Showing papers on "Microheater published in 2019"

Multifunctional and High-Sensitive Sensor Capable of Detecting Humidity, Temperature, and Flow Stimuli Using an Integrated Microheater

Abstract: A multifunctional sensor comprising humidity, temperature, and flow detection capabilities is fabricated with a facile, single-layered device structure. A microheater based on serpentine Pt microlines plays key roles in both humidity and flow sensing at the hot state by introducing an efficient Joule heating effect, and meanwhile functions as a reliable thermistor at the cold state for accurate temperature measurement. For the first time, the strong temperature-dependent humidity-sensing properties of graphene oxide (GO) are revealed using the microheater platform. The GO-based humidity sensor displays ultrahigh sensitivity [124/% relative humidity (RH)], fast response time (3 s), wide detection range (8-95% RH) at room temperature, while the sensitivity drops at elevated temperatures, indicating the non-negligible temperature effect. Interestingly, a linear relationship between sensitivity and voltage is observed for the flow sensor, indicating the capability to manipulate sensitivity by conveniently modifying the voltage applied on the microheater. Because the three sensors work independently with distinguishable output signals, multiparametric sensing is enabled to monitor various human activities, such as respiration, noncontact sensation, and so forth. This work develops a simple, cost-effective, and useful multiparametric-sensing platform using a microheater for potential applications in the growing fields of internet of things, healthcare monitoring, and human-machine interfaces.

Nanohybrids of Pt-Functionalized Al2O3/ZnO Core–Shell Nanorods for High-Performance MEMS-Based Acetylene Gas Sensor

Abstract: Metal oxide nanostructures are the most promising materials for the fabrication of advanced gas sensors. However, the main challenge of these gas sensors is humidity interference and issues related to the selectivity and high operating temperature, which limits their response in real-time applications. In this study, we proposed nanohybrids of Pt-functionalized Al2O3/ZnOcore-shell nanorods (NRs) for a real-time humidity-independent acetylene gas sensor. The core ZnO NRs have been fabricated on microelectromechanical system (MEMS) microheater, followed by a coating of a thin nanoscale moisture-blocking conformal Al2O3 shell by atomic layer deposition (ALD) and decoration of Pt NPs using photochemical deposition and e-beam evaporation. Prior to the fabrication, a COMSOL simulation was performed to optimize the microheater design and moisture-blocking layer thickness. A comparative study of the decoration of Pt NPs on the ZnO surface by photochemical (s-Pt/ZnO) and e-beam evaporation (e-Pt/ZnO) and a Al2O3 thin moisture-blocking shell layer (Pt/Al2O3/ZnO) in sensor response has been conducted. The fabricated sensors (s-Pt/ZnO) and (e-Pt/ZnO) showed a high response ΔR/R (%) of 96.46% and 68.15% to 200 ppm acetylene at 120 °C and detect trace concentrations of acetylene down to 1 ppm, but the response is influenced by humidity. Moreover, the sensor (Pt/Al2O3/ZnO) exhibited nearly the same sensing characteristics and high acetylene selectivity despite the wide range of humidity variation from 20% RH to 70% RH. The Pt-functionalized Al2O3/ZnOcore-shell NR-based sensor showed better sensing and stable performance than other sensors (s-Pt/ZnO and e-Pt/ZnO) under humidity conditions.

3D Printed Microheater Sensor-Integrated, Drug-Encapsulated Microneedle Patch System for Pain Management.

Abstract: Microneedle patch devices have been widely utilized for transdermal drug delivery in pain management, but is challenged by accurate control of drug release and subsequent diffusion to human body. The recent emerging wearable electronics that could be integrated with microneedle devices offer a facile approach to address such a challenge. Here a 3D-printed microheater integrated drug-encapsulated microneedle patch system for drug delivery is presented. The ink solution comprised polydimethylsiloxane (PDMS) and multiwalled carbon nanotubes (MWCNTs) with a mass concentration of up to 45% (≈10 times higher of existing ones) is prepared and used to print crack-free stretchable microheaters on substrates with a broad range of materials and geometric curves. The adhesion strength of the printed microheater on the microneedle patch in elevated temperatures is measured to evaluate their integration performance. Assessments of encapsulated drug release into rat's skin are confirmed by examining degradation of microneedles, skin morphologies, and released fluorescent signals. Results and demonstrations established here creates a new opportunity for developing sensor controlled smart microneedle patch systems by integrating with wearable electronics, potentially useful in clinical and biomedical research.

Development of MEMS MOS gas sensors with CMOS compatible PECVD inter-metal passivation

Abstract: Metal oxide semiconductor (MOS) based micro-electromechanical sensors (MEMS) for gas measurement were developed using back-end-of-line (BEOL) compatible inter-metal dielectric films deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD). As MOS MEMS require sintering above 600°C, a set of PECVD silicon oxide and nitride films was characterized before and after annealing up to 700°C, in order to identify the best candidate inter-metal dielectric materials. The effect of thermal load on the films was determined by measuring stress, thickness and refractive index after annealing both in dry air and nitrogen atmosphere. Nano-indentation was used to estimate the elastic modulus after annealing. The best performing films were employed as inter-metal dielectric in the full fabrication of microheater MEMS gas sensors. Among the selected films, only silicon oxide deposited with high frequency plasma generator allowed for the complete gas sensor fabrication with no damage. SnO2 paste was successfully screen printed on the fabricated membranes and sintered to enable gas sensing. Electrical and gas sensing tests were performed with the fabricated microheaters, demonstrating full functionality. Thermal stress endurance tests were also conducted, with no membrane deformation after more than 500,000 duty cycles. Results show that the proposed PECVD passivation is compliant up to 650°C firing temperature and 450°C operating temperature, and demonstrate the use of CMOS-BEOL PECVD inter-metal passivation for MOS MEMS gas sensor fabrication.

Batch-fabricated CO gas sensor in large-area (8-inch) with sub-10 mW power operation

Abstract: Gas sensors that can operate with sub-10 mW power consumption are in great demand in application where mobile devices are used to detect harmful gases in real time. Such low power gas sensors can be realized by employing miniaturized and air-suspended microheater platforms; however, a productive and reliable fabrication method should be developed for their practical use. Here, we present a batch-fabrication method based on a surface micro-machining process to uniformly and reliably produce the sub-10 mW power oerating gas sensors on an 8-inch wafer area. The fabricated gas sensors showed a reproducible and sensitive response to various concentrations of carbon monoxide gas (as low as 1 ppm) with 5.0 mW power operation, which is among the lowest power achieved for semiconducting metal-oxide gas sensors. In addition, the devices showed low sample-to-sample variation and high reliability in a long-term stability test, verifying their potential for practical use in mobile gas sensing applications.

Plasma assisted formation of 3D highly porous nanostructured metal oxide network on microheater platform for Low power gas sensing

Abstract: A facile and versatile approach that integrates highly porous metal oxide nanostructured network with a low power microheater platform is presented for the creation of low-power, miniaturized gas sensors. Highly porous nanostructured metal oxide network is formed by oxygen plasma treatment of a metal containing polymer film followed by a heat treatment. A generalized aqueous metal precursor solution allows a large variety of metal salts to be incorporated into cast polymer films, thus forming nanostructured metal oxide network with various compositions. Gas sensing behavior is demonstrated for Co3O4 -based devices, exhibiting high sensitivity, low detection limit, and fast response and recovery towards formaldehyde gas. The overall fabrication process is flexible and highly scalable. This facile and flexible fabrication method can be used to reproducibly fabricate a variety of low power gas sensors with tunable performances for many applications and has great potential for mass production.

A Low Power Cantilever-Based Metal Oxide Semiconductor Gas Sensor

Abstract: This letter, for the first time, reports a novel metal oxide semiconductor (MOS) gas sensor based on a single cantilever. The extremely brief Platinum microheater without any coil, is on a $10~\mu \text{m}$ wide cantilever, which shows very low static power consumption and fast heating response. Sensors were fabricated on a four inch Si wafer using typical micro-electro-mechanical system (MEMS) process, and SnO2 was chosen as the sensing material. Test results indicate that the static power consumption is only 2.96 mW. With this applied power, the sensor can reach 400 °C and the heating-up time is just 260 $\mu \text{s}$ . Both of them are enormously improved, comparing with the MEMS MOS gas sensors with suspended membrane supported by slender beams. The sensor shows a good linear characteristic to 0–10 ppm ethanol. Moreover, due to the single cantilever structure, ten sensors can be fabricated inside a die of 1 mm2, improving the integration by an order of magnitude.

High-Q microresonators integrated with microheaters on a 3C-SiC-on-insulator platform.

Abstract: We demonstrate, to the best of our knowledge, the first thermally reconfigurable high-Q silicon carbide (SiC) microring resonators with integrated microheaters on a 3C-SiC-on-insulator platform. We extract a thermo-optic coefficient of around 2.67×10−5/K for 3C-SiC from wavelength shift of a resonator heated by a hot plate. Finally, we fabricate a 40-μm-radius microring resonator with intrinsic Q of 139,000 at infrared wavelengths (∼1550 nm) after integration with a NiCr microheater. By applying current through the microheater, a resonance shift of 30 pm/mW is achieved in the microring, corresponding to ∼50 mW per π phase shift. This platform offers an easy and reliable way for integration with electronic devices as well as great potential for diverse integrated optics applications.

Mechano-thermo-chromic device with supersaturated salt hydrate crystal phase change.

Abstract: Active control of transparency/color is the key to many functional optoelectric devices. Applying an electric field to an electrochromic or liquid crystal material is the typical approach for optical property control. In contrast to the conventional electrochromic method, we developed a new concept of smart glass using new driving mechanisms (based on mechanical stimulus and thermal energy) to control optical properties. This mechano-thermo-chromic smart glass device with an integrated transparent microheater uses a sodium acetate solution, which shows a unique marked optical property change under mechanical impact (mechanochromic) and heat (thermochromic). Such mechano-thermo-chromic devices may provide a useful approach in future smart window applications that could be operated by external environment conditions.

Improved Sensing Capability of Integrated Semiconducting Metal Oxide Gas Sensor Devices.

Abstract: Semiconducting metal oxide (SMO) gas sensors were designed, fabricated, and characterized in terms of their sensing capability and the thermo-mechanical behavior of the micro-hotplate. The sensors demonstrate high sensitivity at low concentrations of volatile organic compounds (VOCs) at a low power consumption of 10.5 mW. In addition, the sensors realize fast response and recovery times of 20 s and 2.3 min, respectively. To further improve the baseline stability and sensing response characteristics at low power consumption, a novel sensor is conceived of and proposed. Tantalum aluminum (TaAl) is used as a microheater, whereas Pt-doped SnO2 is used as a thin film sensing layer. Both layers were deposited on top of a porous silicon nitride membrane. In this paper, two designs are characterized by simulations and experimental measurements, and the results are comparatively reported. Simultaneously, the impact of a heat pulsing mode and rubber smartphone cases on the sensing performance of the gas sensor are highlighted.

Characterization of an Acetone Detector Based on a Suspended WO 3 -Gate AlGaN/GaN HEMT Integrated With Microheater

Abstract: A suspended AlGaN/GaN high electron mobility transistor (HEMT) sensor with a tungsten trioxide (WO3) nanofilm modified gate was microfabricated and characterized for ppm-level acetone gas detection. The sensor featured a suspended circular membrane structure and an integrated microheater to select the optimum working temperature. High working temperature (300°C) increased the sensitivity to up to 25.7% and drain current change ${I}_{{\text {DS}}}$ to 0.31 mA for 1000-ppm acetone in dry air. The transient characteristics of the sensor exhibited stable operation and good repeatability at different temperatures. For 1000-ppm acetone concentration, the measured response and recovery times reduced from 148 and 656 to 48 and 320 s as the temperature increased from 210 °C to 300 °C. The sensitivity to 1000-ppm acetone gas was significantly greater than the sensitivity to ethanol, ammonia, and CO gases, showing low cross-sensitivity. These results demonstrate a promising step toward the realization of an acetone sensor based on the suspended AlGaN/GaN HEMTs.

Ultrahigh temperature platinum microheater encapsulated by reduced-TiO2 barrier layer

Abstract: Thermal stability and adhesion of the Pt/barrier interface were investigated herein. Reduced-TiO2, or TiO2-δ, was found to offer stronger adhesion and greater thermal stability as a barrier layer for Pt than that of TiN and stoichiometric TiO2. It enables a long-term high-temperature operation. No voids or peeling was seen after annealing at a temperature of 700 °C in a stacked layer of Pt/ TiO2-δ; whereas, voids and peeling inevitably appeared in Pt layers on TiN and TiO2, respectively. A microhotplate composed of a Pt/TiO2-δ microheater was confirmed to perform at 800 °C at a heating power of 120 mW. The heating response time was below 20 ms between 150 °C and 800 °C. Ten million cycles of temperature modulation between room temperature and 550 °C did not cause any performance deterioration.

Wafer-level fabrication of low power consumption integrated alcohol microsensor

Abstract: An integrated alcohol microgas sensor was designed and fabricated based on TiO 2 /SnO 2 nanocomposites acting as a sensing layer and microheater providing working temperature. The stacked TiO 2 /SnO 2 nanocomposites were prepared by magnetron sputtering. A unique suspended membrane consisting of Si 3 N 4 /SiO 2 /Si 3 N 4 /SiO 2 four layers was prepared by different methods, respectively, and applied in microheater to support the electrodes and sensing layer for reducing power consumption. The fabrication process tackled the difficulty that the sensing layer preparation is incompatible with microelectromechanical systems micromachining technology and realised the mass production of the wafer-level sensor chips with good consistency. The microalcohol sensors showed excellent response characteristics for alcohol (50-600 ppm) detection at low power consumption (39 mW).

CMOS-Compatible Gas Sensors

Abstract: As transistor scaling along Moore's law approaches its physical limits, the semiconductor industry has been intensely working on functional integration of devices along the More-than-Moore approach. The integration of sensors, RF circuits, and other functionalities with electronics is enabled by innovations in packaging, three-dimensional integration, and most importantly through the fabrication of multiple components and features on silicon using established technology. With the application of semiconductor metal oxide (SMO) thin films, there is potential for the integration of gas sensors with processing electronics. This manuscript describes SMO gas sensors, their fabrication, and operating techniques which require high temperatures and therefore an integrated microheater. Microheaters require the fabrication of a membrane in order to isolate the high temperature component from other circuitry. Finally, the manuscript looks at recent achievements in engineering of SMO films and in understanding and modeling their sensing mechanism.

Design and Fabrication of CMOS Microstructures to Locally Synthesize Carbon Nanotubes for Gas Sensing.

Abstract: Carbon nanotubes (CNTs) can be grown locally on custom-designed CMOS microstructures to use them as a sensing material for manufacturing low-cost gas sensors, where CMOS readout circuits are directly integrated. Such a local CNT synthesis process using thermal chemical vapor deposition (CVD) requires temperatures near 900 °C, which is destructive for CMOS circuits. Therefore, it is necessary to ensure a high thermal gradient around the CNT growth structures to maintain CMOS-compatible temperature (below 300 °C) on the bulk part of the chip, where readout circuits are placed. This paper presents several promising designs of CNT growth microstructures and their thermomechanical analyses (by ANSYS Multiphysics software) to check the feasibility of local CNT synthesis in CMOS. Standard CMOS processes have several conductive interconnecting metal and polysilicon layers, both being suitable to serve as microheaters for local resistive heating to achieve the CNT growth temperature. Most of these microheaters need to be partially or fully suspended to produce the required thermal isolation for CMOS compatibility. Necessary CMOS post-processing steps to realize CNT growth structures are discussed. Layout designs of the microstructures, along with some of the microstructures fabricated in a standard AMS 350 nm CMOS process, are also presented in this paper.

Silicon microheater based low-power full-range methane sensing device

Abstract: For many industrial applications of the methane sensor in a wireless node, the primary requirements are low power consumption and wide detection range. These requirements are considerably challenging as compared to the requirements related with conventional methane sensors. To meet such requirements of Internet of Things (IoT) development for methane monitoring in underground coal mines, we propose a full concentration range methane detector using a micro silicon device with low power consumption. The microheaters are fabricated with a CMOS-compatible SOI (silicon-on-insulator) MEMS (microelectromechanical system) process. Joule heating is utilized to enable micro-local high temperature for methane sensing. To obtain signals with high sensitivity and low heating power under an appropriate supplied current, a working point is determined by means of the maximum voltage variations from the voltage-current characteristics of the microheater. In general, the methane sensitivity of the micro heater increases and the power consumption decreases, as the length of the heater increases. The device has an exponential-decay response in the entire methane concentration range. A typically low power consumption around 27 mW yields an average sensitivity of approximately 20 mV/% CH4 for the methane concentration ranging from 0 to 17%.

A Microheater on Polyimide Substrate for Hand-held Realtime Microfluidic Polymerase Chain Reaction Amplification

Abstract: The development of a DNA microfluidic device with a high speed, low power, and low reagent volume is very critical for real-time genotyping and diagnosis in point-of-care applications. This paper reports a polymer-based thermal cycler for a handheld and battery-powered polymerase chain reaction (PCR) system using a polyimide (PI) film-based micro-fabricated heater module and polymer film microfluidic chambers of 10 μL, with a handheld and low power consumption, compared to state of the art. It took 21 min for 40 thermal cycling for DNA amplification and a maximum power consumption of 0.6 W. The microheater on PI film substrate fabricated and real-time quantification of deoxyribonucleic acid (DNA) using the heater in hand-held sizes experimentally shown here. The device would be applicable for on-site molecular diagnostics.

Maskless visible-light photolithography of copper microheater for dynamic microbioreactor

Abstract: Advances in microfabrication have led to the development of microbioreactor including microheater as one of important components for microbioreactor. Microheater should be fabricated based on specific requirement of microbioreactor including shape, size, target working temperature, and heating rate profile, where they would determine the heat distribution to the microbioreactor. Here, we propose serpentine-shaped and spiral-shaped microheaters for a dynamic-flow microbioreactor. Computer models were generated and characterized by finite element analysis (FEA) to simulate the heating performance. Microheaters were then fabricated by maskless photolithography using visible light generated by a commercial digital light projector (DLP) followed by wet etching. Geometrical features of fabricated microheaters were then measured to characterize the design transfer. FEA result shows that given same amount of input electrical power and observation time; both microheaters have different heat distribution profiles which could affect the heating control scheme. Geometrical measurement on certain segments shows that the current fabrication technique can transfer the design with dimensional error percentage of 0.5 to 39 % without significant change in the geometrical shape.Advances in microfabrication have led to the development of microbioreactor including microheater as one of important components for microbioreactor. Microheater should be fabricated based on specific requirement of microbioreactor including shape, size, target working temperature, and heating rate profile, where they would determine the heat distribution to the microbioreactor. Here, we propose serpentine-shaped and spiral-shaped microheaters for a dynamic-flow microbioreactor. Computer models were generated and characterized by finite element analysis (FEA) to simulate the heating performance. Microheaters were then fabricated by maskless photolithography using visible light generated by a commercial digital light projector (DLP) followed by wet etching. Geometrical features of fabricated microheaters were then measured to characterize the design transfer. FEA result shows that given same amount of input electrical power and observation time; both microheaters have different heat distribution profiles w...

Demonstration of a microelectromechanical tunable Fabry-Pérot cavity based on graphene-bonded fiber devices.

Abstract: Taking advantage of the high thermal conductivity of graphene, this paper demonstrates a microelectromechanical (MEM) tunable Fabry-Perot (F-P) cavity, based on a graphene-bonded fiber device (GFD) which acts as a microheater. By increasing the electric current from 0 mA to 8 mA in the heater, the temperature of the GFD can rise and approach a value of 760 K theoretically. This high temperature will cause a deformation of the fiber, allowing the graphene-bonded fiber end to forma gap adjustable F-P cavity with a cleaved single mode fiber. The gap in the cavity can be reduced by increasing the current applied, leading the transmittance of the cavity to change. In this work, a highly sensitive current sensor (5.9x10⁵nm/A²) and a tunable modelocked fiber laser (1.2x10⁴nm/A²) are created based on the MEM tunable F-P cavity.

Single-use impulsion system for displacement of liquids on thermoplastic-based lab on chip

Abstract: In this paper, an impulsion system of liquids for thermoplastic microfluidic circuits is described. The presented device is composed of a membrane made of polymethylmethacrylate (PMMA) which separates two microchambers (top and bottom microchamber). The bottom microchamber is pressurized to a fixed pressure, while the top microchamber remains at atmospheric pressure. The actuation consists on increasing the temperature of the membrane by Joule effect using an aluminum microheater which is fabricated over the membrane. Once the temperature of the membrane is close to the glass transition temperature of the thermoplastic, the membrane deforms due to the different pressure of the bottom microchamber, blocking the top microchamber. The trapped air fits the volume of liquid which will be impulsed inside the microchannel. Unlike other membranes used in microfluidics, the presented membrane keeps deformed when the actuation is removed. The fabricated impulsion system is designed to move a volume of 30 μL. The experimental results correspond to a theoretical design with an average error of about 6.32%. The proposed impulsion system is easily integrable on thermoplastic lab on chips for liquid management.

Correction to: Thermally Efficient Coplanar Architecture of Microheater and Inter-digitated Electrodes for Nanolayered Metal Oxide Based Hydrogen Gas Sensor

Abstract: Chemoresistive hydrogen gas sensor with zinc oxide (ZnO) thin film as a sensing layer has been studied with a coplanar integrated architecture of microheater and interdigitated electrode (IDE). ZnO thin films are fabricated via a chemical route. The present study is based on the use of a coplanar microheater with IDE’s fabricated for the hydrogen sensor. Further, the effect of the integrated architecture over sensing properties of the sensor has been studied. The sensing response of the sensor with film thickness of 150 nm at an operating temperature of 160 °C comes out to be 10.97. The prime aim of the study is to present coplanar integrated architecture of microheater and IDE’sfor a ZnO based hydrogen sensor.

Parallel Dosing Using a Superhydrophobic, Heated Plate by Evaporation Induced Droplet Transport

Abstract: A highly parallelizable approach for the precise dosing of homogenous liquids is presented. Droplets of the dosing liquid rest on a superhydrophobic plate featuring a 3x3 array of holes, which evaporate with time and therefore reduce in size. If the size of the droplets is small enough, they are able to pass through the holes, which can be subsequently used for further applications. Furthermore, microheaters are screen-printed around the holes of the superhydrophobic plate, in order to accelerate the evaporation process. Experimental data regarding temperature distribution and the improvement due to the addition of the microheaters to the setup is provided.

Ultra-High Sensitive Gas Detection Using Pulse-Driven MEMS Sensor Based on Tin Dioxide

Abstract: Miniaturized semiconductor gas sensors composed of microheater and a sensor electrode allowed a rapid heater switching, pulse-driven operation. SnO 2 nanoparticles was fabricated on the gas sensor device, and the sensor was driven during heater on phase at elevated temperature. Additionally, the gas was introducing into the sensing layer during heater off phase, cooling the sensing layer. On the basis of the behavior of the electrical resistance under pulse-driving, we determined the various types of sensor responses to improve the gas sensing characteristics. The gas sensitivity was drastically enhanced by pulse-driving mode, because utility factor of the pulse-driven sensor was higher than that of conventional sensor. Additionally, newly gas sensing definition also enhanced the gas selectivity, because gas accumulates in the sensing layer during heater off phase. Therefore, pulse-driving mode improved the ability of semiconductor gas sensors.

Monolithically integrated CMOS plus MEMS microheater and preparation method

Abstract: The invention discloses a monolithically integrated CMOS plus MEMS microheater and a preparation method. The monolithically integrated CMOS plus MEMS microheater comprises a heat insulation layer, aninsulating layer, and electrode poles, wherein the heat insulation layer is formed on the surface of a CMOS structure; the insulating layer I is formed on the surface of the heat insulation layer; openings of pad in connection with the electrode poles are drily etched on the heat insulation layer and the insulating layer I; a cavity and a suspended heating structure are formed between the electrode poles; the heating structure is sequentially of a support layer, an insulating layer, a step structural layer, a heating layer and a passivation layer from the bottom to the top; the insulating layer is covered on the support layer; the step structural layer is located on the insulating layer; the heating layer covers a compound structure containing the support layer, the insulating layer and the step structural layer and covers the upper surfaces of the electrode poles; the passivation layer covers the heating layer; a CMOS/ASIC circuit of the heat insulation layer is connected with the electrode poles; and the insulating layer I, the electrode poles and the support layer jointly forms the cavity of the suspended heater structure.

3D Printed Microheater Sensor-Integrated, Drug-Encapsulated Microneedle Patch System for Pain Management

Abstract: Microneedle patch device has been widely utilized for transdermal drug delivery in pain management, but is challenged by accurate control of drug release and subsequent diffusion to human body. The recent emerging wearable electronics that could be integrated with microneedle devices offers a facile approach to address such a challenge. Here a 3D printed microheater integrated drug-encapsulated microneedle patch system for drug delivery is presented. The ink solution comprised of polydimethylsiloxane (PDMS) and multiwalled carbon nanotubes (MWCNTs) with mass concentration of up to 45% is prepared and used to print crack-free stretchable microheaters on substrates with a broad range of materials and geometric curves. The adhesion strength of printed microheater on microneedle patch in elevated temperatures are measured to evaluate their integration performance. Assessments of encapsulated drug release into rat’s skin are confirmed by examining degradation of microneedles, skin morphologies, and released fluorescent signals. Results and demonstrations established here creates a new opportunity for developing sensor controlled smart microneedle patch systems by integrating with wearable electronics, potentially useful in clinic and biomedical research.

Highly-doped in-plane Si electrodes embedded between free-hanging microfluidic channels

Abstract: Highly-doped in-plane Si electrodes were embedded between free-hanging microfluidic channels using Surface Channel Technology. The cross-sectional area of the electrodes can be controlled by tuning the distance between the release windows and the channels. The large cross-sectional area of the electrodes is especially beneficial as microheater, but they also enable resistive or capacitive readout in e.g. flow sensors.