Magnetostrictive Flexible Thin Film Structure for Micro Devices

Polyimide (Kapton, Dupont Corp.) based magnetostrictive thin film structures were designed and fabricated for micro device applications. In particular the growth of films on flexible substrates was studied to allow a simple integration of the system in miniaturized magnetostrictive devices. The films were fabricated on different substrates to compare their different magnetic and structural properties. It showed much more magnetostriction and higher impact resistance results compared with traditional Si based film type actuators. In the fabrication process, amorphous TbDyFe films with thicknesses of 500 nm, 1 μm, 1.5 μm respectively, were deposited on the designed substrate by DC magnetron sputtering. During sputtering process the substrate holder was maintained at room temperature. After the sputter process, X-ray diffraction studies were also carried out to determine the film structure and thickness of the sputtered film. At last, magnetization from VSM (Vibrating Sample Magnetometer) and magnetostriction from optical cantilever method of each structure were measured to estimate the magneto-mechanical characteristics under the external magnetic field lower than 0.7 T for micro-system applications.

Flexible planar micro supercapacitor diode

Supercapacitor diode is a novel ion device that performs both supercapacitor energy storage and ion diode rectification functions.However,previously reported devices are limited by their large size and complex processes.In this work,we demonstrate a screen-printed micro supercapacitor diode(MCAPode)that based on the insertion of a finger mode with spinel ZnCo_(2)O_(4) as cathode and activated carbon as anode for the first time,and featuring an excellent area specific capacitance(1.21 mF cm^(-2)at 10 mV s^(-1))and high rectification characteristics(rectification ratioⅠof 11.99 at 40 mV s^(-1)).Taking advantage of the ionic gel electrolyte,which provides excellent stability during repeated flexing and at high temperatures.In addition,MCAPode exhibits excellent electrochemical performance and rectification capability in"AND"and"OR"logic gates.These findings provide practical solutions for future expansion of micro supercapacitor diode applications.

Active Micro-Nano-Collaborative Bioelectronic Device for Advanced Electrophysiological Recording

The development of precise and sensitive electrophysiological recording platforms holds the utmost importance for research in the fields of cardiology and neuroscience.In recent years,active micro/nano-bioelectronic devices have undergone significant advancements,thereby facilitating the study of electrophysiology.The distinctive configuration and exceptional functionality of these active micro-nano-collaborative bioelectronic devices offer the potential for the recording of high-fidelity action potential signals on a large scale.In this paper,we review three-dimensional active nano-transistors and planar active micro-transistors in terms of their applications in electroexcitable cells,focusing on the evaluation of the effects of active micro/nano-bioelectronic devices on electrophysiological signals.Looking forward to the possibilities,challenges,and wide prospects of active micro-nano-devices,we expect to advance their progress to satisfy the demands of theoretical investigations and medical implementations within the domains of cardiology and neuroscience research.

Accuracy and Electromagnetic Safety Evaluation of a Portable Electromagnetic Localization System for Micro Invasive Medical Devices in Vivo

Aiming at localizing the telemetric capsule for detecting gastrointestinal physiological parameters in vivo accurately,a portable alternating current(AC)electromagnetic localization system is designed.To verify the feasibility of the method,the model and construction of the localization system are detailed.And static and dynamic accuracy of the localization system are tested by experiments.Next,we compare the simulating results of the electromagnetic radiation aroused by the localization system with the electromagnetic safety standards of human(ICNIRP guidelines and IEEE standard C95.1-1991).Finally,in terms of the results of the static and dynamic experiments,conclusions are drawn that the accuracy of portable positioning system is high(less than 10 mm)enough to satisfy the localization need of the micro invasive medical devices in vivo,and there is no harm of electromagnetic radiation to human.

Rapid Manufacturing of Non-Assembly Complex Micro-Devices by Microstereolithography

This paper introduces a non-assembly manufacturing case with microstereolithography technology. The design and manufacturing process of a pneumatic thrust bearing is described, and a special tessellation method is developed to further improve the capability of the manufacturing system thus bigger products can also be easily manufactured. Implemented in a layer-by-layer fashion, stereolithography has been used for the rapid manufacturing of complex devices, and it avoids the expensive assembly process in the traditional manufacturing. This paper presents that microstereolithography can produce high-resolution products with intricate details, small openings, and smooth surfaces. The potential of the microstereolithograhy technique is explored for the rapid manufacturing of small and complex objects.

Integrated microfluidic devices for in vitro diagnostics at point of care

Given the continuous and growing demand for point of care(POC)diagnostic tests,attention has been shifted toward integration and miniaturization of laboratory protocols into“sample-in-answer-out”devices.Microfluidic technologies have been considered an ideal solution to address the requirements of POC diagnostics since many laboratory functions can be miniaturized and incorporated onto a single integrated chip.In this review,we summarize the advances of integrated microfluidic devices for POC diagnostics in the last 3 years.Particularly,we summarize current materials used for microfluidic chip fabrication,discuss the innovation of versatile integrated microfluidic devices,especially the strategies for simplifying sample preparation in manual or self-driven systems,and new detection methods of microfluidic chips.In addition,we describe new integrated microfluidic devices for POC diagnostics of protein-targeted immunodiagnostics,nucleic acid molecular tests,and small molecule metabolites analysis.We also provide future perspectives and current challenges for clinical translation and commercialization of these microfluidic technologies.

Micro/nano biomedical devices for point-of-care diagnosis of infectious respiratory diseases

Corona Virus Disease 2019(COVID-19)has developed into a global pandemic in the last two years,causing significant impacts on our daily life in many countries.Rapid and accurate detection of COVID-19 is of great importance to both treatments and pandemic management.Till now,a variety of point-of-care testing(POCT)approaches devices,including nucleic acid-based test and immunological detection,have been developed and some of them has been rapidly ruled out for clinical diagnosis of COVID-19 due to the requirement of mass testing.In this review,we provide a summary and commentary on the methods and biomedical devices innovated or renovated for the quick and early diagnosis of COVID-19.In particular,some of micro and nano devices with miniaturized structures,showing outstanding analytical performances such as ultra-sensitivity,rapidness,accuracy and low cost,are discussed in this paper.We also provide our insights on the further implementation of biomedical devices using advanced micro and nano technologies to meet the demand of point-of-care diagnosis and home testing to facilitate pandemic management.In general,our paper provides a comprehensive overview of the latest advances on the POCT device for diagnosis of COVID-19,which may provide insightful knowledge for researcher to further develop novel diagnostic technologies for rapid and on-site detection of pathogens including SARS-CoV-2.

Achieving superior performance in thermoelectric Bi_(0.4)Sb_(1.6)Te_(3.72)by enhancing texture and inducing high-density line defects

Miniaturization of efficient thermoelectric(TE)devices has long been hindered by the weak mechanical strength and insufficient heat-to-electricity conversion efficiency of zone-melted(ZM)ingots.Here,we successfully prepared a robust high-performance p-type Bi_(0.4)Sb_(1.6)Te_(3.72)bulk alloy by combining an ultrafast thermal explosion reaction with the spark plasma sintering(TER-SPS)process.It is observed that the introduced excess Te not only enhances the(00l)-oriented texture to ensure an outstanding power factor(PF)of 5 mW m^(−1)K^(−2),but also induces extremely high-density line defects of up to 10^(11)–10^(12)cm^(−2).Benefiting from such heavily dense line defects,the enhancement of the electronic thermal conductance from the increased electron mobility is fully compensated by the stronger phonon scattering,leading to an evident net reduction in total thermal conductivity.As a result,a superior ZT value of~1.4 at 350 K is achieved,which is 40%higher than that of commercial ZM ingots.Moreover,owing to the strengthening of grain refinement and highdensity line defects,the mechanical compressive stress reaches up to 94 MPa,which is 154%more than that of commercial single crystals.This research presents an effective strategy for the collaborative optimization of the texture,TE performance,and mechanical strength of Bi2Te3-based materials.As such,the present study contributes significantly to the future commercial development of miniature TE devices.