scholarly journals Phononic Crystal Sensors: A New Class of Resonant Sensors—Chances and Challenges for the Determination of Liquid Properties

2021 ◽  
Vol 7 ◽  
Author(s):  
Ralf Lucklum ◽  
Nikolay Mukhin ◽  
Bahram Djafari Rouhani ◽  
Yan Pennec
Keyword(s):  
Chemical Sensor ◽  
Phononic Crystal ◽  
Frequency Resolution ◽  
Liquid Volume ◽  
Mechanical Resonator ◽  
Resonant Sensors ◽  
Enhanced Sensitivity ◽  
Acoustic Dissipation ◽  
Mechanical Sensors ◽  
2D And 3D

Resonant mechanical sensors are often considered as mass balance, which responds to an analyte adsorbed on or absorbed in a thin sensitive (and selective) layer deposited on the surface of the resonant device. In a more general sense, the sensor measures properties at the interface of the mechanical resonator to the medium under inspection. A phononic crystal (PnC) sensor employs mechanical resonance as well; however, the working principle is fundamentally different. The liquid medium under inspection becomes an integral part of the PnC sensor. The liquid-filled compartment acts as a mechanical resonator. Therefore, the sensor probes the entire liquid volume within this compartment. In both sensor concepts, the primary sensor value is a resonant frequency. To become an attractive new sensing concept, specifically as a bio and chemical sensor, the PnC sensor must reach an extraordinary sensitivity. We pay attention to the liquid viscosity, which is an important factor limiting sensitivity. The main part of our analysis has been performed on 1D PnC sensors, since they underlie the same material-related acoustic dissipation mechanisms as 2D and 3D PnC sensors. We show that an optimal relation of frequency shift to bandwidth and amplitude of resonance is the key to an enhanced sensitivity of the sensor-to-liquid analyte properties. We finally address additional challenges of 2D and 3D PnC sensor design concept. We conclude that the sensor should seek for a frequency resolution close to 10−6 the probing frequency, or a resolution with speed of sound approaching 1 mm s−1, taking water-based analytes as an example.

Cavity Resonance Biomedical Sensor

2014 ◽  
Author(s):  
Ralf Lucklum ◽  
Mikhail Zubtsov ◽  
Simon Villa Arango
Keyword(s):  
Chemical Sensor ◽  
Sound Propagation ◽  
Point Of Care ◽  
Phononic Crystal ◽  
Acoustic Properties ◽  
Cavity Resonance ◽  
Solid Matrix ◽  
Acoustic Coupling ◽  
Biomedical Sensors ◽  
Mems Resonator

We report on first steps towards a phononic crystal sensor for biomedical applications. Phononic crystals and metamaterials allow for unprecedented control of sound propagation. The classical ultrasonic sensors, acoustic microsensors and MEMS resonator sensors face severe limitations when applying them to small volume liquid analytes. Phononic crystal sensors are a new concept following the route of photonic crystal sensors. Basically, the material of interest, here a liquid analyte confined in a cavity of a phononic crystal having a solid matrix constitutes one component of the phononic crystal. In an application as chemical sensor the value of interest, let’s say the concentration of a toxic compound in liquid, is related to acoustic properties of the liquid in the cavity. A change in the concentration causes measurable changes in the properties of the phononic crystal. Transmission or reflection coefficients are appropriate parameters for measurement. Specifically, a resonance induced well separated transmission peak within the band gap is the most favorable feature. The sensor scheme therefore relies on the determination of the frequency of maximum transmission as measure of concentration. Promising applications like biomedical sensors, point-of-care diagnostics or fast screening introduce further engineering challenges, specifically when considering a disposable element containing the analyte. The three key challenges are the strong restriction coming from limitations to approved materials for the analyte container, geometric dimensions in the mm-range common in hospital or point-of-care environment and acoustic coupling between sensor platform and analyte container.

Novel Chemical Sensor Concept for Neutral Radical Detection in Gas Phase

2005 ◽  
Vol 876 ◽  
Author(s):  
Vladislav V. Styrov ◽  
Alex Y. Kabansky ◽  
Victor P. Grankin ◽  
Stanislav Kh. Shigalugov ◽  
Yuri I. Tyurin
Keyword(s):  
Gas Phase ◽  
Chemical Sensor ◽  
Proximate Analysis ◽  
Semiconductor Films ◽  
Neutral Radical ◽  
Enhanced Sensitivity ◽  
Radical Detection ◽  
State Chemical ◽  
Novel Concept ◽  
Heterogeneous Chemical Reactions

AbstractA novel concept of solid-state chemical sensors for neutral radical detection in gas-phase and related technique are proposed based on chemiluminescence of sensing materials excited by heterogeneous chemical reactions of radicals on sensor surface. The radical species of interest include H, O, N, O2, CO, SO, NO and others. Surface activated phosphors, nano-phosphors and semiconductor films are good candidates for sensors. The advantages of these sensors are the enhanced sensitivity (~105at/cm-3or better), real-time response, reliability, proximate analysis, ability to be fabricated in combination with up-to-date nanotechnologies.

Ceramic Materials for Mass-Sensitive Sensors - Detection of VOCs and Monitoring Oil Degradation

2006 ◽  
Vol 45 ◽  
pp. 1799-1802 ◽  
Author(s):  
Peter A. Lieberzeit ◽  
Gerd Glanznig ◽  
Anton Leidl ◽  
Franz L. Dickert
Keyword(s):  
Chemical Sensor ◽  
Sol Gel ◽  
Ceramic Materials ◽  
Oil Degradation ◽  
Phase Measurements ◽  
Sensor Applications ◽  
Enhanced Sensitivity ◽  
Wave Oscillator ◽  
Quartz Substrates ◽  
Micro Balance

Inorganic frameworks obtained by the sol-gel route can be templated by a molecular imprinting (MIP) approach to generate functional cavities. Such MIP ceramics show highly appreaciable properties for chemical sensor applications, because they are inherently chemically and thermally robust. In combination with mass-sensitive devices (e.g. quartz crystal micro balance – QCM, surface transverse wave oscillator - STW), they yield highly selective and sensitive chemical sensors. Gas phase measurements with volatile organic compounds (VOCs) e.g. lead to sensitivities below 1 ppm. Sensitivity can be tuned by the sol-gel-precursor: when hydrolysing more bulky alkoxides, this leads to enhanced sensitivity by increasing porosity as a consequence of slower solvent evaporation. By adding products of oxidative oil degradation to the sol-gel mixture, we succeeded in generating sensors for degradation processes in these complex matrices. This allows parallelly monitoring both the chemical state of oil and changes in viscosity. Sensitivity is enhanced according to the Sauerbrey equation by going from 10 MHz QCM transducers to higher frequencies either by etching the quartz substrates and so reducing the resonator thickness or by applying STWs.

Enhanced Sensitivity of Wireless Chemical Sensor Based on Love Wave Mode

2008 ◽  
Vol 47 (9) ◽  
pp. 7372-7379 ◽  
Author(s):  
Wen Wang ◽  
Haekwan Oh ◽  
Keekeun Lee ◽  
Sangsik Yang
Keyword(s):  
Love Wave ◽  
Chemical Sensor ◽  
Wave Mode ◽  
Enhanced Sensitivity

Acoustic wave confinement in two-dimensional phononic crystal with multiple nested resonators

2019 ◽  
Vol 33 (36) ◽  
pp. 1950450
Author(s):  
Xiao-Peng Wang ◽  
Hui Sun ◽  
Tian-Ning Chen ◽  
Xing-Guo Wang
Keyword(s):  
Resonant Frequency ◽  
Acoustic Pressure ◽  
Phononic Crystal ◽  
Resonant Cavity ◽  
Acoustic Energy ◽  
Frequency Resolution ◽  
Signal Frequency ◽  
Crystal Resonator ◽  
Acoustic Energy Harvesting ◽  
Energy Harvesting Efficiency

In this research, a novel phononic crystal (PC) is investigated theoretically to enhance acoustic pressure confinement. It consists of multiple nested resonators based on a tapered configuration. Nested phononic crystal resonator (NPCR) can enhance the acoustic pressure amplification at resonant cavity to a great degree better than the traditional one with same dimensions. The resonant frequency of NPCR is mainly located within outermost phononic crystal resonator’s (PCR) band gap. Meanwhile, it does not move significantly to high frequency with the addition of inner tapered resonators. The enhanced acoustic pressure resonant amplification is attributed to the improvement of the confinement mode owing to the nested structure working as a taper. Then effects of geometrical dimensions of inner PCRs on acoustic confinement are studied. It shows that resonant frequency and resonant acoustic pressure can be affected by the geometric parameters. NPCR has stronger acoustic confinement effects, which are conducive to improve acoustic sensing sensitivity, acoustic signal frequency resolution and acoustic energy harvesting efficiency.

scholarly journals Integrating magnetic capabilities to intracellular chips for cell trapping

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
María Isabel Arjona ◽  
Consuelo González-Manchón ◽  
Sara Durán ◽  
Marta Duch ◽  
Rafael P. del Real ◽  
...  
Keyword(s):  
Proof Of Concept ◽  
Promising Technique ◽  
Magnetic Manipulation ◽  
Biochemical Sensors ◽  
Cell Trapping ◽  
Silicon Chips ◽  
Enhanced Sensitivity ◽  
Electrical Devices ◽  
Cell Enrichment ◽  
Mechanical Sensors

AbstractCurrent microtechnologies have shown plenty of room inside a living cell for silicon chips. Microchips as barcodes, biochemical sensors, mechanical sensors and even electrical devices have been internalized into living cells without interfering their cell viability. However, these technologies lack from the ability to trap and preconcentrate cells in a specific region, which are prerequisites for cell separation, purification and posterior studies with enhanced sensitivity. Magnetic manipulation of microobjects, which allows a non-contacting method, has become an attractive and promising technique at small scales. Here, we show intracellular Ni-based chips with magnetic capabilities to allow cell enrichment. As a proof of concept of the potential to integrate multiple functionalities on a single device of this technique, we combine coding and magnetic manipulation capabilities in a single device. Devices were found to be internalized by HeLa cells without interfering in their viability. We demonstrated the tagging of a subpopulation of cells and their subsequent magnetic trapping with internalized barcodes subjected to a force up to 2.57 pN (for magnet-cells distance of 4.9 mm). The work opens the venue for future intracellular chips that integrate multiple functionalities with the magnetic manipulation of cells.

Reliability of Electrostatically Driven Resonant Sensors Under Mechanical Shock

2009 ◽  
Author(s):  
Mahmoud I. Ibrahim ◽  
Mohammad I. Younis
Keyword(s):  
Laser Doppler Vibrometer ◽  
Capacitive Sensor ◽  
Critical Issue ◽  
Shock Duration ◽  
Harmonic Load ◽  
Mechanical Shock ◽  
Resonant Sensors ◽  
Electrostatically Actuated ◽  
Enhanced Sensitivity ◽  
Theoretical Results

This paper presents a theoretical and experimental investigation of the response of electrostatically actuated parallel-plate resonators when subjected to mechanical shock. Resonators are commonly employed in resonant sensors, where they are operated at low pressure for enhanced sensitivity making their response to external disturbances such as shock a critical issue. A single-degree-of-freedom system is used to model a resonator, which is electrostatically driven by a DC load superimposed to an AC harmonic load. Simulation results are demonstrated in a series of shock spectra that help indicate the combined influence of shock, DC, and AC loads. The effect of the shock duration coinciding with the AC harmonic frequency is investigated. It is concluded that accounting for the electrostatic forces, especially the AC load, is crucial when addressing the reliability and performance of resonators against shock. It is found that for specific shock and AC excitation conditions, the resonator may experience early dynamic pull-in instability. Experimental work has been conducted on a capacitive sensor to verify the obtained theoretical results. The sensor is mounted on top of a small shaker and then both are placed inside a vacuum chamber. Acceleration pulses were applied on the sensor while powered by DC and AC load. The response of the device was monitored using a laser-Doppler vibrometer. The experimental results were compared to the theoretical results and were found to be in good agreement.

scholarly journals Enhanced Sensitivity of MoTe2 Chemical Sensor through Light Illumination

Micromachines ◽  
2017 ◽  
Vol 8 (5) ◽  
pp. 155 ◽  
Author(s):  
◽  
◽  
◽  
◽  
◽  
...  
Keyword(s):  
Chemical Sensor ◽  
Light Illumination ◽  
Enhanced Sensitivity

scholarly journals Bifurcation-enhanced ultrahigh sensitivity of a buckled cantilever

2018 ◽  
Vol 115 (12) ◽  
pp. 2884-2889 ◽  
Author(s):  
Sangmin An ◽  
Bongsu Kim ◽  
Soyoung Kwon ◽  
Geol Moon ◽  
Manhee Lee ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
High Sensitivity ◽  
Single Shot ◽  
Nonlinear Phenomenon ◽  
Ambient Conditions ◽  
Research Areas ◽  
Enhanced Sensitivity ◽  
Shot Detection ◽  
Mechanical Sensors

Buckling, first introduced by Euler in 1744 [Euler L (1744) Opera Omnia I 24:231], a sudden mechanical sideways deflection of a structural member under compressive stress, represents a bifurcation in the solution to the equations of static equilibrium. Although it has been investigated in diverse research areas, such a common nonlinear phenomenon may be useful to devise a unique mechanical sensor that addresses the still-challenging features, such as the enhanced sensitivity and polarization-dependent detection capability. We demonstrate the bifurcation-enhanced sensitive measurement of mechanical vibrations using the nonlinear buckled cantilever tip in ambient conditions. The cantilever, initially buckled with its tip pinned, flips its buckling near the bifurcation point (BP), where the buckled tip becomes softened. The enhanced mechanical sensitivity results from the increasing fluctuations, unlike the typical linear sensors, which facilitate the noise-induced buckling-to-flipping transition of the softened cantilever. This allows the in situ continuous or repeated single-shot detection of the surface acoustic waves of different polarizations without any noticeable wear of the tip. We obtained the sensitivity above 106 V(m/s)−1, a 1,000-fold enhancement over the conventional seismometers. Our results lead to development of mechanical sensors of high sensitivity, reproducibility, and durability, which may be applied to detect, e.g., the directional surface waves on the laboratory as well as the geological scale.

A chemical sensor for CBr4 based on quasi-2D and 3D hybrid organic–inorganic perovskites immobilized on TiO2 films

2018 ◽  
Vol 2 (4) ◽  
pp. 730-740 ◽  
Author(s):  
Pavlos Nikolaou ◽  
Anastasia Vassilakopoulou ◽  
Dionysios Papadatos ◽  
Emmanuel Topoglidis ◽  
Ioannis Koutselas
Keyword(s):  
Chemical Sensor ◽  
Tio2 Films ◽  
Low Dimensional ◽  
2D And 3D

It is possible that methylamine by being reduced could escape to the environment, thus, forcing the remaining perovskite to form other perovskite-like chemical moieties based on low dimensional arrangement of PbBr6 octahedra, rather than PbBr2.

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