in healthcare, constituting 80% of bacterial infections and often leading to persistent, chronic conditions. Conventional antibiotics struggle with efficacy against these infections due to the high tolerance and resistance induced by bacterial biofilm barriers. Two-dimensional nanomaterials, such as those from the graphene family, boron nitride, molybdenum disulfide (MoS2), MXene, and black phosphorus, hold immense potential for combating biofilms. These nanomaterial-based antimicrobial strategies are novel tools that show promise in overcoming resistant bacteria and stubborn biofilms, with the ability to circumvent existing drug resistance mechanisms. This review comprehensively summarizes recent developments in two-dimensional nanomaterials, as both therapeutics and nanocarriers for precision antibiotic delivery, with a specific focus on nanoplatforms coupled with photothermal/photodynamic therapy in the elimination of bacteria and penetrating and/or ablating biofilm. This review offers important insight into recent advances and current limitations of current antibacterial nanotherapeutic approaches, together with a discussion on future developments in the field, for the overall benefit of public health.

Superhydrophobic surface of biomass carbon-based PANI composite coatings with the biomimetic structure of goose feather for anticorrosion/antibiofilm applications

Biomass carbon (BMC)-based polyaniline (PANI) composite coatings with superhydrophobic biomimetic surfaces were fabricated through nanocasting to transfer the surface of natural goose feather (GF) to the polymer surface for anticorrosion and antibiofilm applications. First, the as-synthesized PANI powder without/with 1 wt% BMC was dissolved/dispersed in N-methyl-2-pyrrolidone and then dropwise added onto the negative soft template of polydimethylsiloxane, successfully transferring the pattern of natural GF surface to a series of biomimetic PANI coating surfaces (denoted by Bio-PANI and Bio-PANI-1). Scanning electron microscopy (SEM) investigated the surface morphology of biomimetic coatings and revealed the presence of micron-sized rachis decorated with many nanoscaled barbules. Compared with that for non-Bio-PANI coating, the contact angle (CA) increased from 92.88° ± 0.81° to 144.94° ± 0.87° for Bio-PANI and 152.46° ± 1.95°for Bio-PANI-1. For anticorrosion application, the electrochemical corrosion potential (Ecorr)/impedance (Z’) of PANI coating increased significantly (from −633.62 mV/7.41 × 105 Ω to −319.87 mV/1.05 × 107 Ω) compared with that of Bio-PANI-1 coating, indicating that the Bio-PANI composite superhydrophobic coating exhibited the best anticorrosion performance. For antibiofilm application, three types of bacteria (i.e., Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) were used to study long-term antibiofilm formation. The findings revealed that the superhydrophobic Bio-PANI-1 coated surface inhibited bacterial growth and hindered biofilm development. Furthermore, the inherent hydrophobicity of this surface played a crucial role in warding off bacterial adhesion, ensuring impressive sustained antibiofilm efficacy.

TiO2 Nanocomposite Coatings and Inactivation of Carbapenemase-Producing Klebsiella Pneumoniae Biofilm-Opportunities and Challenges.

The worldwide increase of multidrug-resistant Gram-negative bacteria is a global threat. The emergence and global spread of Klebsiella pneumoniae carbapenemase- (KPC-) producing Klebsiella pneumoniae represent a particular concern. This pathogen has increased resistance and abilities to persist in human reservoirs, in hospital environments, on medical devices, and to generate biofilms. Mortality related to this microorganism is high among immunosuppressed oncological patients and those with multiple hospitalizations and an extended stay in intensive care. There is a severe threat posed by the ability of biofilms to grow and resist antibiotics. Various nanotechnology-based strategies have been studied and developed to prevent and combat serious health problems caused by biofilm infections. The aim of this review was to evaluate the implications of nanotechnology in eradicating biofilms with KPC-producing Klebsiella pneumoniae, one of the bacteria most frequently associated with nosocomial infections in intensive care units, including in our department, and to highlight studies presenting the potential applicability of TiO2 nanocomposite materials in hospital practice. We also described the frequency of the presence of bacterial biofilms on medical surfaces, devices, and equipment. TiO2 nanocomposite coatings are one of the best long-term options for antimicrobial efficacy due to their biocompatibility, stability, corrosion resistance, and low cost; they find their applicability in hospital practice due to their critical antimicrobial role for surfaces and orthopedic and dental implants. The International Agency for Research on Cancer has recently classified titanium dioxide nanoparticles (TiO2 NPs) as possibly carcinogenic. Currently, there is an interest in the ecological, non-toxic synthesis of TiO2 nanoparticles via biological methods. Biogenic, non-toxic nanoparticles have remarkable properties due to their biocompatibility, stability, and size. Few studies have mentioned the use of nanoparticle-coated surfaces as antibiofilm agents. A literature review was performed to identify publications related to KPC-producing Klebsiella pneumoniae biofilms and antimicrobial TiO2 photocatalytic nanocomposite coatings. There are few reviews on the antibacterial and antibiofilm applications of TiO2 photocatalytic nanocomposite coatings. TiO2 nanoparticles demonstrated marked antibiofilm activity, but being nano in size, these nanoparticles can penetrate cell membranes and may initiate cellular toxicity and genotoxicity. Biogenic TiO2 nanoparticles obtained via green, ecological technology have less applicability but are actively investigated.

Preparation and characterization of biodegradable gelatine and starch films embedding cerium oxide nanoparticles stabilized by PLGA micelles for antibiofilm applications

Cerium oxide nanoparticles (CeO2NPs) have been widely investigated for numerous applications due to their redox activity, free radical scavenging property, and biofilm inhibition. Here we describe a new antibiofilm system based on CeO2NPs protected and stabilised by PLGA micelles embedded in two different biodegradable and biocompatible films. CeO2NPs were synthesised following the W/O microemulsion method and subsequently encapsulated in PLGA micelles according to the single emulsion/solvent procedure. All formulations (free NPs, empty micelles and loaded micelles) were incorporated in gelatine and starch films aimed at food packaging use. The chemical and physical characterizations of the NPs and micelles solutions were carried out by Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). Blank films and films incorporating micelles and NPs were also characterized by Scanning Electron Microscopy (SEM) and by XPS. Antibacterial experiments were also performed to investigate the system viability for the final use.

Inhibition of Streptococcus mutans growth and biofilm formation through protein acetylation.

Numerous cellular processes are regulated in response to the metabolic state of the cell, and one such regulatory mechanism involves lysine acetylation. Lysine acetylation has been proven to play an important role in the virulence of Streptococcus mutans, a major cariogenic bacterial species. S. mutans' glucosyltransferases (Gtfs) are responsible for synthesizing extracellular polysaccharides (EPS) and contributing to biofilm formation. One of the most common nonsteroidal anti-inflammatory drugs is acetylsalicylic acid (ASA), which can acetylate proteins through a nonenzymatic transacetylation reaction. Herein, we investigated the inhibitory effects of ASA on S. mutans. ASA treatment was observed to impede the growth of S. mutans, leading to a reduction in the production of water-insoluble EPS and the formation of biofilm. Moreover, ASA decreased the enzyme activity of Gtfs while increasing the protein acetylation level. The in vivo anticaries efficacy of ASA has further been proved using the rat caries model. In conclusion, ASA as an acetylation agent attenuated the cariogenic virulence of S. mutans, suggesting the potential value of protein acetylation on antimicrobial and anti-biofilm applications to S. mutans.

Candida krusei M4CK Produces a Bioemulsifier That Acts on Melaleuca Essential Oil and Aids in Its Antibacterial and Antibiofilm Activity.

Surface-active compounds (SACs) of microbial origin are an active group of biomolecules with potential use in the formulation of emulsions. In this sense, the present study aimed to isolate and select yeasts from fruits that could produce SACs for essential oil emulsions. The Candida krusei M4CK was isolated from the Byrsonima crassifolia fruit to make SACs. This emulsification activity (E24) was equal to or greater 50% in all carbon sources, such as olive oil, sunflower oil, kerosene, hexane, and hexadecane. E24 followed exponential growth according to the growth phase. The stability of emulsions was maintained over a wide range of temperatures, pH, and salinity. The OMBE4CK (melaleuca essential oil emulsion) had better and more significant inhibitory potential for biofilm reduction formation. In addition, bioemulsifier BE4CK alone on Escherichia coli and Pseudomonas aeruginosa biofilm showed few effective results, while there was a significant eradication for Staphylococcus aureus biofilms. The biofilms formed by S. aureus were eradicated in all concentrations of OMBE4CK. At the same time, the preformed biofilm by E. coli and P. aeruginosa were removed entirely at concentrations of 25 mg/mL, 12.5 mg/mL, and 6.25 mg/mL. The results show that the bioemulsifier BE4CK may represent a new potential for antibiofilm application.

Multifunctional nanocomposites integrated green synthesized amphiphilic chitosan/thyme extract/nanosilver for antimicrobial and anti-biofilm applications

BackgroundBacterial biofilms pose a significant challenge in various industries, including healthcare and food production, as they can lead to persistent infections, antibiotic resistance, and contamination. Targeted antimicrobial therapies hold great potential for mitigating the detrimental effects of biofilms. MethodsNew amphiphilic chitosans (ACSs) were prepared and used in combination with thyme extract (TE) as synergistic reducing and stabilizing agents in the preparation of biofunctionalized nanosilver (amphiphilic chitosans-TE-nanosilver, ACSs-TE-Ag) for antibacterial and anti-biofilm applications. ResultsACSs-TE-Ag nanocomposites can synergistically inhibt bacterial proliferation and biofilm formation. ACS2-TE-Ag was the most effective antibacterial agent against E. coli and S. aureus, with MIC values of 0.63 and 1.14 μg/mL, respectively. SEM analysis of the treated bacterial cells showed that ACSs-TE-Ag's greater activity is due to their capacity to rupture the bacterial cell membrane, causing intracellular content leaking and cell death. ACSs-TE-Ag can prevent biofilms by inhibiting bacterial cells from adhering to coated surfaces and killing cells in submerged cultures or biofilms. ConclusionsThe ACSs-TE-Ag nanocomposites exhibit strong bactericidal impacts, disrupt biofilm formation, inhibits bacterial adhesion, and effectively kill bacterial cells within the biofilm matrix. Furthermore, its biocompatibility and low cytotoxicity make it a potential candidate for various biomedical applications.

Non-covalent functionalization of surfactant-assisted graphene oxide with silver nanocomposites for highly efficient photocatalysis and anti-biofilm applications

This study presents a comprehensive investigation on the synthesis and characterization of surfactant-assisted graphene oxide non-covalent functionalized silver nanocomposites (rGS-AgNPs) for achieving remarkable photocatalytic and anti-biofilm properties. The approach involves using an anionic surfactant (sodium lauryl sulfate (SLS)), silver nitrate (AgNO3), and reduced graphene oxide (rGO) as stabilizing/reducing agents, metal precursors, and supporting materials, respectively. Different composites were prepared by varying the concentration of AgNO3, resulting in rGS-AgNPs composites with concentrations of 0.9 × 10−3 mM, 1.8 × 10−3 mM, and 2.7 × 10−3 mM. Characterization techniques including XRD, FTIR, SEM, and TEM/EDS analysis confirmed the formation of face-centered cubic AgNPs and amorphous rGO structures. The composites exhibited a firm binding of the surfactant and AgNPs on the surface of rGO nanosheets, resulting in efficient anti-biofilm and photocatalytic activity. The size of the supported AgNPs on rGO/SL was found to be 8–10 nm. The rGS-AgNPs composites displayed significantly improved anti-biofilm and photocatalytic performance, attributed to the increased surface area of AgNPs. Moreover, the photocatalytic efficiency of the rGS-AgNPs composites reached 96.48 % within 60 min, outperforming pure AgNPs. The synthetic producre and practical applications will be utilized for biosensors, food packing technology, biomedical and pharmaceutically valuable reactions.

Green Synthesis of Silver Nanoparticles Generated by the Photoionization Process for Anti-biofilm Application

Green Synthesis of Silver Nanoparticles Generated by the Photoionization Process for Anti-biofilm Application

Arginine Gemini-Based Surfactants for Antimicrobial and Antibiofilm Applications: Molecular Interactions, Skin-Related Anti-Enzymatic Activity and Cytotoxicity.

The antimicrobial and antibiofilm properties of arginine-based surfactants have been evaluated. These two biological properties depend on both the alkyl chain length and the spacer chain nature. These gemini surfactants exhibit good activity against a wide range of bacteria, including some problematic resistant microorganisms such us methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Moreover, surfactants with a C10 alkyl chain and C3 spacer inhibit the (MRSA) and Pseudomonas aeruginosa biofilm formation at concentrations as low as 8 µg/mL and are able to eradicate established biofilms of these two bacteria at 32 µg/mL. The inhibitory activities of the surfactants over key enzymes enrolled in the skin repairing processes (collagenase, elastase and hyaluronidase) were evaluated. They exhibited moderate anti-collagenase activity while the activity of hyaluronidase was boosted by the presence of these surfactants. These biological properties render these gemini arginine-based surfactants as perfect promising candidates for pharmaceutical and biological properties.

Nanostructured N/S doped carbon dots/mesoporous silica nanoparticles and PVA composite hydrogel fabrication for anti-microbial and anti-biofilm application

Regarding the convergence of the worldwide epidemic, the appearance of bacterial infection has occasioned in a melodramatic upsurge in bacterial pathogens with confrontation against one or numerous antibiotics. The implementation of engineered nanostructured particles as a delivery vehicle for antimicrobial agent is one promising approach that could theoretically battle the setbacks mentioned. Among all nanoparticles, silica nanoparticles have been found to provide functional features that are advantageous for combatting bacterial contagion. Apart from that, carbon dots, a zero-dimension nanomaterial, have recently exhibited their photo-responsive property to generate reactive oxygen species facilitating to enhance microorganism suppression and inactivation ability. In this study, potentials of core/shell mesoporous silica nanostructures (MSN) in conjugation with carbon dots (CDs) toward antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli have been investigated. Nitrogen and sulfur doped CDs (NS/CDs) conjugated with MSN which were cost effective nanoparticles exhibited much superior antimicrobial activity for 4 times as much as silver nanoparticles against all bacteria tested. Among all nanoparticles tested, 0.40 M NS/CDs@MSN showed the greatest minimal biofilm inhibitory at very low concentration (< 0.125 mg mL−1), followed by 0.20 M NS/CDs@MSN (0.5 mg mL−1), CD@MSN (25 mg mL−1), and MSN (50 mg mL−1), respectively. Immobilization of NS/CDs@MSN in polyvinyl alcohol (PVA) hydrogel was performed and its effect on antimicrobial activity, biofilm controlling efficiency, and cytotoxicity toward fibroblast (NIH/3 T3 and L-929) cells was additionally studied for further biomedical applications. The results demonstrated that 0.40 M NS/CDs-MSN@PVA hydrogel exhibited the highest inhibitory effect on S. aureus > P. aeruginosa > E. coli. In addition, MTT assay revealed some degree of toxicity of 0.40 M NS/CDs-MSN@PVA hydrogel against L-929 cells by a slight reduction of cell viability from 100% to 81.6% when incubated in the extract from 0.40 M NS/CDs-MSN@PVA hydrogel, while no toxicity of the same hydrogel extract was detected toward NIH/3 T3 cells.

(Digital Presentation) A Review on the Control of Biofilms by Cold-Plasma Technology

Today, biofilm infection is considered a challenge in the field of medicine and biomedical physics and engineering, as it includes 80% of infections worldwide. The complex architecture of the matrix of the extracellular polymeric substance of the biofilm, which houses the microbial cells, is resistant to antimicrobials and detergents. Cold Plasma anti-bio film application is a novel solution to address this challenge. This review study focuses on different parameters and factors affecting the mechanism of plasma-biofilm interaction in two types: direct and indirect processing. The first phase, the direct application of plasma, focuses on the direct processing of biofilms by cold plasma generators. The second phase, the indirect application of plasma is dealt with plasma surface engineering for biomaterial and medical devices which are in contact with the human body. As is known reduction in microbial load and biofilm removal by direct plasma processing is achievable and efficient. This microbial reduction also can happen by plasma surface engineering as an indirect solution, in which the plasma-treated biomaterial surface will gain an antimicrobial property and consequently mitigate biofilm growth. Moreover, the penetration depth of plasma in biofilms and the application of plasma surface pretreatment with 3D printing as a next-generation manufacturing approach have been reviewed. This review study sheds light on the efficient factors in this mechanism. This clarification helps how to optimize the control of biofilms by cold plasma technology.

Immobilization of ZnO-TiO2 Nanocomposite into Polyimidazolium Amphiphilic Chitosan Film, Targeting Improving Its Antimicrobial and Antibiofilm Applications.

This study presents a green protocol for the fabrication of a multifunctional smart nanobiocomposite (NBC) (ZnO-PIACSB-TiO2) for secure antimicrobial and antibiofilm applications. First, shrimp shells were upgraded to a polyimidazolium amphiphilic chitosan Schiff base (PIACSB) through a series of physicochemical processes. After that, the PIACSB was used as an encapsulating and coating agent to manufacture a hybrid NBC in situ by co-encapsulating ZnONPs and TiO2NPs. The physicochemical and visual characteristics of the new NBC were investigated by spectral, microscopic, electrical, and thermal methods. The antimicrobial indices revealed that the newly synthesized, PIACSB-coated TiO2-ZnO nanocomposite is an exciting antibiotic due to its amazing antimicrobial activity (MIC/MBC→0.34/0.68 μg/mL, 0.20/0.40 μg/mL, and 0.15/0.30 μg/mL working against S. aureus, E. coli, and P. aeruginosa, respectively) and antifungal capabilities. Additionally, ZnO-PIACSB-TiO2 is a potential fighter of bacterial biofilms, with the results being superior to those of the positive control (Cipro), which worked against S. aureus (only 8.7% ± 1.9 biofilm growth), E. coli (only 1.4% ± 1.1 biofilm growth), and P. aeruginosa (only 0.85% ± 1.3 biofilm growth). Meanwhile, the NBC exhibits excellent biocompatibility, as evidenced by its IC50 values against both L929 and HSF (135 and 143 µg/mL), which are significantly higher than those of the MIC doses (0.24-24.85 µg/mL) that work against all tested microbes, as well as the uncoated nanocomposite (IC50 = 19.36 ± 2.04 and 23.48 ± 1.56 µg/mL). These findings imply that the new PIACSB-coated nanocomposite film may offer promising multifunctional food packaging additives to address the customer demand for safe, eco-friendly food products with outstanding antimicrobial and antibiofilm capabilities.

Hydrogen-bonded keto-enol mechanized chalcone material for optical and antibiofilm applications

A solid-state photoluminescent 4-(Dimethylamino)-2ʹ-hydroxychalcone (Chalcone) compound was designed and synthesized using the Claisen–Schmidt condensation reaction. The optical and antibacterial of the prepared chalcone material were examined. The chemical structure of the synthesized material was confirmed by attenuated total reflectance–Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The prepared compound was grown as a single crystal in ethanol. The surface morphologies of chalcone material determined by field emission scanning electron microscopy revealed rectangular microcrystal formation in the solid. The thermal stability of the materials was studied using differential scanning calorimetry. A very sharp peak at 176.5 °C revealed its melting temperature to be in a higher range, suggesting that the crystal is highly stable towards temperature. The absorption and emission property of the material was determined by UV–visible and fluorescence spectrophotometry. The hardness test revealed the crystal to be strong and stable. The antibacterial and antibiofilm properties were evaluated against the Staphylococcus aureus (MSSA 6538) strain. The chalcone material was an ideal candidate for improving the antibiofilm and bactericidal agent against S. aureus. The results suggest that the material is suitable for optical and antibacterial applications.

Facile one-precursor and one-pot synthesis of Girard’s reagent T-based carbon dots for bacteria-resistant and anti-biofilm applications

Based on the promising development of carbon dots in antibacterial applications, Girard’s reagent T-based carbon dots (GRT-CDs) with a mean size of 2.41 nm and excellent antibacterial performance were synthesized through a one-step method. The minimum inhibitory concentration of GRT-CDs was 200 μg ml−1 for both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The bacterial growth curves showed that the inhibitory effect of GRT-CDs on bacterial multiplication was strongly concentration-dependent. The bactericidal effect of GRT-CDs was further demonstrated by the large differences in bacterial fluorescence staining plots. Zeta potential measurements and scanning electron microscope images indicated that GRT-CDs formed complexes with bacteria, which affected the normal physiological activities of bacteria, causing their rupture and death. In addition, GRT-CDs efficiently inhibited biofilm formation and removed mature biofilms. Furthermore, GRT-CDs also exhibited a remarkable inhibitory activity on MRSA. Cytotoxicity experiments showed that GRT-CDs had good cytocompatibility and even promoted cell proliferation at low concentrations. Therefore, the GRT-CDs obtained from a one-precursor and one-pot synthesis show good prospects for antibacterial applications.

Photoantimicrobial and photocatalytic hydrogen evolution activities of seleno-Chevrel phases

Chevrel phases are triclinic crystal structures consisting of a refractory metals and chalcogenides, which present unique properties in many applications. Herein, structural, mechanical, dynamical and electronic properties of Fe2Mo6Se8 and Cu2Mo6Se8 seleno-Chevrel phases were theoretically and experimentally investigated. The theoretical studies revealed the mechanical and dynamical stabilities of these phases that lead to the experimental synthesis. These seleno-Chevrel phases were used for photothermal and photodynamic antibacterial and antibiofilm applications, in the absence and presence of near infrared (NIR) and white light-emitting diode (LED) illuminations on Staphylococcus aureus (S. aureus) and Escherichia coli (E.coli) strains. Fe2Mo6Se8 and Cu2Mo6Se8 displayed enhanced antibacterial activities (73.1% and 60.0%, respectively) and biofilm inhibition effects (93.9% and 88.7%, respectively) on S. aureus. For E. coli bacterium, Fe2Mo6Se8 and Cu2Mo6Se8 showed also antibacterial effects (60.0% and 67.5%, respectively) and biofilm inhibition activities (88.7% and 78.1%, respectively). The increased photothermal and photodynamic activities of Fe2Mo6Se8 and Cu2Mo6Se8 can be attributed to the enhanced ROS production, which triggered probably the denaturation of bacterial proteins and nucleic acids by producing photoinduced electrons to obtain super oxide anion (•O₂̄) radical under light irradiation. Therefore, seleno-Chevrel phases could be a good alternative for medical antibacterial surface applications. Moreover, Fe2Mo6Se8 and Cu2Mo6Se8 were also used as catalysts for photocatalytic hydrogen evolution reactions. Fe2Mo6Se8 showed 1.8-fold higher photocatalytic hydrogen evolution rate than that of Cu2Mo6Se8, which can be explained by the bonding properties of catalysts. This article paves the way that Chevrel phases can be effectively used for different photocatalytic and photoantimicrobial applications.

A green formulation for superhydrophobic coatings based on Pickering emulsion templating for anti-biofilm applications

This study reports significant steps toward developing anti-biofilm surfaces based on superhydrophobic properties that meet the complex demands of today's food and medical regulations. It presents inverse Pickering emulsions of water in dimethyl carbonate (DMC) stabilized by hydrophobic silica (R202) as a possible food-grade coating formulation and describes its significant passive anti-biofilm properties. The final coatings are formed by applying the emulsions on the target surface, followed by evaporation to form a rough layer. Analysis shows that the final coatings exhibited a Contact Angle (CA) of up to 155° and a Roll-off Angle (RA) lower than 1° on the polypropylene (PP) surface, along with a relatively high light transition. Dissolving polycaprolactone (PCL) into the continuous phase enhanced the average CA and coating uniformity but hindered the anti-biofilm activity and light transmission. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed a uniform coating by a "Swiss-cheese" like structure with high nanoscale and microscale roughness. Biofilm experiments confirm the coating's anti-biofilm abilities that led to the reduction in survival rates of S.aureus and E.coli, by 90–95% respectively, compared to uncoated PP surfaces.

Biosynthesis of MCC/IL/Ag-AgCl NPs by Cellulose-Based Nanocomposite for Medical Antibiofilm Applications

In biomedical applications, biocompatible and nontoxic compounds are the most critical types of cytotoxic effects. In this work, the nanobiomaterial MCC/IL/Ag-AgCl NPs were fabricated by immobilizing Ag-AgCl nanoparticles on the surface of organic biopolymer [microcrystalline cellulose (MCC)] without using any reducing agent. The physical and chemical properties of nanobiomaterial were characterized by techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), FOurier transform infrared (FT-IR) spectroscopy, and atomic absorption spectroscopy (AAS). The in vitro antibacterial activity of MCC/IL/Ag-AgCl NPs was investigated on methicillin-resistant Staphylococcus aureus (ATCC-43300) and multidrug-resistant Pseudomonas aeruginosa (ATCC-27853). The results such as MIC and MBC illustrated that the antimicrobial effect of MCC/IL/Ag-AgCl NPs against Pseudomonas aeruginosa (1–2 μg/mL of MIC and MBC value) was higher than that of Staphylococcus aureus (4 μg/mL of MIC and MBC value) and also by using the microtiter plate method, the antibiofilm effect of MCC/IL/Ag-AgClNPs against Pseudomonas aeruginosa was remarkable in a variety of low concentrations (32, 16, 8, 4, 2, and 1 μg/mL). Besides, the cytotoxicity study (cell death induction) by MCC/IL/Ag-AgCl NPs in Caco-2 cells revealed low toxic effects in different doses of MCC/IL/Ag-AgCl NPs up to 400 ppm for Ag-AgCl nanoparticles and MCC/IL support, which were further confirmed in biomedical products. It is expected that using these biocompatible compounds can inhibit the biofilm formation of bacteria on surfaces and equipment, to reduce nosocomial infections, in hospital environments, especially in the intensive care unit, and surgery unit/room.