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Jun Kameoka

Waseda University, Graduate School of IPS, Faculty Member

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Papers by Jun Kameoka

Fabrication of Bacteria Environment Cubes with Dry Lift-Off Fabrication Process for Enhanced Nitrification

PLOS ONE, 2016

We have developed a 3D dry lift-off process to localize multiple types of nitrifying bacteria in ... more We have developed a 3D dry lift-off process to localize multiple types of nitrifying bacteria in polyethylene glycol diacrylate (PEGDA) cubes for enhanced nitrification, a two-step biological process that converts ammonium to nitrite and then to nitrate. Ammonia-oxidizing bacteria (AOB) is responsible for converting ammonia into nitrite, and nitrite-oxidizing bacteria (NOB) is responsible for converting nitrite to nitrate. Successful nitrification is often challenging to accomplish, in part because AOB and NOB are slow growers and highly susceptible to many organic and inorganic chemicals in wastewater. Most importantly, the transportation of chemicals among scattered bacteria is extremely inefficient and can be problematic. For example, nitrite, produced from ammonia oxidation, is toxic to AOB and can lead to the failure of nitrification. To address these challenges, we closely localize AOB and NOB in PEGDA cubes as microenvironment modules to promote synergetic interactions. The AOB is first localized in the vicinity of the surface of the PEGDA cubes that enable AOB to efficiently uptake ammonia from a liquid medium and convert it into nitrite. The produced nitrite is then efficiently transported to the NOB localized at the center of the PEGDA particle and converted into non-toxic nitrate. Additionally, the nanoscale PEGDA fibrous structures offer a protective environment for these strains, defending them from sudden toxic chemical shocks and immobilize in cubes. This engineered microenvironment cube significantly enhances nitrification and improves the overall ammonia removal rate per single AOB cell. This approach-encapsulation of multiple strains at close range in

Use of a micro- to nanochannel for the characterization of surface-enhanced Raman spectroscopy signals from unique functionalized nanoparticles

by Brian Walton and Jun Kameoka

Journal of biomedical optics, Aug 1, 2016

A micro- to nanochannel nanoparticle aggregating device that does not require any input energy to... more A micro- to nanochannel nanoparticle aggregating device that does not require any input energy to organize the particles to a specific location, i.e., no pumps, plugs, heat, or magnets, has been designed and used to characterize the surface-enhanced Raman spectroscopy (SERS) signal from four unique functionalized nanoparticles (gold, silver-gold nanocages, silver nanocubes, and silica-gold nanoshells). The SERS signal was assessed in terms of the peak signal strength from the four different Raman reporter functionalized nanoparticles to determine which nanoparticle had better utility in the channel to provide the most robust platform for a future biological analyte detection device. The innovation used to fabricate the micro- to nanochannel device is described; the TEM images of the nanoparticles are shown; the absorption data for the nanoparticles are given; and the spectral data for the Raman reporter, mercaptobenzoic acid (MBA), are depicted. In the micro- to nanochannel describe...

Fabrication of Nanomechanical Oscillators using Electrospun Polymeric Fibers

Aps Meeting Abstracts, Mar 1, 2004

ABSTRACT We have employed electrospun nanofibers for the fabrication of released beam structures ... more ABSTRACT We have employed electrospun nanofibers for the fabrication of released beam structures down to 100 nm in width, and at various lengths. Microfabricated electrospray tips were used in order to deposit nanoscale PMMA fibers onto a target substrate. The substrate consisted of a silicon nitride device layer over a sacrificial silicon dioxide layer, on a standard silicon wafer. The PMMA fibers were used as an etch mask for nanoscale beams, with beam support structures patterned using contact photolithography. A CF4 plasma etch was used to define the nitride beams, followed by an undercutting of the oxide layer. Modes of oscillation of released devices with widths down to 150 nm were detected using laser interference methods. This technique offers an alternative to electron beam lithography and high resolution photolithography for the construction of beam devices down to the 100 nm scale.

Nanomechanical Oscillators Fabricated Using Polymeric Nanofiber Templates

Nano Letters, Feb 24, 2004

We have used deposited polymer nanofibers as templates for the formation of functional nanomechan... more We have used deposited polymer nanofibers as templates for the formation of functional nanomechanical devices, interfaced to lithographically defined surface microstructures. The deposition of oriented poly(methyl methacrylate) nanofibers, combined with contact photolithography, created silicon nitride nanomechanical oscillators with dimensions on the order of 100 nm. We used contact photolithography to define the support structures for the oscillators. The moving beams were defined in the device layer by using the deposited fiber as a mask for reactive ion etching using a CF 4 plasma chemistry, followed by removal of a sacrificial underlying layer. After releasing the devices, the frequencies of the modes of oscillation of the beams were determined by laser interference techniques. The devices would self-oscillate due to the interferometric effects of the continuous wave (CW) detection laser. The oriented polymeric nanofiber deposition method, used in this experiment, offers an approach for the rapid formation of arrays of nanomechanical devices, connected to micromechanical structures, that would be difficult to form using a completely self-assembled or completely lithographic approach. This direction may provide a useful method for realizing nanoscale device architectures in a variety of active materials.

Development of automated high throughput single molecular microfluidic detection platform for signal transduction analysis

SPIE Proceedings, 2016

Signal transductions including multiple protein post-translational modifications (PTM), protein-p... more Signal transductions including multiple protein post-translational modifications (PTM), protein-protein interactions (PPI), and protein-nucleic acid interaction (PNI) play critical roles for cell proliferation and differentiation that are directly related to the cancer biology. Traditional methods, like mass spectrometry, immunoprecipitation, fluorescence resonance energy transfer, and fluorescence correlation spectroscopy require a large amount of sample and long processing time. “microchannel for multiple-parameter analysis of proteins in single-complex (mMAPS)”we proposed can reduce the process time and sample volume because this system is composed by microfluidic channels, fluorescence microscopy, and computerized data analysis. In this paper, we will present an automated mMAPS including integrated microfluidic device, automated stage and electrical relay for high-throughput clinical screening. Based on this result, we estimated that this automated detection system will be able to screen approximately 150 patient samples in a 24-hour period, providing a practical application to analyze tissue samples in a clinical setting.

Fabrication of oriented polymeric nanofibers on planar surfaces by electrospinning

Applied Physics Letters, Jul 14, 2003

We present a method for the formation of oriented polymeric nanofibers using electrospinning depo... more 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.

Electrospray emitter for microfluidic channel

Nanofabricated photon tunneling based sensor

Sorting of Silica Nanocups by Diameter during Fabrication Process

Journal of Nanomaterials, 2007

We demonstrated a new technique to sort nanoparticles based on their dimensions. Due to the inter... more We demonstrated a new technique to sort nanoparticles based on their dimensions. Due to the interactions between charged droplets and a nonlinear electrostatic field, nanoparticles with different dimensions were deposited at different spatial locations on a given target substrate. By using this principle, we have been able to sort nanocups into three groups with mean diameters of 0.31μm, 0.7μm, and 1.1μm and a standard deviation of 20%. This technique improves the nanoparticle fabrication process not only by decreasing the standard deviation of its dimensions but also by increasing its yield since nanoparticles with different mean diameters can be generated at the same time.

Nonlithographic approach to nanostructure fabrication using a scanned electrospinning source

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, 2003

We have used deposited polymeric nanofibers as nonlithographic templates for the fabrication of s... more 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 nano...

An Arrow Shaped Silicon Tip for Polymeric Nanofiber Fabrication

Journal of Photopolymer Science and Technology, 2003

Fabrication of Blended Polyphenylenevinylene Nanowires By Scanned Electrospinning

Journal of Photopolymer Science and Technology, 2004

Rapid Prototyping of Nanofluidic Systems Using Size‐Reduced Electrospun Nanofibers for Biomolecular Analysis

by Jun Kameoka and Harold Craighead

Small, 2010

Biomolecular transport in nanofluidic confinement offers various means to investigate the behavio... more Biomolecular transport in nanofluidic confinement offers various means to investigate the behavior of biomolecules in their native aqueous environments, and to develop tools for diverse single‐molecule manipulations. Recently, a number of simple nanofluidic fabrication techniques has been demonstrated that utilize electrospun nanofibers as a backbone structure. These techniques are limited by the arbitrary dimension of the resulting nanochannels due to the random nature of electrospinning. Here, a new method for fabricating nanofluidic systems from size‐reduced electrospun nanofibers is reported and demonstrated. As it is demonstrated, this method uses the scanned electrospinning technique for generation of oriented sacrificial nanofibers and exposes these nanofibers to harsh, but isotropic etching/heating environments to reduce their cross‐sectional dimension. The creation of various nanofluidic systems as small as 20 nm is demonstrated, and practical examples of single biomolecula...

$Research paper thumbnail of Nanofabricated refractive index sensor based on photon tunneling in nanofluidic channel$

Nanofabricated refractive index sensor based on photon tunneling in nanofluidic channel

Sensors and Actuators B: Chemical, 2001

We have fabricated and tested a refractive index sensor based on photon tunneling in a nano¯uidic... more We have fabricated and tested a refractive index sensor based on photon tunneling in a nano¯uidic system. The device comprises an extremely thin ¯uid chamber formed between two optically transparent layers. It can be used to detect changes in refractive index due to chemical composition changes of a ¯uid in the small test volume. Because the physical property measured is a refractive index change, no staining or labeling is required. We tested the device with ®ve samples, water and water with 1% ethanol, 2% ethanol, 5% ethanol and 10% ethanol. The sensing was done by measuring the intensity of a re¯ected laser beam incident on the sensing element at around the critical angle. The measured response agrees well with the calculated re¯ectance.

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

by Leon Bellan and Jun Kameoka

Nanotechnology, 2005

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

Fabrication of silica nanocomposite-cups using electrospraying

Nanotechnology, 2006

Nanomechanical Oscillators Fabricated Using Polymeric Nanofiber Templates

Nano Letters, 2004

Nanofluidic channels with elliptical cross sections formed using a nonlithographic process

Applied Physics Letters, 2003

We fabricated nanofluidic channels that have elliptical cross sections with major and minor radii... more 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.

Fabrication of oriented polymeric nanofibers on planar surfaces by electrospinning

Applied Physics Letters, 2003

We present a method for the formation of oriented polymeric nanofibers using electrospinning depo... more 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.

Fabrication of Nanomechanical Oscillators using Electrospun Polymeric Fibers

ABSTRACT We have employed electrospun nanofibers for the fabrication of released beam structures ... more ABSTRACT We have employed electrospun nanofibers for the fabrication of released beam structures down to 100 nm in width, and at various lengths. Microfabricated electrospray tips were used in order to deposit nanoscale PMMA fibers onto a target substrate. The substrate consisted of a silicon nitride device layer over a sacrificial silicon dioxide layer, on a standard silicon wafer. The PMMA fibers were used as an etch mask for nanoscale beams, with beam support structures patterned using contact photolithography. A CF4 plasma etch was used to define the nitride beams, followed by an undercutting of the oxide layer. Modes of oscillation of released devices with widths down to 150 nm were detected using laser interference methods. This technique offers an alternative to electron beam lithography and high resolution photolithography for the construction of beam devices down to the 100 nm scale.

Fabrication of Bacteria Environment Cubes with Dry Lift-Off Fabrication Process for Enhanced Nitrification

PLOS ONE, 2016

We have developed a 3D dry lift-off process to localize multiple types of nitrifying bacteria in ... more We have developed a 3D dry lift-off process to localize multiple types of nitrifying bacteria in polyethylene glycol diacrylate (PEGDA) cubes for enhanced nitrification, a two-step biological process that converts ammonium to nitrite and then to nitrate. Ammonia-oxidizing bacteria (AOB) is responsible for converting ammonia into nitrite, and nitrite-oxidizing bacteria (NOB) is responsible for converting nitrite to nitrate. Successful nitrification is often challenging to accomplish, in part because AOB and NOB are slow growers and highly susceptible to many organic and inorganic chemicals in wastewater. Most importantly, the transportation of chemicals among scattered bacteria is extremely inefficient and can be problematic. For example, nitrite, produced from ammonia oxidation, is toxic to AOB and can lead to the failure of nitrification. To address these challenges, we closely localize AOB and NOB in PEGDA cubes as microenvironment modules to promote synergetic interactions. The AOB is first localized in the vicinity of the surface of the PEGDA cubes that enable AOB to efficiently uptake ammonia from a liquid medium and convert it into nitrite. The produced nitrite is then efficiently transported to the NOB localized at the center of the PEGDA particle and converted into non-toxic nitrate. Additionally, the nanoscale PEGDA fibrous structures offer a protective environment for these strains, defending them from sudden toxic chemical shocks and immobilize in cubes. This engineered microenvironment cube significantly enhances nitrification and improves the overall ammonia removal rate per single AOB cell. This approach-encapsulation of multiple strains at close range in

Use of a micro- to nanochannel for the characterization of surface-enhanced Raman spectroscopy signals from unique functionalized nanoparticles

by Brian Walton and Jun Kameoka

Journal of biomedical optics, Aug 1, 2016

A micro- to nanochannel nanoparticle aggregating device that does not require any input energy to... more A micro- to nanochannel nanoparticle aggregating device that does not require any input energy to organize the particles to a specific location, i.e., no pumps, plugs, heat, or magnets, has been designed and used to characterize the surface-enhanced Raman spectroscopy (SERS) signal from four unique functionalized nanoparticles (gold, silver-gold nanocages, silver nanocubes, and silica-gold nanoshells). The SERS signal was assessed in terms of the peak signal strength from the four different Raman reporter functionalized nanoparticles to determine which nanoparticle had better utility in the channel to provide the most robust platform for a future biological analyte detection device. The innovation used to fabricate the micro- to nanochannel device is described; the TEM images of the nanoparticles are shown; the absorption data for the nanoparticles are given; and the spectral data for the Raman reporter, mercaptobenzoic acid (MBA), are depicted. In the micro- to nanochannel describe...

Fabrication of Nanomechanical Oscillators using Electrospun Polymeric Fibers

Aps Meeting Abstracts, Mar 1, 2004

ABSTRACT We have employed electrospun nanofibers for the fabrication of released beam structures ... more ABSTRACT We have employed electrospun nanofibers for the fabrication of released beam structures down to 100 nm in width, and at various lengths. Microfabricated electrospray tips were used in order to deposit nanoscale PMMA fibers onto a target substrate. The substrate consisted of a silicon nitride device layer over a sacrificial silicon dioxide layer, on a standard silicon wafer. The PMMA fibers were used as an etch mask for nanoscale beams, with beam support structures patterned using contact photolithography. A CF4 plasma etch was used to define the nitride beams, followed by an undercutting of the oxide layer. Modes of oscillation of released devices with widths down to 150 nm were detected using laser interference methods. This technique offers an alternative to electron beam lithography and high resolution photolithography for the construction of beam devices down to the 100 nm scale.

Nanomechanical Oscillators Fabricated Using Polymeric Nanofiber Templates

Nano Letters, Feb 24, 2004

We have used deposited polymer nanofibers as templates for the formation of functional nanomechan... more We have used deposited polymer nanofibers as templates for the formation of functional nanomechanical devices, interfaced to lithographically defined surface microstructures. The deposition of oriented poly(methyl methacrylate) nanofibers, combined with contact photolithography, created silicon nitride nanomechanical oscillators with dimensions on the order of 100 nm. We used contact photolithography to define the support structures for the oscillators. The moving beams were defined in the device layer by using the deposited fiber as a mask for reactive ion etching using a CF 4 plasma chemistry, followed by removal of a sacrificial underlying layer. After releasing the devices, the frequencies of the modes of oscillation of the beams were determined by laser interference techniques. The devices would self-oscillate due to the interferometric effects of the continuous wave (CW) detection laser. The oriented polymeric nanofiber deposition method, used in this experiment, offers an approach for the rapid formation of arrays of nanomechanical devices, connected to micromechanical structures, that would be difficult to form using a completely self-assembled or completely lithographic approach. This direction may provide a useful method for realizing nanoscale device architectures in a variety of active materials.

Development of automated high throughput single molecular microfluidic detection platform for signal transduction analysis

SPIE Proceedings, 2016

Signal transductions including multiple protein post-translational modifications (PTM), protein-p... more Signal transductions including multiple protein post-translational modifications (PTM), protein-protein interactions (PPI), and protein-nucleic acid interaction (PNI) play critical roles for cell proliferation and differentiation that are directly related to the cancer biology. Traditional methods, like mass spectrometry, immunoprecipitation, fluorescence resonance energy transfer, and fluorescence correlation spectroscopy require a large amount of sample and long processing time. “microchannel for multiple-parameter analysis of proteins in single-complex (mMAPS)”we proposed can reduce the process time and sample volume because this system is composed by microfluidic channels, fluorescence microscopy, and computerized data analysis. In this paper, we will present an automated mMAPS including integrated microfluidic device, automated stage and electrical relay for high-throughput clinical screening. Based on this result, we estimated that this automated detection system will be able to screen approximately 150 patient samples in a 24-hour period, providing a practical application to analyze tissue samples in a clinical setting.

Fabrication of oriented polymeric nanofibers on planar surfaces by electrospinning

Applied Physics Letters, Jul 14, 2003

We present a method for the formation of oriented polymeric nanofibers using electrospinning depo... more 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.

Electrospray emitter for microfluidic channel

Nanofabricated photon tunneling based sensor

Sorting of Silica Nanocups by Diameter during Fabrication Process

Journal of Nanomaterials, 2007

We demonstrated a new technique to sort nanoparticles based on their dimensions. Due to the inter... more We demonstrated a new technique to sort nanoparticles based on their dimensions. Due to the interactions between charged droplets and a nonlinear electrostatic field, nanoparticles with different dimensions were deposited at different spatial locations on a given target substrate. By using this principle, we have been able to sort nanocups into three groups with mean diameters of 0.31μm, 0.7μm, and 1.1μm and a standard deviation of 20%. This technique improves the nanoparticle fabrication process not only by decreasing the standard deviation of its dimensions but also by increasing its yield since nanoparticles with different mean diameters can be generated at the same time.

Nonlithographic approach to nanostructure fabrication using a scanned electrospinning source

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, 2003

We have used deposited polymeric nanofibers as nonlithographic templates for the fabrication of s... more 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 nano...

An Arrow Shaped Silicon Tip for Polymeric Nanofiber Fabrication

Journal of Photopolymer Science and Technology, 2003

Fabrication of Blended Polyphenylenevinylene Nanowires By Scanned Electrospinning

Journal of Photopolymer Science and Technology, 2004

Rapid Prototyping of Nanofluidic Systems Using Size‐Reduced Electrospun Nanofibers for Biomolecular Analysis

by Jun Kameoka and Harold Craighead

Small, 2010

Biomolecular transport in nanofluidic confinement offers various means to investigate the behavio... more Biomolecular transport in nanofluidic confinement offers various means to investigate the behavior of biomolecules in their native aqueous environments, and to develop tools for diverse single‐molecule manipulations. Recently, a number of simple nanofluidic fabrication techniques has been demonstrated that utilize electrospun nanofibers as a backbone structure. These techniques are limited by the arbitrary dimension of the resulting nanochannels due to the random nature of electrospinning. Here, a new method for fabricating nanofluidic systems from size‐reduced electrospun nanofibers is reported and demonstrated. As it is demonstrated, this method uses the scanned electrospinning technique for generation of oriented sacrificial nanofibers and exposes these nanofibers to harsh, but isotropic etching/heating environments to reduce their cross‐sectional dimension. The creation of various nanofluidic systems as small as 20 nm is demonstrated, and practical examples of single biomolecula...

$Research paper thumbnail of Nanofabricated refractive index sensor based on photon tunneling in nanofluidic channel$

Nanofabricated refractive index sensor based on photon tunneling in nanofluidic channel

Sensors and Actuators B: Chemical, 2001

We have fabricated and tested a refractive index sensor based on photon tunneling in a nano¯uidic... more We have fabricated and tested a refractive index sensor based on photon tunneling in a nano¯uidic system. The device comprises an extremely thin ¯uid chamber formed between two optically transparent layers. It can be used to detect changes in refractive index due to chemical composition changes of a ¯uid in the small test volume. Because the physical property measured is a refractive index change, no staining or labeling is required. We tested the device with ®ve samples, water and water with 1% ethanol, 2% ethanol, 5% ethanol and 10% ethanol. The sensing was done by measuring the intensity of a re¯ected laser beam incident on the sensing element at around the critical angle. The measured response agrees well with the calculated re¯ectance.

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

by Leon Bellan and Jun Kameoka

Nanotechnology, 2005

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

Fabrication of silica nanocomposite-cups using electrospraying

Nanotechnology, 2006

Nanomechanical Oscillators Fabricated Using Polymeric Nanofiber Templates

Nano Letters, 2004

Nanofluidic channels with elliptical cross sections formed using a nonlithographic process

Applied Physics Letters, 2003

We fabricated nanofluidic channels that have elliptical cross sections with major and minor radii... more 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.

Fabrication of oriented polymeric nanofibers on planar surfaces by electrospinning

Applied Physics Letters, 2003

We present a method for the formation of oriented polymeric nanofibers using electrospinning depo... more 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.

Fabrication of Nanomechanical Oscillators using Electrospun Polymeric Fibers

ABSTRACT We have employed electrospun nanofibers for the fabrication of released beam structures ... more ABSTRACT We have employed electrospun nanofibers for the fabrication of released beam structures down to 100 nm in width, and at various lengths. Microfabricated electrospray tips were used in order to deposit nanoscale PMMA fibers onto a target substrate. The substrate consisted of a silicon nitride device layer over a sacrificial silicon dioxide layer, on a standard silicon wafer. The PMMA fibers were used as an etch mask for nanoscale beams, with beam support structures patterned using contact photolithography. A CF4 plasma etch was used to define the nitride beams, followed by an undercutting of the oxide layer. Modes of oscillation of released devices with widths down to 150 nm were detected using laser interference methods. This technique offers an alternative to electron beam lithography and high resolution photolithography for the construction of beam devices down to the 100 nm scale.