Del Mar Photonics - Newsletter Fall 2010 - Newsletter Winter 2010

Carbon nanotubes as optical antennae

Carbon nanotubes, cylindrical rolled-up sheets of carbon atoms, might one day make ideal optical scattering wires — tiny, mostly invisible antennae with the ability to control, absorb and emit certain colors of light at the nanoscale — according to research led by Jiwoong Park, assistant professor of chemistry and chemical biology. The study, which includes co-author Garnet K.-L.Chan, associate professor of chemistry, was published online in the journal Nature Nanotechnology. The paper’s first author is Daniel Y. Joh, a former student in Park’s lab. (link)

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Photocurrent Imaging of p-n Junctions in Ambipolar Carbon Nanotube Transistors

Del Mar Photonics is involved in research of CNTs, graphene nanoplatelets and graphene materials, develops advanced multifunctional materials for variety of applications as well as research instrumentation for characterization of the above.

Carbon nanotubes form ultrasensitive biosensor to detect proteins

Sunday, June 27, 2010

A cluster of carbon nanotubes coated with a thin layer of protein-recognizing polymer form a biosensor capable of using electrochemical signals to detect minute amounts of proteins, which could provide a crucial new diagnostic tool for the detection of a range of illnesses, a team of Boston College researchers report in the journal Nature Nanotechnology.

The nanotube biosensor proved capable of detecting human ferritin, the primary iron-storing protein of cells, and E7 oncoprotein derived from human papillomavirus. Further tests using calmodulin showed the sensor could discriminate between varieties of the protein that take different shapes, according to the multi-disciplinary team of biologists, chemists and physicists.

Molecular imprinting techniques have shown that polymer structures can be used in the development of sensors capable of recognizing certain organic compounds, but recognizing proteins has presented a difficult set of challenges. The BC team used arrays of wire-like nanotubes approximately one 300th the size of a human hair coated with a non-conducting polymer coating capable of recognizing proteins with subpicogram per liter sensitivity.

Central to the function of the sensor are imprints of the protein molecules within the non-conducting polymer coating. Because the imprints reduce the thickness of the coating, these regions of the polymer register a lower level of impedance than the rest of the polymer insulator when contacted by the charges inherent to the proteins and an ionized saline solution. When a protein molecule drops into its mirror image, it fills the void in the insulator, allowing the nanotubes to register a corresponding change in impedance, signaling the presence of the protein, according to co-author Dong Cai, an associate research professor of Biology at BC.

The detection can be read in real time, instead of after days or weeks of laboratory analysis, meaning the nanotube molecular imprinting technique could pave the way for biosensors capable of detecting human papillomavirus or other viruses weeks sooner than available diagnostic techniques currently allow. As opposed to searching for the HPV antibody or cell-mediated immine responses after initial infection, the nanotube sensor can track the HPV protein directly. In addition, no chemical marker is required by the lebel-free electrochemical detection methods.

"In the case of some diseases, no one can be sure why someone is ill," said Cai. "All that may be known is that it might be a virus. At that time, the patient may not have detectable serum antibodies. So at a time when it is critical to obtain a diagnosis, there may not be any traces of the virus. You've basically lost your chance. Now we can detect surface proteins of the virus itself through molecular imprinting and do the analysis."

Carbon-nanotubes as Ultrafast Photodetectors
 

Trestles CW/fs laser for carbon nanotubes spectroscopy and photophysics research at Rice University

Single nanotube experiment with tunable Ti:Sapphire laser Trestles Finesse

Del Mar Photonics

Del Mar Photonics featured customer Bruce Weisman. Professor Weisman ordered Trestles Ti:Sapphire laser with built-in DPSS pump laser.

Professor Weisman wrote: Our applications are for carbon nanotube excitation, mostly with a cw beam but in some experiments with mode-locked pulses.

Del Mar Photonics offered Trestles Ti:Sapphire model with both CW and femtosecond modes of operation.
Detailed laser specifications are as follows (request a quote):

Trestles Ti:Sapphire laser with built-in DPSS pump laser
Ti:Sapphire oscillator having a tuning range of 710-920 nm;
Output power: 30mW (@3W pump, in the whole range);
Spatial mode: TEMoo;
Polarization: linear horizontal;
Repetition rate: 80 MHz;
Pulse duration: <100 fs
Electronic starter with TTL output for mode-locked mode
observation. Output mirrors included.
USB-controlled tuning slit for wavelength tuning

3BRF-TM 3-plate BRF for CW lasers (step motor controlled tuning)
Provides CW tuning and 40 GHz linewidth of the Trestles fs
lasers in CW mode; output power @700 nm - >50 mW (3W pump)

3 W pump DPSS laser with control and power supply unit
Power: 3 W
Wavelength: 532 nm
Beam size: 2.0 mm
Spatial mode: TEM00
Bandwidth: 30 GHz
Divergence: 0.4 mrad
M squared: < 1.1
Power stability: < 0.4 % RMS
Noise: < 0.4% RMS
Noise bandwidth: 1 Hz - 6 MHz
Pointing stability: < 2 microrads/C
Polarization ratio: 100:1
Polarization direction: horizontal
Coherence length: < 1 cm
Beam angle: < 1 mrad
Umbilical length: 1.5 m
Warm-up time: 10 min

R. Bruce Weisman Professor of Chemistry

Research Statement
Dr. R. Bruce Weisman and his group investigate the spectroscopy and photophysics of fullerenes and carbon nanotubes. All of these are closed nanoscopic structures formed from carbon atoms. Fullerenes, such as C60, C70, and their chemical derivatives, have unusual molecular properties that cause interesting behaviors following the absorption of light. Time-resolved absorption and emission methods are used to study radiationless decay, photochemical reactions, and energy transfer in fullerenes. Another major research topic is single-walled carbon nanotube spectroscopy. Following the discovery in Weisman?s lab of near-infrared nanotube fluorescence, the group has measured and unraveled the absorption and emission spectra of more than 30 semiconducting nanotube species. Follow-up projects include detailed elucidation of nanotube electronic structure, as well as applications in non-invasive biomedical imaging and analytical nanotechnology.

Selected Publications
R. Bruce Weisman and Shekhar Subramoney "Carbon Nanotubes." Interface (Summer, 2006): 42-46.

J. P. Casey, S. M. Bachilo, C. H. Moran, and R. B. Weisman "Chirality-Resolved Length Analysis of Single-Walled Carbon Nanotube Samples through Shear-Aligned Photoluminescence Anisotropy." ACS Nano, 2 (2008): 1738-1746.

J. P. Casey, S. M. Bachilo, and R. B. Weisman "Efficient Photosensitized Energy Transfer and Near-IR Fluorescence from Porphyrin/SWNT Complexes." J. Mater. Chem., 18 (2008): 1510-1516.

R. B. Weisman "Optical Spectroscopy of Single-Walled Carbon Nanotubes." Contemporary Concepts of Condensed Matter Science. Carbon Nanotubes: Quantum Cylinders of Graphene, 3 (2008): 109-133.

D. A. Tsyboulski, E. L. Bakota, L. S. Witus, J.-D. R. Rocha, J. D. Hartgerink, and R. B. Weisman "Self-Assembling Peptide Coatings Designed for Highly Luminescent Suspension of Single-Walled Carbon Nanotubes." J. Am. Chem. Soc., 130 (2008): 17134-117140.

C. D. Doyle, J.-D. R. Rocha, R. B. Weisman, and J. M. Tour "Structure-dependent Reactivity of Semiconducting Single-Walled Carbon Nanotubes with Benzene Diazonium Salts." J. Am. Chem. Soc., 130 (2008): 6795-6800.

D. A. Tsyboulski, S. M. Bachilo, A. B. Kolomeisky, and R. B. Weisman "Translational and Rotational Dynamics of Individual Single-Walled Carbon Nanotubes in Aqueous Suspension." ACS Nano, 2 (2008): 1770-1776.

Robert F. Curl and R. Bruce Weisman "Biography of Richard Errett Smalley." J. Phys. Chem. C, 111 (2007): 17653-17655.

Christopher J. Gannon, Paul Cherukuri, Boris I. Yakobson, Laurent Cognet, John S. Kanzius, Carter Kittrell, R. Bruce Weisman, Matteo Pasquali, Howard K. Schmidt, Richard E. Smalley, and Steven A. Curley "Carbon Nanotube-enhanced Thermal Destruction of Cancer Cells in a Noninvasive Radiofrequency Field." Cancer, 110 (2007): 2654-2665.

Laurent Cognet, Dmitri A. Tsyboulski, John-David R. Rocha, Condell D. Doyle, James M. Tour and R. Bruce Weisman "Stepwise Quenching of Exciton Fluorescence in Carbon Nanotubes by Single Molecule Reactions." Science, 316 (2007): 1465-1468.


Presentations
"Quantitative Analysis of Bulk SWCNT Samples using Near-IR Fluorimetry,” Focus Session on Development of Purity Evaluation Criteria and Quality Assurance Standards for Carbon Nanotubes,." Materials Research Society Meeting, Boston, Massachusetts. (November 30, 2008)

"Near-infrared Fluorescence of Single-Walled Carbon Nanotubes: a Tool for Developing Medical Applications." Nanomedicine Summit 08, Cleveland, Ohio. (September 25, 2008)

"Single-walled Carbon Nanotubes: Physical Properties and Biomedical Applications." Howard Hughes Medical Institute Summer Lecture Series, Harvey Mudd College, Claremont, California. (July 16, 2008)

"Near-IR Fluorescence of Single-Walled Carbon Nanotubes: A Tool for Developing Medical Applications." Carbon Nanotube Biology, Medicine, and Toxicology Symposium, Montpelier, France. (June 28, 2008)

"Qualitative and Quantitative Analysis of Bulk SWNT Samples using Near-IR Fluorimetry." Workshop on Metrology, Standardization, and Industrial Quality of Nanotubes, Montpelier, France. (June 28, 2008)

Editorial Positions

Associate Editor, Applied Physics A, Springer-Verlag,, (2008).
Theses
Paul Cherukuri, Ph.D. "Biomedical Studies of Single-Walled Carbon Nanotubes Using Near-Infrared Fluorescence." (2007).(Thesis or Dissertation Director)

Dmitry Tsyboulski, Ph.D. "Spectroscopic and Optical Imaging Studies of Fullerene Complexes and Single-Walled Carbon Nanotubes." (2006).(Thesis or Dissertation Director)

Eric Booth, PhD. "Photophysical Studies of Selected C84 Isomers, C80 Species, Aqueous C60 Colloid, and a C60-Amino Acid Derivative." (2005).(Thesis or Dissertation Director)

Awards
Elected Fellow, American Physical Society. (2008).
Paul Frison Accelator Award for Applied NanoFluorescence, Houston Business Journal. (2007).
Institute of Physics in Ireland Lecturer, . (2005).

Del Mar Photonics - Newsletter Fall 2010 - Newsletter Winter 2010

Del Mar Photonics is involved in research of CNTs, graphene nanoplatelets and graphene materials, develops advanced multifunctional materials for variety of applications as well as research instrumentation for characterization of the above.

We currently we can offer:

1) Graphene nanoplatelets: the stack of multi-layer graphene sheets with high aspect ratio, diameter: 0.5-20 µm, thickness: 5-25 nm.
2) Graphene materials: Graphene Powder, Graphene Oxide Powder, Graphene Suspension.
3) Carbon Nanotubes.
 

Contact our application team to discuss your requirements for high-performance nanocomposite materials, display materials, sensing materials, ultracapacitors, batteries, energy storage and other area to improve electrical, thermal, barrier, or mechanical properties by using low-cost nano-additive.

Graphene nanoplatelets are the stack of multi-layer graphene sheets including platelet morphology, with characteristics as follows:

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Applications:

The high performance composite additives in PPO, POM, PPS, PC, ABS, PP, PE, PS, Nylon and rubbers.
To improve composite tensile strength, stiffness, corrosion resistance, abrasion resistance and anti-static and lubricant properties.
Mechanical properties modifications.
Conductivity modification.
Fuel tank coating.
In electronic enclosures add electrical conductivity to polymers at low densities of 3 to 5 wt%.
Adding EMI or RFI shielding capabilities to a variety of polymers.
Automotive parts: a composite with nanoplatelets can be painted electrostatically, thereby saving costs.
Aerospace: graphite has long been used in aerospace composites. Nanoplatelets can be combined with other additives to reinforce stiffness, add electrical conductivity, EMI shielding, etc.
Appliances: fortified polymers provide superior thermal and electrical conductivity, thereby saving the costs of separate heat dissipation mechanisms.
Sporting goods: graphite-based composites are stronger and stiffer and lighter than comparable materials.
Coatings and paints: graphene nanoplatelets can be dispersed in a wide variety of materials to add electrical conductivity and surface durability.
Batteries: graphene nanoplatelets increase the effectiveness of Lithium-ion batteries when used to formulate electrodes.
Fuel cells: both bi-polar plate and electrode efficiencies can be improved.

Del Mar Photonics develops advanced instrumentation for research of CNTs, graphene nanoplatelets and graphene materials including lasers for broadband spectroscopy, femtosecond transient absorption and fluorescence measurements.

T&D Scan high resolution Laser Spectrometer based on broadly tunable CW laser
CW single-frequency ring Dye laser
Beacon Femtosecond Optically Gated Fluorescence Kinetic Measurement System
New Hatteras femtosecond transient absorption system
Photon Scanning Tunneling Microscope