Topic
Microheater
About: Microheater is a research topic. Over the lifetime, 814 publications have been published within this topic receiving 12478 citations.
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TL;DR: It is found that this approach provides a simple method to locally synthesize suspended CuO nanowires on polysilicon microbridges on silicon substrates, thus allowing for integration of CuO Nanowires into silicon-based devices.
Abstract: This paper presents the synthesis of CuO nanowires using a localized thermal heating method in ambient air. It employs local heat sources defined in micro-resistive heaters fabricated by a standard polysilicon-based surface micromachining process instead of a global furnace heating. Since the synthesis is performed globally at room temperature, the presented process is compatible with standard CMOS. The synthesized CuO nanowires are characterized by scanning electron microscopy, transmission electron microscopy and high resolution transmission electron microscopy. It is found that this approach provides a simple method to locally synthesize suspended CuO nanowires on polysilicon microbridges on silicon substrates, thus allowing for integration of CuO nanowires into silicon-based devices. It provides a significant step towards the process integration of CuO nanowires with MEMS to realize functional devices.
46 citations
TL;DR: In this paper, a flexible and noninvasive approach for efficient continuous micromixing and microreaction based on direct current-induced thermal buoyancy convection in a single microfluidic unit is presented.
Abstract: We present a flexible and noninvasive approach for efficient continuous micromixing and microreaction based on direct current-induced thermal buoyancy convection in a single microfluidic unit. Theoretically, microfluids in this microsystem are unevenly heated by powering the asymmetrically arranged microheater. The thermal buoyancy convection is then formed to induce microvortices that cause effective fluidic interface disturbance, thereby promoting the diffusion and convective mass transfer. The temperature distribution and the convection flow in the microchip are first characterized and studied, which can be flexibly adjusted by changing the DC voltage. Then the mixing performance of the presented method is validated by joint numerical and experimental analyses. Specifically, at U = 7 V, the mixing efficiencies are higher than 90% as the flow rate is lower than Qv= 600 nL/s. So high-quality chemical or biochemical reactions needing both suitable heating and efficient mixing can be achieved using this method. Finally, as one example, we use this method to synthesize nano-sized cuprous oxide (Cu2O) particles by effectively mixing the Benedict’s solution and glucose buffer. Remarkably, the particle size can be tuned by changing the voltage and the concentration of Benedict’s solution. Therefore, this micromixer can be attractive for diverse applications needing homogeneous sample mixtures.
46 citations
TL;DR: Using microfabrication techniques, a microscale platinum heater was fabricated on a Pyrex glass wafer and located in a shallow, but nearly trapezoidal microchannel with a hydraulic diameter of D h ǫ = 56 microns as discussed by the authors.
46 citations
TL;DR: In this article, the fabrication of microheaters based on a conducting composite of silver microparticles embedded in polydimethylsioxane (PDMS) is described. But the microheater's performance in temperature rise and decay characteristics is not evaluated.
Abstract: The authors report the fabrication of microheaters based on a conducting composite of silver microparticles embedded in polydimethylsioxane (PDMS). Experimental results show that the microheaters exhibit good performance in temperature rise and decay characteristics, with localized heating at targeted spatial domains. A unique feature of the microheater here is its excellent integration capability with biocompatible PDMS and other polymer materials, with potential microchip applications for bioprocessing and chemical reactions.
43 citations
TL;DR: A single cell extraction chip with an open structure, which utilizes vibration-induced whirling flow and a single cell catcher and achieved a 60% success rate, of which 61% cells yielded live cells.
Abstract: We propose a single cell extraction chip with an open structure, which utilizes vibration-induced whirling flow and a single cell catcher. By applying a circular vibration to a micropillar array spiral pattern, a whirling flow is induced around the micropillars, and target cells are transported towards the single cell catcher placed at the center of the spiral. The single cell catcher is composed of a single-cell-sized hole pattern of thermo-responsive gel. The gel swells at low temperatures (≲32 ◦C) and shrinks at high temperatures (≳32 ◦C), therefore, its volume expansion can be controlled by an integrated microheater. When the microheater is turned on, a single cell is trapped by the hole pattern of the single cell catcher. Then, when the microheater is turned off, the single cell catcher is cooled by the ambient temperature. The gel swells at this temperature, and the hole closes to catch the single cell. The caught cell can then be released into culture wells on a microtiter plate by heating the gel again. We conducted single cell extraction with the proposed chip and achieved a 60% success rate, of which 61% cells yielded live cells.
43 citations