Microsystem Technologies

Benbrahim, Abdelghani; Benchenane, Halima; Hammar, Salim; Aour, Benaoumeur; Mekkakia-Maaza, Nasreddine

doi: 10.1007/s00542-024-05674-3pmid: N/A

The objective of this work is to create a finite element model of different magnetic actuator topologies using COMSOL Multiphysics software. The aim is to simulate and improve the magnetic field generated by different planar microcoil topologies while minimising energy dissipation. The magnetic field generated by square and circular spiral planar microcoils was compared with that produced by serpentine meander planar microcoils. It has been found that the trapping efficiency in a magnetic manipulation microfluidic system for biological applications is closely linked to the geometry and electrical parameters of the planar microcoils. In addition, the location of these microcoils within the microfluidic channel intended for the circulation of the paramagnetic microbeads also play a crucial role. The obtained results show that bu reducing the inter-turn spacing using a thinner conductor cross-section and injected a higher electrical intensity in the actuator, both the magnetic field strength and its gradient can be increased, and therefore cause a higher magnetic actuation force.

Chen, Jyh Jian; Qiu, Xian Cheng

doi: 10.1007/s00542-024-05675-2pmid: N/A

Infectious diseases are illnesses caused by harmful pathogens from the exterior. Vaccines could prevent many people from disease infection. Over the past several years, the development and application of molecular diagnostic techniques have launched a revolution in monitoring infectious diseases. Polymerase chain reaction (PCR)-based systems to diagnose the etiologic agents of disease from clinical samples have been applicable in pathogen detection. We demonstrate a microfluidic chip for continuous flow PCR. The PDMS/glass bonding chip provides a miniaturized, cheap, and disposable material for pathogen diagnosis. The homemade thermal control module integrated with two cartridge heaters and one Peltier element supports the denaturation, extension, and annealing regions created inside the chip. Due to the large surface-to-volume ratio in the microchannel, the surface characteristics might augment the protein adsorption onto the channel surfaces and reduce the PCR amplification efficiency. We measure the hydrophilic properties, roughness of the wall and the structure of the surface under various surface treatments and express the PCR amplification efficiency. Results show that the most detailed is the PDMS sheet with the modification of Tween 20 of a concentration of 20% for the reduction of methyl peak of the absorption spectrum, the lowest contact angle, and the minor surface roughness. Next, the continuous flow PCR system amplifies a 385-bp segment of Q fever virus DNA to evaluate the performance of the DNA amplification. The overall product of Tween 20 is good because Tween 20 is an emulsifier, and it has excellent performance in both adhesion properties and coated samples. The need for point-of-care test (PoCT) devices has increased rapidly since the outbreak of COVID-19. The current portable device for PoCT will provide essential tools for real-time diagnosis.

Kondavitee, Girija Sravani; Desala, Ramakrishna

doi: 10.1007/s00542-024-05682-3pmid: N/A

This paper focuses on the design of a micropump specifically tailored for drug delivery applications. The micropump is an essential component in microfluidics systems that require precise handling of small volumes of fluids. Its main objective is to achieve a high flow rate while operating at a low voltage of 90 VP-P. To meet this goal, the micropump utilizes two stacked ring-type piezoelectric actuators (SPZT). The adoption of the ring-type actuators offers several advantages. Firstly, it reduces the contact area between the actuator and the membrane, minimizing the need for gluing. This enhances the overall reliability and robustness of the micropump. Additionally, the stacked configuration of the actuators allows for greater strain generation at lower applied voltages. This leads to improved performance and efficiency of the micropump. The paper includes a comprehensive study of membrane displacement by varying the inner radius of the ring-type SPZT actuator. This parametric analysis is conducted using finite element method (FEM) numerical analysis, providing insights into the optimal design parameters for achieving the desired flow rate. Through the proposed design and analysis, the micropump demonstrates a flow rate of 800 μl/min, making it suitable for drug delivery applications. The findings of this study contribute to the advancement of micropump technology and its potential use in various fields, including healthcare systems, microelectronic cooling devices, and more. Overall, this paper presents a detailed investigation into the design, performance, and optimization of a micropump specifically tailored for drug delivery applications. The utilization of stacked ring-type SPZT actuators and the achieved high flow rate highlight the potential of this micropump design in enhancing the efficiency and effectiveness of drug delivery systems.

Jongmanns, Marcel; Kaiser, Bert; Ruffert, Christine; Langa, Sergiu

doi: 10.1007/s00542-024-05684-1pmid: N/A

We designed a MEMS microvalve based on the nanoscopic electrostatic drive (NED) technology (Nat Commun 6:10078, 2015). NED actuators, electrostatically controlled bending beams, are implemented in a clamped-clamped configuration. A normally open plunger valve was designed and characterized. The device is manufactured from silicon. Gas flow rates of up to 37 SCCM can be proportionally controlled between 10% and 100%. A 10% leakage is always present at low backpressures (< 10 kPa) and increases to roughly 20% at 75 kPa backpressure. The structure has been tested up to backpressures of 300 kPa without damage to the structures, but the leakage increases to over 95%. Our unprecedented microvalve concept shows that it is possible to manufacture all-silicon MEMS microvalves with proportional control of the flow rate. The presented work is a proof of concept to test the capabilities of the NED technology for the use in microvalves. There are plans to decrease the leakage in future designs by introducing an additional sealing layer as well as manufacturing a shutter instead of a plunger design.

Dewangan, Priyanka; Purohit, Soumya; Sahu, Vishal; Vardhan, Robbi Vivek; Peddigari, Mahesh; Pal, Prem

doi: 10.1007/s00542-024-05688-xpmid: N/A

Isotropic wet etching is a popular technique to fabricate microfluidic channels in silicon wafers that are used in various fields of engineering and medicine. In this work, SiO2 and Cr thin films, along with positive photoresist (SiO2/Cr/PR), is employed as a novel masking layer on 3-inch silicon {100} wafers. SiO2 and Cr thin films are deposited through thermal oxidation and DC sputtering, respectively, and the photoresist is deposited by spin coating, followed by patterning using UV-photolithography. Here, a mixture of HF, HNO3, and CH3COOH, known as hydrofluoric acid–nitric acid–acetic acid solution (HNA solution), is used to fabricate microfluidic channel on silicon wafers via isotropic wet etching. The volume of HF is maintained constant, and the volumes of HNO3 and CH3COOH are varied in the HNA solution. The etching of the silicon wafers is performed in various compositions of HNA solution for 5, 10, and 15 min, respectively, and the resultant etching parameters and surface features are investigated. The vertical and lateral etch rates increased with the increment of HNO3 volume in HNA solution. Among all HNA solutions, the solution of composition 10:20:20 (HF: HNO3: CH3COOH) delivered a better outcome in terms of surface quality. The derived microfluidic channel using the mentioned 10:20:20 HNA solution comprised sharp edges and a defect-free surface.

Ha, Thi Dep

doi: 10.1007/s00542-024-05697-wpmid: N/A

Energy dissipation through support structures is one of the dominant loss mechanisms in MEMS resonators, which results in a very low quality (Q) factor. This paper aims to propose a one-dimensional phononic crystal (PnC) structure, namely a compound leaf-shaped phononic crystal (PnC) strip (TYPE_PROP), as anchor tethers to boost the anchor quality factor (Qanchor\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Q_{anchor}$$\end{document}) of a thin-film aluminium nitride (AlN)-on-silicon (Si) MEMS resonator. Thus, its Q can achieve a superior value. The operating frequency and mode of the resonator are 123.49 MHz and a length extensional (LE) mode, respectively. This frequency falls into the band gap frequency range of 52 MHz of the TYPE_PROP. The Qanchor\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Q_{anchor}$$\end{document} of the resonator with unit cell number variation of the TYPE_PROP tether is studied. From these investigations, the effectiveness of the tether in reducing/eliminating the anchor energy loss is evaluated. Furthermore, this Qanchor\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Q_{anchor}$$\end{document} is also compared to the same resonator structure with two conventional tether types. Additionally, the variation of the band gaps’ properties versus the dimensional parameters of the TYPE_PROP are also evaluated. The COMSOL Multiphysics platform based numerical results demonstrate that the Qanchor\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Q_{anchor}$$\end{document} of the resonator with the TYPE_PROP based tethers achieves superior values compared to its counterparts. Specifically, this value is about 5.42   ×\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\times$$\end{document}  1012\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$10^{12}$$\end{document} and 23.74 times higher than that of the TYPE_CON1 and TYPE_CON2, respectively. The Qanchor\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$Q_{anchor}$$\end{document} improvement of the LE mode MEMS resonator using the TYPE_PROP achieves higher values than that using two conventional tether configurations.

Razaghpour, Davoud; Ghasemi, Mir Majid; Fathi, Amir

doi: 10.1007/s00542-024-05701-3pmid: N/A

A new electrostatically tunable capacitor for wide range of frequencies is proposed in this paper. A complete design rule is proposed to design a variable capacitor in the range of 0.01 pF–2.05 pF due t the its application. The designed capacitor occupies 0.03 mm2–1.12 mm2 space based on the required capacitance value which is so small comparing the related published works. The floating technique is used to get the high-quality factor. The quality factor of the proposed capacitor is in the range of 45 to 100 over the frequency range of 1.28 G to 2.78 GHz, and also the tunability range of the tunable capacitor is 374%. After presenting a complete design rule with the related equations, the proposed capacitor is used in an amplifier circuit with a spiral inductor and the performance of the proposed capacitor is evaluated and compared with other capacitors. The COMSOL Multiphysics is used for simulation.

Chaujar, Rishu; Yirak, Mekonnen Getnet

doi: 10.1007/s00542-024-05705-zpmid: N/A

In this manuscript, a numerical model based on the electric field, threshold voltage, sub-threshold current, and electrostatic potential in cylindrical coordinates using Poisson’s equation for triple hybrid metal (THM) gate dielectric modulated junctionless silicon-nanowire gate all around FET based uricase and ChOX biosensor was developed at 40 nm technology (20 nm gate length) to study different gate engineering optimization effects on the performance of the proposed device. The results of the ATLAS-3D TCAD" device simulator agreed with a derived analytical model. Three types of gate optimization (gate engineering) are denoted by Mϕ (4.86, 4.96 and 4.50 eV), Oϕ (4.96, 4.86 and 4.50 eV), and Qϕ (4.86, 4.50 and 4.96 eV) each have three different metal work-function, including uricase and cholesterol oxidase (ChOX) biomolecules have been coated in the nanocavity to determine their impact on the device performance and also, the effect of nanogap cavity length on the proposed device was examined taking numerous simulations. Our findings conclude that nanocavity coated with ChOX dielectric and having tunable work-function optimized at “O” signifies better output results in the device sensitivity, shifting threshold voltage, switching ratio, transconductance, intrinsic voltage gain, and device efficiency. For instance, the switching ratio in the case of ChOX biomolecule for M, O, and Q gate optimizations are 5.22 × 105, 1.36 × 106, and 2.18 × 104, respectively. We conclude that the proposed devices with optimizing gate work function at “O” suggest new opportunities for future ultra-large-scale integration (ULSI) development to achieve highly efficient device performance.

Kamili, Jagadeesh Babu; Bandi, Kiran Kumar

doi: 10.1007/s00542-024-05716-wpmid: N/A

A highly sensitive and novel antenna sensor is designed for evaluating concentration of glucose in the human blood. The proposed sensor is constructed on an FR4 substrate layer of dimensions 20 mm × 30 mm × 1.6 mm with dielectric constant value of 4.3 resonance at 5 GHz with a quality factor of 471. In order to predict the amount of glucose, a human finger phantom model is developed in the electromagnetic simulator. The glucose levels are varied in various degrees from 0 to 1000 mg/dL and the resulting frequency shifts are measured by placing the phantom at various locations at different angles on the developed antenna sensor. When the phantom is located at 00 on the proposed sensor, a total frequency shift of 24 MHz, FDR of 24 kHz/(mg/dL) and sensitivity of 0.48x\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${10}^{-3}{(mg/dL)}^{-1}$$\end{document} are observed enabling the proposed sensor to detect diabetic conditions in the patients with high precision. The performance of the proposed sensor is analyzed for different real human finger positions and the resulting resonant frequencies are measured to verify the sensor’s performance in real-time scenario. The proposed sensor shows the average measurement error of about 1.9875% to detect glucose concentration levels.

Liao, Yanfei; Liu, Shihuang; Li, Xiao; Feng, Guang; Xue, Wei; Li, Fengping; Zhang, Kunpeng

doi: 10.1007/s00542-024-05718-8pmid: N/A

Kenics static mixer (KSM), which comprises helical blades twisted 180° in left and right-hand directions alternatively and connected 90° to each other, has been widely used in macroscale because of its excellent mixing performance. Despite the high mixing efficiency, it is hard to apply in microscale conditions since it is difficult to fabricate the helical blades with conventional manufacturing methods and still mainly stays in the simulation stage. In this study, the Inkjet 3D printing method, which provides a rapid and cost-effective manufacturing method in one step without considering the complex three-dimensional structures for microfluidics, was adopted to build the Kenics static mixer and the Fibonacci’s golden ratio theory that caused a small pressure loss in spiral motion was introduced into the helical blade design. Both simulations and experiments were conducted to characterize the mixing performance of the 3D printed KSM and compared with the slanted groove micromixer (SGM) and Y-shaped micromixer. The results demonstrated the superiority (mixing efficiency > 90%) of the 3D printed KSM proposed in this study.