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Dive into the research topics where Jun Kameoka is active.

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Featured researches published by Jun Kameoka.


Nanotechnology | 2003

A scanning tip electrospinning source for deposition of oriented nanofibres

Jun Kameoka; Reid N. Orth; Yanou Yang; David A. Czaplewski; Robert T. Mathers; Geoffrey W. Coates; Harold G. Craighead

We present a method for controlled deposition of oriented polymeric nanofibres. The method uses a microfabricated scanned tip as an electrospinning source. The tip is dipped in a polymer solution to gather a droplet as a source material. A voltage applied to the tip causes the formation of a Taylor cone, and at sufficiently high voltages, a polymer jet is extracted from the droplet. By moving the source relative to a surface, acting as a counter-electrode, oriented nanofibres can be deposited and integrated with microfabricated surface structures. For example, we deposited fibres of polyethylene oxide with diameters ranging from 100 to 1800 nm, with the diameter primarily depending on the concentration of the polymeric solution. In addition to the uniform fibre deposition, the scanning tip electrospinning source can produce self-assembled composite fibres of micro-and nanoparticles aligned in a polymeric fibre. We also deposited oriented conductive polymeric fibres of polyaniline and investigated the conductivity of these fibres as components for polymeric nanoelectronics.


Nano Letters | 2008

Nanofluidic Biosensing for β-Amyloid Detection Using Surface Enhanced Raman Spectroscopy

I-Hsien Chou; Melodie Benford; Hope T. Beier; Gerard L. Coté; Miao Wang; Nan Jing; Jun Kameoka; Theresa A. Good

Trace detection of the conformational transition of beta-amyloid peptide (Abeta) from a predominantly alpha-helical structure to beta-sheet could have a large impact in understanding and diagnosing Alzheimers disease. We demonstrate how a novel nanofluidic biosensor using a controlled, reproducible surface enhanced Raman spectroscopy active site was developed to observe Abeta in different conformational states during the Abeta self-assembly process as well as to distinguish Abeta from confounder proteins commonly found in cerebral spinal fluid.


Applied Physics Letters | 2003

Fabrication of oriented polymeric nanofibers on planar surfaces by electrospinning

Jun Kameoka; Harold G. Craighead

We present a method for the formation of oriented polymeric nanofibers using electrospinning deposition from an integrated microfluidic device. The source includes a microfabricated triangular shaped tip, integrated at the exit of a microfluidic channel to form a source that can be brought close to a counter electrode and scanned over surface features. Using the ability to orient the nanofiber deposition, we formed a 140 nm diameter suspended nanofiber over etched trenches on a silicon wafer, a configuration that allows for electrical and mechanical measurements of deposited nanofibers.


Applied Physics Letters | 2003

Nanofluidic channels with elliptical cross sections formed using a nonlithographic process

David A. Czaplewski; Jun Kameoka; Robert T. Mathers; Geoffrey W. Coates; Harold G. Craighead

We fabricated nanofluidic channels that have elliptical cross sections with major and minor radii of less than 100 nm, without the use of electron-beam or other high-resolution lithography. The channels were formed by thermal removal of sacrificial polymer nanofibers. The sacrificial template fiber was deposited on a target substrate by electrospinning and encapsulated by a spin-on glass. The elliptical shape of the channels eliminates sharp corners, at which fluid flow is hindered, and provides convenient boundary conditions for theoretical modeling of fluid flow in the channels. Also, the spin-on glass is optically transparent and compatible with chemical analysis, thereby opening up application in biomolecular separation and single molecule analysis. Hundreds of parallel channels have also been formed by the oriented spinning process.


Lab on a Chip | 2007

An optofluidic device for surface enhanced Raman spectroscopy

Miao Wang; Nan Jing; I-Hsien Chou; Gerard L. Coté; Jun Kameoka

We have developed an optofluidic device that improves the sensitivity of surface enhanced Raman spectroscopy (SERS) when compared to other SERS approaches. This device has a pinched and step microchannel-nanochannel junction that can trap and assemble nanoparticles/target molecules into optically enhanced SERS active clusters by using capillary force. These SERS active clusters provide an electromagnetic enhancement factor of approximately 10(8). In addition, due to the continuous capillary flow that can transport nanoparticles/target molecules into the junction sites, the numbers of nanoparticles/target molecules and SERS active sites are increased. As a result, the detection limit of SERS for adenine molecules was better than 10 pM.


Nanotechnology | 2005

Measurement of the Young's moduli of individual polyethylene oxide and glass nanofibres

Leon M. Bellan; Jun Kameoka; Harold G. Craighead

We have used scanned electrospinning to deposit oriented polyethylene oxide and silica glass fibres over trenches etched in silicon. We measured the Youngs moduli of the fibres using an atomic force microscope. The Youngs moduli of the glass fibres agree with values calculated from previously measured mechanical resonance frequencies of similar fibres. The Youngs moduli of the polyethylene oxide fibres are significantly larger than those reported for polyethylene oxide bulk and films, suggesting molecular orientation in the fibres.


Applied Physics Letters | 2006

Electrospinning of silica nanochannels for single molecule detection

Miao Wang; Nan Jing; Chin B. Su; Jun Kameoka; Chao Kai Chou; Mien Chie Hung; Kuang-An Chang

We have fabricated silica nanochannels with inner diameter as small as 20nm using a scanned coaxial electrospinning and demonstrated their application for single molecule detection. A coaxial jet, with the use of motor oil as the core and silica sol-gel solution as the shell, is extruded through a coaxial source and deposited on the rotating collector as oriented nanofibers. They are then annealed to cross-link silica and eliminate motor oil, thereby forming nanochannels. Subsequently, a fluorescent dye was injected into the individual nanochannels via a capillary force and single molecule detection was performed by monitoring the photon signals from 5-Iodoacetamidofluorescein.


Journal of Materials Chemistry | 2004

Polymeric nanowire architectureElectronic supplementary information (ESI) available: frontispiece figure. See http://www.rsc.org/suppdata/jm/b4/b401804b/

Jun Kameoka; David A. Czaplewski; Haiqing Liu; Harold G. Craighead

We describe a newly developed scanned electrospinning technique that can be used to form a variety of one-dimensional polymeric nanostructures. It is a straightforward technique that enables the rapid fabrication of oriented polymeric nanowires as well as their integration with lithographically defined surfaces. It presents new opportunities for the manufacture and applications of nanowire devices.


Journal of Vacuum Science & Technology B | 2003

Nonlithographic approach to nanostructure fabrication using a scanned electrospinning source

David A. Czaplewski; Jun Kameoka; Harold G. Craighead

We have used deposited polymeric nanofibers as nonlithographic templates for the fabrication of semiconductor nanostructures. We deposited oriented poly(methyl methacrylate) (PMMA) fibers, with diameters ranging from 85 to 350 nm, on the surface of various substrates using a microfabricated electrospinning source. By utilizing the small apex of a microfabricated source, a stable Taylor cone was formed as an electrostatically driven source of polymer solution directed toward the substrate. By attaching the target substrate to a rotating counter electrode, isolated and oriented PMMA fibers were deposited. We used these fibers as etch masks to pattern nanostructures in the surface of a silicon wafer. This method provides a simple, nonlithographic approach to forming nanostructures on a wide variety of substrates, such as silicon, aluminum, silicon dioxide, silicon nitride, and glass. The fiber deposition can be oriented with respect to surface features, allowing for realization of nanodevice architectures.


Nanotechnology | 2006

Fabrication of silica nanocomposite-cups using electrospraying

Parag B. Deotare; Jun Kameoka

We have investigated a new process for the fabrication of nanocomposite cups by electrospraying blended polymer–sol–gel solutions followed by calcination. Due to the low viscosity and high surface tension of the blended polymer–sol–gel solutions, the electrostatically extruded continuous liquid jet from the spray source became tiny droplets with diameters of less than 1 µm. These droplets dried in transit and were collected at the counter electrode. To eliminate polymers, as well as cross-link sol–gel material, they were calcined at 850 °C for 3 h. We also investigated a probable method to control the morphology of the nanocups by changing the ionic concentration of the polymer solution. This is a simple and efficient approach for producing nanocomposite cups, which cannot be made by the aggregation method. These nanocomposite cups may find applications in drug delivery and filtration media.

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Mien Chie Hung

University of Texas MD Anderson Cancer Center

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Chao Kai Chou

University of Texas MD Anderson Cancer Center

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Hirohito Yamaguchi

University of Texas MD Anderson Cancer Center

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