scholarly journals Sampling and Mass Detection of a Countable Number of Microparticles Using on-Cantilever Imprinting

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2508
Author(s):  
Wilson Ombati Nyang’au ◽  
Andi Setiono ◽  
Angelika Schmidt ◽  
Harald Bosse ◽  
Erwin Peiner
Keyword(s):  
Resonant Frequency ◽  
Microscopic Analysis ◽  
Beam Width ◽  
Target Point ◽  
Mass Detection ◽  
Single Particles ◽  
Cantilever Sensors ◽  
Enhanced Sensitivity ◽  
Disease Diagnostics ◽  
Number Of Particles

Liquid-borne particles sampling and cantilever-based mass detection are widely applied in many industrial and scientific fields e.g., in the detection of physical, chemical, and biological particles, and disease diagnostics, etc. Microscopic analysis of particles-adsorbed cantilever-samples can provide a good basis for measurement comparison. However, when a particles-laden droplet on a solid surface is vaporized, a cluster-ring deposit is often yielded which makes particles counting difficult or impractical. Nevertheless, in this study, we present an approach, i.e., on-cantilever particles imprinting, which effectively defies such odds to sample and deposit countable single particles on a sensing surface. Initially, we designed and fabricated a triangular microcantilever sensor whose mass m0, total beam-length L, and clamped-end beam-width w are equivalent to that of a rectangular/normal cantilever but with a higher resonant frequency (271 kHz), enhanced sensitivity (0.13 Hz/pg), and quality factor (~3000). To imprint particles on these cantilever sensors, various calibrated stainless steel dispensing tips were utilized to pioneer this study by dipping and retracting each tip from a small particle-laden droplet (resting on a hydrophobic n-type silicon substrate), followed by tip-sensor-contact (at a target point on the sensing area) to detach the solution (from the tip) and adsorb the particles, and ultimately determine the particles mass concentration. Upon imprinting/adsorbing the particles on the sensor, resonant frequency response measurements were made to determine the mass (or number of particles). A minimum detectable mass of ~0.05 pg was demonstrated. To further validate and compare such results, cantilever samples (containing adsorbed particles) were imaged by scanning electron microscopy (SEM) to determine the number of particles through counting (from which, the lowest count of about 11 magnetic polystyrene particles was obtained). The practicality of particle counting was essentially due to monolayer particle arrangement on the sensing surface. Moreover, in this work, the main measurement process influences are also explicitly examined.

scholarly journals Which particles to select, and if yes, how many?

2021 ◽  
Author(s):  
Christian Schwaferts ◽  
Patrick Schwaferts ◽  
Elisabeth von der Esch ◽  
Martin Elsner ◽  
Natalia P. Ivleva
Keyword(s):  
Confidence Intervals ◽  
Bootstrap Method ◽  
Analytical Techniques ◽  
Single Particles ◽  
Minimal Sample ◽  
Error Quantification ◽  
Measurement Algorithm ◽  
Reliable Quantification ◽  
Window Selection ◽  
Number Of Particles

AbstractMicro- and nanoplastic contamination is becoming a growing concern for environmental protection and food safety. Therefore, analytical techniques need to produce reliable quantification to ensure proper risk assessment. Raman microspectroscopy (RM) offers identification of single particles, but to ensure that the results are reliable, a certain number of particles has to be analyzed. For larger MP, all particles on the Raman filter can be detected, errors can be quantified, and the minimal sample size can be calculated easily by random sampling. In contrast, very small particles might not all be detected, demanding a window-based analysis of the filter. A bootstrap method is presented to provide an error quantification with confidence intervals from the available window data. In this context, different window selection schemes are evaluated and there is a clear recommendation to employ random (rather than systematically placed) window locations with many small rather than few larger windows. Ultimately, these results are united in a proposed RM measurement algorithm that computes confidence intervals on-the-fly during the analysis and, by checking whether given precision requirements are already met, automatically stops if an appropriate number of particles are identified, thus improving efficiency.

scholarly journals Enhanced sensitivity of magnetoelectric sensors by tuning the resonant frequency

2011 ◽  
Vol 99 (4) ◽  
pp. 043504 ◽  
Author(s):  
Jonathan R. Petrie ◽  
Jonathan Fine ◽  
Sanjay Mandal ◽  
Gollapudi Sreenivasulu ◽  
Gopalan Srinivasan ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Enhanced Sensitivity ◽  
Magnetoelectric Sensors

Analysis of a Pot-Like Ultrasonic Sensor with an Anisotropic Beam Pattern

2010 ◽  
Vol 26 (3) ◽  
pp. 373-384 ◽  
Author(s):  
C.-C. Cheng ◽  
C.-Y. Lin ◽  
J.-H. Ho ◽  
C.-S. Chen ◽  
J. Shieh ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Fourier Transforms ◽  
Numerical Models ◽  
Beam Width ◽  
Ultrasonic Sensor ◽  
Beam Pattern ◽  
Design Parameters ◽  
Far Field ◽  
Vertical Beam ◽  
Vibrating Plate

AbstractWe investigated the design parameters of a compact pot-like ultrasonic sensor which possesses a highly anisotropic beam pattern. As the sensor size is small due to its application constraint, the parameters are thus highly coupled to one another. We analyzed the respective effects of the parameters in the case where there is a vertical beam width reduction. The parameters investigated include resonant frequency, vibrating plate width-expanded angle, and ratio of thickness discontinuity of the vibrating plate. Numerical models developed by combining finite-element analysis and spatial Fourier transforms were adopted to predict the far-field radiating beam pattern of the various design configurations. The displacement distribution of the vibrating plate was measured using a microscopic laser Doppler vibrometer and the far-field pressure beam patterns were measured using a standard microphone in a semianechoic environment. The three configurations we used to validate the simulation model resulted in an H-V ratio of 2.67, 2.68 and 3.13, respectively which all agreed well with the numerical calculations. We found that by increasing the operating resonant frequency from 40kHz to 58kHz, the vertical far-field beam width of an ultrasonic sensor can be reduced by 31.62%. We found that the vertical beam width can be significantly reduced when the ratio of the thickness discontinuity of the vibrating plate decreases from 1 to 0.4 and is incorporated with its optimal width-expanded angle of the vibrating plate. It appears that an ultrasonic sensor with this type of anisotropic beam pattern can be ideally adopted for today's automotive applications.

scholarly journals Modeling and Simulation of Triple Coupled Cantilever Sensor for Mass Sensing Applications

2015 ◽  
Vol 5 (3) ◽  
pp. 403 ◽  
Author(s):  
Nalluri Siddaiah ◽  
D.V. Rama Koti Reddy ◽  
Y. Bhavani Sankar ◽  
R. Anil Kumar ◽  
Hossein Pakdast
Keyword(s):  
Resonant Frequency ◽  
Simulation Software ◽  
Mass Sensing ◽  
Modeling And Analysis ◽  
Critical Dimensions ◽  
Cantilever Sensors ◽  
Sensing Applications ◽  
Cantilever Sensor ◽  
Modeling Techniques ◽  
Mass Detector

Cantilever sensors have been the growing attention in last decades and their use as a mass detector. This work presents design, modeling and analysis of Triple coupled cantilever(TCC) sensor using MEMS simulation software Comsol Multiphysics with critical  dimensions of 100μm length,20μm width and 2μm thickness. Simulations were performed based on finite element modeling techniques, where different resonant frequencies were observed for different modes of operation. It is also observed that the resonant frequency of the sensor decreases as some mass is applied on one particular cantilever. The various parameters greatly affecting the performance of TCC such as resonant frequency, dimensions, material and pressure or force applied on it.we also observed that while adding some mass on any one lateral cantilever, the resonant frequency of that respective mode reduced.

Tacky dot arrays for ordered particle mounting

1993 ◽  
Vol 51 ◽  
pp. 716-717
Author(s):  
Allan Cairncross ◽  
David M. Flaherty ◽  
Ulrich Klabunde
Keyword(s):  
Average Weight ◽  
Plastic Film ◽  
Single Particles ◽  
Ordered Arrays ◽  
Innovative Method ◽  
Glass Slides ◽  
Clear Plastic ◽  
Pattern Number ◽  
First Time ◽  
Number Of Particles

We describe for the first time a rapid way to mount particles on regularly spaced centers for microscopic examination. This innovative method mounts particles in ordered arrays rather than the random chaos of usual methods and therefore simplifies particle examination, identification and analysis. Advantages include the ability to easily mount single particles in controlled patterns and known locations, to mount tight clusters of 2 or more particles per center (Fig. 3); to repeatedly mount the same pattern/number of particles; to mount particles in unusual orientations (Fig. 5, 6) and to easily get the average weight of single particles. Examples of applications include mounting and examination of ores (Fig. 1), pollens (Fig. 2, 3), milled products, seeds (Fig. 4) and crystalline products(Fig. 5, 6).The mounting medium consists of a pattern of fine adhesive centers typically on 1 by 3 inch glass slides or on clear plastic film that is easily cut to any size or shape.

A Silicon Resonant Micro-Cantilever Biosensor with Closed-Loop Self-Excitation System for Biomacromolecular Detection

2014 ◽  
Vol 1030-1032 ◽  
pp. 2320-2325
Author(s):  
Long Fei Ma ◽  
Guo Yin Huang ◽  
Ming Yuan Guan ◽  
Yong Huang ◽  
Guo Wei Shi ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Closed Loop ◽  
Detection System ◽  
Mass Effect ◽  
Experimental Result ◽  
Excitation System ◽  
Cantilever Sensors ◽  
Order Of Magnitude ◽  
Equivalent Mass ◽  
Micro Cantilever

A silicon resonant micro-cantilever biosensor was introduced to detect biomacromolecular based on the relationship between the cantilever resonant frequency and the cantilever equivalent mass. A closed-loop self-excitation system was designed to acquire the resonant frequency of micro-cantilever. Two groups of resonant micro-cantilever sensors with different resonant frequencies of 18.192 kHz and 17.688 kHz respectively were tested. The result showed that the detection system can automatically search the resonant frequency of micro-cantilever and locked quickly. To demonstrate the feasibility of this approach, human immunoglobulin G(IgG) as model target biomacromolecular was employed, different concentration of IgG was detected by the resonant micro-cantilever sensors, the mass effect of micro-cantilever was adept and the micro-cantilever was drive by closed-loop circuit. The linearity of micro-cantilever biosensor was very well and the experimental result of sensitivity of micro-cantilever biosensor was about 6.6×106. All the results showed that sensitivity of the presented immunoassay significantly increased by one-order of magnitude and offered great application promises in providing a sensitive, specific, and potent method for real-time detection of biological detection.

Spore Detection in Air and Fluid Using Micro-cantilever Sensors

2005 ◽  
Vol 888 ◽  
Author(s):  
Angelica P. Davila ◽  
Amit Gupta ◽  
Tom Walter ◽  
Demir Akin ◽  
Arthur Aronson ◽  
...  
Keyword(s):  
Thermal Noise ◽  
Laser Doppler Vibrometer ◽  
Added Mass ◽  
Mass Detection ◽  
Liquid Environment ◽  
Average Mass ◽  
Cantilever Sensors ◽  
Micro Cantilever ◽  
Spore Detection ◽  
Biological Organisms

ABSTRACTThe purpose of this paper is to report on our work to develop a real-time monitoring device by using micro-cantilevers for the mass detection of biological organisms in air and fluid. The biological agent used was Bacillus anthracis Sterne spore. The experiment was conducted using a laser Doppler vibrometer (LDV) to measure the resonant frequency of the thermal noise cantilevers and the corresponding decrease in frequency as a result of the added mass. Moreover, the added mass attributed to the spores was quantified and compared in air and deionized (DI) water. The silicon cantilevers used in this study were of lengths ranging from 25 μm to 50 μm, 200 nm thick and a width of approximately 9 μm. The first part of the experiment consisted of suspending spores onto the cantilevers in fluid, drying the cantilevers, performing measurements in air and extracting the mass of the added spores. The average mass of a spore in air was 367 fg. The second part of the experiment utilized antibody and bovine serum albumin (BSA) physically adsorbed onto the cantilevers in order to fix the spores on the surface during the measurements in deionized water. The extracted mass of a spore in fluid was measured to be an average of 1.85 pg. This study demonstrated the ability to detect biological samples not only in air but also in a liquid environment.

Enhanced sensitivity of mass detection using the first torsional mode of microcantilevers

2008 ◽  
Vol 19 (5) ◽  
pp. 055207 ◽  
Author(s):  
Hui Xie ◽  
Julien Vitard ◽  
Sinan Haliyo ◽  
Stéphane Régnier
Keyword(s):  
Mass Detection ◽  
Torsional Mode ◽  
Enhanced Sensitivity

Sensing the Presence and Amount of Microbes Using Double Walled Carbon Nanotubes

2017 ◽  
pp. 78-117
Author(s):  
Anand Y Joshi ◽  
Ajay M Patel
Keyword(s):  
Carbon Nanotubes ◽  
Resonant Frequency ◽  
Mass Detection ◽  
Bartonella Bacilliformis ◽  
Amino Terminal ◽  
Biological Objects ◽  
Vibration Responses ◽  
Identification Of Bacteria ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The principle of mass detection using nano biosensors is based on the fact that the resonant frequency is very much sensitive to the mass of the bio-molecule, as with mass changes stiffness varies. The change of the attached mass on the CNT causes a shift to the resonant frequency. The key issue of mass detection is in quantifying the shift in the resonant frequency due to the mass of the attached molecule.This study, explores the vibration responses of the cantilever single and double-walled carbon nanotube with various attached microbes on the tip with an aim of developing a sensor. The biological objects studied include Alanine with Amino terminal residue, Deoxyadeonosine with free residue, Coronaviridae, Bartonella bacilliformis etc.. This sensor will be utilized to facilitate the identification of bacteria or virus that may be attached to CNT.

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