Categoría publications

Tuning Charge Storage Properties of Supercapacitive Electrodes Evidenced by In Situ Gravimetric and Viscoelastic Explorations

Journal:  Anal. Chem.

Authors:  FWanli Gao, Catherine Debiemme-Chouvy, Mohammed Lahcini, Hubert Perrot, and Ozlem Sel

Abstract: Revealed by an integrated electrogravimetric and viscoelastic method, slightly electrochemically reduced graphene oxide (ERGO) presents an anion preference for charge storage and delivery, while with the progressive removal of oxygen functionalities on its basal planes, cations begin to predominate in charge compensation. This “anion-to-cation” evolution in neutral aqueous media can not only affect the electrochemical charge storage, but also play an important role in electrode’s viscoelasticity. It was demonstrated that oxygen functionalities could modify the interactions between graphene layers and even contribute to pseudocapacitances. However, the role of oxygen functionalities in species transfer and viscoelastic variations still remains poorly understood. Herein, a combined methodology of electrochemical quartz crystal microbalance (EQCM), ac-electrogravimetry and electroacoustic impedance measurements was proposed for characterizing the electrochemical and viscoelastic responses of graphene oxides with various degree of electrochemical reduction. With the removal of oxygen containing functional groups, ERGO electrode exhibits (i) a gradually enhanced specific capacitance (Cs) with increased flexibility (decreased storage moduli, G′); (ii) a dehydration process of cations (i.e., from Na+·2H2O to Na+·H2O); and (iii) a potential-dependent “stiffened-softened” behavior. These results open the door for a suitable design of GO-based materials for electrochemical energy storage and shed light on electronic devices where ion-selective behavior plays a key role.Keywords: Electrochemical Quartz crystal microbalance, ,


Ion Dynamics at the Single Wall Carbon Nanotube Based Composite Electrode/Electrolyte Interface: Influence of the Cation Size and the Electrolyte pH

Journal:  J. Phys. Chem. C

Authors:  Freddy Escobar-Teran, Hubert Perrot, and Ozlem Sel

Abstract: Electrochemical quartz crystal microbalance (EQCM) and ac-electrogravimetry methods were employed to study ion dynamics in single wall carbon nanotube (SWCNT) based electrodes in various aqueous electrolytes and different electrolyte pH. The pH dependence of the electroadsorption phenomena studied in NaCl at pH 2, pH 7 and pH 10 indicated that low and high pH values amplify the anion and cation contribution, respectively; which means that in the same potential range, the pH of the aqueous electrolyte is adjustable to preferentially electroadsorb cations or anions. The cation size dependence of the electrodeposition phenomena was also studied by changing the electrolyte cation from Li+, Na+ to K+. The results indicated that Li+ and Na+ species are more tightly bonded to their water molecules in their hydration shell compared to the potassium species, i.e. dehydration of K+ is easier than that of Na+ and Li+. K+ ions due their completely dehydrated state, probably become equivalent to partially dehydrated Na+.nH2O, in terms of kinetics. Li+.nH2O ions dynamics is slower since it is much more difficult for them to get rid of their hydration shell making their transfer the slowest among the other cations. Our electrogravimetric results clearly indicate that the dehydration affinity and the ions size play a role in the electroadsorption dynamics of the species on the SWCNT based composite electrodes.

Keywords: Electrochemical Quartz crystal microbalance, carbon nanotube electrodes, aqueous electrolytes ,


Piezoelectric biosensors

Authors:  Petr Skládal

Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic

Journal: Trends in Analytical Chemistry

Abstract: Progress in the field of piezoelectric (quartz crystal microbalance-based) biosensors in the recent five years is reviewed. In addition to the traditional immunosensing assays, the combination with detection of nucleic acids is addressed, biosensing of microbes and novel applications in the field of cellular biology are highlighted. The signal enhancing strategies based on both biochemical cascades (often involving nanoparticles) and technological improvements of instrumentation are discussed.

Keywords: Quartz crystal microbalance, Immunosensor, Nucleic acid sensor, Eukaryotic cellular studies, Instrumentation for piezosensors

High Fundamental Frequency Quartz Crystal Microbalance (HFF-QCM) immunosensor for pesticide detection in honey

Authors:  Lourdes Cervera-Chinera , Marisol Juan-Borrása , Carmen Marchb , Antonio Arnaub , Isabel Escrichea,c, Ángel Montoyab , Yolanda Jiménezb

aInstituto de Ingeniería de Alimentos para el Desarrollo, Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain
bCentro de Investigación e Innovación en Bioingeniería (Ci2B), Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain
cFood Technology Department (DTA), Universitat Politècnica de València, Camino de Vera s/n, 46022, Valencia, Spain

Journal: Food Control (2018)

Abstract: Quantification of chemical residues in honey is a market requirement to ensure consumer safety. The most common method used to analyze these compounds is the LC/MS/MS methodology, which requires highly qualified technicians and a tedious pre-treatment of the sample. The honey-packaging industry needs cheaper and faster alternatives for routine control. HFF-QCM (High Fundamental Frequency Quartz Crystal Microbalance) sensors are becoming a good option due to their high sensitivity, fast detection and low cost, while avoiding complex sample pre-treatment. The HFF-QCM technology is based on piezoelectric sensors with frequencies in the range from several tenths of MHz to hundreds of MHz. In this work a 100 MHz HFF-QCM sensor was used in a monoclonal antibody-based competitive immunoassay for specific bio-recognition of carbaryl pesticide as testing contaminant. The work intends to validate the use of HFF-QCM technology, in comparison with liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique, for the detection of contaminants in honey. For this purpose, the validation criteria required by SANCO 12571/2013 guidance document were considered. The precision and accuracy (recovery) of both methods were determined by comparison of 5 replicates at 4 different concentrations (from 0 to 100 μg/kg) using the same honey matrix. HFF-QCM technology showed good accuracy, with recovery percentages always between 110 and 120%. As regards to precision, HFF-QCM coefficients of variation (CV) were around 10% higher than those recommended by GC SANCO 12571/2013. HFF-QCM limits of detection (LOD) and quantification (LOQ) were in the same order of magnitude as those for LC-MS/MS, which allows the analysis of carbaryl residues in honey under the established maximum residue limits (MRL), without sample pre-treatment. These results show that biosensors based on HFF-QCM technology has become a serious alternative to the traditional analytical techniques for food quality and safety applications.

Keywords: High-fundamental-frequency QCM, Piezoelectric immunosensors, Carbaryl, Pesticides, Honey

pH-Controlled Electrochemical Deposition of Polyelectrolyte Complex Films

Authors: Kazi Sadman1, Qifen Wang1, Shawn H. Chen1, David  E. Delgado1 and Kenneth R. Shull1

1Department of Materials Science & Engineering, Northwestern University, Evanston, Illinois 60208, United States

Journal: Langmuir (2017)

Abstract: Polyelectrolyte complex (PEC) films made from oppositely charged polymer chains have applications as drug-delivery vehicles, separation membranes, and biocompatible coatings. Conventional layer-by-layer techniques for polyelectrolyte coatings are low-throughput and multistep processes that are quite slow for building films on the order of micrometers. In this work, PEC films are electrochemically deposited using a rapid one-pot method, yielding thick (1 μm) films within short experimental time scales (5 min). This rapid electrodeposition is achieved by exploiting the reduction of hydrogen peroxide at mild electrode potentials that avoid water electrolysis yet trigger the pH-responsive self-assembly of a PEC film composed of poly(acrylic) acid and poly(allylamine) HCl. In situ rheology using an electrochemical quartz crystal microbalance quantified the shear modulus−density product of the deposited layer to be on the order of 107 Pa g/cm3 at a frequency of 15 MHz, with a viscoelastic phase angle of approximately 50°. This electrodeposition scheme furthers the development of PEC coatings for more high-throughput applications, where a fast and efficient single-step approach would be desirable for obtaining coatings.

Keywords: Electrodeposition, polyelecrolyte, QCM.

Electro-Assisted Deposition of Calcium Phosphate on Self-Assembled Monolayers

Authors: Noah Metoki1, Kazi Sadman2, Kenneth Shull2, Noam Eliaz1 and Daniel Mandler3

1Biomaterials and Corrosion Lab, Department of Materials Science and Engineering, Tel-Aviv University, Ramat Aviv 6997801, Israel
2Polymer Surfaces & Inferfaces Lab, Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
3Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel

Journal: Electrochimica Acta (2016)

Abstract: Calcium phosphate (CaP) ceramics are used in orthopedics and dentistry due to their excellent biocompatibility and osseointegration. Here, the electro-assisted deposition of CaP on two different selfassembled monolayers (SAMs), 2-mercaptoacetic acid (MAA) and 2-mercaptoethanol (ME), was studied both at short (up to 3 min) and long (2 hours) deposition periods on well-defined evaporated gold surfaces. It was found that the end group of the monolayer has a major effect on the growth of the CaP coating. The deposition was slower and less electrically efficient on MAA SAM, but surface cracking was essentially eliminated due to reduction of the crystallographic mismatch. The carboxylic acid may
facilitate CaP growth by attracting Ca2+ ions to the surface, which could explain the higher amount of side reactions occurring at the beginning of the deposition.

Keywords: Calcium phosphate (CaP), hydroxyapatite (HAp), electrodeposition, self- assembled monolayers (SAMs)

Design and Validation of a 150 MHz HFFQCM Sensor for Bio-Sensing Applications

Authors: Román Fernández1, Pablo García1, María García1, José V. García1, Yolanda Jiménez2 and Antonio Arnau2

1Advanced Wave Sensors S. L., Algepser 24, 46988 Paterna, Spain
2Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Camí de Vera S/N, 46022 Valencia, Spain

Journal: Sensors Journal (2017)

Abstract: Acoustic wave resonators have become suitable devices for a broad range of sensing applications due to their sensitivity, low cost, and integration capability, which are all factors that meet the requirements for the resonators to be used as sensing elements for portable point of care (PoC) platforms. In this work, the design, characterization, and validation of a 150 MHz high fundamental frequency quartz crystal microbalance (HFF-QCM) sensor for bio-sensing applications are introduced. Finite element method (FEM) simulations of the proposed design are in good agreement with the electrical characterization of the manufactured resonators. The sensor is also validated for bio-sensing applications. For this purpose, a specific sensor cell was designed and manufactured that addresses the critical requirements associated with this type of sensor and application. Due to the small sensing area and the sensor’s fragility, these requirements include a low-volume flow chamber in the nanoliter range, and a system approach that provides the appropriate pressure control for assuring liquid confinement while maintaining the integrity of the sensor with a good base line stability and easy sensor replacement. The sensor characteristics make it suitable for consideration as the elemental part of a sensor matrix in a multichannel platform for point of care applications.

Keywords: HFF-QCM (high fundamental frequency quartz crystal microbalance); finite element method (FEM); flow cell; biosensor; PoC (point of care); MQCM (monolithic quartz crystal microbalance)

 Sensors 17 02057 g002 550

You can download the full paper here

A liquid biopsy platform combining a high fundamental frequency QCM device with dynamic chemistry for detecting mutations in circulating DNA

Authors: A. Grammoustianou, G. Papadakis, M. Tabraue, J.J. Díaz-Mochon, R. Fernández, J.V. García, A. Arnau, E. Gizeli. AWSensors S.L., Institute of Molecular Biology and Biotechnology- FORTH, University of Crete, Destina Genomics S.L., Centro de Investigación e Innovación en Bioingeniería – Universidad Politécnica de Valencia

Event:  5th International Conference on Bio-sensing Technology, Riva del Garda, Italy (2017)

In the past decade, the analysis of circulating tumour DNA (ctDNA) in blood has been a major breakthrough; ctDNA has been proposed as a priceless source for cancer diagnostic, prognostic and treatment monitoring through a new methodology known as “Liquid Biopsy”. This study presents a novel diagnostic method for the acoustic detection of KRAS mutations in ctDNAs based on: (1) DNA analysis by “dynamic chemistry” that utilizes aldehyde modified nucleobases (SMART) and abasic peptide nucleic acids (DGL probes) capable for the errorfree detection of nucleic acids and their mutations; and, (2) a high fundamental frequency (100 MHz) acoustic wave microsensor (AWS HFF-QCM) that allows the accurate, inexpensive, label-free and real time monitoring of the “dynamic chemistry”. Surface-immobilized DGL probes on the AWS HFF-QCM device are used to detect ctDNAs of wild type and mutated KRAS variants. Upon hybridization of the DGL probe with its target ssDNA, a duplex is formed where biotin- tagged SMART bases can lock in front of the position under interrogation; streptavidin binding detected in a follow-up step confirms the presence of the SMART bases. The use of DGL probes in combination with an isothermal DNA amplification step RPA) have allowed the sensitive and specific recognition of single mismatches in KRAS genes in less than 1 hour. This work presents a unique and novel technology that can emerge as a promising tool in the field of cancer diagnostics.

Liquid Biopsy detection protocol

Schema for complete detection protocol:

(A) Extracted DNA containing mutant (red) and wild type DNA fragments (black) are enzymatically amplified.

(B) Denatured amplicons are hybridized on surface immobilized DGL probes. Chemical locking of a specific tagged SMART base takes place only in the appropriate position.

(C) Incorporated SMART bases are recognized by streptavidin and monitored in real-time during an acoustic measurement.

A High Fundamental Frequency QCM Immunosensor for Tuberculosis Detection

AWSensors biosensor for tuberculosis detection

Authors: Ángel Montoya, Carmen March, Yeison J. Montagut, Maria J. Moreno, Juan J. Manclus, Antonio Arnau, Yolanda Jiménez, Marisol Jaramillo, Paula A. Marin, Robinson A. Torres

Journal:  Current topics in Medicinal Chemistry (2017)

Background: Tuberculosis, one of the oldest diseases affecting human beings, is still considered as a world public health problem by the World Health Organization.

Method & Material: Therefore, there is a need for new and more powerful analytical methods for early illness diagnosis. With this idea in mind, the development of a High Fundamental Frequency (HFF) piezoelectric immunosensor for the sensitive detection of tuberculosis was undertaken. A 38 kDa protein secreted by Mycobacterium tuberculosis was first selected as the target biomarker. Then, specific monoclonal antibodies (MAbs) were obtained. Myc-31 MAb, which showed the highest affinity to the analyte, was employed to set up a reference enzyme-linked immunosorbent assay (ELISA) with a limit of detection of 14 ng mL-1 of 38 kDa antigen.

Results & Discussion: For the development of the HFF piezoelectric immunosensor, 100 MHz AWSensors quartz crystals were used as transducer elements. The gold electrode surface was functionalized by covalent immobilization of the target biomarker through mixed self-assembled monolayers (mSAM) of carboxylic alkane thiols. A competitive immunoassay based on Myc-31 MAb was integrated with the transducer as sensing bio-recognition event. Reliable assay signals were obtained using low concentrations of antigen for functionalization and MAb for the competitive immunoassay. Under optimized conditions, the HFF immunosensor calibration curve for 38 kDa determination showed a limit of detection as low as 11 ng mL-1 of the biomarker. The high detectability attained by this immunosensor, in the picomolar range, makes it a promising tool for the easy, direct and sensitive detection of the tuberculosis biomarker in biological fluids such as sputum.

You may review the full paper here

Dynamic Resolution of Ion Transfer in Electrochemically Reduced Graphene Oxides Revealed by Electrogravimetric Impedance

Authors: Hamza Goubaa, Freddy Escobar-Teran, Ibtissam Ressam, Wanli Gao, Abdelkrim el Kadib, Ivan T. Lucas, Mustapha Raihane, Mohammed Lahcini, Hubert Perrot, Ozlem Sel. Sorbonne Université, UPMC, Univ Paris 06, CNRS, France. Laboratoire Interfaces et Systèmes Électroquimiques; Université Cadi Ayyad, Faculté des Sciences et Techniques, Laboratoire de Chimie Organométallique et Macromoléculaire Matériaux composites, Marrakech, Morocco.

Journal:  The Journal of Physical Chemistry (2017)

To accompany the search for optimal materials in electrochemical supercapacitors, appropriate characterization tools to assess key parameters of newly developed electrodes are required. Here we demonstrate the capabilities of ac-mode electrogravimetry to study in details the capacitive charge storage mechanisms in electrochemically reduced graphene oxide (ERGO) thin films electrodes. The coupling of electrochemical impedance spectroscopy (EIS) with fast quartz crystal microbalance (QCM) complements classical electrochemical quartz crystal microbalance (EQCM) by capturing here the dynamics of the electroadsorption process, identifying charged moieties and detecting solvation effects. We evidenced the co-electroadsorption of two types of cationic species (fully and partially hydrated cations) in the potential range studied and the indirect intervention of free solvent molecules. Further kinetic information on electroadsorption is also obtained which leads to a full deconvolution of the global EQCM response at both gravimetric and temporal level. Through a fine analysis of the interactions of different cations of period one elements, Li+, Na+ and Kwith ERGO, we evidenced the critical role of solvation processes on the kinetics of electroadsorption, and provided an experimental proof to the phenomena that smaller ions are more tightly bound to their water molecules such that an inverse relationship exists between the dehydration energy and the ion size. Such gravimetric and dynamic subleties are unreachable with classical tools and with EQCM method alone which permits us to suggest the ac-mode electrogravimetry as a baseline diagnostic tool to explore charge transfer mechanisms at the nanoscale.