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27 pages, 10272 KB

Open AccessArticle

The Dynamics of Soil Mesofauna Communities in a Tropical Urban Coastal Wetland: Responses to Spatiotemporal Fluctuations in Phreatic Level and Salinity

by Gloria Ortiz-Ramírez, Elix Hernández, Solimar Pinto-Pacheco and Elvira Cuevas

Arthropoda 2024, 2(1), 1-27; https://doi.org/10.3390/arthropoda2010001 - 9 Jan 2024

Viewed by 2943

Abstract

Coastal wetlands, vital for ecological diversity, have been significantly altered by anthropogenic activities, particularly in the Caribbean. These changes have created a complex mosaic of habitats and physicochemical conditions, further stressed by climate variability and sea-level rise. This study, conducted in Las Cucharillas [...] Read more.

Coastal wetlands, vital for ecological diversity, have been significantly altered by anthropogenic activities, particularly in the Caribbean. These changes have created a complex mosaic of habitats and physicochemical conditions, further stressed by climate variability and sea-level rise. This study, conducted in Las Cucharillas Natural Reserve, a tropical urban coastal wetland in Puerto Rico, aimed to determine the effects of spatiotemporal variations in phreatic levels and salinity on soil mesofauna assemblages, crucial bio-indicators of environmental change. In 2020 and 2021, soil samples were collected from five diverse habitat types during different hydroperiods. Each sample was taken under four randomly selected plant types and processed using lighted Tullgren–Berlese extractors. Phreatic level and salinity were also measured. A total of 43 families were quantified, underscoring distinct habitat differences, similarities, and overall ecosystem diversity. Moderate correlations between phreatic levels, salinity, and mesofauna richness and abundance were determined. Peak richness and abundance were quantified at shallow (−0.03 to −0.07 m) and slightly moderate (−0.12 to −0.17 m) phreatic levels where oligohaline salinity (>0.5 to 5.0 ppt) prevails. The study highlights the adaptability of mesofauna to environmental shifts and their potential as biosensors for effective coastal wetland management amid climatic and anthropogenic pressures. Full article

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13 pages, 815 KB

Open AccessArticle

Label Free Detection of L-Glutamate Using Microfluidic Based Thermal Biosensor

by Varun Lingaiah Kopparthy, Siva Mahesh Tangutooru and Eric J. Guilbeau

Bioengineering 2015, 2(1), 2-14; https://doi.org/10.3390/bioengineering2010002 - 12 Jan 2015

Cited by 16 | Viewed by 8043

Abstract

A thermoelectric biosensor for the detection of L-glutamate concentration was developed. The thermoelectric sensor is integrated into a micro-calorimeter which measures the heat produced by biochemical reactions. The device contains a single flow channel that is 120 µm high and 10 mm wide [...] Read more.

A thermoelectric biosensor for the detection of L-glutamate concentration was developed. The thermoelectric sensor is integrated into a micro-calorimeter which measures the heat produced by biochemical reactions. The device contains a single flow channel that is 120 µm high and 10 mm wide with two fluid inlets and one fluid outlet. An antimony-bismuth (Sb-Bi) thermopile with high common mode rejection ratio is attached to the lower channel wall and measures the dynamic changes in the temperature when L-glutamate undergoes oxidative deamination in the presence of glutamate oxidase (GLOD). The thermopile has a Seebeck coefficient of ~7 µV·(m·K)⁻¹. The device geometry, together with hydrodynamic focusing, eliminates the need of extensive temperature control. Layer-by-layer assembly is used to immobilize GLOD on the surface of glass coverslips by alternate electrostatic adsorption of polyelectrolyte and GLOD. The impulse injection mode using a 6-port injection valve minimizes sample volume to 5 µL. The sensitivity of the sensor for glutamate is 17.9 nVs·mM⁻¹ in the linear range of 0–54 mM with an R² value of 0.9873. The lowest detection limit of the sensor for glutamate is 5.3 mM. Full article

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17 pages, 717 KB

Open AccessArticle

Ink-Jet Printing of Gluconobacter oxydans: Micropatterned Coatings As High Surface-to-Volume Ratio Bio-Reactive Coatings

by Marcello Fidaleo, Nadia Bortone, Mark Schulte and Michael C. Flickinger

Coatings 2014, 4(1), 1-17; https://doi.org/10.3390/coatings4010001 - 19 Dec 2013

Cited by 10 | Viewed by 8020

Abstract

We formulated a latex ink for ink-jet deposition of viable Gram-negative bacterium Gluconobacter oxydans as a model adhesive, thin, highly bio-reactive microstructured microbial coating. Control of G. oxydans latex-based ink viscosity by dilution with water allowed ink-jet piezoelectric droplet deposition of 30 × [...] Read more.

We formulated a latex ink for ink-jet deposition of viable Gram-negative bacterium Gluconobacter oxydans as a model adhesive, thin, highly bio-reactive microstructured microbial coating. Control of G. oxydans latex-based ink viscosity by dilution with water allowed ink-jet piezoelectric droplet deposition of 30 × 30 arrays of two or three droplets/dot microstructures on a polyester substrate. Profilometry analysis was used to study the resulting dry microstructures. Arrays of individual dots with base diameters of ~233–241 µm were obtained. Ring-shaped dots with dot edges higher than the center, 2.2 and 0.9 µm respectively, were obtained when a one-to-four diluted ink was used. With a less diluted ink (one-to-two diluted), the microstructure became more uniform with an average height of 3.0 µm, but the ink-jet printability was more difficult. Reactivity of the ink-jet deposited microstructures following drying and rehydration was studied in a non-growth medium by oxidation of 50 g/L D-sorbitol to L-sorbose, and a high dot volumetric reaction rate was measured (~435 g·L⁻¹·h⁻¹). These results indicate that latex ink microstructures generated by ink-jet printing may hold considerable potential for 3D fabrication of high surface-to-volume ratio biocoatings for use as microbial biosensors with the aim of coating microbes as reactive biosensors on electronic devices and circuit chips. Full article

(This article belongs to the Special Issue Advancing Coatings with Biotechnology)

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23 pages, 626 KB

Open AccessArticle

Testing a Microarray to Detect and Monitor Toxic Microalgae in Arcachon Bay in France

by Jessica U. Kegel, Yolanda Del Amo, Laurence Costes and Linda K. Medlin

Microarrays 2013, 2(1), 1-23; https://doi.org/10.3390/microarrays2010001 - 5 Mar 2013

Cited by 22 | Viewed by 8125

Abstract

Harmful algal blooms (HABs) occur worldwide, causing health problems and economic damages to fisheries and tourism. Monitoring agencies are therefore essential, yet monitoring is based only on time-consuming light microscopy, a level at which a correct identification can be limited by insufficient morphological [...] Read more.

Harmful algal blooms (HABs) occur worldwide, causing health problems and economic damages to fisheries and tourism. Monitoring agencies are therefore essential, yet monitoring is based only on time-consuming light microscopy, a level at which a correct identification can be limited by insufficient morphological characters. The project MIDTAL (Microarray Detection of Toxic Algae)—an FP7-funded EU project—used rRNA genes (SSU and LSU) as a target on microarrays to identify toxic species. Furthermore, toxins were detected with a newly developed multiplex optical Surface Plasmon Resonance biosensor (Multi SPR) and compared with an enzyme-linked immunosorbent assay (ELISA). In this study, we demonstrate the latest generation of MIDTAL microarrays (version 3) and show the correlation between cell counts, detected toxin and microarray signals from field samples taken in Arcachon Bay in France in 2011. The MIDTAL microarray always detected more potentially toxic species than those detected by microscopic counts. The toxin detection was even more sensitive than both methods. Because of the universal nature of both toxin and species microarrays, they can be used to detect invasive species. Nevertheless, the MIDTAL microarray is not completely universal: first, because not all toxic species are on the chip, and second, because invasive species, such as Ostreopsis, already influence European coasts. Full article

(This article belongs to the Special Issue Feature Papers)

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17 pages, 974 KB

Open AccessArticle

Application of Paper-Supported Printed Gold Electrodes for Impedimetric Immunosensor Development

by Petri Ihalainen, Himadri Majumdar, Tapani Viitala, Björn Törngren, Tuomas Närjeoja, Anni Määttänen, Jawad Sarfraz, Harri Härmä, Marjo Yliperttula, Ronald Österbacka and Jouko Peltonen

Biosensors 2013, 3(1), 1-17; https://doi.org/10.3390/bios3010001 - 27 Dec 2012

Cited by 36 | Viewed by 13199

Abstract

In this article, we report on the formation and mode-of-operation of an affinity biosensor, where alternate layers of biotin/streptavidin/biotinylated-CRP-antigen/anti-CRP antibody are grown on printed gold electrodes on disposable paper-substrates. We have successfully demonstrated and detected the formation of consecutive layers of supra-molecular protein [...] Read more.

In this article, we report on the formation and mode-of-operation of an affinity biosensor, where alternate layers of biotin/streptavidin/biotinylated-CRP-antigen/anti-CRP antibody are grown on printed gold electrodes on disposable paper-substrates. We have successfully demonstrated and detected the formation of consecutive layers of supra-molecular protein assembly using an electrical (impedimetric) technique. The formation process is also supplemented and verified using conventional surface plasmon resonance (SPR) measurements and surface sensitive characterization techniques, such as X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The article provides a possible biosensor development scheme, where—(1) fabrication of paper substrate (2) synthesis of gold nanoparticle inks (3) inkjet printing of gold electrodes on paper (4) formation of the biorecognition layers on the gold electrodes and (5) electrical (impedimetric) analysis of growth—all are coupled together to form a test-structure for a recyclable and inexpensive point-of-care diagnostic platform. Full article

(This article belongs to the Special Issue Organic Electronic Bio-Devices)

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14 pages, 291 KB

Open AccessReview

Graphene and Other Nanomaterial-Based Electrochemical Aptasensors

by Frank J. Hernandez and Veli Cengiz Ozalp

Biosensors 2012, 2(1), 1-14; https://doi.org/10.3390/bios2010001 - 13 Jan 2012

Cited by 70 | Viewed by 16200

Abstract

Electrochemical aptasensors, which are based on the specificity of aptamer-target recognition, with electrochemical transduction for analytical purposes have received particular attention due to their high sensitivity and selectivity, simple instrumentation, as well as low production cost. Aptamers are functional nucleic acids with specific [...] Read more.

Electrochemical aptasensors, which are based on the specificity of aptamer-target recognition, with electrochemical transduction for analytical purposes have received particular attention due to their high sensitivity and selectivity, simple instrumentation, as well as low production cost. Aptamers are functional nucleic acids with specific and high affinity to their targets, similar to antibodies. However, they are completely selected in vitro in contrast to antibodies. Due to their stability, easy chemical modifications and proneness to nanostructured device construction, aptamer-based sensors have been incorporated in a variety of applications including electrochemical sensing devices. In recent years, the performance of aptasensors has been augmented by incorporating novel nanomaterials in the preparation of better electrochemical sensors. In this review, we summarize the recent trends in the use of nanomaterials for developing electrochemical aptasensors. Full article

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3 pages, 24 KB

Open AccessEditorial

Welcome to Biosensors: A New Open-Access Journal

by Jeffrey D. Newman

Biosensors 2011, 1(1), 1-3; https://doi.org/10.3390/bios1010001 - 19 Jan 2011

Viewed by 5807

Abstract

The journal Biosensors has been started as a peer-reviewed, open access journal. As editors, we believe that it will fulfill an important role in the community of researchers and developers in the field of biosensors. The addition of a “free access” journal to [...] Read more.

The journal Biosensors has been started as a peer-reviewed, open access journal. As editors, we believe that it will fulfill an important role in the community of researchers and developers in the field of biosensors. The addition of a “free access” journal to the existing, high quality publications in this field is something that we believe is very important in a field which is now so entwined with commercial activity and where researchers aim, not only at academic research, but on the development of products at a potentially massive scale. For these researchers, it is important that they can publish their results in a journal that guarantees quality that comes from peer-review, but that at the same time breaks the traditional boundaries of academic journals which need a subscription or a pay-per-view option to access the published data. [...] Full article

36 pages, 1032 KB

Open AccessReview

Negative Refractive Index Metasurfaces for Enhanced Biosensing

by Zoran Jakšić, Slobodan Vuković, Jovan Matovic and Dragan Tanasković

Materials 2011, 4(1), 1-36; https://doi.org/10.3390/ma4010001 - 23 Dec 2010

Cited by 109 | Viewed by 16867

Abstract

In this paper we review some metasurfaces with negative values of effective refractive index, as scaffolds for a new generation of surface plasmon polariton-based biological or chemical sensors. The electromagnetic properties of a metasurface may be tuned by its full immersion into analyte, [...] Read more.

In this paper we review some metasurfaces with negative values of effective refractive index, as scaffolds for a new generation of surface plasmon polariton-based biological or chemical sensors. The electromagnetic properties of a metasurface may be tuned by its full immersion into analyte, or by the adsorption of a thin layer on it, both of which change its properties as a plasmonic guide. We consider various simple forms of plasmonic crystals suitable for this purpose. We start with the basic case of a freestanding, electromagnetically symmetrical plasmonic slab and analyze different ultrathin, multilayer structures, to finally consider some two-dimensional “wallpaper” geometries like split ring resonator arrays and fishnet structures. A part of the text is dedicated to the possibility of multifunctionalization where a metasurface structure is simultaneously utilized both for sensing and for selectivity enhancement. Finally we give an overview of surface-bound intrinsic electromagnetic noise phenomena that limits the ultimate performance of a metasurfaces sensor. Full article

(This article belongs to the Special Issue Next Wave of Metamaterials)

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13 pages, 1271 KB

Open AccessReview

Biosensor Recognition Elements

by James P. Chambers, Bernard P. Arulanandam, Leann L. Matta, Alex Weis and James J. Valdes

Curr. Issues Mol. Biol. 2008, 10(1-2), 1-12; https://doi.org/10.21775/cimb.010.001 - 6 Jun 2008

Cited by 9 | Viewed by 1713

Abstract

Molecular recognition is central to biosensing. [...] Full article

10 pages, 215 KB

Open AccessArticle

Voltammetric Detection of Antioxidative Properties of Flavonoids Using Electrically Heated DNA Modified Carbon Paste Electrode

by O. Korbut, M. Bučková, J. Labuda and P. Gründler

Sensors 2003, 3(1), 1-10; https://doi.org/10.3390/s30100001 - 24 Jan 2003

Cited by 46 | Viewed by 14546

Abstract

A simple electrochemical sensor consisting of electrically heated carbon paste electrode with the surface modified by dsDNA is used to characterize voltammetric behaviour and antioxidative activity of four selected flavonoids. Quercetin, rutin, catechin and epigallocatechin gallate accumulate within the DNA layer. A positive [...] Read more.

A simple electrochemical sensor consisting of electrically heated carbon paste electrode with the surface modified by dsDNA is used to characterize voltammetric behaviour and antioxidative activity of four selected flavonoids. Quercetin, rutin, catechin and epigallocatechin gallate accumulate within the DNA layer. A positive effect of the electrode temperature within the range of 20 to 38 ºC on the detection of a deep DNA degradation by a copper(II)/H₂O₂/ascorbic acid cleavage mixture as well as an antioxidative effect of flavonoids was evaluated. Full article

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10 pages, 140 KB

Open AccessArticle

Detection of Antioxidative Activity of Plant Extracts at the DNA-Modified Screen-Printed Electrode

by J. Labuda, M. Bučková, L. Heilerová, A. Čaniová-Žiaková, E. Brandšteterová, J. Mattusch and R. Wennrich

Sensors 2002, 2(1), 1-10; https://doi.org/10.3390/s20100001 - 15 Jan 2002

Cited by 36 | Viewed by 13655

Abstract

A simple procedure for the voltammetric detection of antioxidative activity of plant extracts based on the protection from DNA damage at the electrode surface is reported. A disposable electrochemical DNA biosensor fabricated as a carbon-based screen-printed electrode modified by a surface layer of [...] Read more.

A simple procedure for the voltammetric detection of antioxidative activity of plant extracts based on the protection from DNA damage at the electrode surface is reported. A disposable electrochemical DNA biosensor fabricated as a carbon-based screen-printed electrode modified by a surface layer of the calf thymus double stranded (ds) DNA was used as a working electrode in combination with a silver/silver chloride reference electrode and a separate platinum auxiliary electrode. The [Co(phen)₃]³⁺ ion served as the dsDNA redox marker and the [Fe(EDTA)]- complex with hydrogen peroxide under the electrochemical reduction of the iron atom were used as the DNA cleavage mixture. A remarkable antioxidative activity of phenolic antioxidants such as rosmarinic and caffeic acids as standards and the extracts of lemon balm, oregano, thyme and agrimony was found which is quite in agreement with an antiradical activity determined spectrophotometrically using 2,2’-diphenyl-1-picrylhydrazyl (DPPH) radical. Full article

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