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This paper describes the self-assembly of “cell springs” using smooth muscle-like cells differentiated from multipotent dedifferentiated fat (DFAT) cells. Using a microfluidic co-axial device, DFAT cells suspended in extracellular matrix (ECM) mixture of fibrin and collagen were encapsulated within tubular alginate microfibers and formed into 3D fiber-shaped micro-constructs. Such DFAT cell fibers...
The diffraction limit imposes a fundamental technology barrier in optoelectronics, photonics, and information technology. In the past decade, a new discipline coined as “plasmonics” has emerged as an enabling technology not only to overcome the diffraction limit, but also to enhance the capabilities of light harvesting (solar cells), emission (light-emitting devices), and detection (optical detectors...
This paper presents a novel in-liquid method to manipulate and micro-assemble MEMS in 3D by means of holographic optical trapping and hydrophobic interaction. Up to eight traps can be simultaneously generated with a trapping stiffness of 5 pN/μm each. SU8 cylinders (10μm diameter, 10μm-40μm height) were used as test MEMS, which could be translated with a speed of 6μm/s and rotated at 30 rpm. All forces...
This study presents a novel approach to fabricate highly-structured 3D vertically-aligned carbon nanotubes (VA-CNTs) architectures, and further integrates 3D VA-CNTs with MEMS surface micromachining to fabricate suspended 3D CNTs structures. The merits of presented approach are as follows: (1) highly-structured 3D VA-CNTs stacks can be achieved by predefining multilayered Al/Fe catalyst films; (2)...
We present a 2 cm-diameter rotary stage electrostatically actuated by ∼15 VDC. Multiple rings of an ionic liquid are used as both low-friction mechanical bearings and electric connections between the rotor and the substrate. The ring-bearing device is the first that was successfully rotated by electrostatic forces among the recent rotary devices involving a liquid bearing. Compared with the recent...
Microenvironmental biophysical stimuli influence diverse cellular functions, such as directional motility and stem cell differentiation. Previously, researchers have tuned the linear stiffness of microposts to investigate cell mechanobiological processes and direct cellular behavior; however, microposts suffer from an inherent, yet critical drawback — regulation of micropost stiffness is fundamentally...
A simple, novel assay for pathogen diagnosis was implemented on a new integrated microfluidic system using a nanogold modified DNA probe and vancomycin conjugated magnetic beads. The developed microfluidic device was fabricated by microfluidic technology and composed of many micro-modules. The pneumatically-driven, suction-type micropump, microvalves, microchannels and loading chambers were integrated...
This paper presents a magnetically actuated droplet platform for automated sample preparation and gene detection. Our platform integrates nucleic acid extraction using silicacoated magnetic particles with real-time polymerase chain reaction (PCR) on a single cartridge. The device consists of seven compartments in which reagent droplets are serially loaded. The assay utilizes solid phase nucleic acid...
This paper introduces a new type of energy harvester for converting multi-axial and low-frequency motion from humans and the environment into the electrical domain. An innovative array of electrostatic transducer cells is used to convert the mechanical energy captured from the environment by a freely rolling spherical magnetic proof mass. The magnet never comes in contact with the transducer cells...
This paper reports the method and results of amplifying the power output of a piezoelectric energy harvester excited by random vibrations. The amplification is achieved by applying a dual-mass-spring system. A maximum power amplification of 80 times has been experimentally demonstrated. The generated power output from a piezoelectric energy harvester, when excited by as-measured random vibrations,...
This paper presents a new technique of converting mechanical energy to electrical energy that can be used to harvest mW — W power level from a vibrating surface of tens — hundreds microns amplitude. The technique uses an array of alternating north- and south-orientation magnets to enhance magnetic flux change by more than an order of magnitude. Experimental results show that a microfabricated energy...
The use of capacitive-piezoelectric transducers, formed by separating a piezoelectric structure from its electrodes by sub-micron gaps, has raised the measured quality factor of aluminum nitride (AlN) Lamb wave resonators (LWR) from the ∼1,000 of typical square-edged conventional devices (with contacting electrodes) to over 5,000 at 940 MHz, posting the highest reported Q for non-overmoded pure AlN...
A self-sustained Radiation-Pressure driven MEMS ring OptoMechanical Oscillator (RP-OMO) attaining an anchor-loss-limited mechanical Q-factor of 10,400 in vacuum has posted a best-to-date phase noise of −102 dBc/Hz at a 1 kHz offset from a 74 MHz carrier, more than 15 dB better than the best previously published mark [1]. While enhanced optical and mechanical Q both serve to lower the optical threshold...
In this paper, we report on high-performance piezoelectric-on-silica micromechanical resonators for integrated timing applications. Fused silica is used as the resonator structural material for its excellent material properties, and thin film aluminum nitride is used as the piezoelectric transduction layer. A silica resonator is demonstrated with a high quality factor (QU∼25,841), low motional impedance...
In an effort to improve the situational awareness of maritime vehicles, flexible MEMS pressure sensor arrays are developed for underwater sensing applications. This paper outlines the development of piezoelectric microdiaphragm pressure sensor arrays that can perform a passive fish-like underwater sensing. Individual sensors have a low footprint of 1.8 × 1.8 mm2 and do not require any power for their...
This paper describes preliminary result of a specially patterned and aligned neural bundle formed by neural stem cell (NSC) microfibers for neural transplantation. The NSC microfibers are made by core-shell hydrogel microfiber encapsulating mouse NSCs. We developed a technique to align microfibers in a straight line and arrange the fibers in special patterns. Using this technique, we formed a neural...
Most of currently employed laparoscopes use a single and non-tunable solid lens to visualize the surgical environment during minimal invasive interventions. These devices are limited due to the loss of depth perception, fixed view direction and narrow field-of-view (FOV). In this study, a three-dimensional deformable liquid lens array with adaptive focusing and directional view capability is developed...
This paper presents a handheld device for reflectance confocal imaging of biological tissue. A two-dimensional fiber optic raster scanner has been designed, manufactured and assembled in standard half-inch lens tubes. The scanner is driven by electromagnetic forces and provides large actuation range of ≥1 mm in both directions with driving current of ≤ 200 mA. Light polarization effects have been...
For high-speed adhesion-based cell separation, we propose a new cell-motion model including the shear-induced lift force, with which the cell motion at high flow velocities can be analyzed. Also, we have developed a novel sub-micron-accuracy measurement method of the three-dimensional position of cells. We have clarified the effect of the shear-induced lift force on the cell motion near adhesive walls...
In this study, we purpose the microfabricated system to manipulate single host cells of parasites toward the analysis of invasion at single cell level. We fabricated the microplates made from Parylene and modified the shape and structure of surface by using lithography techniques. This device is able to not only control the shape and morphology of adhering host cells, but also handle them maintaining...
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