Bacteria In Solution Research Articles

Antibacterial synergistic effect of sea cucumber extract and kelulut honey combination

Natural products remain one of the major sources of new drug molecules today. The combination of sea cucumber extract with stingless bee honey holds great potential for health supplement. However, the specific results of the combination have yet to be determined. In this study, the antibacterial activity of kelulut honey and Phyllophorus spiculata sea cucumber extract samples individually and in combination were assessed with disk-diffusion assays and broth dilution method. Most of the samples exhibit small or absence of inhibitory activity using disk-diffusion assay method. Only kelulut honey sample with 100% concentration has a positive antagonism effect against Escherichia coli and Staphylococcus epidermidis. For the broth dilution method, Gram-positive bacteria were found to be more susceptible as compared to Gram-negative bacteria species, with lower minimum inhibitory concentration (MIC) value of kelulut honey, sea cucumber or combination sample. The growth of gram-positive S. epidermidis is inhibited by sea cucumber extract at MIC value of 0.031 mg/mL, kelulut honey at MIC value of 0.063 mg/ mL and combination sample at MIC value of 0.063 mg/mL, all of which are of lower MIC value as compared to E. coli inhibition. The absorbance at optical density (OD) 600nm wavelength was also measured to monitor the growth of bacteria in solution. From the results, broth dilution proves to be a more effective method to assess the antibacterial activity in the combination samples. Two combinations showed the best antibacterial synergy (OD600 value of 0.000) against both Gram-positive and Gram-negative bacteria, which were (1) ½ sea cucumber: ½ kelulut honey combination and (2) ¾ sea cucumber: ¼ kelulut honey combination. This preliminary evidence on their antibacterial synergistic activities is promising and shows possible commercialization potential.

Inactivation Effects of Negative Pressures by A Metal Berthelot Technique on Bacteria Solutions

Bacterial solutions are anticipated to be inactivated under absolute liquid negative pressures much lower in magnitude than positive ones. The pressures, however, have been hard to be produced by experiments because liquids form cavities easily through heterogeneous nucleation. To investigate the anticipation, solutions including two kinds of bacteria, namely Bacillus subtilis and Escherichia coli, were exposed to negative pressures repeatedly by a metal Berthelot tube which was designed newly. Then, numbers of colonies in bacteria which were cultured by a paper strip method and an agar dilute plate one were counted. Numbers of colonies which underwent negative pressures were less than those for non-treatment, and reduction rates of colonies increased with numbers of repetition. It was thought that inactivation effects of negative pressure on bacteria were due to destabilization of kinds of protein constituting the bacteria. Inactivation effects of negative pressure on bacteria will contribute to development of apparatus using ultrasound radiation by considering not only cavitation but also negative pressures without no chemical compound.

Ion Depletion in the Interfacial Microenvironment from Cell-Surface Interactions.

The nanoscale region immediately adjacent to surfaces, although challenging to probe, is directly responsible for local chemical and physical interactions between a material and its surroundings. Cell-surface contacts are mediated by a combination of electrostatic and acid-base interactions that alter the local environment over time. In this study, a label-free vibrational probe with a nanometer length scale reveals that the electrostatic potential at a silica surface gradually increases in the presence of bacteria in solution. We illustrate that the cells themselves are not responsible for this effect. Rather, they alter the interfacial chemical environment in a manner that is consistent with a reduction of the ionic strength to a level that is roughly four times lower than that of the bulk aqueous phase.

An Improved Chemotaxis Assay for the Rapid Identification of Rhizobacterial Chemoattractants in Root Exudates.

Chemotaxis identification is very important for the research and application of rhizosphere growth-promoting bacteria. We established a straightforward method to quickly identify the chemoattractants that could induce the chemotactic movement of rhizosphere growth-promoting bacteria on sterile glass slides via simple steps. Bacteria solution (OD600 = 0.5) and sterile chemoattractant aqueous solution were added dropwise on the glass slide at an interval of 1 cm. An inoculating loop was used to connect the chemoattractant aqueous solution to the bacterial solution. The slide was kept at room temperature for 20 min on the clean bench. Finally, the chemoattractant aqueous solution was collected for bacterial counting and microscopic observation. In this study, through multiple comparisons of experimental results, the method overcame multiple shortcomings of traditional bacterial chemotaxis methods. The method reduced the error of plate counting and shortened the experimental cycle. For the identification of chemoattractant substances, this new method can save 2-3 days compared to the traditional method. Additionally, this method allows any researcher to systematically complete a bacterial chemotaxis experiment within 1-2 days. The protocol can be considered a valuable resource for understanding plant-microbe interactions.

Microfluidic paper-based aptasensor devices for multiplexed detection of pathogenic bacteria

Foodborne pathogens are major public health concerns worldwide. Paper-based microfluidic devices are versatile, user friendly and low cost. We report a novel paper-based single input channel microfluidic device that can detect more than one whole-cell foodborne bacteria at the same time, and comes with quantitative reading via image analysis. This microfluidic paper-based multiplexed aptasensor simultaneously detects E. coli O157:H7 and S. Typhimurium. Custom designed particles provide colorimetric signal enhancement and false results prevention. Several aptamers were screened and the highest-affinity aptamers were optimized and employed for detection of these bacteria in solution, both in a buffer as well as pear juice. Image analysis was used to read and quantify the colorimetric signal and measure bacteria concentration, thus rendering this paper based microfluidic device quantitative. The colorimetric results show linearity over a wide concentration range (102CFU/mL to 108CFU/mL) and a limit of detection (LOD) of 103CFU/mL and 102CFU/mL for E. coli O157:H7 and S. Typhimurium, respectively. An insignificant change in colorimetric response for non-target bacteria indicates the aptasesnors are specific. The reported multiplexed colorimetric paper-based microfluidic devices is likely to perform well for on-site rapid screening of pathogenic bacteria in water and food products.

The Effects of Water Volume and Bacterial Concentration on the Water Filtration Assay Used in Zebrafish Health Surveillance.

The number of zebrafish in biomedical research has increased exponentially over the past decades, leading to pressure on the laboratory animal community to develop and refine techniques to monitor zebrafish health so that suitable stocks can be maintained for research. The water filtration assay is a promising technique in which water from a zebrafish system is filtered, and the filter analyzed by PCR. In the present report, we studied how the volume of water tested and the concentration of bacterial pathogens affected test results. To do so, we used stock solutions of 3 zebrafish pathogens: Edwardsiella ictaluri, Aeromonas hydrophila, and Mycobacterium marinum. We used these stocks to create solutions with known concentrations of each pathogen, ranging between 10² and 107 Colony Forming Units (CFU) per ml. One, 2, and 3 L of each solution was filtered using positive pressure, and the filters were submitted to a commercial lab for PCR testing. Results were fit with a logistic regression model, and the probability of obtaining a positive result were calculated. Test sensitivity varied by organism, but in general, test results were positively correlated with the volume of the water filtered and with the concentration of bacteria in solution. We conclude that a positive result can be expected for E. ictaluri at 105 CFU per mL, A. hydrophila at 106 CFU per ml, and M. marinum at 106 CFU per mL, when 3 L of solution are filtered.

Effect of copper addition in carbon steel on biocorrosion by sulfate-reducing bacteria in solution

Purpose This paper aims to investigate the anti-biocorrosion performance and mechanism of the Cu-bearing carbon steel in the environment containing sulfate-reducing bacterial (SRB). Design/methodology/approach The biocorrosion behavior of specimens with Cu concentration of 0 Wt.%, 0.1 Wt.%, 0.3 Wt.% and 0.6 Wt.% were investigated by immersion test in SRB solution. By examining the prepared cross-section of the biofilm using focused ion beam microscopy, SRB distribution, bacterial morphology, biofilm structure and composition were determined. The ion selectivity of the biofilm was also obtained by membrane potential measurement. Moreover, the anti-biocorrosion performance of the Cu-bearing carbon steel pipeline was tested in a shale gas field in Chongqing, China. Findings Both the results of the laboratory test and shale gas field test indicate that Cu-bearing carbon steel possesses obvious resistance to microbiologically influenced corrosion (MIC). The SRB, corrosion rate and pitting depth decreased dramatically with Cu concentration in the substrate. The local acidification caused by hydrolyze of ferric ion coming from SRB metabolism and furtherly aggravated by anion selectivity biofilm promoted the pitting corrosion. Anti-biocorrosion of Cu-bearing carbon steel was attributed to the accumulation of Cu compounds in the biofilm and the weaker anion selectivity of the biofilm. This research results provide an approach to the development of economical antibacterial metallic material. Originality/value MIC occurs extensively and has become one of the most frequent reasons for corrosion-induced failure in the oil and gas industry. In this study, Cu-bearing carbon steel was obtained by Cu addition in carbon steel and possessed excellent anti-biocorrosion property both in the laboratory and shale gas field. This study provides an approach to the development of an economical antibacterial carbon steel pipeline to resist MIC.

Amphiphilic Peptide with Dual Functionality Resists Biofouling.

Biofouling, the accumulation of organisms on surfaces, can lead to several undesirable phenomena, including hospital-acquired infections, blockage of water purification systems, and food contamination. The solution to the problem should be nontoxic and environmentally friendly, so that it could be applied on different surfaces and could come into contact with food, water, or human tissues. Peptides can provide such a solution, since they are biocompatible and biodegradable materials that can resist biofouling, either by preventing the attachment of organisms to the surface (antifouling) or by killing the bacteria (antimicrobial activity). This paper presents an amphiphilic peptide with antifouling, antimicrobial, and adhesive properties. The peptide adheres to titanium surfaces and inhibits the adhesion of both Gram-negative and Gram-positive bacteria to surfaces. In addition, it reduces the growth of bacteria in solution. This peptide has both antifouling and antimicrobial properties, which could be useful in health care systems, food packaging, and other systems that suffer from biocontamination.

The effect of Streptococcus mutans on the Corrosion Behavior of Nickel-Titanium Dental Alloys - In Vitro Study

This study aimed to compare the resistance of dental alloys to corrosion in a solution containing oral bacteria named Streptococcus mutans (S.mutans). The electrochemical behavior of Nickel-Titanium (NiTi) was investigated in sterile Fusayama artificial saliva (AS) with the enrichment medium tryptic soy broth (TSB) in solution 1 and (AS) with (TSB) and bacteria in solution 2. The electrochemical procedures selected for this work were open circuit potentials (OCP), Potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). The NiTi surface was examined using optical microscopy.   After 24 hours of immersion in artificial saliva, the results have shown that NiTi revealed high corrosion reactivity in the presence of S. mutans and present pitting corrosion on the surface.

O-Phthalate derived from plastics' plasticizers and a bacterium's solution to its anaerobic degradation.

Phthalic acid esters (phthalates) are anthropogenic compounds that are used as plasticizers. Unfortunately, because phthalates are non-covalently intercalated into plastic polymers they leach into the environment, accumulating in anoxic sediments. This has negative consequences for animal and human health. Denitrifying Betaproteobacteria, such as Aromatoleum aromaticum, can use ortho-phthalate, derived by ester hydrolysis, as a carbon and energy source. Mergelsberg et al. () deconstruct the pathway whereby ortho-phthalic acid is converted, via the highly unstable phthaloyl-CoA, to the central intermediate of anaerobic aromatic degradation, benzoyl-CoA. The latter reaction is catalysed by UbiD-like phthaloyl-CoA decarboxylase (PCD). Succinyl-CoA:o-phthalate CoA-transferase (SPT) generates phthaloyl-CoA, which accumulates at only sub-micromolar concentrations, while the Km of PCD for phthaloyl-CoA is two-orders of magnitude higher. This seemingly insurmountable kinetic barrier is overcome because A. aromatoleum massively over-produces PCD and because the decarboxylation reaction is irreversible. These features of the pathway facilitate capture of phthaloyl-CoA as it is released from SPT without the need for direct substrate-channelling. The authors provide strong evidence from both in vivo and in vitro studies to support their conclusions. This work reveals how these anaerobic bacteria have rapidly evolved a stop-gap measure to allow them to completely degrade an otherwise recalcitrant aromatic xenobiotic.

The effect of bacterial growth phase and culture concentration on U(VI) removal from aqueous solution

Abstract Bacteria play a key role in controlling the mobility of contaminants, such as uranium (U), in the environment. Uranium could be sourced from disposed radioactive waste, derived either from surface disposal trenches for Low Level Waste (LLW) that, because of the waste type and disposal concept, would typically present acidic conditions or from the geological disposal of LLW or Intermediate Level Waste (ILW) that, because of the waste type and the disposal concept, would typically present alkaline conditions. In disposed radioactive waste, there could be variable amounts of cellulosic material. Bacterial cells may be living in a range of different growth phases, depending on the growth conditions and nutrients available at the time any waste-derived U migrated to the cells. A key knowledge gap to date has been the lack of a mechanistic understanding of how bacterial growth phases (exponential, stationary, and death phase) affect the ability of bacteria to remove U(VI) from solution. To address this, we first characterised the cells using potentiometric titrations to detect any differences in proton binding to proton active sites on Pseudomonas putida cells at each growth phase under aerobic conditions, or under anaerobic conditions favourable to U(IV) reoxidation. We then conducted batch U(VI) removal experiments with bacteria at each phase suspended in 1 and 10 ppm U aqueous solutions with the pH adjusted from 2 to 12 as well as with culture concentrations from 0.01 to 10 g/L, to identify the minimal concentration of bacteria in solution necessary to affect U removal. We found that, in death phase, P. putida cells exhibited double the concentration of proton active sites than bacteria grown to exponential and stationary phase. However, we did not see a difference in the extent of U(VI) removal, from a 10 ppm U solution, between the different growth phases as a function of pH (2 to 12). Culture concentration affected U removal between pH 2–8, where U removal decreased with a decreasing concentration of cells in solution. When the pH was 10–12, ≤55% of U precipitated abiotically. The presence of bacteria in solution (0.01–10 g/L), regardless of growth phase, increased the precipitation of U from ≤55% up to 70–90%, accumulating inside the cells and on the cell walls as ~0.2 μm uranyl phosphate precipitates. These precipitates were also found at low pH with the exception of cells at exponential growth phase. This study demonstrates that growth phase affects the proton-active site concentration but not the extent of U bound to P. putida cells and that growth phase dictates the form of U removed from solution. Since the pH of trench-disposed LLW is controlled by the degradation of cellulosic waste, leading to acidic conditions (pH 4–6), bacterial concentrations would be expected to highly affect the extent of U removed from solution. The cement in grouted ILW and LLW, for geologic disposal, will allow for the development of extremely high pH values in solution (pH 9–13), where even the smallest concentrations of bacteria were able to significantly increase the removal of U from solution under aerobic conditions, or under anaerobic conditions favourable to U(IV) reoxidation.

Thiabicyclononane-Based Antimicrobial Polycations.

Bicyclo[3.3.1]nonane (BCN) polycations were synthesized by the reaction of the bivalent electrophile thiabicyclo[3.3.1]nonane dinitrate with a series of simple bis(pyridine) nucleophiles. Oligomers of moderate chain length were formed in a modular approach that tolerated the inclusion of functionalized and variable-length linkers between the pyridine units. Post-polymerization modification via copper-catalyzed azide-alkyne cyloaddition was enabled by the inclusion of terminal alkyne groups in these monomers. Most of the resulting polymers, new members of the polyionene class, inhibited the growth of bacteria at the μg/mL level and killed static bacterial cells at polymer concentrations of tens of ng/mL, with moderate to good selectivity with respect to lysis of red blood cells. While resistance to the BCN polymers was developed only very slowly over multiple passages, a degradable version of the polycation was observed to make E. coli cells more susceptible to other quaternary ammonium based antimicrobials. Solid substrates (glass and crystalline silicon) covalently functionalized with a representative BCN polycation were also able to repetitively kill bacteria in solution at high rates and with cleaning by simple sonication between exposures.

Surface-Modified Cobalt Ferrite Nanoparticles for Rapid Capture, Detection, and Removal of Pathogens: a Potential Material for Water Purification.

Enteric infections resulting from the consumption of contaminated drinking water, inadequate supply of water for personal hygiene, and poor sanitation take a heavy toll worldwide, and developing countries are the major sufferers. Consumption of microbiologically contaminated water leads to diseases such as amoebiasis, cholera, shigellosis, typhoid, and viral infections leading to gastroenteritis and hepatitis B. The present investigation deals with the development of effective method to capture and eliminate microbial contamination of water and improve the quality of water and thus decreasing the contaminated waterborne infections. Over the last decade, numerous biomedical applications have emerged for magnetic nanoparticles (MNPs) specifically iron oxide nanoparticles. For the first time, we have explored functionalized cobalt ferrite nanoparticles (NPs) for capture and detection of pathogens. The captured bacterial were separated by using simple magnet. To begin with, the prepared NPs were confirmed for biocompatibility study and further used for their ability to detect the bacteria in solution. For this, standard bacterial concentrations were prepared and used to confirm the ability of these particles to capture and detect the bacteria. The effect of particle concentration, time, and pH has been studied, and the respective results have been discussed. It is observed that the presence of amine group on the surface of NPs shows nonspecific affinity and capability to capture Escherichia coli and Staphylococcus aureus. The possible underlying mechanism is discussed in the present manuscript. Based upon this, the present material can be considered for large-scale bacteria capture in water purification application.

Development of electrochemical inhibition biosensor based on bacteria for detection of environmental pollutants

The main aim of this work is to develop a simple inhibition electrochemical sensor array for detection of heavy metals using bacteria. A series of electrical measurements (cyclic voltammograms) were carried out on samples of two types of bacteria, namely Escherichia coli and Shewanella oneidensis along with optical measurements (fluorescence microscopy, optical density, and flow cytometry) for comparison purposes. As a first step, a correlation between DC electrical conductivity and bacteria concentration in solution was established. The study of the effect of heavy metal ions (Hg2+) on DC electrical characteristics of bacteria revealed a possibility of pattern recognition of inhibition agents. Electrical properties of bacteria in solution were compared to those for immobilized bacteria.

Ferrous Ion oxidation monitoring by using magnetic resonance imaging for bio-oxidation laboratory testing

A non-invasive, non-destructive monitoring approach using three-dimensional (3D) Magnetic Resonance Imaging (MRI) is proposed to study the iron oxidation process driven by Ferrooxidans’ bacterial activity. This activity is related to the oxidation of Fe2+ into Fe3+. Fe3+ ion has paramagnetic properties that could be used to visualize its presence using MRI. A novel MRI methodology has been implemented to visualize Fe3+ in solution with the aim to be used as a marker of iron oxidizer bacteria activity. A proof of concept test has been performed with bacteria in solution and in two solids media: an inert vegetal material (luffa) and solid particles, both dipped in acid solutions. The samples were scanned using a clinical 1.5T MRI scan at several time points to test the capabilities of detecting different Fe3+ concentrations in the solution in time, while Ferrous Ion oxidation is driven by Ferrroxidans. The measurements were contrasted with titration methods to account for Ferrous Ion consumption during the process. The result reveals that a characteristic parameter obtained with MRI imaging, known as R1 relaxivity time measured in Hertz, correlates with Fe2+ oxidation (increment in Fe3+ concentration). 3D images of the distribution of Fe3+ production in the samples were acquired. Results are promising and open opportunities to continue complementary laboratory research at the network porous level to capture the spatial 3D distribution of Ferric Ions as distributed inside the porous network during a bio-reaction test.

Contact-active antibacterial aerogels from cellulose nanofibrils

The use of cellulose aerogels as antibacterial materials has been investigated by applying a contact-active layer-by-layer modification to the aerogel surface. Studying the adsorption of multilayers of polyvinylamine (PVAm) and polyacrylic acid to aerogels comprising crosslinked cellulose nanofibrils and monitoring the subsequent bacterial adhesion revealed that up to 26mgPVAmgaerogel⿿1 was adsorbed without noticeably affecting the aerogel structure. The antibacterial effect was tested by measuring the reduction of viable bacteria in solution when the aerogels were present. The results show that >99.9% of the bacteria adhered to the surface of the aerogels. Microscopy further showed adherence of bacteria to the surfaces of the modified aerogels. These results indicate that it is possible to create materials with three-dimensional cellulose structures that adsorb bacteria with very high efficiency utilizing the high specific surface area of the aerogels in combination with their open structure.

Relating the Surface Properties of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) to Their Bactericidal Effect towards a Biofilm of Streptococcus mutans.

This study was designed to determine the effects of superparamagnetic iron oxide nanoparticles (SPIONs) on the biological activity of a bacterial biofilm (Streptococcus mutans). Our hypothesis was that the diffusion of the SPIONs into biofilms would depend on their surface properties, which in turn would largely be determined by their surface functionality. Bare, positively charged and negatively charged SPIONs, with hydrodynamic diameters of 14.6 ± 1.4 nm, 20.4 ± 1.3 nm and 21.2 ± 1.6 nm were evaluated. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and electrophoretic mobility (EPM) measurements were used to confirm that carboxylic functional groups predominated on the negatively charged SPIONS, whereas amine functional groups predominated on the positively charged particles. Transmission electron microscopy (TEM) showed the morphology and sizes of SPIONs. Scanning electron microscopy (SEM) and EPM measurements indicated that the surfaces of the SPIONs were covered with biomolecules following their incubation with the biofilm. Bare SPIONs killed bacteria less than the positively charged SPIONs at the highest exposure concentrations, but the toxicity of the bare and positively charged SPIONs was the same for lower SPION concentrations. The positively charged SPIONs were more effective in killing bacteria than the negatively charged ones. Nonetheless, electrophoretic mobilities of all three SPIONs (negative, bare and positively charged) became more negative following incubation with the (negatively-charged) biofilm. Therefore, while the surface charge of SPIONS was important in determining their biological activity, the initial surface charge was not constant in the presence of the biofilm, leading eventually to SPIONS with fairly similar surface charges in situ. The study nonetheless suggests that the surface characteristics of the SPIONS is an important parameter controlling the efficiency of antimicrobial agents. The analysis of the CFU/mL values shows that the SPIONs have the same toxicity on bacteria in solution in comparison with that on the biofilm.

Albert Coons: harnessing the power of the antibody

Albert Coons: harnessing the power of the antibody

Novel platform technology to allow direct grafting of antimicrobial agents onto implantable metals.

Event Abstract Back to Event Novel platform technology to allow direct grafting of antimicrobial agents onto implantable metals. Felicity De Cogan1, Olachi Anuforom1, Anna F. Peacock2 and Ann Logan1 1 University of Birmingham, Institute of Infection and Ageing, United Kingdom 2 University of Birmingham, School of Chemistry, United Kingdom Introduction: The current management of microbial infection in injured tissues is by the systemic administration of antibiotic drugs. These are designed to eliminate pathogens while leaving the patient unharmed. This method is of limited efficacy as systemic antibiotics are not targeted to the site of infection and will often have poor penetration to areas around wounds and implants. The widespread use of prophylactic antibiotics has also led to increasing microbial resistance. Biomaterial solutions to target implant infections rely heavily on introducing an initial coating such as a polymer onto the metal, which then allows antibiotic agents to be included onto an implant surface. The antimicrobial agent can then either leach from the polymer or be covalently attached to the polymer. While this methodology is well established there are two significant drawbacks. Firstly, the inclusion of coatings such as polymers onto the surface of metal implants can hinder the osseointegration of the implant. Secondly, the leaching of materials gives sustained release over several months yet only tend to last for months. The majority of joint infections occur at greater than one year, this means these biomaterials don’t address the real unmet clinical need. In this work we report a novel attachment method which allows attachment of novel antimicrobial peptides directly to a metal surface. This grafting method also remains on the surface for extended periods of time (>1 year). Materials and Methods: Titanium was plasma nitrided at 440 °C for 19 hours. The metals were then washed using acetone to clean the surface. The surfaces were functionalised in N,N-dimethylformamide (DMF) using antimicrobial peptide (100µg), HBTU (0.5mM in DMF) and DIEA ( 60% v/v in DMF). The surfaces were washed extensively to remove unreacted material and then tested for efficacy at inhibiting bacterial growth against a range of bacteria and fungi. Lab strains were used initially, and multi-resistant clinical isolates later. Results: The peptides showed broad spectrum activity against a range of bacteria including lab strains and clinical isolates of both Gram positive and Gram negative bacteria. Peptides were tested for inhibition of growth in solution and their ability to prevent bacterial growth on the metal surfaces. Peptide coated titanium designed for orthopaedic implants showed significant reductions in the number of bacteria in solution around the surface with bacteria numbers reduced from 1x1012 to 1x103. The peptide coating also completely inhibited growth of bacteria on the surfaces (Figure 1). Conclusions: We have demonstrated the efficacy of our novel coating technology to both reduce bacterial load in solution around an implant and prevent bacteria creating a biofilm on the implant surface. We believe this has great potential to revolutionise implant materials and reduce the rate of implant associated infections. NIHR SRMRC for funding Keywords: Bacteria, Infection, Implant, bioactive interface Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Anti-infective biomaterials Citation: De Cogan F, Anuforom O, Peacock AF and Logan A (2016). Novel platform technology to allow direct grafting of antimicrobial agents onto implantable metals.. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00052 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Felicity De Cogan Olachi Anuforom Anna F Peacock Ann Logan Google Felicity De Cogan Olachi Anuforom Anna F Peacock Ann Logan Google Scholar Felicity De Cogan Olachi Anuforom Anna F Peacock Ann Logan PubMed Felicity De Cogan Olachi Anuforom Anna F Peacock Ann Logan Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

A rapid SERS method for label-free bacteria detection using polyethylenimine-modified Au-coated magnetic microspheres and Au@Ag nanoparticles.

A rapid, sensitive, and label-free SERS detection method for bacteria pathogens is reported for the first time. The method, which is based on the combination of polyethylenimine (PEI)-modified Au-coated magnetic microspheres (Fe3O4@Au@PEI) and concentrated Au@Ag nanoparticles (NPs), was named the capture-enrichment-enhancement (CEE) three-step method. A novel Fe3O4@Au microsphere with monodispersity and strong magnetic responsiveness was synthesized as a magnetic SERS substrate and amino functionalized by PEI self-assembly. The negatively charged bacteria were quickly captured and enriched by the positively charged Fe3O4@Au@PEI microspheres, and the bacteria SERS signal was synergistically enhanced by using Fe3O4@Au@PEI microspheres and Au@Ag NPs in conjunction. The CEE three-step method proved useful in tap water and milk samples, and the total assay time required was only 10 min. Results further demonstrated that the CEE three-step method could be a common approach for detecting a wide range of bacteria, as verified by its detection of the Gram-positive bacterium E. coli and Gram-positive bacterium S. aureus at a detection limit of as low as 103 cells per mL. Therefore, our CEE three-step method offered the significant advantages of short assay time, simple operating procedure, and higher sensitivity than previously reported methods of SERS-based bacteria detection.