This is a copy of a student file that I will compile for each student in the
class. This should give you an idea of how I want you to email the
citations and the summaries of citations. Note how the student
submitted his name and date for each assignment.
Name of student
Writing and Presentation for Chemistry
Dr. Schlegel
Paragraph Summary #1
2/17/05
Name of Student
CARBON NANOTUBES AS CHEMICAL SENSORS
8 Seminars attended@2 each =
8x1= 8
8
1st 2 citations submitted@2 each = 2x 1 = 2
2
1st 2 summaries submitted@1 each = 2 x 1 = 2
2
2nd 4 citations submitted@1 each = 4 x 1 = 4
4
2nd 4 summaries submitted@1 each =4 x 1 = 4
4
Poster presentation ..................................... = 10
7
Poster content .............................................. = 20
16
Total for seminar portion............................. 100
43
Total for writing portion................................100
98
Grand total .....................................................150
141
Grade in the course ………………………………………A
Overall good presentation of your poster. I would have liked to have known how
scientists were able to distinguish between the three different forms of the carbon
nanotubes.
1. Li, J., Y. Lu, Q. Ye, M. Cinke, J. Han, and M. Meyyappan. (2003) Carbon
Nanotube Sensors for Gas and Organic Vapor Detection. Nano Letters Vol. 3, No.
7, 929-933
2. Durkop T., S.A. Getty, E. Cobas, and M.S. Fuhrer. (2004) Extraordinary Mobility
in Semiconducting Carbon Nanotubes. Nano Letters Vol. 4, No. 1, 35-39
3. Yun, M., Myung, N.V., Vasquez, R.P., Lee, C., Menke, E., and Penner, R.M.
(2004) Electronically Grown Wires for Individually Addressable Sensor Arrays.
Nano Letters Vol. 4, No. 3, 419-422
4. Chen, R.J., Bangsaruntip, S., Drouvalakis, K.A., Kam, N.W.S., Shim, M., Li, Y.,
Kim, W., Utz, P.J., and Dai, H. (2003) Noncovalent Functionalization of Carbon
Nanotubes for Highly Specific Electronic Biosensors. PNAS Vol. 100, No. 9,
4984-4989
==================================================sent2/19/05
Name of student
Writing and Presentation for Chemistry
Dr. Schlegel
Paragraph Summary #1
2/17/05
A nanomaterial called single-walled carbon nanotubes (SWNTs) is becoming
important in biology because of their potential use as biological sensors. One proposed
use is for detecting certain proteins that are associated with certain diseases. A specific
example is detection of multiclonal antibodies (mAbs) that bind to human U1A, which
are believed to be involved with diseases such as systemic lupus erythematosus and
mixed connective tissue disease. Using Atomic Force Microscopy (AFM), Quartz
Crystal Microbalance (QCM), and electronic transport measurements, it can be shown
that proteins exhibit non-specific binding (NSB) to SWNTs. Adding substances such as
polyethylene oxide (PEO), Tween 20, and triblock copolymers will prevent proteins from
binding to the SWNTs because they are adsorbed to the surface of SWNTs and are
“protein blocking”. Binding these substances to SWNTs, however, does not affect the
electrical properties of them, but the electrical current produced by the nanotubes is
greatly reduced due to the absence of proteins. This fact shows that the SWNTs, not the
proteins, that have potential for use as sensors because they give off more electrical
current (they “sense”) when the proteins are attached. In order to allow for selective
binding of certain proteins to the SWNTs, “binding partners”, or proteins that are
attached to allow specific binding, are added to the protein-blocking layer already
present. This allows for binding with high specificity to occur. This specificity and the
electrical conductance of the SWNTs is promising evidence that SWNTs could be used
as biological sensors someday.
Citation:
Chen, R.J., S. Bangsaruntip, K. A. Drouvalakis, N. W. S. Kam, M. Shim, Y. Li, W. Kim,
P. J. Utz, and H. Dai. 2003. Noncovalent Functionalization of Carbon Nanotubes for
Highly Specific Electronic Biosensors. PNAS 100: 4984-4989
Name of student
2-22-05
Writing and Presentation for Chemistry
Dr. Schlegel
Carbon Nanotube Sensors for Gas and Organic Vapor Detection
Single-walled carbon nanotubes (SWNTs) can detect gases such as nitrogen
dioxide (NO2) and ammonia (NH3) at room temperature, unlike metal oxide microfilm
sensors, which work at temperatures greater than 350˚C. At room temperature, SWNT
sensors have poor sensitivity, but they do function. The sensitivity of SWNTs is
accounted for by large changes in electrical conductance of semi-conducting SWNTs
induced by charge transfer of gas molecules to them. The problem with using SWNTs
lies within the production of the SWNTs because a combination of metallic and semiconducting SWNTs forms, and metallic SWNTs do not work as sensors. This results in
low sensitivity of the sensors. Metal oxide microfilm sensors have better sensitivity, but
only function at temperatures greater than 350˚C. Combining these two different types of
sensors makes for a better sensor because it can be used in a practical environment. To
make the improved sensor, researches combined SWNTs and metal oxide microfilm
sensors to make a simple SWNT sensor platform. This increases the sensitivity of the
sensors and allows for use at room temperature (or near-room temperature). The
detection of molecules other than NO2 and NH3 was also a problem. Using the
combination sensors allows for sensing of molecules such as benzene, acetone, and
nitrotoluene because the mechanism of sensing is different than each type of sensors’
sensing mechanisms.
Li, J., Y. Lu, Q. Ye M. Cinke, J. Han, and M. Meyyappan. 2003. Carbon Nanotube
Sensors for Gas and Organic Vapor Detection. Nano Letters 3: 929-933
Extraordinary Mobility in Semi-conducting Carbon Nanotubes
Mobility is used to determine the conductivity difference per charge. It
determines the sensitivity of devices that use semi-conducting nanotubes, such as fieldeffect transistors or chemical and biochemical sensors. In chemical sensors, mobility is
used to detect charge or chemical signal that has been converted to charge. The values
that were previously determined range from 20 cm2/Vs to infinity for short instruments
that lack Ohmic contacts. With devices containing long (greater than 300 micrometer)
ohmically contacted nanotube devices, mobility in semi-conducting nanotubes is about
79,000 cm2/Vs at room temperature and their intrinsic mobility is even greater (>100,000
cm2/Vs). These values are greater than the values for any present semi-conducting device
and are promising news for the development of sensors using carbon nanotubes in largerscale devices.
Durkop, T., S. A. Getty, E. Cobas, and M. S. Fuhrer. 2004. Extraordinary Mobility in
Semi-conducting Carbon Nanotubes. Nano Letters 4: 35-39
Electrochemically Grown Wires for Individually Addressable Sensor Arrays
Nanomaterials have been looked at for their potential use as sensors for detecting
things proteins, gases, etc. In assembling devices using nanomaterials, problems
involving controllability, reproducibility, and operation in large-scale environments have
arisen. Electrodepositing materials such as metals, alloys, metal oxides, semi-conductors,
and conducting polymers onto nanowires can help reduce the effects of these problems.
Using this technique allows for “growing” the wires electrochemically (i.e. making the
wires and while being able to control their length and other properties) to help the
developer have more control over the nanowires’ sensitivity and the reproducibility of the
results.
Yun, M., N. V. Myung, R. P. Vasquez, C. Lee, E. Menke, and R. M. Penner. 2004.
Electrochemically Grown Wires for Individually Addressable Sensor Arrays. Nano
Letters 4: 419-422
=============================================== sent 3/1
Citations #2 for Writing and Presentation for Chemistry
1. Dai, Y. and K. Shiu. 2004. Glucose Biosensor Based on Multi-Walled Carbon
Nanotube Glassy Carbon Electrode. Electroanalysis 16: 1697-1703.
2. Heirold, C. 2004. From Micro- to Nanosystems: Mechanical Sensors Go Nano.
Journal of Micromechanics and Microenginering.14: S1-S11.
3. Chen, R.J., H. C. Choi, S. Bangsaruntip, E. Yenilmez, X. Tang, Q. Wang, Y.
Chang, and H. Dai. 2004. An Investigation of the Mechanisms of Electronic
Sensing of Protein Adsorption on Carbon Nanotube Devices. JACS 126: 15631568.
4. Sotiropoulou, S. V. Gavalas, V. Vamvakaki, and V. A. Chaniotakis. 2003. Novel
Carbon Materials in Biosensor Systems. Biosensors and Bioelectronics 18: 211215.
============================================== sent 3/5
Name of student
Writing and Presentation for Chemistry
3/6/05
Dr. Schlegel
Second Set of Paragraph Summaries for Writing and Presentation for Chemistry
Dai, Y. and K. Shiu. 2004. Glucose Biosensor Based on Multi-Walled Carbon Nanotube
Glassy Carbon Electrode. Electroanalysis 16: 1697-1703.
1.
A biological sensor is in the works that detects glucose. This sensor uses
multi-walled carbon nanotubes (MWNTs) and a glucose oxidase electrode to
sense glucose. To measure the effects of glucose binding to these sensors,
electrochemistry was involved using an electrochemical analyzer, which
contained a silver/silver chloride reference electrode. In the experiment,
oxygen was dissolved on the electrode and acted as a catalyst for glucose
binding to the electrode as part of the “sensing”. Oxygen binds less to
electrodes without MWNTs attached, so putting the MWNTs on the
electrodes, increases the oxygen binding, which, in turn, increases glucose
binding. Potential differences were then measured when adding glucose from
the zero point. Current was found to top-out when the MWNTs loading was
higher than 280 μg/cm2. The sensitivity of the sensor at this concentration for
glucose seems to be the best. Biologically common species were also added
to see if they would interfere with the signal response. When using a negative
zero point potential, none of the species introduced interfered with the signal
response.
Heirold, C. 2004. From Micro- to Nanosystems: Mechanical Sensors Go Nano. Journal
of Micromechanics and Microenginering.14: S1-S11.
2.
Miniaturization is something that is always a topic of discussion, especially in
electronics. It is important for many different reasons: smaller size can be
important in application, it usually results in using less energy, it can be more
cost-effective, and carbon nanotubes are a very strong material.
Nanomaterials such as carbon nanotubes are being looked at for use in sensors
because they fulfill all of these qualifications and can even be more sensitive
as sensors than microsystems. A problem that has arisen in using CNTs in
sensors is reproducing the CNTs so that their sensitivity is the same. Right
now, using CNTs as sensors seems to be an idea that is in its initial stage of
research and is not something that is being used as of yet. One idea to
circumvent this problem is to use CNTs and micromaterials as a sensor.
Chen, R.J., H. C. Choi, S. Bangsaruntip, E. Yenilmez, X. Tang, Q. Wang, Y. Chang, and
H. Dai. 2004. An Investigation of the Mechanisms of Electronic Sensing of Protein
Adsorption on Carbon Nanotube Devices. JACS 126: 1563-1568.
3.
This article describes a possible mechanism for how adsorption of proteins
leads to a change in current in a carbon nanotube. One thought for a
mechanism of how protein adsorption causes electrical conductance to change
in a carbon nanotube is that when proteins are adsorbed to a CNT surface the
proteins exert a charge transfer, which causes the change in conductance.
Another proposed mechanism, which is discussed in this article, is that the
metal-nanotube boundary in a sensor causes the change because the
nanotube’s electrical properties are changed when the proteins are adsorbed
and a reduction of the work function of the metal is thought to occur. To
support this mechanism, these researchers added proteins to three different
types of sensors. One was a bare nanotube-metal based sensor that allowed
proteins to be adsorbed to both the nanotube and the metal (Pd or Pd/Au)
electrode. A second device allowed for adsorption on the CNTs and not the
electrode by coating the electrodes with methoxy(poly(ethylene glycol))thiol
(mPEG-SH), which prevents protein binding. A third device was coated with
mPEG-SH on both the electrode and the CNT. By adding the same proteins
to each type of sensor the group showed that a change in conductance of a
nanotube based sensor is mostly due to the metal-nanotube contact region.
Sotiropoulou, S. V. Gavalas, V. Vamvakaki, and V. A. Chaniotakis. 2003. Novel Carbon
Materials in Biosensor Systems. Biosensors and Bioelectronics 18: 211-215.
4.
Many different materials are made from carbon are being used towards
developing a biosensor, such as porous carbon, fullerenes, and carbon
nanotubes. In this article, the authors discuss using fullerenes and carbon
nanotubes in their experiment, but other experiments have showed that
nanotubes can be used in biosensors. This experiment shows how fullerenes,
in addition to other carbon materials, can be used in biosensors. The group
developed two glucose biosensors. One used porous carbon and the other
used fullerenes. They showed that both will sense the glucose, but the
fullerene-based sensor was better at detecting the glucose than the porous
carbon.