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We present a straightforward method for measuring in-plane linear displacements of microelectromechanical systems (MEMS) with subnanometer resolution. The technique is based on Fourier transform analysis of a video recorded with a Charge-Coupled Device (CCD) camera attached to an optical microscope and can be used to characterize any device featuring periodic patterns along the direction of motion...
Isolation and detection of tumor cells (TCs) from a large amount of biological samples have been a major challenge in clinical diagnosis. To tackle this problem, a three-dimensional micro incubator using deflecting membranes has been reported by our group previously. However, it requires a relatively complicated fabrication process, which involves bonding of multiple polydimethyl siloxane (PDMS) layers...
This paper investigates the potential uses of graphene nanomechanical devices for NEMS applications fabricated using Helium Ion Microscope (HIM). Suspended nanomechanical graphene drum structures of diameter (∼ 2 – 3 µm) and thickness ranging from few atomic layers (∼10 Å) to about 11 nm have been fabricated and characterized using Atomic Force Microscopy (AFM). The initial suspension profile and...
We present a portable microendoscope based on a microelectromechanical systems (MEMS) scanner, compound gradient refractive index micro-lenses and a photonics bandgap fiber (PBF). It overcomes the size (2.0 × 1.9 × 1.1 cm3) and weight (less than 3 grams) limitations of conventional two-photon fluorescence microscopy toward freely moving subjects. The microendoscope utilizes a PBF for laser excitation...
The paper reports a microcantilever-based microprobe that will be applied at a versatile instrument in combination of atomic force microscopy with mass spectrometry. Due to the special requirements for the microprobe, the probe is expected to equip with an in-plane sharp tip for high-resolution image scanning and easy sample electrical extraction, as well as a self-actuated cantilever that owns huge...
We demonstrate MEMS micromirror enabled hand-held confocal imaging probe for portable oral cancer detection, where large field of view (FOV) is achieved through the lissajous scanning operation of the MEMS mirror. The imaging speed up to 2 frames per second was demonstrated with the improved Labview and Java based data acquisition and control programs. We also examined the axial resolution (3.4 um)...
We present a precise cell trapping platform, structure-confined electrophoresis, which utilize microchannel with lateral cavity to bend the electric field for generating positive dielectrophoresis (DEP) force. A revealed metal electrode, 10µm × 20µm, is placed inside the deep place of cavity. Providing stronger DEP force to trap mobile cells and reducing the flow shear stress acting on the trapped...
Sperm motility analysis is an indispensable test in male infertility diagnosis. The current microscopic method cannot select the sperm of specific velocity for further in vitro Fertilization (IVF) usage or research purposes. Here, we report a novel and simple microfluidic device capable of balancing sperm's swimming speed with local flow velocity. The results suggested that sperm motility was quantitatively...
This paper presents the first gamete holding device containing both sperm and oocytes on the same device. The device is of low-cost and disposable. Experiments demonstrated a success rate of 100% for holding/releasing hamster oocytes. Intracytoplasmic sperm injection (ICSI) experiments on 120 hamster oocytes with donated human sperm resulted in an average oocyte survival rate of 90.7%, which compares...
This paper presents a simple and robust microfluidic device that allows on-chip gelation and temporal control of alginate droplets in a continuous oil phase to enhance hydrogel recovery and collection rate. The additional control flow including calcified oleic acid leads to adjust droplet interval and gelation of the alginate droplet simultaneously through microtunnel structures. The gelated alginate...
Temperature oscillations allow one to modulate the concentration of reagents and products with given amplitude and phase shift, both parameters depending on the dynamics of the chemical system under study. We here rely on thermal excitation in a microdevice, associated with fluorescence video microscopy as well as image filtering protocols, to selectively enhance the signal issued from a labeled probe...
We present a CMOS-MEMS atomic force microscope (AFM) with integrated 3-D MEMS actuation and 3-axis position sensing. CMOS driving and sensing electronics have been integrated in the same fabrication process. Our goal is to replace piezoelectric positioning systems which are bulky (leading to thermal drift and poor vibration immunity) and suffer from inherent creep (leading to image distortion). As...
A filter-less multi-wavelength fluorescence detector is proposed and successfully demonstrated. The developed sensor detected the respective light intensity of several wavelength lights in a mixture simultaneously, without using optical filters or gratings. An array of the developed sensor achieved a multi-color fluorescence imaging system at standard television scan rates, was impossible for the...
Mechanical stimuli play an important role in various cellular processes. Current equipments used for the study of cell response to stresses and strains are not all compatible with existing lab cell culture facilities. This work demonstrates for the first time that miniaturized devices can be used in combination with off-the-shelf equipment to study cell responses under mechanical strain. Cells cultured...
Precise heating is important for biological culturing, biological characterization, and thermal lysis, while cellular manipulation has been an area of significant interest and has been explored by a variety of methods. In this work, we present a preliminary study of the use of metallic thermal probes. The probes were used for magnetophoresis and micromanipulation of magnetically labeled HeLa cells...
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