- Nanotechnology Find out what NIST is currently working on in Nanotechnology.
Jack Pevenstein
Technology Partnership Office
301-975-5519
nisttech@nist.gov
100 Bureau Drive, M/S 2200
Gaithersburg, MD, 20899
Tightly focused beams of laser light are used as "optical tweezers" to trap and manipulate polarizable objects such as microspheres of glass or latex with diameters on the order of 4.5 µm. When analytes are allowed to adhere to the microspheres, small quantities of these analytes can be manipulated, thus allowing their detection and quantitation even when amounts and concentrations of the analytes are extremely small. Illustrative examples include measuring the strength needed to break antibody-antigen bonds and the detection of DNA sequences.
A microchannel device is provided with a plastic substrate having a microchannel formed therein. Polyelectrolyte multilayers are disposed along selected surfaces of the microchannel. The polyelectrolyte layers comprise alternating net positively charged layers and net negatively charged layers. A microchannel lid has a surface facing the microchannel. In making the microchannel device, selected surfaces of the microchannel are alternatively exposed to solutions comprising positively charged polyelectrolytes and negatively charged polyelectrolytes to form the desired number of polyelectrolyte layers.
Disclosed is an apparatus and method for the mixing of two microfluidic channels wherein several wells are oriented diagonally across the width of a mixing channel. The device effectively mixes the confluent streams with electrokinetic flow, and to a lesser degree, with pressure driven flow. The device and method may be further adapted to split a pair of confluent streams into two or more streams of equal or non-equal concentrations of reactants. Further, under electrokinetic flow, the surfaces of said wells may be specially coated so that the differing electroosmotic mobility between the surfaces of the wells and the surfaces of the channel may increase the mixing efficiency. The device and method are applicable to the steady state mixing as well as the dynamic application of mixing a plug of reagent with a confluent stream.
A method for modifying and controlling fluid flow in channels formed in substrates. The method involves exposing a portion of a fluid flow channel to light at a fluence which modifies the surface charge of the substrate at the exposure site. The method can be used to immobilize chemical compounds or biological species in the fluid flow channels at the modified surfaces. The method can be used to fabricate or modify microfluidic systems.
Arrays of spin-valve elements that can be selectively activated to trap, hold, manipulate and release magnetically tagged biological and chemical particles, including molecules and polymers. The spin-valve elements that can be selectively activated and deactivated by applying a momentary applied magnetic field thereto. The spin valve element array can be used for selectively sorting and transporting magnetic particles one particle at a time within the array. As the magnetically tagged particles are held by the spin-valve elements, application of an auxiliary magnetic field can be used to apply tension or torsion to the held particles or to move, e.g. rotate, the trapped particles. The arrays of spin-valve elements can be used in a variety of applications including drug screening, nucleic acid sequencing, structural control and analysis of RNA/DNA and proteins, medical diagnosis, and magnetic particle susceptibility and size homogenization for other medical applications.
Methods for the formation of liposomes that encapsulate reagents in a continuous 2-phase flow microfluidic network with precision control of size, for example, from 100 nm to 300 nm, by manipulation of liquid flow rates are described. By creating a solvent-aqueous interfacial region in a microfluidic format that is homogenous and controllable on the length scale of a liposome, fine control of liposome size and polydispersity can be achieved.
A nanocomposite superparamagnetic material that includes nanosize particles of a magnetic component, preferably a rare earth and a transition element, dispersed finely within a bulk matrix component provides finely dispersed magnetic clusters, whereby a high magnetocaloric effect is obtained in using the nanocomposite material in a conventional magnetic refrigeration system. In one aspect of the present invention, an element formed of such a nanocomposite superparamagnetic material is reciprocated into and out of a heat exchanger within a controlled magnetic field and is in heat transfer communication with a second heat exchanger to facilitate the production of a refrigeration heat transfer effect thereby. In another aspect of the present invention, a generally disk-like element formed of the nanocomposite superparamagnetic material is rotated so that portions thereof move between a first heat exchanger and a second heat exchanger that is within a controlled magnetic field, to thereby perform refrigeration heat transfer between the two heat exchangers.
A spray pyrolysis method for producing pure metal and/or metal oxide particles uses a mixture of a carrier gas and a solution of a metal salt precursor, water and a co-solvent reducing agent. The metal salt precursors preferably comprise metals from the group consisting of Fe, Co, Ni, Cu, Zn, Pd, Ag and Au, whereas the salt anions preferably comprise nitrates, acetates, oxalates and chlorides. The co-solvents are those that act as a reducing agent, are vaporizable, are inert with respect to the carrier gas, and are hydrophilic, such as alcohols, in particular, low-carbon numbered alcohols such as methanol or ethanol.
A positioning device and method for positioning objects is provided. The device includes a movable stage and a pair of levers. The pair of levers is symmetric about a first axis of the movable stage. Additionally, the pair of levers is parallel to a second axis of the movable stage. This second axis is perpendicular to the first axis. Each of the pair of levers applies a force to the movable stage. Each of the pair of levers moves in an arc. The two levers move in opposite directions along their respective arc. The two arcs are symmetrical about an axis of the movable stage.
Multi-layer transition-edge sensors (TES) having improved performance, a method for preparing them and methods of using them. Specifically, the improvement lies in providing normal metal strips along the edges of the superconducting and normal metal layers parallel to the current flow in the TES during operation. These strips (referred to as "banks") provide for both improved detector performance and improved detector robustness against corrosion. This improvement is an important advance particularly for TES-based microcalorimeter detectors. The improved TESs also have many other applications based on the very precise thermometer function achieved by the TES.
A system and method for using one or more localized weak-link structures, and damping on the electrical bias circuit, to improve the performance of superconducting transition-edge sensors (TES). The weak links generally consist of an area or areas having a reduction in cross-sectional geometry in an otherwise uniform bilayer TES applied to a substrate. The weak links control the dissipation of power in the sensor, making it quieter and making its electrical response smoother and less hysteretic. The TES response is also made smoother by implementing a damping circuit on the electrical output of the TES.
The present invention provides a novel humidity chamber suitable for use with an atomic force microscope (AFM). The humidity chamber of the present invention employs an intricate geometrical design which can accommodate a scanned-stylus AFM with an optical lever. This geometrical design allows the invention to enclose one or more of the AFM scanner, tip assembly, optical lever detection system, sample and an optical microscope objective lens, without degrading the ability to operate the AFM or the related systems. The invention is comprised of two major pieces: a chamber within which the AFM scanning head assembly is placed, and an integrated sample platform and spring-loaded base-plate that allows samples to be loaded and unloaded without removal of the chamber from the AFM scanning head assembly. The sample platform, which extends up from the base-plate and is inserted into the chamber, can include a magnet that is securely attached to the base. Once the sample platform is positioned inside the chamber, a locking pin can be inserted between the chamber and the bottom portion of the sample platform to secure the sample platform and base-plate. The spring-loaded base allows the z-directional motors of the AFM to be used to position the sample just below the probe prior to scanning, while at the same time providing an essentially air-tight fit between the chamber and the AFM scanning head. An embodiment of the present invention is suitable for use with components that sense and control the relative humidity inside the chamber.
The present invention provides a novel humidity chamber suitable for use with an atomic force microscope (AFM). The humidity chamber of the present invention employs an intricate geometrical design which can accommodate a scanned-stylus AFM with an optical lever. This geometrical design allows the invention to enclose one or more of the AFM scanner, tip assembly, optical lever detection system, sample and an optical microscope objective lens, without degrading the ability to operate the AFM or the related systems. The invention is comprised of two major pieces: a chamber within which the AFM scanning head assembly is placed, and an integrated sample platform and spring-loaded base-plate that allows samples to be loaded and unloaded without removal of the chamber from the AFM scanning head assembly. The sample platform, which extends up from the base-plate and is inserted into the chamber, can include a magnet that is securely attached to the base. Once the sample platform is positioned inside the chamber, a locking pin can be inserted between the chamber and the bottom portion of the sample platform to secure the sample platform and base-plate. The spring-loaded base allows the z-directional motors of the AFM to be used to position the sample just below the probe prior to scanning, while at the same time providing an essentially air-tight fit between the chamber and the AFM scanning head. An embodiment of the present invention is suitable for use with components that sense and control the relative humidity inside the chamber.
Method of Stabilization of Functional Nanoscale Pores for Device Applications: Application # 20050191616
A membrane is disclosed made from a compound having a hydrophilic head group, an aliphatic tail group, and a polymerizable functional group. The membrane spans an aperte and may be polymerized. The membrane may be useful for DNA sequencing when the membrane includes an ion channel.
Single Molecule Mass Spectrometry in Solution Using a Solitary Nanopore: Docket # 08-003
The invention consists of a means to measure an electrical current passing through a stable nanopore under an applied voltage while partial occlusion of the pore occurs by molecules that reduce the electrical current because the pore's size is commensurate with the molecules'. The pores may be modified to interact selectively with chosen targets. Specific averaging methods are used that, in effect, act as signal averaging of the individual currents and allows these current levels to be assigned to molecules of different sizes. In addition, the time courses of the chemical interactions of the analytes with the pore can be found once the current levels are assigned. The set of current levels together with the time courses provide a novel two-dimensional method of analysis for charged and uncharged molecules in solution.
This document describes a method for bonding two or more objects using nanometerscale to micrometer-scale adhesive particles manipulated and cured by optical tweezers, including holographic optical tweezers.
A system and method for bonding and unbonding of small objects using small adhesive particles. The system and method includes the use of a plurality of optical tweezers to manipulate objects to be bonded and adhesive particles suspended in a fluid. The objects to be bonded (or unbonded) and the adhesive particles are positioned by lower power optical tweezers and then an intense bonding optical tweezer is activated to cause the adhesive to join the objects together (or used to unbond objects).
A parallel nanotomography imaging system is provided having an x-ray source, which is preferably a laser-based x-ray source that generates x-rays that are collected using a collector optic and are received in a composite objective assembly. The composite objective assembly includes plural micro-objectives, each imaging the target. The x-ray image is received by an x-ray image formation and acquisition apparatus, and processed and/or displayed.
In this disclosure, we present a widely applicable technique which enables two (or more) mechanically independent structures (e.g. an atomic force microscopy (AFM) tip and a reference mark on the sample substrate) whose respective positions in three dimensional space can be maintained with sub-nanometer precision for long (~100 s) periods of time. The method is based on the scattering of laser light by one (or more) fiducial marks. One mark is coupled to each structure to be positioned, except in the case where a lens is one of the structures to be stabilized. The scattered light is collected in a photo-sensitive device which enables real-time high-bandwidth position-sensing of each structure. The method requires one of the structures to be mounted onto a precision (e.g. piezoelectric) 2D or 3D translational stage. Signals generated by the scattered light field are used in a feedback loop to modulate the stage position. The technique presented here could potentially find utility across a number of disciplines including: optical tweezers, optical microscopy, scanning probe microscopy and semiconductor pattering and processing.
A method of imaging critical dimensions by measuring the zeroeth order of diffracted light. The method involves providing a target, directing light onto the target so as to cause the target to diffract the light. The zeroeth order of the diffracted light is collected and analyzed to determine structural features of the target. The target can be an article of manufacture, such as a semiconductor device, or a separate target that is provided or fabricated on an article of manufacture. One of at least the wavelength and the angle at which the light is directed onto the target can be scanned. The target can fill all or only a portion of the field of view.
Highly Charged Ion Modified Oxides (HCIMO) are achieved by irradiating a thin, high resistance oxide with highly charged ions (HCIs) and then depositing a conducting material of choice on top the irradiated oxide. The irradiation by HCIs preferentially ablates a region on the order of a cubic nanometer at each HCI’s impact site breaking a hole through the ultra-thin oxide. This is demonstrated by the inventors by preparing an insulating layer of aluminum oxide on a cobalt lower electrode layer, exposing the oxide to very dilute HCI radiation, and then depositing a cobalt upper layer. The data show a clear and systematic decrease in the resistance of the multilayer devices correlated to the HCI dose at very dilute doses, i.e., an HCI density of 100 HCIs/ìm2 (108 HCIs/mm2) yields a resistance reduction by a factor of greater than 100. The nanometer dimensions of individual HCI impacts and the precise control over the dose combine to allow high precision selection of the material’s resistance over a wide range of values, currently demonstrated over three orders of magnitude.
As HCI modification only occurs within a few nanometers of the surface and generally does not affect metals, no special measures are needed to protect surrounding device structures from HCI damage. Since the size of the material modification is determined by the properties of a single ion, precise alignment is not required, only uniform illumination of the device area by the HCI beam, greatly simplifying commercial integration of HCI irradiation.
We have further employed this strategy of producing an ensemble of small, discrete pockets of one material within another using HCIs to produce a new type of magnetic sensor. This approach may provide a solution to the current perpendicular to the plane (CPP) magnetic sensor resistance problem. In that problem, state-of-the-art CPP type magnetic sensors produced by using metal-metal interfaces or metal-insulator interfaces lead to resistances too low or too high, respectively, to be commercially viable. By using HCIMO as the buffer material instead of a metal (as in giant magneto-resistance [GMR] type sensors) or an insulator (magnetic tunnel junction [MTJ] type sensor) we can produce devices with the desired resistance values needed for advanced magnetic sensors for future hard drive read heads.
By using HCIMO as the buffer layer in a magnetic multilayer structure, we are creating a new type of sensor that uses a superposition of metal-insulator and metal-metal sensor junctions at a controlled density without advanced fabrication techniques. Magnetic sensitivity in this new type of device has also been demonstrated with evidence that both the metal-insulator and metal-metal parts of the HCIMO type sensors produce a clearly measurable response to small external magnetic fields.
A new approach towards electrically contacting the top of an aligned nanowire or nanotube array using a conductive nanoparticle film has been developed. This contact method allows surfaces along the length of the nanowire or nanotube to remain untreated. Previously the only way to attach electrical contacts to the non-substrate ends of vertically oriented nanowires or nanotubes involved attempts at filling the spaces between the nanorods with some material. This would be followed by some kind of electro-polish to expose the top ends of the nanorods, over which a continuous film would be developed. In such a process contamination of the nanorods by the fill material, and contamination at the metal. contact interface posed problems. In the new approach, only the contact material is present. Briefly, conducting nanoparicles (metals such as gold, silver etc.) are generated, charged and deposited onto the sample containing the nanowire or nanotube array within an electrostatic precipitator. The electric field enhancement from the tips of the nanowires (or nanotubes) is utilized to attract charged nanoparticles exclusively onto the top of the array. The result is an array of standing nanorods with a continuous and porous top contact layer.
A new approach towards electrically contacting the top of an aligned nanowire or nanotube array using a conductive nanoparticle film has been developed. This contact method allows surfaces along the length of the nanowire or nanotube to remain untreated. Previously the only way to attach electrical contacts to the non-substrate ends of vertically oriented nanowires or nanotubes involved attempts at filling the spaces between the nanorods with some material. This would be followed by some kind of electro-polish to expose the top ends of the nanorods, over which a continuous film would be developed. In such a process contamination of the nanorods by the fill material, and contamination at the metal. contact interface posed problems. In the new approach, only the contact material is present. Briefly, conducting nanoparicles (metals such as gold, silver etc.) are generated, charged and deposited onto the sample containing the nanowire or nanotube array within an electrostatic precipitator. The electric field enhancement from the tips of the nanowires (or nanotubes) is utilized to attract charged nanoparticles exclusively onto the top of the array. The result is an array of standing nanorods with a continuous and porous top contact layer.
A thermometer is provided. A housing has at least one opening. A dielectric element is disposed in the housing. At least one microwave guide is coupled to the at least one opening for providing a signal into the dielectric element for propagation at a resonant frequency and for receiving the signal from the dielectric element. A temperature determination unit receives the signal from the at least one microwave guide, measures the resonant frequency of the dielectric element, and determines the temperature of the dielectric element based on a relationship between resonant frequency and temperature of the dielectric element.
The invention is the exploitation of a difference in scaling with length of the hydrodynaiic drag on a nanotube, and the buoyancy force of the same nanotube to sort the nanotubes by their length. The buoyancy is generated by using a commercial density medium, a surfactant, such as sodium deoxycholate, that forms a miceller shell around the nanotube. The surfactat shell acts both to keep the nanotube individually dispersed, and as a buoyant volume with an effective density different from the surrounding medium.
This invention consists of a new source for creating a focused ion beam. A magneto-optical trap serves as a source of cold atoms that are photo ionized to produce the ion source. Under appropriate conditions, the resulting ion cloud has temperature and spatial characteristics similar to that of the initial neutral atom cloud. An external electric field extracts the ions which can be focused using standard charged-particle optics. The cold temperatures achieved through laser cooling yield an ion beam with excellent characteristics which should allow for a beam resolution of 10 nm or less. The current produced from this source depends on the operating parameters of the MOT and can range from single ions on demand to over 100 pA, a much wider range than is currently possible. In addition, the wide range of elements that can be laser cooled greatly extends the possibilities for ionic species that can be used in FIBs, The net result is a source that has improved characteristics as well as expanded capabilities over current technology.
A method of harvesting carbon nanotubes (CNTs) is provided. According to this method, CNT bundles, comprising CNTs associated with metallic catalysts and having amorphous carbon coatings are agitated in an aqueous liquid containing a dispersant with free-flowing grit particles to disassociate the CNTs from the metallic catalysts, remove the amorphous carbon of the amorphous carbon coatings and shorten the CNTs via shearing.
This invention allows control over the location and direction of nanowires on a large size single crystal wafer.
A laser Doppler vibrometer for vibration measurement that employs active feedback to cancel the effect of large vibration excursions at low frequencies, obviating the need to unwrap phase data. The Doppler shift of a reflective vibrating test object is sensed interferometrically and compensated by means of a voltage-controlled oscillator driving an acousto-optic modulator. For frequencies within the servo bandwidth, the feedback signal provides a direct measurement of vibration velocity. For frequencies outside the servo bandwidth, feedback biases the interferometer at a point of maximal sensitivity, thus enabling phase-sensitive measurement of the high-frequency excursions. Using two measurements, one with a low bandwidth and one with a high bandwidth, more than five decades of frequency may be spanned. This approach is of particular interest for the frequently occurring situation where vibration amplitudes at low frequency exceed an optical wavelength, but knowledge of the vibration spectrum at high frequency is also important.
A nanofabrication Process for use with a photoresist that is disposed on a substrate includes the steps of exposing the photoresist to a grayscale radiation pattern, developing the photoresist to remove the irradiated portions and form a patterned topography having a plurality of nanoscale critical dimensions, and selectively etching the photoresist and the substrate to transfer a corresponding topography having a plurality of nanoscale critical dimensions into the substrate.
A National Institute of Standards and Technology (NIST) researcher has come up with a method designed to improve the energy efficiency of water chillers that cool the nation’s large commercial buildings. The NIST method, if confirmed through experiments with full-scale chiller systems, could save as much as 1 percent of the 320 billion kWh of electricity used annually by chillers or an equivalent 5.5 million barrels of oil per year, according to Mark Kedzierski, the NIST mechanical engineer who developed the technique.
A method for simultaneously forming microstructures in substrates and altering their chemical character. The method involves exposing a surface portion of a substrate to light source, which is strong enough and of the appropriate wavelength to cause ablation of the substrate. The ablation of the substrate is controlled to form microstructures therein, such as channels. The ablation is conducted under a chemical atmosphere, which causes a change in the chemical functionality of the microstructures. The chemical atmosphere can be a gas, liquid or solid that is provided on the substrate surface. The method can be used to fabricate or modify microfluidic systems.
An optical method with the potential to discriminate between changes in the physical parameters of a target as represented in the properties of light scattered off of the target. For example, whether a change in the scattered light is due to a change in the height or width of a line.
Here we introduce a technique which allows sharp objects (e.g. scanning tunneling microscope tips, atomic force microscope tips, near-field scanning optical microscope tips, pipette tips, etc.) to be rapidly brought into close proximity to a particular region of a surface with high precision and accuracy in three dimensions. The method has potential applications in a broad array of tip-based research instrumentation and manufacturing techniques, including: scanning probe microscopy, atomic force microscopy, proximal probe lithography, dip-pen lithography, tip-indent lithography, molecule array manufacturing, and single atom manipulation.
In a typical atomic force microscope, course approach between tip and sample is achieved via a translation by a long range (0.1-1000 microns) stage followed by a fine stage movement (0.1-1000 nm); if the surface is not found, this process is repeated. Often, optical microscopes are used to aid in this process. Prior art does not allow registered tip approach due to the lack of a reliable method to yield precise three dimensional simultaneous localization of a tip and a sample surface. This knowledge is necessary in order to bring these objects into close proximity or contact with high resolution registration and speed.
Single-walled nanotubes--cylinders of carbon about a nanometer in diameter--have been highly touted for potential applications such as ultrastrong fibers, electrical wires in molecular devices, or hydrogen storage components for fuel cells. Thanks to a new development by researchers at the National Institute of Standards and Technology (NIST) and five partners, you can add one more application to the list: detection and destruction of an aggressive form of breast cancer.
Disclosed is an apparatus and method for the mixing of two microfluidic channels wherein several wells are oriented diagonally across the width of a mixing channel. The device effectively mixes the confluent streams with electrokinetic flow, and to a lesser degree, with pressure driven flow. The device and method may be further adapted to split a pair of confluent streams into two or more streams of equal or non-equal concentrations of reactants. Further, under electrokinetic flow, the surfaces of said wells may be specially coated so that the differing electroosmotic mobility between the surfaces of the wells and the surfaces of the channel may increase the mixing efficiency. The device and method are applicable to the steady state mixing as well as the dynamic application of mixing a plug of reagent with a confluent stream.
Arrays of spin-valve elements that can be selectively activated to trap, hold, manipulate and release magnetically tagged biological and chemical particles, including molecules and polymers. The spin-valve elements that can be selectively activated and deactivated by applying a momentary applied magnetic field thereto. The spin valve element array can be used for selectively sorting and transporting magnetic particles one particle at a time within the array. As the magnetically tagged particles are held by the spin-valve elements, application of an auxiliary magnetic field can be used to apply tension or torsion to the held particles or to move, e.g. rotate, the trapped particles. The arrays of spin-valve elements can be used in a variety of applications including drug screening, nucleic acid sequencing, structural control and analysis of RNA/DNA and proteins, medical diagnosis, and magnetic particle susceptibility and size homogenization for other medical applications.
This invention is a system for producing a charged particle beam from a photoionized cold atom beam. A vapor of neutral atoms is generated. From these atoms, an atom beam having axial and transverse velocity distributions controlled by the application of laser light is produced.The produced atom beam is spatially compressed along each transverse axis, thus reducing the cross-sectional area of the produced beam and reducing a velocity spread of the produced beam along directions transverse to the beam’s direction of propagation. Laser light is directed onto at least a portion of the neutral atoms in the atom beam, thereby producing ions and electrons. An electric field is generated at the location of the produced ions and electrons, thereby producing a beam of ions traveling in a first direction and electrons traveling in substantially the opposite direction. A vacuum chamber contains the atom beam, the ion beam and the electron beam.