Inhibit Biofilm Growth Research Articles

Preparation and Optimization of Hydrophilic Modified Pullulan Encapsulated Tetracycline for Significant Antibacterial and Anti-Biofilm Activity Against Stenotrophomonas maltophilia Isolates.

Stenotrophomonas maltophilia (S. maltophilia), resistant to antibiotics, is a hazardous illness and a well-known worldwide public health issue. The present investigation included the preparation of formulations of tetracycline encapsulated in pullulan (referred to as HM-PULL-Tetracycline). The study aimed to assess the effectiveness of these formulations against strains of S. maltophilia in terms of their antimicrobial and anti-biofilm properties. The physicochemical characteristics of HM-PULL-Tetracycline were analyzed using a field scanning electron microscope, X-ray dispersion, Zeta potential, and dynamic light scattering analysis. The antibacterial and anti-biofilm activity was assessed using minimal biofilm inhibitory concentration and broth micro-dilution. In addition, the biocompatibility of HM-PULL-Tetracycline was assessed by investigating its cytotoxicity on the human diploid fibroblasts (HDF) normal cell line using the MTT test. The HM-PULL-Tetracycline formulation successfully prevented biofilm formation, measuring 179.7±2.66 nm in size and with an encapsulation efficiency of 84.86±3.14 %. It exhibited a biofilm growth inhibition rating of 69 % and significantly down-regulated the expression of the smf-1, rpfF, rmlA, and spgM biofilm genes in S. maltophilia strains (p<0.05). Furthermore, the HM-PULL-Tetracycline formulation exhibited a 4 to 6-fold increase in antibacterial efficacy compared to unbound tetracycline. The HM-PULL-Tetracycline formulation demonstrated cell viability of over 90 % at all doses tested against HDF normal cells. The findings of the current investigation demonstrate that HM-PULL-Tetracycline enhances the bactericidal and anti-biofilm properties without causing harm to healthy human cells. This suggests that Could be a promising approach for medication administration.

Tooth-Binding Graphene Quantum Dots Silver Nanocomposites for Prevention of Dental Caries.

The objectives of this study were to develop a tooth-binding graphene quantum dots silver nanocomposites (ALN-GQDs-Ag) and evaluate their antibacterial, mineralising, and discolouring properties for the prevention of dental caries. In this study, ALN-GQDs-Ag were developed by synthesising nano silver (Ag) with graphene quantum dots (GQDs) and functionalised GQDs with alendronate (ALN). ALN-GQDs-Ag were characterised by transmission electron microscopy (TEM), zeta potential analysis, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. The cytotoxicity of ALN-GQDs-Ag against human gingival fibroblasts (HGF-1) and stem cells from human exfoliated deciduous teeth (SHED) was examined using a colorimetric assay with reference to silver nitrate solution. The affinity of ALN-GQDs-Ag for hydroxyapatite particles was investigated using inductively coupled plasma spectroscopy (ICP). The antibacterial properties of ALN-GQDs-Ag against Streptococcus mutans were evaluated by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and colony-forming units counting (CFUs). The mineralisation properties of ALN-GQDs-Ag on human dentine were assessed using micro-computed tomography (micro-CT), scanning electron microscopy (SEM), and Fourier transform infrared in a biochemical cycling model. The discolouring properties of ALN-GQDs-Ag on artificial dentine caries were determined using spectrophotometry. TEM, Zeta potential, XPS, FTIR, and Raman spectroscopy confirmed the synthesis of stable spherical ALN-GQD-Ag nanocomposites with a 10.3 ± 5.5 nm diameter. The colorimetric assay demonstrated that ALN-GQDs-Ag were less cytotoxic than silver nitrate to HGF-1 and SHED (p<0.001). ICP showed that ALN-GQDs-Ag were bound to hydroxyapatite. SEM, CLSM, and CFUs showed that ALN-GQDs-Ag was bactericidal and inhibited biofilm growth of Streptococcus mutans. Micro-CT, SEM, and FTIR showed that ALN-GQDs-Ag repressed dentine demineralisation under a cariogenic challenge. Spectrophotometry revealed no significant discolouration of dentine caries in the ALN-GQDs-Ag. This study developed a biocompatible and tooth-binding ALN-GQDs-Ag with promising antibacterial, mineralising, and non-discolouring properties. ALN-GQDs-Ag could be a novel anti-caries agent for preventing dentine caries if translated for clinical use.

Edible thermosensitive chitosan/hydroxypropyl β-cyclodextrin hydrogel with natural licoricidin for enhancing oral health: Biofilm disruption and demineralization prevention

Dental caries, a widespread and significantly detrimental health condition, is characterized by demineralization, pain, compromised tooth functionality, and various other adverse effects. Licoricidin (LC), a natural isoflavonoid, demonstrates potent antimicrobial properties for maintaining oral health. However, its practical application is significantly hindered by its limited water solubility and susceptibility to removal within the oral environment. To tackle this issue, we developed a delivery oral system by an edible thermosensitive chitosan- disodium beta-glycerol phosphate pentahydrate (CS/β-GP) hydrogel to load LC/Hydroxypropyl beta-cyclodextrin (HP-β-CD) inclusion complexes. These hydrogels (LC/HP-β-CD/CS/β-GP) could solidify rapidly at oral temperature and sustainably release LC, thereby preventing its rapid clearance from the oral cavity. We confirmed the significant antibacterial activity of this hydrogel against Streptococcus mutans and Staphylococcus aureus. Additionally, the HP-β-CD combination enhanced LC to penetrate bacterial biofilms and inhibit biofilm growth, leading to leakage of cellular proteins and DNA. Additionally, we studied the effect of LC/HP-β-CD/CS/β-GP on intracellular ROS levels and MMP, comprehensively exploring its antimicrobial mechanism. Furthermore, LC/HP-β-CD/CS/β-GP exhibited the ability to inhibit demineralization and demonstrated excellent biocompatibility. In summary, this study presented a safer approach to oral delivering bioactive substances, offering a promising strategy for enhanced oral health and safety.

Exploring diflunisal as a synergistic agent against Staphylococcus aureus biofilm formation.

Staphylococcus aureus is a bacterial pathogen of considerable significance in public health, capable of inducing a diverse range of infectious diseases. One of the most notorious mechanisms used by S. aureus to survive and colonize the site of infection is its ability to form biofilms. Diflunisal, a non-steroidal anti-inflammatory drug (NSAID), is a known inhibitor of the Agr system in S. aureus, which is key in regulating biofilm formation. This study evaluated the effect of broad-spectrum antibiotics in combination with diflunisal on S. aureus biofilm density. Eight antibiotics were tested independently at different concentrations and in combination with diflunisal to assess their effect on S. aureus biofilm formation. When using the antibiotics alone and with diflunisal, a significant control effect on biofilm formation was observed (p < 0.05), irrespective of diflunisal presence, but did not achieve a complete biofilm growth inhibition. Over time, diflunisal influenced biofilm formation; however, such an effect was correlated with antibiotic concentration and exposure time. With amikacin treatments, biofilm density increased with extended exposure time. In the case of imipenem, doripenem, levofloxacin, and ciprofloxacin, lower doses and absence of diflunisal showed higher control over biofilm growth with longer exposure. However, in all cases, diflunisal did not significantly affect the treatment effect on biofilm formation. In the absence of antibiotics, diflunisal significantly reduced biofilm formation by 53.12% (p < 0.05). This study suggests that diflunisal could be a potential treatment to control S. aureus biofilms, but it does not enhance biofilm inhibition when combined with antibiotics.

Green synthesis of ZnO nanoparticles and biological applications as broad-spectrum bactericidal, antibiofilm effects and biocompatibility studies on Zebrafish embryo

This work generated zinc oxide nanoparticles (ZnO NPs) using Ocimum tenuiflorum in an inexpensive and environmentally friendly manner. The generated ZnO NPs were analysed using Ultra visible spectroscopy (UV–Vis), Fourier transformed infrared spectroscopy (FTIR), Scanning electron microscopy-Energy X-ray diffraction spectroscopy (SEM-EDX), Transmission electron microscopy (TEM), and X-ray diffraction (XRD). Bio-synthesized ZnO NPs showed UV–Visible absorbance maxima at 290 nm, indicating bio reduction and stability. The DRS spectra revealed a straight band gap value of 3.24 eV. Alcohols, alkanes, phenols, and amines in FTIR may contain reduced and capped zinc ions. Crystalline ZnO nanoparticles were verified by XRD. Biosynthesized ZnO NPs were exhibited in spherical and 5–35.49 nm in size by FESEM and TEM. EDX confirmed NPs zinc elemental signatures. Antibacterial properties showed that ZnO NPs effectively inhibited gram (+ve) and gram (−ve) pathogens, including E. coli (20.0 ± 0.8 mm), E. faecalis (20.0 ± 0.5 mm), S. aureus (18.01 ± 1.2 mm), and S. mutans (17.5 ± 1.0 mm). This study shows that biosynthesized ZnO NPs inhibit biofilm growth by 0.198–1.431 O.D values (Optical density). Antibiofilm inhibition was concentration-dependent. Nanoparticles proved effective against E. coli, S. mutans, S. aureus, and E. faecalis with MICs of 15 and 25 µg/mL. Time-dependent death kinetic studies indicated that 8–12 h ZnO NPs killed all bacteria. Also, ZnO NPs had low harmful effects on zebrafish eggs at doses upto 1 mg/mL. In summary, the production of green ZnO NPs offers a sustainable and biocompatible approach that is well-suited for various biological applications.

From 0D-complex to 3D-MOF: changing the antimicrobial activity of zinc(II) via reaction with aminocinnamic acids.

Combining zinc nitrate with 3- and/or 4- aminocinnamic acid (3-ACA and 4-ACA, respectively) leads to the formation of the 0D complex [Zn(4-AC)2(H2O)2], the 1D coordination polymer [Zn(3-AC)(4-AC)], and the 2D and 3D MOFs [Zn(3-AC)2]∙2H2O and [Zn(4-AC)2]∙H2O, respectively. These compounds result from the deprotonation of the acid molecules, with the resulting 3- and 4-aminocinnamate anions serving as bidentate terminal or bridging ligands. All solids were fully characterized via single crystal and powder X-ray diffraction and thermal techniques. Given the mild antimicrobial properties of cinnamic acid derivatives and the antibacterial nature of the metal cation, these compounds were assessed and demonstrated very good planktonic cell killing as well as inhibition of biofilm growth against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus.

New Fe3O4-Based Coatings with Enhanced Anti-Biofilm Activity for Medical Devices.

With the increasing use of invasive, interventional, indwelling, and implanted medical devices, healthcare-associated infections caused by pathogenic biofilms have become a major cause of morbidity and mortality. Herein, we present the fabrication, characterization, and in vitro evaluation of biocompatibility and anti-biofilm properties of new coatings based on Fe3O4 nanoparticles (NPs) loaded with usnic acid (UA) and ceftriaxone (CEF). Sodium lauryl sulfate (SLS) was employed as a stabilizer and modulator of the polarity, dispersibility, shape, and anti-biofilm properties of the magnetite nanoparticles. The resulting Fe3O4 functionalized NPs, namely Fe3O4@SLS, Fe3O4@SLS/UA, and Fe3O4@SLS/CEF, respectively, were prepared by co-precipitation method and fully characterized by XRD, TEM, SAED, SEM, FTIR, and TGA. They were further used to produce nanostructured coatings by matrix-assisted pulsed laser evaporation (MAPLE) technique. The biocompatibility of the coatings was assessed by measuring the cell viability, lactate dehydrogenase release, and nitric oxide level in the culture medium and by evaluating the actin cytoskeleton morphology of murine pre-osteoblasts. All prepared nanostructured coatings exhibited good biocompatibility. Biofilm growth inhibition ability was tested at 24 h and 48 h against Staphylococcus aureus and Pseudomonas aeruginosa as representative models for Gram-positive and Gram-negative bacteria. The coatings demonstrated good biocompatibility, promoting osteoblast adhesion, migration, and growth without significant impact on cell viability or morphology, highlighting their potential for developing safe and effective antibacterial surfaces.

Natural Prenylflavonoids from Sophora flavescens Root Bark against Multidrug-Resistant Methicillin-Sensitive Staphylococcus aureus Targeting the Membrane Permeability.

The overuse of antibiotics in animal farming and aquaculture has led to multidrug-resistant methicillin-sensitive Staphylococcus aureus (MR-MSSA) becoming a common pathogen in foodborne diseases. Sophora flavescens Ait. serves as a traditional plant antibacterial agent and functional food ingredient. A total of 30 compounds (1-30) were isolated from the root bark of S. flavescens, consisting of 20 new compounds (1-20). In the biological activity assay, compound 1 demonstrated a remarkable inhibitory effect on MR-MSSA, with an MIC of 2 μg/mL. Furthermore, 1 was found to rapidly eliminate bacteria, inhibit biofilm growth, and exhibit exceptionally low cytotoxicity. Mechanistic studies have revealed that 1 possesses an enhanced membrane-targeting ability, binding to the bacterial cell membrane components phosphatidylglycerol (PG), phosphatidylethanolamine (PE), and cardiolipin (CL). This disruption of bacterial cell membrane integrity increases intracellular reactive oxygen species, protein and DNA leakage, reduced bacterial metabolism, and ultimately bacterial death. In summary, these findings suggest that compound 1 holds promise as a lead compound against MR-MSSA.

Ice nucleation active bacteria metabolites as antibiofilm agent to control Aeromonas hydrophila and Streptococcus agalactiae infections in Aquaculture

ObjectivesThe aim of this study was to quantify and identify metabolites of Ice Nucleation Active (INA) bacteria as an anti-biofilm agent against biofilms of fish pathogens such as Aeromonas hydrophila and Streptococcus agalactiae.ResultsIce nucleation active bacteria, which have the ability to catalyze ice nucleation, isolated from rainwater in previous studies, were used. All INA isolates were tested in several assays, including the antimicrobial test, which uses streptomycin as the positive control and none of the isolates were found positive in the antimicrobial test. As for the quorum quenching assay, it was found that four out of ten isolates were able to disturb the communication system in Chromobacterium violaceum wild type, which was used as the indicator bacteria. On the next assay, all ten isolates were tested for Biofilm Inhibition and Destruction and showed anti-biofilm activity with the highest percentage inhibition of 33.49% by isolate A40 against A. hydrophila and 77.26% by isolate A19 against S. agalactiae. C1 performed the highest destruction against A. hydrophila and S. agalactiae, with percentages of 32.11% and 51.88%, respectively. As for the GC-MS analysis, supernatants of INA bacteria contain bioactive compounds such as sarcosine and fatty acids, which are known to have antibiofilm activity against several biofilm-forming bacteria. Through 16s rRNA sequencing, identified bacteria are from the Pantoea, Enterobacter, and Acinetobacter genera. As for the conclusion, ice nucleation active bacteria metabolites tested showed positive results against pathogenic bacteria Aeromonas hydrophila and Streptococcus agalactiae in destructing and inhibiting biofilm growth.

A facile microwave assisted synthesis of thymohydroquinone with antibiofilm properties against Salmonella typhi and Listeria monocytogenes

Thymoquinone (TQ), a monoterpene isolated from the Nigella sativa L. seeds using the oil expeller method, gave about 40% of the total oil. Clevenger hydrodistillation of the obtained oil yielded volatile oil (0.55%) with 30% of TQ. Subsequent purification through silica gel column chromatography resulted in the isolation of pure TQ. The microwave assisted reduction of TQ with zinc and acetic acid resulted in the formation of thymohydroquinone within 5 min (THQ, yield 85%). The conventional reduction method gives 42% - 60% yield and is found to be time-consuming (4–12 h). The prepared THQ was tested at various concentrations for the inhibition of planktonic as well as biofilm of Listeria monocytogenes Scott A and Salmonella typhi FB231 bacterial cultures. Minimum inhibitory concentration (MIC) using MTT assay showed 50 μg/mL and 100 μg/mL for L. monocytogenes and S. typhi, respectively. Further, the biofilm growth inhibition and development were assessed using a crystal violet (CV) assay, which confirmed that THQ and TQ significantly eradicated biofilm formed after 6 h and 24 h, as evidenced by bright field microscopy. Thus, the results provide scope on the quicker microwave assisted synthesis, which is considered a greener method and the THQ showed potential antimicrobial and antibiofilm activities against common food borne pathogens.

Biofilm ablation on titanium alloy surface by photothermal and chemotherapeutic synergistic therapy

With prolonged exposure in the human body, titanium alloy implants face challenges associated with bacterial attachment and proliferation, leading to implant failure and severe complications. Photothermal therapy (PTT) emerges as an efficient strategy for biofilm elimination. However, the local high temperature of PTT and incomplete bacteria ablation in low-temperature PTT pose risks of damage to normal tissues and biofilm recalcitrance, respectively. In this study, we synergistically combined photothermal therapy and chemotherapy to mildly disrupt biofilms of Staphylococcus aureus (S. aureus) to enhance the efficiency of biofilm ablation. The synergistic nanoplatform comprises near-infrared-light responsive conjugated polymers, heat-sensitive liposomes, and the antibiotic daptomycin for biofilm elimination. The heat generated by conjugated polymers, stimulated with 808 nm light, alters biofilm permeability and releases antibiotics locally to eradicate biofilm. The nanoparticles exhibit biofilm dispersion activity and can effectively inhibit biofilm growth for up to 5 days. Consequently, this nanoplatform based on conjugated polymers offers a reliable method for ablating biofilms on titanium alloy implant and exhibits potential in drug-resistant clinical applications.

Synthesis, theoretical analysis, and biological properties of a novel tridentate Schiff base palladium (II) complex.

Schiff base complexes play a crucial role in bioinorganic chemistry. A novel curcumin/phenylalanine tridentate Schiff base ligand and its palladium (II) complex were synthesized so that they were stable in aqueous buffer. The structure of the complex was investigated using a variety of methods, including DFT, NBO analysis, FMOs, and MESP. The interaction of the complex with a plasmid (pUC19) and CT-DNA was studied. The anticancer, antibacterial, and antioxidant activities of the complex were examined. The statistical analysis of the MTT assay was compared using the 1-way ANOVA and Tukey test. Results showed that the complexes were stable in aqueous buffer, pH 8. The extrinsic fluorescence emission of the plasmid and CT-DNA was quenched while interacting with the complex. The complex had an IC50 of 72.47 µM against MCF-7 cells. The ANOVA and Tukey analysis of MTT data demonstrated a statistically significant difference between groups (P < 0.0001). The minimum inhibitory concentrations (MIC) of the complex for E. coli and S. aureus were 300 and 200µg/mL, with 96.3 and 95.2% biofilm growth inhibition at 250µg/mL, respectively. The sample concentrations contributing to 50% radical inhibition in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) test for curcumin, ligand, and palladium (II) complex were 33.62, 21.27, and 51.26 µM, respectively. The results suggest that the complex interaction with DNA is one of the potential mechanisms for eliminating cancer cells and bacteria in the planktonic and biofilm. On the other hand, while stability in an aqueous buffer at pH 8 increases, the modified curcumin antioxidant effect decreases.

Nanoemulsion and nanoencapsulation of a hydroethanolic extract of Nettle (Urtica dioica) and Wormwood (Artemisia absinthium): comparison of antibacterial and anticancer activity.

Introduction: Nanoemulsion and nanoencapsulation are attractive novel methods that can be used for incorporating active plant extracts in food preparations and pharmaceutical formulations. In the current study, we aimed to investigate the anticancer and antibacterial effects of hydroethanolic extracts of Nettle (NE), Wormwood (WE), and the combination of the two plants (CNWE), as well as their nanoemulsion forms (NN, NW, CNNW) and nanoencapsulation forms (CN, CW, and CCNW). Methods: The morphology and structure of the nanoemulsion and nanoencapsulation preparations were assessed utilizing dynamic light scattering (DLS) along with transmission electron microscopy (TEM). The antibacterial activity of the prepared formulations were assessed by determining minimum inhibitory concentration (MIC), zone of inhibition diameter, minimum bactericidal concentration (MBC), along with biofilm growth inhibition against Salmonaella typhimurium and Klebsiella. pneumoniae. The anticancer activity was evaluated via a MTT assay in the colon cancer cell line (HCT116). Results: The nanoemulsion and nanoencapsulation particle size varied between 10 and 50nm and 60 and 110nm, respectively. The MIC values were between 11.25 and 95µg/mL along with MBC values between 11.25 and 190µg/mL. The highest inhibition of biofilm formation was observed with CCNW against K. pneumoniae (∼78.5%) and S. typhimurium (∼73%). In descending order, the inhibition of biofilm formation was CCNW > CW > CN > CNNW > NN > NW > CNWE > NE > WE against the tested bacteria. The IC50 values for NE, WE, CNWE, NN, NW, CNNW, CN, CW, and CCNW were determined as 250, 170, 560, 380, 312, 370, 250, 420, and 700µg/mL, respectively. Exposure to a high concentration of NW resulted in a significantly lower HCT116 viability compared to other groups. Taken together, CNNW, and CCNW showed the highest antibacterial and anticancer activitiy. Discussion: Nanoemulsion and nanoencapsulation were effective ways to increase the antibacterial and anticancer activity of the extracts and could be used in the food and pharmaceutical industries.

Antibiofilm peptides enhance the corrosion resistance of titanium in the presence of Streptococcus mutans.

Titanium alloys have gained popularity in implant dentistry for the restoration of missing teeth and related hard tissues because of their biocompatibility and enhanced strength. However, titanium corrosion and infection caused by microbial biofilms remains a significant clinical challenge leading to implant failure. This study aimed to evaluate the effectiveness of antibiofilm peptides 1018 and DJK-5 on the corrosion resistance of titanium in the presence of Streptococcus mutans. Commercially pure titanium disks were prepared and used to form biofilms. The disks were randomly assigned to different treatment groups (exposed to S. mutans supplied with sucrose) including a positive control with untreated biofilms, peptides 1018 or DJK-5 at concentrations of 5μg/mL or 10μg/mL, and a negative control with no S. mutans. Dynamic biofilm growth and pH variation of all disks were measured after one or two treatment periods of 48h. After incubation, the dead bacterial proportion, surface morphology, and electrochemical behaviors of the disks were determined. The results showed that peptides 1018 and DJK-5 exhibited significantly higher dead bacterial proportions than the positive control group in a concentration dependent manner (p < 0.01), as well as far less defects in microstructure. DJK-5 at 10μg/mL killed 84.82% of biofilms and inhibited biofilm growth, preventing acidification due to S. mutans and maintaining a neutral pH. Potential polarization and electrochemical impedance spectroscopy data revealed that both peptides significantly reduced the corrosion and passive currents on titanium compared to titanium surfaces with untreated biofilms, and increased the resistance of the passive film (p < 0.05), with 10μg/mL of DJK-5 achieving the greatest effect. These findings demonstrated that antibiofilm peptides are effective in promoting corrosion resistance of titanium against S. mutans, suggesting a promising strategy to enhance the stability of dental implants by endowing them with antibiofilm and anticorrosion properties.

Isolation of Thermophilic Bacteria Geobacillus subterraneus From Mount Tangkuban Perahu and the Novelty as a Candidate for Streptococcus mutans Anti‐Biofilm

Thermophilic bacteria living in extreme areas with high temperatures are capable of producing secondary metabolites, such as antimicrobial peptides (AMPs). AMPs are stable at high temperatures and show good antibacterial activity. Therefore, this study aimed to identify thermophilic bacteria from the crater of Mount Tangkuban Perahu around West Java and assess antibacterial effectiveness of AMPs against Streptococcus mutans, which contribute to oral biofilm formation. The isolate obtained was identified using 16S ribosomal ribonucleic acid (rRNA) gene sequencing, and the supernatant of the isolate was tested against S. mutans American Type Culture Collection (ATCC) 25175 using the disc assay method. To determine AMPs‐coding genes, its genome was uploaded to antibiotic and secondary metabolite analysis shell (antiSMASH) 5.0.0 platform and biofilm inhibition was tested using the microtiter plate technique (with a 96‐well bottom). Subsequently, the results were assessed using a microplate reader operating at 595 nm wavelength. The isolate was identified as Geobacillus subterraneus, with antibacterial activity against S. mutans, and produced an inhibition zone of 8.40 mm at an optimum pH of 8. The output of AMPs‐coding gene showed that AMPs of the isolate were a member of the lanthipeptide class I, or bacteriocin‐I group. AMPs of G. subterraneus suppressed the growth of S. mutans biofilm at a supernatant concentration of 5%, with the lowest optical density (OD) value of 0.061 and the highest percentage of biofilm growth inhibition at 28.24%. Based on the results, G. subterraneus derived from the crater of Mount Tangkuban Perahu showed potent antibacterial properties against S. mutans, making it a promising novel S. mutans anti‐biofilm candidate.

The potential of nano graphene oxide and chlorhexidine composite membranes for use as a surface layer in functionally graded membranes for periodontal lesions

Membranes have been used for treating periodontal defects and play a crucial role in guided bone regeneration applications. Nano graphene oxide have been exploited in tissue engineering due to its biomechanical properties. Its composite formulations with hydroxyapatite and chitosan with controlled degradation could aid in becoming part of a surface layer in a functionally graded membrane. The aim of the study was to synthesize chitosan and composite formulations of nano graphene oxide, hydroxyapatite and chlorhexidine digluconate using solvent casting technique and to characterize the physiochemical, mechanical, water vapor transmission rate (barrier), degradation and antimicrobial potential of the membranes. Altogether four different membranes were prepared (CH, CCG, 3511 and 3322). Results revealed the chemical interactions of hydroxyapatite, chitosan and nanographene oxide due to inter and intra molecular hydrogen bonding. The tensile strength of 3322 (33.72 ± 6.3 MPa) and 3511 (32.06 ± 5.4 MPa) was higher than CH (27.46 ± 9.6 MPa). CCG showed the lowest water vapor transmission rate (0.23 ± 0.01 g/h.m2) but the highest weight loss at day 14 (76.6 %). 3511 showed a higher drug release after 72 h (55.6 %) Significant biofilm growth inhibition was observed for all membranes. 3511 showed complete inhibition against A. actinomycetemcomitans. Detailed characterization of the synthesized membranes revealed that 3511 composite membrane proved to be a promising candidate for use as a surface layer of membranes for guided bone regeneration of periodontal lesions.Graphical

Carbon-infiltrated carbon nanotubes inhibit the development of Staphylococcus aureus biofilms

Staphylococcus aureus forms biofilms that cause considerable morbidity and mortality in patients who receive implanted devices such as prosthetics or fixator pins. An ideal surface for such medical devices would inhibit biofilm growth. Recently, it was reported that surface modification of stainless steel materials with carbon-infiltrated carbon nanotubes (CICNT) inhibits the growth of S. aureus biofilms. The purpose of this study was to investigate this antimicrobial effect on titanium materials with CICNT coated surfaces in a variety of surface morphologies and across a broader spectrum of S. aureus isolates. Study samples of CICNT-coated titanium, and control samples of bare titanium, a common implant material, were exposed to S. aureus. Viable bacteria were removed from adhered biofilms and quantified as colony forming units. Scanning electron microscopy was used to qualitatively analyze biofilms both before and after removal of cells. The CICNT surface was found to have significantly fewer adherent bacteria than bare titanium control surfaces, both via colony forming unit and microscopic analyses. This effect was most pronounced on CICNT surfaces with an average nanotube diameter of 150 nm, showing a 2.5-fold reduction in adherent bacteria. Since S. aureus forms different biofilm structures by isolate and by growth conditions, we tested 7 total isolates and found a significant reduction in the biofilm load in six out of seven S. aureus isolates tested. To examine whether the anti-biofilm effect was due to the structure of the nanotubes, we generated an unstructured carbon surface. Significantly more bacteria adhered to a nonstructured carbon surface than to the 150 nm CICNT surface, suggesting that the topography of the nanotube structure itself has anti-biofilm properties. The CICNT surface possesses anti-biofilm properties that result in fewer adherent S. aureus bacteria. These anti-biofilm properties are consistent across multiple isolates of S. aureus and are affected by nanotube diameter. The experiments performed in this study suggest that this effect is due to the nanostructure of the CICNT surface.

Correlation Analyses of the Oral Biofilm Growth Inhibition towards Hydrophobicity Reduction of Oral Pathogenic Bacteria

Correlation Analyses of the Oral Biofilm Growth Inhibition towards Hydrophobicity Reduction of Oral Pathogenic Bacteria

Inhibiting Biofilm Formation via Simultaneous Application of Nitric Oxide and Quorum Quenching Bacteria.

Membrane biofouling is an inevitable challenge in membrane-based water treatment systems such as membrane bioreactors. Recent studies have shown that biological approaches based on bacterial signaling can effectively control biofilm formation. Quorum quenching (QQ) is known to inhibit biofilm growth by disrupting quorum sensing (QS) signaling, while nitric oxide (NO) signaling helps to disperse biofilms. In this study, batch biofilm experiments were conducted to investigate the impact of simultaneously applying NO signaling and QQ for biofilm control using Pseudomonas aeruginosa PAO1 as a model microorganism. The NO treatment involved the injection of NONOates (NO donor compounds) into mature biofilms, while QQ was implemented by immobilizing QQ bacteria (Escherichia coli TOP10-AiiO or Rhodococcus sp. BH4) in alginate or polyvinyl alcohol/alginate beads to preserve the QQ activity. When QQ beads were applied together with (Z)-1-[N-(3-aminopropyl)-N-(n-propyl) amino]diazen-1-ium-1,2-diolate (PAPA NONOate), they achieved a 39.0% to 71.3% reduction in biofilm formation, which was substantially higher compared to their individual applications (16.0% to 54.4%). These findings highlight the significant potential of combining QQ and NO technologies for effective biofilm control across a variety of processes that require enhanced biofilm inhibition.

A comparative analysis of the proanthocyanidins from fruit and non-fruit trees and shrubs of Northern Europe: Chemical characteristics and biological activity

The comparative analysis of the chemical composition and biological activity of extracts and proanthocyanidins (PACs) isolated from harvesting and pruning agro-waste of fruit shrub-trees (Hippophae rhamnoides L. and Aronia melanocarpa) and forest cleaning waste of non-fruit trees and shrubs (Alnus incana L., Alnus glutinosa and Salix caprea) of Northern Europe was carried out. Aronia melanocarpa and Hippophae rhamnoides L. biomass had the highest proanthocyanidins content (up to 12%) on dry biomass. Fruit trees-derived purified PACs which contained structures with higher polymerization degree had slightly higher antioxidant activity. Both fruit and non-fruit trees PACs can be successfully used in antimicrobial preparations and as antioxidants, and could be interchangeable in the compositions of the antimicrobial preparations, especially against E. coli, P. aeruginosa and S. aureus. Salix caprea, which contained wider range of gallocatechin subunits, and Alnus spp., which contained diarylheptanoids, had shown better anti-microbial activity against B. cereus. Non-fruit trees PACs are desirable in the preparations against C. albicans. PACs from Hippophae rhamnoides L. and Aronia melanocarpa inhibited biofilm formation to 50%, but the extract from Hippophae rhamnoides L. showed the most significant MRSA biofilm growth inhibition (onto 80%). Preparations on the basis of waste biomass-derived compounds will contribute to sustainable pharmacy since their application will allow to diminish the use of antibiotics and to have less toxic side effects both for humans and the environment.