Impedimetric Sensors for Bacteria Detection

The application of electrochemical biosensors based on impedance detection has grown during the past years due to their high sensitivity and rapid response, making this technique extremely useful to detect biological interactions with biosensor platforms. This chapter is focused on the use of electrochemical impedance spectroscopy (EIS) for bacterial detection in two ways. On one hand, bacteria presence may be determined by the detection of metabolites produced by bacterial growth involving the media conductivity changes. On the other hand, faster and more selective bacterial detection may be achieved by the immobilization of bacteria on a sensor surface using biorecognition elements (antibodies, antimicrobial peptides, aptamers, etc.) and registering changes produced in the charge transfer resistance (faradic process) or interfacial impedance (nonfaradic process). Here we discuss different types of impedimetric biosensors for microbiological applications, making stress on their most important parameters, such as detection limits, detection times, selectivity, and sensitivity. The aim of the paper was to give a critical review of recent publications in the field and mark the future trends

Cell Concentration Systems for Enhanced Biosensor Sensitivity

Concentration processes for analytical systems based on different types of biosensors are very important for many applications. The sample conditioning is oriented to enhance the sensitivity or directly to make the detection or analysis possible. Processes that may be used for concentration and conditioning of original samples are very diverse, depending on applications that may range from clinical diagnostics to industrial processes control, and there are different strategies to achieve the final goal

Additional file 2: Table S2. of Electrochemical performance and microbial community profiles in microbial fuel cells in relation to electron transfer mechanisms

Number of sequences and diferent OTUs found in each sample by 454-pyrosequencing. (TIFF 96 kb

Additional file 2: Table S2. of Electrochemical performance and microbial community profiles in microbial fuel cells in relation to electron transfer mechanisms

Number of sequences and diferent OTUs found in each sample by 454-pyrosequencing. (TIFF 96 kb

Development of an integrated method of concentrationand immunodetection of bacteria

The microbial quality of water is a key aspect to avoid environmental and public health problems. The low pathogen concentration needed to produce a disease outbreak makes it essential to process large water volumes and use sensitive and specific methods such as immunoassays for its detection. In the present work, we describe the development of a device based on microfiltration membranes to integrate the concentration and the immunodetection of waterborne bacteria. A microfiltration membrane treatment protocol was designed to reduce the non-specific binding of antibodies, for which different blocking agents were tested. Thus, the proof of concept of the microbial detection system was also carried out using Escherichia coli as the bacterial pathogen model. E. coli suspensions were filtered through the membranes at 0.5 mL s−1, and the E. coli concentration measurements were made by absorbance, at 620 nm, of the resultant product of the enzymatic reaction among the horseradish peroxidase (HRP) bonded to the antibody, and the substrate 3,3′,5,5′-tetramethylbenzidine (TMB). The results showed that the homemade concentration system together with the developed membrane treatment protocol is able to detect E. coli cells with a limit of detection (LoD) of about 100 CFU in 100 mL.The authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (BACSYS pro- ject CTQ2014-54553-C3-1-R). N.U. and O.C. acknowledge funding from the People Programme (Marie Curie Actions) of the 7th Framework Programme of the E uropean Union (FP7/2007-2013), TECNIO-spring program from the Agency for Business Competitiveness of the Government of Catalonia (ACCIÓ). J.J.E. ac- knowledges financial support from the Catalan Industrial Doctorate pro- gram and Waterologies. S.L. and N.P. acknowledge financial support from Gas Natural Fenosa.Peer reviewe

Miniaturized metal oxide pH sensors for bacteria detection

It is well known that the metabolic activity of some microorganisms results in changes of pH of the culture medium, a phenomenon that can be used for detection and quantification of bacteria. However, conventional glass electrodes that are commonly used for pH measurements are bulky, fragile and expensive, which hinders their application in miniaturized systems and encouraged to the search for alternatives. In this work, two types of metal oxide pH sensors have been tested to detect the metabolic activity of the bacterium Escherichia coli (E. coli). These pH sensors were produced on silicon chips with platinum metal contacts, onto which thin layers of IrOx or Ta2O5 were incorporated by two different methods (electrodeposition and e-beam sputtering, respectively). In order to facilitate measurement in small sample volumes, an Ag/AgCl pseudo-reference was also screen-printed in the chip and was assayed in parallel to an external Ag/AgCl reference electrode. As it is shown, the developed sensors generated results indistinguishable from those provided by a conventional glass pH-electrode but could be operated in significantly smaller sample volumes. After optimization of the detection conditions, the metal oxide sensors are successfully applied for detection of increasing concentrations of viable E. coli, with detection of less than 103 cfu mL−1 in undiluted culture medium in just 5 h.Authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (Project CTQ2014-54553-C3-1-R), and from European Union (Project ENIAC-ED-52 v161210). E.B. is supported by the Miguel Servet Program, funded by the Fondo de Investigaciones Sanitarias of the Instituto de Salud Carlos III (Grant CP13/00052) and co-financed by the European Regional Development Fund (ERDF). This work was partially financially supported by Government of Russian Federation, Grant 074-U01.Peer reviewe

Barriers to Physical Activity for Women with Physical Disabilities: A Systematic Review

Physical activity is essential for women with physical disabilities. This review aims to identify the barriers they face in practicing sport. A systematic review was conducted using the PubMed/Medline, Scopus, and Web of Science databases in January 2023, with an update in March 2023. The eligibility criteria used for inclusion were as follows. (i) Women with physical disabilities; (ii) women who engage in or want to engage in physical activities and/or sport, both adapted and non-adapted; (iii) identification of women’s barriers to such practice; (iv) research articles; and (v) papers written in English and published in peer-reviewed journals. The exclusion were as follows. (i) Women with illness, injury or transient physical activity difficulties; (ii) mention of rehabilitative physical activity; and (iii) results showing no differentiation in barrier types by gender. This review identified different barriers, grouped into eight types according to the differentiating factor, thus showing that disable people’s participation in physical activity is directly related to some specific barriers which seem to differ according to their gender. Therefore, the success of participation in physical activities depends not only on the user’s concern, but also on an inclusive social environment

Current and near-future technologies for antibiotic susceptibility testing and resistant bacteria detection

The emergence and spread of bacterial resistances to antibiotics is now leading to the antibiotic crisis. This is driven by the antibiotic misuse and disabuse, rendered possible due to the absence of fast and accurate technologies for antibiotic screening and resistant bacteria identification in infectious diseases. Technologies that provide sensitive, quick and easy read-outs, conveying information about the optimal treatment are required. A multitude of these tests is readily available on the market, with many more being developed. However, current methods have their shortcomings. An in depth study overview and analysis of the field, with a deep focus on the current market, will serve as a guideline for the future emerging technologies involving susceptibility testing and antibiotic resistance evaluation. From such a dynamic and growing field, the current review provides a critical discussion on how the susceptibility-testing field is developing and where it is going.This work was supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 675412 (ND4ID project). N. U. and X. M.-B. also acknowledge SMARTECOPONICS project financed under the ERA-NET Cofund WaterWorks 2015 Call (this ERA-NET is an integral part of the 2016 Joint Activities developed by the Water Challenges for a Changing World Joint Programme Initiative, Water JPI). We gratefully acknowledge the financial support from the Ministry of Science, Innovation and Universities Spain (QS4CF, RTI2018-096278-B-C21) and to the Marató TV3 Foundation (QS-Motion, TV32018-201825-30-31).Peer reviewe

Fast determination of viable bacterial cells in milk samples using impedimetric sensor and a novel calibration method

As a first stage toward the development of an impedimetric biosensor to quantify viable bacterial cells, this work defines the relationships between microbial growth and impedance changes associated with acidification of the culture medium. Escherichia coli bacterium was used as a model of a common pathogenic bacterium found in a foodstuff. Impedance was measured at a fix frequency of 10 kHz using interdigitated microelectrodes. Impedance changes were found to depend on the number of microorganisms in a sample. However, as the kinetics greatly depends on the bacterial concentration, it was not possible to obtain a single calibration curve in a wide concentration range at a fixed incubation time. To resolve this, a novel calibration method was proposed by measuring the sensor response at 270 and 390 min of incubation and taking a mean value. Obtained calibration plots were used to determine E. coli in a spiked milk samples. Performed experiments demonstrated the capacity of the method to detect E.coli concentrations in a range between 102 and 106 cfu mL−1 in milk in only 6 hours with 5–12% error margin.Authors acknowledge financial support from Spanish Ministry of Economy and Competitiveness (project CTQ2014-54553-C3-1-R) and European Union (project ENIAC-ED-52 v161210). This work was partially financially supported by Government of Russian Federation, Grant 074-U01.Peer reviewe

Porta-filtros integrado y procedimiento de concentración y detección de microorganismos

[EN] An integrated filter-holder that enables a target microorganism in a fluid to be concentrated by filtering the fluid and culturing the target mechanism to enable the detection thereof. The filter-holder comprises a top piece (1), an intermediate piece (5) and a bottom piece (4) joined together. A filtration membrane is arranged on the intermediate piece (5) and a reaction chamber (6) is provided over the former for the culture of the microorganism trapped in the filtration membrane when the sample is filtered. The filtration membrane is kept inside the device during the entire concentration and detection method. The invention also relates to the method for the concentration and detection of microorganisms using a filter-holder such as the one described above.[ES] Porta-filtros integrado que permite realizar la concentración de un microorganismo diana de un fluido mediante filtrado de dicho fluido y un cultivo de dicho mecanismo diana para permitir su detección. El porta-filtros comprende una pieza superior (1), una pieza intermedia (5) y una pieza inferior (4) unidas entre sí. En la pieza intermedia (5) se dispone una membrana de filtrado y sobre ésta una cámara de reacción (6)en la que se realiza el cultivo del microorganismo atrapado en la membrana de filtrado al filtrar la muestra. La membrana de filtrado se mantiene en el interior del dispositivo durante todo el procedimiento de concentración y detección. Es también un objeto de la invención el procedimiento de concentración y detección de microorganismos en un porta-filtros como el descrito.Peer reviewedConsejo Superior de Investigaciones Científicas (España), Institut D'Investigació Germans Trias i Pujol, Centro de Investigación Biomédica en Red (CIBER), Universitat Autónoma de BarcelonaA1 Solicitud de patente con informe sobre el estado de la técnic