Application of Photocured Polymer Ion Selective Membranes for Solid-State Chemical Sensors

Application of conducting polymers with additional functional groups for a solid contact formation and photocurable membranes as sensitive elements of solid-state chemical sensors is discussed. Problems associated with application of UV-curable polymers for sensors are analyzed. A method of sensor fabrication using copolymerized conductive layer and sensitive membrane is presented and the proof of concept is confirmed by two examples of solid-contact electrodes for Ca ions and pH.Authors acknowledge financial support from Spanish Ministry of Economy and Competitiveness (projects IPT-2011-1055-900000 and CTQ2011-29163-C03-02).We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe

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

Impedimetric antimicrobial peptide-based sensor for the early detection of periodontopathogenic bacteria

Peri-implantitis, an inflammation caused by biofilm formation, constitutes a major cause of implant failure in dentistry. Thus, the detection of bacteria at the early steps of biofilm growth represents a powerful strategy to prevent implant-related infections. In this regard, antimicrobial peptides (AMPs) can be used as effective biological recognition elements to selectively detect the presence of bacteria. Thus, the aim of the present study was to combine the use of miniaturized and integrated impedimetric transducers and AMPs to obtain biosensors with high sensitivity to monitor bacterial colonization. Streptococcus sanguinis, which is one of the most prevalent strains in the onset of periodontal diseases, was used as a model of oral bacteria. To this end, a potent AMP derived from human lactoferrin was synthesized and covalently immobilized on interdigitated electrode arrays (IDEA). X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) were employed to optimize and characterize the method of immobilization. Noteworthy, the interaction of Streptococcus sanguinis with AMP-coated sensors provoked significant changes in the impedance spectra, which were univocally associated with the presence of bacteria, proving the feasibility of our method. In this regard, the developed biosensor permits to detect the presence of bacteria at concentrations starting from 101 colony forming units (CFU) mL-1 in KCl and from 102 CFU mL-1 in artificial saliva. Moreover, the system was devoid of cytotoxicity for human fibroblasts. These results indicate that the proposed approach can be effective in the detection of initial stages of biofilm formation, and may be useful in the early prevention and treatment of peri-implantitisPeer ReviewedPostprint (author's final draft

Sensor de determinación directa de la presencia de detergentes en una muestra

La presente invención describe un nuevo sensor impedimétrico tridimensional en el que los electrodos interdigitados comprenden dígitos altamente conductivos que están separados por una barrera de un material aislante, útil para la determinación directa de la presencia de residuos de detergentes en agua en los procesos de lavado y ciclos de aclarado. El sensor cambia su impedancia cuando capta la presencia de moléculas de detergente en una muestra debido al cambio que sufre el campo eléctrico cuyas líneas de campo parten de un dígito (2) hasta llegar al otro dígito (3) sobrepasando la barrera aislante (4).Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Encapsulación automatizada de sensores químicos de estado sólido empleando fotopolímeros que contienen resinas epoxi y poliuretanos acrilatos

Referencia OEPM: P9500646.-- Fecha de solicitud: 31/03/1995.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).Encapsulación automatizada de sensores químicos de estado sólido empleando fotopolímeros que contienen resinas epoxi y poliuretanos acrilatos (ver figura en archivo de texto adjunto). Es un procedimiento para la encapsulación de sensores químicos tipo ISFET mediante utilización de polímeros fotocurables, tipo epoxi y poliuretano acrilatos. De esta manera se consigue realizar el proceso de encapsulación en dos etapas automatizadas, una primera a nivel de oblea utilizando técnicas fotolitográficas y la segunda por dispensación automática en moldes. Aplicando esta técnica se evita la encapsulación manual de estos dispositivos, mientras que se consiguen obtener toda una serie de ventajas tales como rapidez de curado, fiabilidad y bajo coste, así como, un bajo consumo de energía. Aplicaciones en industrias de sensores químicos, instrumentación analítica, biomedicina, control clínico, control de procesos en industria alimentaria, etc.Peer reviewe

Impedimetric label-free sensor for specific bacteria endotoxin detection by surface charge registration

An impedimetric sensor based on a three dimensional electrode array modified with concanavalin A (Con A) was used for label-free detection of bacterial endotoxin: lipopolysaccharide (LPS) from Escherichia coli. The transducer permits the detection of the surface charge changes due to interaction of immobilized Con A biorecognition element and LPS of E. coli in test solution. The deposition of Con A on the surface was carried out using the layer-by-layer method with polyethyleneimine (PEI) polycation as an initial layer. The sensor surface characterization by means of electrochemical impedance spectroscopy technique allowed registering variations in superficial resistance provoked by surface charge changes and is demonstrated as an effective method to monitor sensor parameters at each modification step as well as to follow Con A – LPS reaction. In order to prevent non-specific adsorption of LPS on PEI covered surface different blocking strategies were tested to achieve the specific response between Con A and LPS. Results obtained in this work clearly show that blocking with bovine serum albumin (BSA) is not sufficient to prevent non-specific interactions of PEI and to ensure the selective biorecognition of LPS by Con A. To achieve more efficient PEI blocking a new method was proposed based on consecutive deposition of Con A-glycogen-Con A layers. Sensors modified with PEI-(Con A-Gly)2-Con A multilayers are shown to be highly sensitive, selective and reproducible. Presented biosensor is able to detect bacterial LPS in a very short detection time (20 min) with 2 μg mL−1 limit of detection, which is much lower than reported for other biosensors with Con A.The authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (project CTQ2014-54553-C3-1-R and S.B.O. fellowship of FPI-MICINN program BES-2015-071250) co-funded by the European Regional Development Fund (Feder) and from the Government of Russian Federation (Grant 074-U01).Peer reviewe

Sensor de determinación directa de la presencia de detergentes en una muestra

[EN] The invention relates to a novel three-dimensional impedimetric sensor in which the interdigitated electrodes comprise highly conductive digits separated by a barrier of insulating material. The sensor can be used for directly determining the presence of detergent residue in water during washing processes and rinsing cycles. The impedance of the sensor changes upon detection of the presence of molecules of detergent in a sample, owing to the change in the electric field in which the field lines extend from one digit (2) to the other digit (3), extending beyond the insulating barrier (4).[ES] La presente invención desccribe un nuevo sensor impedimétrico tridimensional en el que los electrodos interdigitados comprenden dígitos altamente conductivos que están separados por una barrera de un material aislante, útil para la determinación directa de la presencia de residuos de detergentes en agua en los procesos de lavado y ciclos de aclarado. El sensor cambia su impedancia cuando capta la presencia de moléculas de detergente en una muesra debido al cambio que sufre el campo eléctrico cuyas líneas de campo parten de un dígito (2) hasta llegar al otro dígito (3) sobrepasando la barrera aislante (4).Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Comparison of Different Commercial Conducting Materials as Ion-to-Electron Transducer Layers in Low-Cost Selective Solid-Contact Electrodes

© 2020 by the authors.Simple, robust, sensitive and low-cost all-solid-state ion-selective electrodes (SCISEs) are of interest in different fields, such as medicine, veterinary, water treatment, food control, environmental and pollution monitoring, security, etc. as a replacement for traditional ion-selective electrodes with liquid inner contact. In spite of their potential advantages, SCISEs remain mainly in the research laboratories. With the motivation of developing simple and low-cost SCISEs with possible commercial applications, we report a comparison study of six different commercial conducting materials, namely, polypyrrole-block-polycaprolactone (PPy-b-PCaprol), graphene/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) ink, poly(3,4-ethylenedioxythiophene):polyethylenglycol (PEDOT:PEG), high conductivity PEDOT:PSS, polyethylenimine (PEI) with PEDOT:PSS for their possible use as ion-to-electron transducer in polyurethane based pH-SCISEs. Among all studied pH-SCISES, PEDOT:PEG based electrodes exhibited the best results in terms of sensitivity, reproducibility and lifetime. Finally, these sensors were tested in different real samples showing good accuracy.This research was funded by SMARTECOPONIC Project (PCIN-2017-031) from WATERWORKS15 ERA-NET and by INTRAMURAL Project (201850E071) from CSIC.Peer reviewe