Traditional Quartz Crystal Microbalance (QCM) sensors used for biological detection are limited in mass sensitivity due to their large thickness. This study presents a biosensor utilizing a Shear Horizontal Acoustic Plate Mode (SHAPM) resonator constructed from a suspended Y+36 degrees cut LiNbO3 (LNO) plate. LNO is chosen over quartz or AlN for its higher permittivity, which reduces capacitive coupling when in contact with water. Finite Element Method (FEM) simulations reveal that mass sensitivity (S-m) increases with decreasing LNO plate thickness, yet structural integrity limits the minimum thickness to 2 mu m, resulting in S-m = 70 Hz center dot cm(2)/ng. The device is integrated into a microfluidic system and a printed circuit board for real-time detection. The sensor exhibits a limit of detection (LOD) of 15 ng/cm(2) for non-specific binding of Bovine Serum Albumin (BSA). This is comparable to that of previously reported Love wave devices.

This study deals with the biofunctionalization of silicon photonic Mach-Zehnder interferometers (MZIs) for bacterial biosensor development. Compact arrays of tens of MZIs were locally functionalized with E. coli specific IgG through an organo-silane linker. Bacterial detection assays were performed on whole and lysed bacterial cells suspensions. Mechanically lysed bacteria, with no further purification, allow for specific detection from 10 7 to 10 4 CFU/ml confirming the potential of MZI arrays to pave the way for miniaturized, label free and multiplexed biosensor development.

SummarySurface Acoustic Wave (SAW) sensors have raised an interest for biological sensing applications. Operation in water requires exploiting Shear Horizontal SAW (SH-SAW), which however suffer from losses due to radiation in the substrate. Therefore, we adopt here a resonator structure consisting in a LiNbO 3 layer bonded to a Si substrate and covered by a thin SiO 2 layer to provide electrical insulation when in contact with water. The resonator operates at 378 MHz and its quality factor was evaluated in air/water operation with a Q water of 280.

Ferroelecticity, one of the keys to realize nonvolatile memories owing to the remanent electric polarization, has been an emerging phenomenon in the two-dimensional (2D) limit. Yet the demonstrations of van der Waals (vdW) memories using 2D ferroelectric materials as an ingredient are very limited. Especially, gate-tunable ferroelectric vdW memristive device, which holds promises in future neuromorphic applications, remains challenging. Here, we show a prototype gate-programmable memory by vertically assembling graphite, CuInP2S6, and MoS2 layers into a metal-ferroelectric-semiconductor architecture. The resulted devices exhibit two-terminal switchable electro-resistance with on-off ratios exceeding 105 and long-term retention, akin to a conventional memristor but strongly coupled to the ferroelectric characteristics of the CuInP2S6 layer. By controlling the top gate, Fermi level of MoS2 can be set inside (outside) of its band gap to quench (enable) the memristive behaviour, yielding a three-terminal gate programmable nonvolatile vdW memory. Our findings pave the way for the engineering of ferroelectric-mediated memories in future implementations of nanoelectronics.

We present a preliminary study of a wearable system to monitor biomarkers for dairy and suckling cattle. Finding the optimal location on the cow body (ears) and designing the adapted microneedles to reach the interstitial fluids underneath the cow skin are the two points addressed here.For the selection of the location, 4 breeds of suckling cows (Aubrac, Charolaise, Lim-ousine, Salers) and 3 breeds of dairy cows (Abondance, Montbe ?liarde, Holstein) were chosen. Measurements of the thickness of the ear tissues were conducted on three areas of the ear (top, apex and base of the pinna), on the external and internal sides. Results show that the apex of the pinna, external side, is the best area for microneedle implantation with an implantation window of 1403 +/- 589 mm (DeepDe), considering all breeds. To reach this implantation window located between the stratum corneum and the cartilage, the microneedle has to pass through 1323 +/- 404 mm of tissues (SupDe), considering all breeds. From these results, a microneedle design was made on SolidWorks. With a conical shape 2.89 mm in height and a conical channel 300 mm in diameter (at the tip of the microneedle), the model was made using 3D printing. The resulting microneedles respect the SolidWorks design with fair accuracy. They were connected to a microfluidic channel for sampling or releasing fluids.(c) 2022 IAgrE. Published by Elsevier Ltd. All rights reserved.

The acceleration of climatic, digital, and health challenges is testing scientific communities. Scientists must provide concrete answers in terms of technological solutions to a society which expects immediate returns on the public investment. We are living such a scenario on a global scale with the pandemic crisis of COVID-19 where expectations for virological and serological diagnosis tests have been and are still gigantic. In this Perspective, we focus on a class of biosensors (mechanical biosensors) which are ubiquitous in the literature in the form of high performance, sensitive, selective, low-cost biological analysis systems. The spectacular development announced in their performance in the last 20 years suggested the possibility of finding these mechanical sensors on the front line of COVID-19, but the reality was quite different. We analyze the cause of this rendez-vous manqué, the operational criteria that kept these biosensors away from the field, and we indicate the pitfalls to avoid in the future in the development of all types of biosensors of which the ultimate goal is to be immediately operational for the intended application.

Since its invention in the 1960s, one of the most significant evolutions of metal-oxide-semiconductor field effect transistors (MOS-FETs) would be the three dimensionalized version that makes the semiconducting channel vertically wrapped by conformal gate electrodes, also recognized as FinFET. During the past decades, the width of fin (W[Formula: see text]) in FinFETs has shrunk from about 150 nm to a few nanometers. However, W[Formula: see text] seems to have been levelling off in recent years, owing to the limitation of lithography precision. Here, we show that by adapting a template-growth method, different types of mono-layered two-dimensional crystals are isolated in a vertical manner. Based on this, FinFETs with one atomic layer fin are obtained, with on/off ratios reaching [Formula: see text]. Our findings push the FinFET to the sub 1 nm fin-width limit, and may shed light on the next generation nanoelectronics for higher integration and lower power consumption.

This paper describes the analysis of a mixture of 16 polycyclic aromatic hydrocarbons using gas chromatography (GC) and nano-electromechanical systems (NEMS). The performance of NEMS to detect PAHs is assessed and compared with that of commercial flame ionization detector (FID). The limit of detection of the GC-NEMS system ranges from 70 pg to 500 pg, which confirm the potential of NEMS to quantify high molecular weight molecules. The limitations of such a system to detect PAHs are discussed.

Most technologies, including conventional mass spectrometry, struggle to measure the mass of particles in the MDa to GDa range. Although this mass range appears optimal for nanomechanical resonators, early nanomechanical-MS systems suffered from prohibitive sample loss, extended analysis time or inadequate resolution. Here, we report on a novel system architecture combining nebulization of the analytes from solution, their efficient transfer and focusing without relying on electromagnetic fields, and the mass measurements of individual particles using nanomechanical resonator arrays. This system determined the mass distribution of ~30 MDa polystyrene nanoparticles with a detection efficiency 6 orders of magnitude higher than previous nanomechanical-MS systems with ion guides, and successfully performed the highest molecular mass measurement to date with less than 1 picomole of bacteriophage T5 105 MDa viral capsids.

One of the main challenges to overcome to perform nanomechanical mass spectrometry analysis in a practical time frame stems from the size mismatch between the analyte beam and the small nanomechanical detector area. We report here the demonstration of mass spectrometry with arrays of 20 multiplexed nanomechanical resonators; each resonator is designed with a distinct resonance frequency which becomes its individual address. Mass spectra of metallic aggregates in the MDa range are acquired with more than one order of magnitude improvement in analysis time compared to individual resonators. A 20 NEMS array is probed in 150 ms with the same mass limit of detection as a single resonator. Spectra acquired with a conventional time-of-flight mass spectrometer in the same system show excellent agreement. We also demonstrate how mass spectrometry imaging at the single-particle level becomes possible by mapping a 4-cm-particle beam in the MDa range and above.

Nano-optomechanical resonators have demonstrated in the last few years their enormous potential for applications such as mass and chemical sensing. Operation in liquid of such resonators has been demonstrated very recently by two groups, showing that biosensing could potentially be performed. Nonetheless, going a step further towards the next generation of high-end biosensors requires scaling up the fabrication process and being able to perform this type of measurement routinely. This paper reports the first Very Large Scale Integration silicon optomechanical microdisk resonators with state-of-the-art performance: high optical-Q and optomechanical coupling allow the Brownian noise of these resonators to be easily resolved at few 100 MHz in ambient air with many different devices and we show how optical performance is maintained in liquid.

The first Very Large Scale Integration process with variable shape beam lithography for optomechanical devices is presented. State of the art performance was obtained with silicon microdisk resonators showing 1 million optical quality factors and 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-17</sup> m.Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(-1/2)</sup> displacement resolution. Single-particle mass spectrometry could be performed with these optomechanical resonators in vacuum. The devices retained high performance when directly immersed in liquid media, allowing for biosensing experiments. These results open the door to large, dense arrays of optomechanical sensors.

Measurement of the mass of particles in the mega- to gigadalton range is challenging with conventional mass spectrometry. Although this mass range appears optimal for nanomechanical resonators, nanomechanical mass spectrometers often suffer from prohibitive sample loss, extended analysis time, or inadequate resolution. We report on a system architecture combining nebulization of the analytes from solution, their efficient transfer and focusing without relying on electromagnetic fields, and the mass measurements of individual particles using nanomechanical resonator arrays. This system determined the mass distribution of ~30-megadalton polystyrene nanoparticles with high detection efficiency and effectively performed molecular mass measurements of empty or DNA-filled bacteriophage T5 capsids with masses up to 105 megadaltons using less than 1 picomole of sample and with an instrument resolution above 100.

The first Very Large Scale Integration process with variable shape beam lithography for optomechanical devices is presented. State of the art performance was obtained with silicon microdisk resonators showing 1 million optical quality factors and 10−17m.Hz(−1/2) displacement resolution. Single-particle mass spectrometry could be performed with these optomechanical resonators in vacuum. The devices retained high performance when directly immersed in liquid media, allowing for biosensing experiments. These results open the door to large, dense arrays of optomechanical sensors.

Cavity optomechanics have become a promising route towards the development of ultrasensitive sensors for a wide range of applications including mass, chemical and biological sensing. We demonstrate the potential of Very Large Scale Integration (VLSI) with state-of-the-art low-loss performance silicon optomechanical microdisks for real-world applications. We report microdisks exhibiting optical Whispering Gallery Modes (WGM) with 1 million quality factors. These high-Q microdisks allow their Brownian motion to be resolved at few 100 MHz in ambient air. Such performance shows our VLSI process is a viable approach for the next generation of highend sensors operating in vacuum, gas or liquid phase.

It has been recently shown that resonance frequency fluctuations degrade the limit-of-detection of high-purity monocrystalline resonating sensors. A thorough literature study has shown this is likely the case for a wide variety of resonators. Here we provide additional insight into the physical source of these fluctuations: our results suggest that defect motion in the crystalline structure of the material is not a major source of frequency fluctuations in silicon resonators.

This paper presents the optimization of the ionization, extraction and focalization of our new generation of microfabricated time-of-flight mass spectrometer (mu-TOF). Using electron impact ionization, we show ionization efficiencies in the range of 1.10-6 ion/neutral, which is in the same order of magnitude as macroscale electron impact ionizers. A generated ion current in the range of a few tens of nanoamperes lead to an ionization yield around 0.1%, in the same range as the best microfabricated ionizers. The extracted and focalized ion beam is collected in a Micro Channel Plate detector and used to record mass spectra. Using decreasingly concentrated gas mixtures, we show the ability of the linear microfabricated time-of-flight mass spectrometer to detect up to 100 ppm of alkanes in helium. This work pulls the mu-TOF one step closer towards a fully integrated portable analytical system. (C) 2017 Elsevier B.V. All rights reserved.

We present a nanofabricated Thermal Conductivity Detector (nano-TCD), designed to be monolithically integrated with a CMOS technology compatible NEMS, in order to widen its analyte spectrum in the low molecular weight volatile organic compounds range. The nano-TCD uses arrays of silicon nano-wires, with 220 nm x 250 nm cross sections and 2 m suspension gap over the silicon bulk. In order to filter out the 1/f flicker noise produced by the silicon nanowires, we used a signal modulation technique based on the 3 omega method, thanks to the fast response time of the nano-TCD. Experimental results demonstrate detection of pentane and butane with a limit of detection of 60 ppm and 70 ppm respectively (mole fraction). (C) 2017 Elsevier B.V. All rights reserved.