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A conductometric transducer is proposed for the first time for the detection of ethanol vapor. This ethanol microsensor is prepared by encapsulation of alcohol dehydrogenase (ADH) in chitosan. Interdigitated electrodes fabricated by silicon technology were used. The electrodeposition of chitosan allows the addressing of the chitosan film on the microconductometric devices and to encapsulate ADH and nicotinamide adenine dinucleotide (NAD+), which was monitored by FTIR. The analytical performance of the ethanol microsensor was determined in gaseous methanol, ethanol, and acetone samples, collected from the headspace above aqueous solutions of known concentration. The response time (tRec) of the sensor varies from 7 to 21 s from lower concentrations to higher concentrations. The detection limit is 0.12v/v % in the gas phase, corresponding to 0.22 M in the liquid phase. The relative standard deviation for the same sensor is from 12% for lower concentrations to 2% for higher concentrations. The ethanol sensor presents 2.6 times lower sensitivity for methanol and 28.3 times lower sensitivity for acetone. A detection of ethanol in the headspace of a red wine sample lead to an alcohol content in good agreement with the value given by the producer.

Heart failure (HF) is a chronic cardiovascular disease that represents main cause of mortality worldwide, particularly for elderly. N-terminal pro-brain natriuretic peptide (NT-proBNP) was identified as the gold standard biomarker for HF diagnosis and therapy monitoring. Presently, saliva analysis represents an emerging and powerful tool for clinical applications and electrochemical immunosensors have shown their potential in Healthcare applications as selective and reliable systems for detecting clinical biomarkers. This work presents the detection of NT-proBNP in saliva samples by an immunologically modified Field effect Transistor (IMFET). TESUD ((11-triethoxysilyl) undecanal) was used as cross-linker to immobilise anti-NT-proBNP antibody onto the device. Our IMFET that was then tested in different matrices (e.g. phosphate buffered saline (PBS), artificial saliva and human saliva) using electrochemical impedance spectroscopy (EIS), and it resulted selective to NT-proBNP with good sensitivity (detection limit of 0.02 pg/mL) and a wide linear range (0.02-1 pg/mL and 0.5-20 pg/mL). Finally, NT-proBNP concentration in ten saliva samples was determined by performing the standard addition method. An enzyme-linked immunosorbent assay was used for confirming IMFET results, highlighting both IMFET accuracy (analyte recovery of 99 ± 8%) and precision (coefficient of variation always10%), and supporting the suitability of the device for determining salivary NT-proBNP.

Impedance spectroscopy is an electrochemical technique widely used for the electrical characterization of the behavior of biomaterials in all kinds of biosensors. Field-effect devices, and in particular ion-sensitive field-effect transistors (ISFETs), have been extensively studied as transducers for biosensing. They however have not been much analyzed with impedance spectroscopy, because they typically generate non-Faradaic capacitance measurements, since there is no charge transfer through the insulating gate in contact with the liquid solution. We have recently experimentally shown that Faradaic-like impedance spectroscopy spectra can be obtained with ISFET devices, allowing high-sensitivity measurements for different pH and biomarker concentrations. In this paper, we report that both Faradaic-like and non-Faradaic impedance behavior can be well understood by a DC and small-signal AC model of the ISFET working in different conditions. Faradaic-like impedance measurements are described by the operation of the ISFET in subthreshold conditions. A Nyquist plot semicircle is obtained, corresponding to the transimpedance 1/gm of the ISFET in parallel to the gate capacitances. We show that this behavior is independent of the presence of membrane material on the gate surface. In these conditions, the change in the semicircle diameter for different pH or biomarker concentrations can be understood by the change of 1/gm corresponding to a threshold voltage shift of the transistor. This description is illustrated with our recent results for pH measurements and the detection of tumor necrosis factor-α with functionalized devices in standard solutions in the concentration range of 1–20 pg/ml. The use of the impedance spectroscopy technique takes advantage of the exponential behavior of the gm(VGS) curves in the subthreshold (weak inversion) operation of the ISFET. This results in a large signal amplification, where a small change in the threshold voltage results in a large change in the impedance spectrum, thus achieving an increased precision in the measurement of the device response to changes in the analyte concentration.

The detection of a drug belonging to the Sulfonamide class of compounds, namely Sulfapyridine, is reported in this work using an in-situ and fast potentiometric method. The strategy employed for this detection is based on the novel ion pair complex, [Sulfapyridine-H]+[Co(C2B9H11)2]- acting as the active site for highly selective recognition of Sulfapyridine. This enables the sensor's selectivity to be improved by incorporating the target molecule to the selective membrane. In this work, all solid state Sulfapyridine selective microelectrodes based on PVC-type membranes were prepared using three different plasticizers and the aforementioned ion pair complex. The sensors developed have provided quick and accurate response within the range of 10−6 mol/dm3 to 10−3 mol/dm3 of Sulfapyridine concentration and showed a Nernstian slope between 47 and 61 depending upon the type of plasticizer used. The lowest limit of detection achieved was 4 μmol/dm3. The potentiometric coefficient of selectivity, KA,Bpot, has shown that the Sulfapyridine-selective microsensors were highly selective towards Sulfapyridine even when compared to other members of the Sulfonamides class of compounds. In addition, from the Reilley diagram it can be observed that the sensor signal is stable for a working pH interval between 6.00 and 8.00.

Tetracycline (TC) is a veterinary drug, wildly prescribed for prophylactic and therapeutic purposes. Consequently, its remaining residues in food products have to be regularized. We report in this paper about the development of a novel immunosensor based on an integrated bio micro-electromechanical system (Bio-MEMS) containing eight gold microelectrodes (µWEs), an integrated silver and platinum reference and counter electrodes, respectively. TC immobilization on the µWEs surface was conducted using three methods. The first through functionalization with 4-aminophenylacetic acid (CMA), the second by functionalization with CMA followed by preconcentration of a new structure of magnetic nanoparticles (MNPs) coated with poly (pyrrole-co-pyrrole-2-carboxylic acid) (Py/Py-COOH/MNPs) cross-linked with Ab-TC, and the last one directly through the functionalization with Py/Py-COOH/MNPs. The analyte was quantified by competitive detection with TC immobilized on the µWEs surface toward specific polyclonal antibody (Ab-TC), using a mixture of a fixed concentration of Ab-TC and decreasing levels of TC one from 0.1 pg mL−1 to 1000 pg mL−1. Microcontact printing, followed by fluorescence microscopy characterization were performed during the functionalization of the immunosensor surface to certify that the corresponding immune detection process is taking place. This immunosensor was found to be highly sensitive with a limit of detection of 1.2 pg mL−1 and specific in the presence of interferents. The standard addition method was exploited to detect TC in honey samples. The present immunosensor platform is up-and-coming for TC detection which can dramatically decrease the time of analysis providing a new pathway for advanced immunoassays development in industrial food control.

In this study, chitosan based molecularly imprinted polymer (MIP) combined with polypyrrole (PPy) conductive film was applied to develop a novel impedimetric microsensor for the sensitive detection of lysozyme (LYS). MIP-chitosan was electrodeposited with LYS as a template on a PPy film electropolymerized on a gold microlectrode. Cyclic voltammetry measurement (CV), electrochemical impedance spectrometry (EIS), FT-IR analysis and scanning electron microscopy (SEM) were carried out to characterize the resulting microsensors and to confirm the different stages in the manufacturing process. Electrochemical Impedance Spectroscopy (EIS) was used for the determination of LYS in a linear range from 2.17 × 10−11M to 3.5 × 10-6M with a low detection limit of 5 × 10-12M. EIS responses of the different micro-sensors were modeled by using mathematical model that described the phenomena at the electrode/electrolyte interface, while showing the effect of each parameter on the response signal, highlighting how LYS concentration can affect EIS parameters. Meanwhile, the microsensor showed a high sensitivity, a good selectivity, a good reproducibility, good reusability. The construction process was relatively simple and provided a rapid and economical method. The microsensor was successfully applied to detect LYS in fresh chicken-egg white sample.

Heart failure is a chronic condition that sorely affects the worldwide population with huge health and economic costs. The purpose of this research is to present an ISFET-based immunosensor sensible to low concentrations of TNF-α biomarker in saliva, a protein related with the severity state of heart failure patients, together with a proof-of-concept IoT-based user-centered health ecosystem, aiming to reduce hospital-centered associated costs and improving patient monitoring. The immunosensor presents a low limit of detection of 5pg/mL, with good cross-selectivity versus other saliva biomarkers, using a low cost and short run-time detection technique, optimal for its implementation in a distributed monitoring system.

Over the past years, to achieve better sensing performance, hafnium dioxide (HfO2) has been studied as an ion-sensitive layer. In this work, thin layers of hafnium dioxide (HfO2) were used as pH-sensitive membranes and were deposited by atomic layer deposition (ALD) process onto an electrolytic-insulating-semiconductor structure Al/Si/SiO2/HfO2 for the realization of a pH sensor. The thicknesses of the layer of the HfO2 studied in this work was 15, 19.5 and 39.9 nm. HfO2 thickness was controlled by ALD during the fabrication process. The sensitivity toward H+ was clearly higher when compared to other interfering ions such as potassium K+, lithium Li+, and sodium Na+ ions. Mott&minus, Schottky and electrochemical impedance spectroscopy (EIS) analyses were used to characterise and to investigate the pH sensitivity. This was recorded by Mott&ndash, Schottky at 54.5, 51.1 and 49.2 mV/pH and by EIS at 5.86 p[H&minus, 1], 10.63 p[H&minus, 1], 12.72 p[H&minus, 1] for 15, 19.5 and 30 nm thickness of HfO2 ions sensitive layer, respectively. The developed pH sensor was highly sensitive and selective for H+ ions for the three thicknesses, 15, 19.5 and 39.9 nm, of HfO2-sensitive layer when compared to the other previously mentioned interferences. However, the pH sensor performances were better with 15 nm HfO2 thickness for the Mott&ndash, Schottky technique, whilst for EIS analyses, the pH sensors were more sensitive at 39.9 nm HfO2 thickness.

International audience; According to the European statistics, approximately 26 million patients worldwide suffer from heart failure (HF), and this number seems to be steadily increasing. Inflammation plays a central role in the development of HF, and the pro-inflammatory cytokine Tumor necrosis factor-α (TNF-α) represents inflammation gold-standard biomarker. Early detection plays a crucial role for the prognosis and treatment of HF. An Ion Sensitive Field Effect Transistor (ISFET) based on silicon nitride transducer and biofunctionalized with anti-TNF-α antibody for label-free detection of salivary TNF-α is proposed. Electrochemical impedance spectroscopy (EIS) was used for TNF-α detection. Our ImmunoFET offered a detection limit of 1 pg mL−1, with an analytical reproducibility expressed by a coefficient of variance (CV) resulted < 10% for the analysis of saliva samples, and an analyte recovery of 94 ± 6%. In addition, it demonstrated high selectivity when compared to other HF biomarkers such as Inteleukin-10, N-terminal pro B-type natriuretic peptide, and Cortisol. Finally, ImmunoFET accuracy in determining the unknown concentration of TNF-α was successfully tested in saliva samples by performing standard addition method. The proposed ImmunoFET showed great promise as a complementary tool for biomedical application for HF monitoring by a non-invasive, rapid and accurate assessment of TNF-α.

In this chapter, we describe the development and fabrication of gold microelectrodes based on silicon by silicon technology, for multiplex detection of cytokines. Cytokines have become a crucial biomarker for the identification of end-stage heart failure (ESHF) for patients during early phase of left ventricular assisted device (LVAD) implantation. The microelectrode device consists of three gold working microelectrodes that were activated and 4-aminophenylacetic acid (CMA) was electroaddressed onto individual gold WEs. The carboxylic acid functionalities of the diazotated aromatic amine were activated through carbodiimide chemistry and anti-interleukin-10 monoclonal antibodies (anti-IL-10 mAb) were immobilized onto the transducers surface. The interaction between the antibody-antigen (Ab-Ag) was characterized by electrochemical impedance spectroscopy (EIS). Here, Nyquist plots have shown a stepwise variation due to the charge transfer resistance (Rct) between the Ab activated surfaces with the detection of the human IL-10. For early expression monitoring, commercial proteins of human IL-10 were analyzed between 1 pg/mL and 100 pg/mL. The protein concentrations within the linear range of 1–50 pg/mL were detected and these values formulated a sensitivity of 0.008 (pg/mL)\(^{-1}\) (\(R^2 = 0.9840\)). These preliminary results demonstrated that the developed biosensor was sensitive to the detection of human IL-10 and the calculated limit of detection (LOD) was measured at 0.156 (pg/mL)\(^{-1}\). To validate the biosensors response, the experiment was repeated several times on different gold working WEs by applying the same conditions. The overall relative standard deviation percentage (% R.S.D.) was 4.9% which demonstrates the successful fabrication for the detection of human IL-10 through diazonium salt electroreduction.

A novel impedimetric microsensor based on a double-layered imprinted polymer film has been constructed for the sensitive detection of the herbicide, glyphosate (GLY), in water. It is based on electropolymerized polypyrrole films, doped with cobaltabis(dicarbollide) ions ([3,3&prime, Co(1,2-C2B9H11)2]), as a solid contact layer between the gold microelectrode surface and the molecularly imprinted chitosan film (CS-MIPs/PPy/Au). Electrochemical Impedance Spectroscopy (EIS) was used for the characterization of the CS-molecular imprinted polymers (MIPs)/PPy/Au in the presence of GLY concentrations between 0.31 pg/mL and 50 ng/mL. Experimental responses of CS-MIPs/PPy/Au are modeled for the first time using an exact mathematical model based on physical theories. From the developed model, it was possible to define the optimal range of the parameters that will impact the quality of impedance spectra and then the analytical performance of the obtained microsensor. The obtained microsensor shows a low detection limit of 1 fg/mL (S/N = 3), a good selectivity, a good reproducibility, and it is regenerable.

Carry out an electronic device/circuit at the scale of few nanometers usually implies a high level of uncertainty due to device variability along the fabrication process. In fact, hybrid SET-FET circuit can be extremely delicate in front of parasitic elements, due to the low level of current provided by the SET device. So, in this contribution and study of their influence is done. Moreover, the suitability to implement this circuit by using FinFET SOI is observed, as well.

This contribution explores different strategies to electrically contact vertical pillars with diameters less than 100 nm. Two process strategies have been defined, the first based on Atomic Force Microscope (AFM) indentation and the second based on planarization and reactive ion etching (RIE). We have demonstrated that both proposals provide suitable contacts. The results help to conclude that the most feasible strategy to be implementable is the one using planarization and reactive ion etching since it is more suitable for parallel and/or high-volume manufacturing processing., This work received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 688072 (Ions4SET), by the Spanish Ministry of Economy and Competitiveness (MINECO) under Contract Nos, TEC2015-69864-R and RTI2018-102007-B-I00 and by the Generalitat de Catalunya (2017 SGR 1187). This work made use of the Spanish ICTS Network MICRONANOFABS, partially supported by MEINCOM.

The detection of the algaecide Irgarol using in-situ and fast potentiometric measurements is reported in this work. For this purpose, three all-solid-state Irgarol-selective microelectrodes based on PVC-type sensitive membrane were prepared using three different plasticizers and the novel ion-pair complex [Irgarol-H]+[Co(C2B9H11)2]− as the active site for selective irgarol recognition. This strategy enables the sensor’s selectivity to be improved by incorporating the target molecule to the sensitive membrane. The chemical sensors developed have provided excellent and quick response within the range 10−6 mol/dm3 to 10−3 mol/dm3 of irgarol concentration, a limit of detection between 2 and 4 μmol/dm3 and a slope between 48 and 57 mV/decade depending on the membrane composition. The potentiometric coefficient of selectivity, KA,Bpot, shown that the Irgarol-selective microsensors were highly selective towards irgarol when compared to some possible interfering phytotoxins. In addition, from the Reilley diagram it can be observed that the sensor signal is stable for a working pH interval between 6.00 and 12.0 making possible its application in sea water monitoring.

We investigate the benefits of the use of arrays of vertical nanowire (vNW) field-effect transistors (FETs) to implement integrated circuits. By means of technology computer aided design and circuit simulations, the optimal dimensions of the vNWFETs are determined. Device and circuit variability levels have been investigated. The benefits of using array configurations are the decrease of the response time and a significant mitigation of the variability level as the number of the elements in the array increases.

We analyze the performance of hybrid single-electron transistor (SET)–FET circuits when different variability sources are considered, e.g., SET’s quantum dot location and FET device dimension variations. For the FET device, FinFET and vertical nanowire configurations have been studied. The hybrid SET–FET circuits with both SET and FET in vertical topology depict the best circuit performance and the highest integration level. The variability impact on different SET-based circuits has been analyzed, including negative differential resistance and logic inverters.

International audience

Assessing cortisol level in human bodies has become an essential tool to recognize heart failure (HF). In this work, the label-free detection of cortisol using a novel capacitive substrate based on hafnium oxide (HfO 2 ) was accomplished. In this context, the interaction between the cortisol with its corresponding polyclonal antibody (pAb) has been studied, and the detection event was followed by electrochemical impedance spectroscopy (EIS). Cortisol was detectable between a wide range of concentration from 2 ng/mL to 50 ng/mL. Moreover, the cross-selectivity study showed that the developed biosensor demonstrated to be highly selective toward cortisol when compared to some related biomarkers such as Tumor Necrosis Factor (TNF-) and N-terminal pro B-type Natriuretic Peptide (NT-proBNP). To the best of our knowledge, this is the first biosensor that has been based on capacitive HfO 2 for cortisol detection by EIS.

International audience; The present work reports on the development of a new generation of Lab-on-a-chip (LOC) to perform in-situ and real-time potentiometric measurements in flowing water. The device consisted of two differentiated parts: a poly (dimethylsiloxane) (PDMS) microfluidic structure obtained by soft lithography and a fully integrated chemical sensing platform including four working microelectrodes, two reference microelectrodes and one counter microelectrode for detecting ammonium in a continuous mode. The performance of the device was evaluated following its potentiometric response when analyzing ammonium containing samples. As a key parameter, its time of response was compared to that of a commercially available electrical conductivity sensor used as reference sensor during tests in laboratory using flowing tap water and technical scale using flowing wastewater. As a result, the LOC showed a slope of 55 mV/decade, a limit of detection of 4·10−5 M and a time of full response between 10 and 12 s. It was demonstrated that the device can provide fast and reliable data at real time when immersed in a laminar flow of water. Moreover, the test of robustness showed that it was still functional after immersion in sewage for at least 15 min. Besides, the LOC reported here can be helpful for a wide variety of flowing-water applications such as aqua culture outlets control, in-situ and continuous analysis of rivers effluents and sea waters monitoring among others.

Quantum dots (QDs) can be used as conductive islands to build-up single-electron transistors (SETs). The characteristics of the QDs define the functional performance of the SETs. In consequence, analyzing the influence of the variations of QD dimensions on the performance of hybrid SET-FET circuits is of high relevance. We employ a self-developed SET compact model which is calibrated to 3-D quantum-mechanics-based simulations in order to obtain realistic model parameters. A method to improve the circuit behavior, i.e., to increase the output current, is proposed. It is concluded that the variation of the QD size presents the largest influence on the overall circuit behavior.

Monitoring of circulating N-terminal proBNP (NT-proBNP) biomarkers is crucial for the diagnosis of people suffering from heart failure (HF). In this work, we describe a novel ultra-sensitive NT-proBNP immunosensor for NT-proBNP detection in artificial human saliva. The surface of the developed immunosensor based on gold working microelectrodes (WEs) was biofunctionalized through carboxyl diazonium to immobilize anti-NT-proBNP antibodies. The chemical surface modification of WEs was carried out by cyclic voltammetery CV whilst the quantification of NT-proBNP biomarkers was made by electrochemical impedance spectroscopy (EIS). The immunosensor has demonstrated a linear detection response within the range 1–20 pg/mL for NTproBNP detection in artificial human saliva with a good selectivity in the presence of other interferences.

Acetone in human breath has been regarded as the important disease marker of Heart failure (HF). Therefore, preliminary study has been carried out for the use chemical sensor based on Polyaniline doped with [3,3′-Co(1,2-C2B9H11)2]−1 anion (PANI/COSANE) for the detection and quantification of acetone in human breath. This chemical sensor was prepared by Galvano-statically growing a polymeric layer based on PANI/COSANE and PANI/Nitrate by electrochemical polymerization onto the two different interdigitated gold microelectrodes on a silicon chip surface using cyclic voltammetry. Measurement of change in conductance due to the presence of acetone in its vicinity at room temperature (20⁻25 °C) is performed in differential configuration mode using Lock-in amplifier. The developed acetone sensor has been calibrated under different acetone atmospheres using a Lock-in amplifier. This novel Acetone micro sensor showed good response, recovery, and stability for the detection of acetone in the range of 1 ppm⁻8 ppm.

In this work, an electrical study of a vertical nanowire (NW)-based Field Effect Transistor (FET) is presented. The resulting output current from the modelled NW-FET is optimized in terms of multiple parameters, in order to enhance the behavior at subthreshold regime. Variability tolerance is analyzed as well, in order to attain improvements concerning average device performance and stability. A process simulation model for a NW-FET is built in perspective for its further manufacturability and implementation into hybrid SET-FET circuits.

In this study, we report the development of a sensitive electrochemical immunosensor for the detection of the tumor necrosis factor-α (TNF-α) cytokine in human saliva samples. The fabricated immunosensor was based on gold substrates. The anti-TNF-α antibody (Ab-TNF-α) was electro-addressed onto the gold working electrodes (WEs) through functionalization with 4-carboxymethylaniline (CMA). Cyclic voltammetry (CV) was applied during the functionalization process to characterize the gold WEs surface properties. Finally, the chronoamperometry technique was applied to characterize the modified gold WEs. The use of a secondary antibody anti-TNF-α (Ab-TNF-α-HRP) labelled with horseradish peroxidase (HRP) was investigated using tetramethylbenzidine (TMB) as electrochemical substrate. A sandwich-type detection strategy was then employed for TNF-α detection through the labelled antibody Ab-TNF-α-HRP activity in a TMB solution. Under the optimal experimental conditions, the specificity of the immunosensor was investigated by analysing solutions containing possible salivary interferences represented by other molecules secreted in acute stage of inflammation such as interleukin-10 (IL-10) and the hormone cortisol. The developed immunosensor showed good performances for Ag-TNF-α cytokine detection within the range of 1 pg mL−1–30 pg mL−1 with a limit of detection (LOD) of 1 pg mL−1. As there is a correlation between TNF-α and the severity of heart failure (HF), this new immunosensor may represent a promising bioanalytical tool for the HF monitoring by saliva analysis. Moreover, the CA technique provides analyses in 5 s for each concentration, which save time and provides rapid data to doctors and clinicians.

International audience

Poly(pyrrole)-nanowires (PPy-NWs) were efficiently printed by using nano printing on flexible thermoplastics, and then used to device an impedimetric immunosensor. The present pioneering technology allow to create high sensitive and disponsable immunosensor devised using a low cost and simple fabrication. The innovative nanocontact printing uses a PDMS stamp replicated from a CD mold. The PPyNW printing uses controlled chemical polymerization to print PPy-NWs on poly (ethylene terephthalate) and polyether ether ketone surfaces. Atomic force microscopy analysis of PPyNW revealed a width, height and a separation length of 125 ± 8 nm, 377 ± 5 nm and 172 ± 4 nm, respectively. The PPy-NWs were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The XPS results evidenced the covalent bonding between the thermoplastic surface and the PPyNWs. As a final point, the immunosensor was tested for the quantification of Interleukin 6 recombinant human (IL6, Ag) using EIS. The PPy-NWs were functionalized via diazonium coupling reaction and carbodiimide crosslinker chemistry for the immobilization of Anti-human IL-6 monoclonal antibodies (IL6 mAb’s). The developed immunosensor exhibited a sensitivity of 0.013 (pg/mL) −1 (linear fitting at R 2 = 0.99) and limit of detection (LOD) of 0.36 pg/mL in a linear range of 1–50 pg/mL for Ag IL-6, with a relative standard deviation percentage (RSD%) at 7.6%.

Microfabricated cantilevers have enabled a wide range of applications in scanning probe microscopies (SPM) and in high-sensitivity nanomechanical sensors. The use of piezoresistivity for self-sensing the cantilever motion is preferred to the standard optical readout for some applications, in view of the advantages that it offers in terms of miniaturization, operation in non-transparent liquid media and capability of simultaneously addressing arrays of devices. Although in principle piezoresistive cantilevers should have a lower resolution than their optical counterparts, current devices can achieve similar performances. This is because a large amount of work has been devoted in the past two decades to their development. This paper provides a short review of the field of piezoresistive cantilevers. We discuss the device performances for the measurement of forces or surface stresses in static operation, or masses in dynamic operation. We then describe the fabrication technologies and materials that are typically used to manufacture the cantilevers. Finally, the main applications in the domains of SPM and nanomechanical sensing are presented.

Miniaturizing potentiostats, keeping their cost low and yet preserving full measurement characteristics (e.g. bandwidth, determination of capacitive/inductive contribution to sensor's impedance and parallel screening) is still an unresolved challenge in bioelectronics. In this work, the combination of simple analogue circuitry together with powerful microcontrollers and a digital filter implementation is presented as an alternative to complex and incomplete architectures reported in the literature. A low-cost acquisition electronic system fully integrated with a biosensors platform containing eight gold working microelectrodes and integrated reference and counter electrodes was developed and validated. The manufacturing cost of the prototype was kept below 300 USD. The performance of the proposed device was benchmarked against a commercial impedance analyzer through the electrochemical analysis of a highly sensitive biosensor for the detection of tumor necrosis factor α (TNF-α) within the randomly chosen range of 266 pg/mL to 666 ng/mL in physiological medium (PBS). A strong correlation between the outputs of both devices was found in a critical range of frequencies (1–10 Hz), and several TNF-α cytokine concentrations were properly discriminated. These results are very promising for the development of low-cost, portable and miniaturized electrochemical systems for point-of-care and environmental diagnosis.