Beatriz Prieto-Simón

University of South Australia, Tarndarnya, South Australia, Australia

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Publications (40)173.77 Total impact

  • Xavier Cetó · Nicolas H. Voelcker · Beatriz Prieto-Simón
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    ABSTRACT: Over the last years, there has been an increasing demand for fast, highly sensitive and selective methods of analysis to meet new challenges in environmental monitoring, food safety and public health. In response to this demand, biosensors have arisen as a promising tool, which offers accurate chemical data in a timely and cost-effective manner. However, the difficulty to obtain sensors with appropriate selectivity and sensitivity for a given analyte, and to solve analytical problems which do not require the quantification of a certain analyte, but an overall effect on a biological system (e.g. toxicity, quality indices, provenance, freshness, etc.), led to the concept of electronic tongues as a new strategy to tackle these problems.
    No preview · Article · May 2016 · Biosensors & Bioelectronics
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    ABSTRACT: Bacterial wound infections can cause septicemia and lead to limb amputation or death. Therefore, early detection of bacteria is important in chronic wound management. Here, an optical biosensor based on porous silicon resonant microcavity (pSiRM) structure modified with fluorogenic peptide substrate is demonstrated to detect the presence of Sortase A (SrtA), a bacterial enzyme found in the cell membrane protein of Staphylococcus aureus. The combination of fluorescence enhancement effects of the pSiRM architecture with the incorporation of SrtA fluorogenic peptide substrate within the pSi matrix enables the sensing of SrtA with an outstanding limit of detection of 8 × 10−14m. Modification of the pSiRM structure with microscale spots of two fluorogenic peptide substrates, one specific for SrtA and the other for matrix metalloproteinases, effectively demonstrates the feasibility to perform multiplexed biomarker analysis. The results in this study highlight the potential of the pSiRM sensing platform as a point-of-care diagnostic tool for biomarkers of bacterial wound infection.
    No preview · Article · Feb 2016
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    ABSTRACT: A proof of concept for the label-free detection of bacteriophage MS2, a model indicator of microbiological contamination, is validated in this work as a porous silicon (pSi) membrane-based electrochemical biosensor. PSi membranes were used to afford nanochannel architectures. The sensing mechanism was based on the nanochannel blockage caused by MS2 binding to immobilized capture antibodies. This blockage was quantified by measuring the oxidation current of the electroactive species reaching the electrode surface, by means of differential pulse voltammetry (DPV). The immunosensor showed a limit of detection of 6 pfu/mL in buffer, allowing the detection of MS2 to levels commonly found in real-world applications, and proved to be unaffected by matrix effects when analyzing MS2 in river water. By choosing the proper functionalization strategy and nanochannels diameter, this platform affords the possibility to simply, directly and sensitively detect a broad range of target analytes, being a promising approach towards the development of point-of-care portable electronic devices.
    No preview · Article · Jan 2016 · Biosensors & Bioelectronics
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    ABSTRACT: We demonstrate microwave-induced heating of gold nanoparticles and nanorods. An appreciably higher and concentration-dependent microwave-induced heating rate was observed with aqueous dispersions of the nanomaterials as opposed to pure water and other controls. Grafted with the thermo-responsive polymer poly(N-isopropylacrylamide), these gold nanomaterials react to microwave-induced heating with a conformational change in the polymer shell, leading to particle aggregation. We subsequently covalently immobilize concanavalin A (Con A) on the thermo-responsive gold nanoparticles. Con A is a bio-receptor commonly used in bacterial sensors due to its affinity for carbohydrates on bacterial cell surfaces. The microwave-induced thermal transitions of the polymer reversibly switch on and off the display of Con A on the particle surface and hence the interactions of the nanomaterials with carbohydrate-functionalized surfaces. This effect was determined using linear sweep voltammetry on a methyl-α-D-mannopyranoside functionalized electrode.
    No preview · Article · Dec 2015 · ACS Applied Materials & Interfaces
  • Sandra Leonardo · Beatriz Prieto-Simón · Mònica Campàs
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    ABSTRACT: Diatoms possess natural nanostructures and unique properties of great interest in nanotechnological applications. Among them, their use as nanostructured supports in biosensing platforms, although still in its childhood, is promising. Herein, the works focused on the immobilisation of diatom frustules, the modification of their composition and chemical features, and their functionalisation with biomolecules, are reviewed. The preservation of the three-dimensional nanostructure is almost always pursued and thus, processes are carried out under strict control. Additionally, high immobilisation yields, appropriate spatial distributions, modification or coating with specific components and oriented immobilisation of biomolecules, are also sought. The biocompatibility of diatom frustules, together with the nanofeatures, and the wide variety of processing methods, indicate that their exploitation in biosensing is imminent.
    No preview · Article · Dec 2015 · TrAC Trends in Analytical Chemistry
  • Laia Reverté · Beatriz Prieto-Simón · Mònica Campàs
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    ABSTRACT: The use of nanotechnology in bioanalytical devices has special advantages in the detection of toxins of interest in food safety and environmental applications. The low levels to be detected and the small size of toxins justify the increasing number of publications dealing with electrochemical biosensors, due to their high sensitivity and design versatility. The incorporation of nanomaterials in their development has been exploited to further increase their sensitivity, providing simple and fast devices, with multiplexed capabilities. This paper gives an overview of the electrochemical biosensors that have incorporated carbon and metal nanomaterials in their configurations for the detection of toxins. Biosensing systems based on magnetic beads or integrated into microfluidics systems have also been considered because of their contribution to the development of compact analytical devices. The roles of these materials, the methods used for their incorporation in the biosensor configurations as well as the advantages they provide to the analyses are summarised.
    No preview · Article · Dec 2015 · Analytica chimica acta
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    ABSTRACT: Here we describe a label-free electrochemical DNA sensor based on poly(3,4-ethylenedioxythiophene)-modified (PEDOT-modified) electrodes. An acetylene-terminated DNA probe, complementary to a specific "Hepatitis C" virus sequence, was immobilized onto azido-derivatized conducting PEDOT electrodes using "click" chemistry. DNA hybridization was then detected by differential pulse voltammetry, evaluating the changes in the electrochemical properties of the polymer produced by the recognition event. A limit of detection of 0.13nM was achieved using this highly selective PEDOT-based genosensor, without the need for labeling techniques or microelectrode fabrication processes. These results are promising for the development of label-free and reagentless DNA hybridization sensors based on conducting polymeric substrates. Biosensors can be easily prepared using any DNA sequence containing an alkyne moiety. The data presented here reveal the potential of this DNA sensor for diagnostic applications in the screening of diseases, such as "Hepatitis C", and genetic mutations. Copyright © 2015 Elsevier B.V. All rights reserved.
    Full-text · Article · Jul 2015 · Biosensors & Bioelectronics
  • S N Aisyiyah Jenie · Beatriz Prieto-Simon · Nicolas H Voelcker
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    ABSTRACT: The up-regulation of l-lactate dehydrogenase (LDH), an intracellular enzyme present in most of all body tissues, is indicative of several pathological conditions and cellular death. Herein, we demonstrate LDH detection using porous silicon (pSi) microcavities as a luminescence-enhancing optical biosensing platform. Non-fluorescent resazurin was covalently attached onto the pSi surface via thermal hydrocarbonisation, thermal hydrosylilation and acylation. Each surface modification step was confirmed by means of FTIR and the optical shifts of the resonance wavelength of the microcavity. Thermal hydrocarbonisation also afforded excellent surface stability, ensuring that the resazurin was not reduced on the pSi surface. Using a pSi microcavity biosensor, the fluorescence signal upon detection of LDH was amplified by 10 and 5-fold compared to that of a single layer and a detuned microcavity, respectively, giving a limit of detection of 0.08U/ml. The biosensor showed a linear response between 0.16 and 6.5U/ml, covering the concentration range of LDH in normal as well as damaged tissues. The biosensor was selective for LDH and did not produce a signal upon incubation with another NAD-dependant enzyme l-glutamic dehydrogenase. The use of the pSi microcavity as a sensing platform reduced reagent usage by 30% and analysis time threefold compared to the standard LDH assay in solution. Copyright © 2015 Elsevier B.V. All rights reserved.
    No preview · Article · Jul 2015 · Biosensors & Bioelectronics
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    ABSTRACT: We report a versatile particle-based route to dense arrays of parallel submicron pores with high aspect ratio in silicon, and explore the application of these arrays in sensors, optics, and polymer micropatterning. Polystyrene (PS) spheres are convectively assembled on gold-coated silicon wafers and sputter-etched, resulting in well-defined gold disc arrays with excellent long-range order. The gold discs act as catalysts in Metal-Assisted Chemical Etching (MACE), yielding uniform pores with straight walls, flat bottoms and high aspect ratio. The resulting pore arrays can be used as robust antireflective surfaces, in biosensing applications, and as templates for polymer replica molding.
    Full-text · Article · Dec 2014 · ACS Applied Materials & Interfaces
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    ABSTRACT: Immunosensors are devices that exploit immobilized antibodies to promote the binding of specific analytes related to diseases of medical importance, such as cancer or cardiac dysfunctions. Label-free immunosensors have an important role, due to their simplicity and fast read-out. Here, the proof of concept for an immunosensor based on a 2-D photonic crystal silicon nitride membrane is presented. The device has been fabricated by means of a well-tuned nanofabrication protocol, achieving a high-quality photonic pattern on a large-area membrane (1 mm × 1 mm), and it has been tested for the detection of interleukin-6, getting protein detection at pg/mL concentrations.
    Full-text · Article · Dec 2014 · IEEE Photonics Journal
  • B Prieto-Simón · N M Bandaru · C Saint · N H Voelcker
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    ABSTRACT: The use of carbon nanotubes (CNTs) as building blocks in the design of electrochemical biosensors has been attracting attention over the last few years, mainly due to their high electrical conductivity and large surface area. Here, we present two approaches based on tailored single-walled CNTs (SWCNTs) architectures to develop immunosensors for the bacteriophage MS2, a virus often detected in sewage-impacted water supplies. In the first approach, SWCNTs were used in the bottom-up design of sensors as antibody immobilization support. Carboxy-functionalised SWCNTs were covalently tethered onto gold electrodes via carbodiimide coupling to cysteamine-modified gold electrodes. These SWCNTs were hydrazide functionalized by electrochemical grafting of diazonium salts. Site-oriented immobilization of antibodies was then carried out through hydrazone bond formation. Results showed microarray electrode behavior, greatly improving the signal-to-noise ratio. Excellent sensitivity and limit of detection (9.3pfu/mL and 9.8pfu/mL in buffer and in river water, respectively) were achieved, due to the combination of the SWCNTs' ability to promote electron transfer reactions with electroactive species at low overpotentials and their high surface-to-volume ratio providing a favorable environment to immobilize biomolecules. In the second approach, SWCNTs were decorated with iron oxide nanoparticles. Diazonium salts were electrochemically grafted on iron-oxide-nanoparticle-decorated SWCNTs to functionalize them with hydrazide groups that facilitate site-directed immobilization of antibodies via hydrazone coupling. These magnetic immunocarriers facilitated MS2 separation and concentration on an electrode surface. This approach minimized non-specific adsorptions and matrix effects and allowed low limits of detection (12pfu/mL and 39pfu/mL in buffer and in river water, respectively) that could be further decreased by incubating the magnetic immunocarriers with larger volumes of sample. Significantly, both approaches permitted the detection of MS2 to levels regularly encountered in sewage-impacted environments.
    No preview · Article · Oct 2014 · Biosensors & Bioelectronics
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    ABSTRACT: Here we describe the fabrication of a highly sensitive and label-free ITO-based impedimetric immunosensor for the detection of pathogenic bacteria Escherichia coli O157:H7. Anti-E. coli antibodies were immobilized onto ITO electrodes using a simple, robust and direct methodology. First, the covalent attachment of epoxysilane on the ITO surface was demonstrated by Atomic Force Microscopy and cyclic voltammetry. The immobilization of antibody on the epoxysilane layer was quantified by Optical Waveguide Lightmode Spectroscopy, obtaining a mass variation of 12ngcm(-2) (0.08pmolcm(-2)). Microcontact printing and fluorescence microscopy were used to demonstrate the specific binding of E. coli O157:H7 to the antibody-patterned surface. We achieved a ratio of 1:500 Salmonella typhimurium/E. coli O157:H7, thus confirming the selectivity of the antibodies and efficiency of the functionalization procedure. Finally, the detection capacity of the ITO-based immunosensor was evaluated by Electrochemical Impedance Spectroscopy. A very low limit of detection was obtained (1CFUmL(-1)) over a large linear working range (10-10(6)CFUmL(-1)). The specificity of the impedimetric immunosensor was also examined. Less than 20% of non-specific bacteria (S. typhimurium and E. coli K12) was observed. Our results reveal the applicability of ITO for the development of highly sensitive and selective impedimetric immunosensors. Copyright © 2014 Elsevier B.V. All rights reserved.
    No preview · Article · Sep 2014 · Bioelectrochemistry
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    ABSTRACT: In this work, protein phosphatase inhibition assays (PPIAs) have been used to evaluate the performance of recombinant PP1 and recombinant and wild-type PP2As. The enzymes have been compared using microcystins-LR (MC-LR) as a model cyanotoxin. Whereas PP2ARec provides a limit of detection (LOD) of 3.1 μg/L, PP1Rec and PP2AWild provide LODs of 0.6 and 0.5 μg/L, respectively, lower than the guideline value proposed by the World Health Organization (1 μg/L). The inhibitory potencies of seven MC variants (-LR, -RR, -dmLR, -YR, -LY, -LW and -LF) have been evaluated, resulting on 50 % inhibition coefficient (IC50) values ranging from 1.4 to 359.3 μg/L depending on the MC variant and the PP. The PPIAs have been applied to the determination of MC equivalent contents in a natural cyanobacterial bloom and an artificially contaminated sample, with multi-MC profiles. The inhibition equivalency factors (IEFs) have been applied to the individual MC quantifications determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and the estimated MC-LR equivalent content has been compared to PPIA results. PPIAs have demonstrated to be applicable as MC screening tools for environmental applications and to protect human and animal health.
    No preview · Article · Sep 2014 · Environmental Science and Pollution Research
  • Núria Serrano · Beatriz Prieto-Simón · Xavier Cetó · Manel del Valle
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    ABSTRACT: This paper reports the development of three peptide modified sensors in which glutathione (GSH) and its fragments Cys-Gly and γ-Glu-Cys were immobilized respectively through aryl diazonium electrochemical grafting onto the surface of graphite-epoxy composite electrodes (GEC), and used for the simultaneous determination of Cd(II), Pb(II) and Zn(II). The concentration interval ranged from 0.1 to 1.5 μmol L-1 for each metal, and the technique used was differential pulse adsorptive stripping voltammetry. This study aimed to the comparison of the information provided by one single modified electrode at both fixed and multiple pH values (pH 6.8, 7.5 and 8.2) for the simultaneous determination of the three metals, with those supplied by the three-sensor array at multiple pH values. For the processing of the voltammograms, the fast Fourier transform was selected as the preprocessing tool for data compression coupled with an artificial neural network for the modeling of the obtained responses.
    No preview · Article · Jul 2014 · Talanta
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    ABSTRACT: The progress in medical field has provided fast remedies for the most of diseases affecting today's society. Now, the next step is to propose a fast way of diagnosis, avoiding long waiting time and expensive laboratory assays. Thanks to the recent research findings and progress in nano-technological fabrication techniques, new biosensors have been developed with the purpose to introduce portable and user-friendly instruments for medical analysis aimed to improve life quality and lower healthcare costs. In this work, we propose a proof-of-concept of an immunosensor based on a two-dimensional silicon nitride photonic crystal membrane able to efficiently detect the concentration of Interleukin-6 in a buffer solution.
    No preview · Conference Paper · May 2014
  • Beatriz Prieto-Simón · Josep Samitier
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    ABSTRACT: A novel sensing strategy for electrochemical aptamer-based sensors is presented. Nucleic acid aptamers are considered alternatives to antibodies. However, some of their intrinsic properties, such as that they can undergo conformational changes during the binding of the target, can be used to design novel sensing strategies. Unlike other electrochemical "signal off" aptamer-based sensors, we report a strategy based on enzymatic inhibition. Our approach shows the feasibility to detect small molecules based on the aptamer conformational change induced by the target that leads to the inhibition of the enzyme used as label. Additionally, we prove the ability to regenerate the function of the aptasensor by simply applying a short potential pulse. As a proof-of-concept, the widely used aptamer for ochratoxin A (OTA) has been selected as a model. After self-assembling short oligonucleotides onto a gold electrode, complementary to the 3' end of the aptamer, hybridisation of the aptamer takes place. To investigate the mechanism induced by the OTA-binding, Surface Plasmon Resonance assays were performed, which confirmed the conformational switch of the aptamer rather than the aptamer displacement by dehybridisation from the DNA-modified sensor surface. The electrochemical sensor can successfully detect OTA in wine at the limits stipulated by the European Commission. Given its sensitivity, rapid and easy detection and regeneration, it can be envisaged as screening tool for OTA detection. Moreover, this sensing strategy has the potential to be applied to other aptamer-based biochemical assays for the detection of small molecules in the fields of food safety, environmental monitoring and medical diagnostics.
    No preview · Article · Dec 2013 · Analytical Chemistry
  • Beatriz Prieto-Simón · Christopher Saint · Nicolas H Voelcker
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    ABSTRACT: Appropriate site-directed chemistry is essential to maximise the performance of immunosensors. We present two new functionalisation strategies that preserve proper folding and binding potential of antibodies by forcing their oriented immobilisation. Both strategies are based on the formation of hydrazone bonds between aldehyde groups on the Fc moieties of periodate-oxidised antibodies and hydrazide groups on functionalised gold electrodes. Those hydrazide groups are introduced by electrografting of diazonium salts or by self-assembly of mono- and dithiolated hydrazide linkers, resulting in films with tailored functional groups and, thus, antibody distribution and spacing. Their barrier properties and permeability towards electroactive species are evaluated. To demonstrate the potential of these new functionalisation strategies, detection of bacteriophage MS2 is performed through either a direct assay using electrochemical impedance spectroscopy (EIS) or through a sandwich assay using differential pulse voltammetry (DPV). Diazonium and monothiolated self-assembled monolayers-modified electrodes enable the detection of less than 1 plaque forming unit (pfu)/mL in a direct EIS assay. However, non-specific adsorption renders measurements in river water samples difficult. In contrast, sandwich-assays on electrodes with electrografted diazonium salts and monothiolated self-assembled monolayers do not show significant matrix effects using river water samples, but the limits of detection are 108 times higher than those of the direct assay. Best results are achieved for immunosensors based on mixed monolayers of hydrazide and hydroxyl diothiolated linkers (15 pfu/mL). These new functionalisation techniques are facile to implement. They afford the possibility to tune surface composition and tailor the electrochemical properties of electrochemical sensors. These advantages should translate into broad interest in this type of surface chemistry for biosensor development.
    No preview · Article · Dec 2013 · Analytical Chemistry
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    Cheng Yang · Vasilica Lates · Beatriz Prieto-Simón · Jean-Louis Marty · Xiurong Yang
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    ABSTRACT: We report a new label-free colorimetric aptasensor based on DNAzyme-aptamer conjugate for rapid and high-throughput detection of Ochratoxin A (OTA, a possible human carcinogen, group 2B) in wine. Two oligonucleotides were designed for this detection. One is N1 for biorecognition, which includes two adjacent sequences: the OTA-specific aptamer sequence and the horseradish peroxidase (HRP)-mimicking DNAzyme sequence. The other is a blocking DNA (B2), which is partially complementary to a part of the OTA aptamer and partially complementary to a part of the DNAzyme. The existence of OTA reduces the hybridization between N1 and B2. Thus, the activity of the non-hybridized DNAzyme is linearly correlated with the concentration of OTA up to 30nM with a limit of detection of 4nM (3σ). Meanwhile, a double liquid-liquid extraction (LLE) method is accordingly developed to purify OTA from wine. Compared with the existing HPLC-FD or immunoassay methods, the proposed strategy presents the most appropriate balance between accuracy and facility, resulting in a considerable improvement of real-time quality control, and thereby, preventing chronic poisoning caused by OTA contained red wine.
    Full-text · Article · Nov 2013 · Talanta
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    ABSTRACT: Biosensors are devices able to reduce costs and time in biological assays. They are efficient and useful tools also in biochemical assays, providing high performance in sensitivity and selectivity of measurements. In this work, we developed a label-free biosensor based on a two-dimensional photonic crystal patterned on a large area silicon nitride membrane that operates in the visible spectrum for the detection of proteins. The biosensor has been preliminarily tested in solutions of different refractive index, showing as expected a shift of the resonance in the reflection spectrum.
    No preview · Conference Paper · May 2013
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    ABSTRACT: The presence of enterohemorrhagic Escherichia coli bacteria in food can cause serious foodborne disease outbreaks. Early detection and identification of these pathogens is extremely important for public health and safety. Here we present a highly sensitive label-free immunosensor for the detection of pathogenic E. coli O157:H7. Anti-E. coli antibodies were covalently immobilised onto gold electrodes via a self-assembled monolayer (SAM) of mercaptohexadecanoic acid and the pathogenic bacteria were detected by electrochemical impedance spectroscopy (EIS). Surface Plasmon Resonance (SPR) was used to monitor the antibody immobilisation protocol and antibody patterned surfaces were used to demonstrate the specificity of the antibody coated surfaces against the pathogenic bacteria. The immunosensor showed a very low limit of detection (2CFU/mL) and a large linear range (3×10-3×10(4)CFU/mL). Finally, the selectivity of the sensor was demonstrated and no significant adsorption of Salmonella typhimurium was observed.
    No preview · Article · Jan 2013 · Biosensors & Bioelectronics

Publication Stats

664 Citations
173.77 Total Impact Points

Institutions

  • 2013-2016
    • University of South Australia
      • Mawson Institute
      Tarndarnya, South Australia, Australia
  • 2014
    • Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN)
      Caesaraugusta, Aragon, Spain
  • 2006-2014
    • Autonomous University of Barcelona
      • Department of Chemistry
      Cerdanyola del Vallès, Catalonia, Spain
  • 2010-2013
    • IBEC Institute for Bioengineering of Catalonia
      Barcino, Catalonia, Spain
  • 2009-2012
    • Tokyo University of Technology
      • • School of Bioscience and Biotechnology
      • • School of Bionics
      Edo, Tōkyō, Japan
  • 2007-2010
    • Université de Perpignan
      • IMAgES Institute of Modelling and Analysis in Geo- Environment and Health
      Perpinyà, Languedoc-Roussillon, France
  • 2004
    • University of Ioannina
      • Department of Chemistry
      Yannina, Epirus, Greece