|
Researchers directly deposit gold nanoparticles in suspension
August 10, 2007The delivery, manipulation and assembly of functional materials such as metal nanoparticles into predefined architectures and patterns is of great interest in nanotechnology. Nanoscale patterns of nanoparticles have the potential to be used in miniature electronic circuits or in plasmon waveguides to guide the transport of electromagnetic energy below the diffraction limit. Nanoparticles functionalized with biological materials can also be placed between electrodes for use in biosensing applications.
Researchers from Northwestern University have now demonstrated the ability of a third-generation nanofountain probe (NFP) to directly deposit gold nanoparticles, 15 nanometers in diameter, onto silicon substrates. The research is published online by the scientific journal Langmuir.
"Such a direct-write method of deposition provides better control over resultant patterns and simplifies the process of fabricating functional structures, as compared to conventional photolithographic or microstamping techniques," said Horacio D. Espinosa, professor of mechanical engineering in the Robert R. McCormick School of Engineering and Applied Science and co-author of the paper. Espinosa's group pioneered the development of the nanofountain probe.
The NFP is a cantilevered probe chip that can be mounted on commercial atomic force microscopy (AFM) equipment. On-chip reservoirs hold liquid inks such as nanoparticle solutions, which are delivered through enclosed channels to ring-shaped apertured tips. High throughput microfluidic transport of molecular inks to AFM tips is of great interest since fluid is a very effective medium for the direct delivery of molecules, which self-assemble on substrates with very specific nanoscale architectures.
"The ultimate goal of this project is to develop a robust microsystem platform for the mass production of nanoscale devices, sensors and structures using chemicals, biomolecules, nanoparticles, nanotubes and nanowires," said Espinosa.
Previous versions of the nanofountain probes were shown to be capable of depositing solutions of fluorescent dyes, alkanethiols and DNA. Among several design changes, the latest nanofountain probes have deeper microchannels to allow the facile delivery of larger particles such as gold nanoparticles 15 nanometers in diameter.
Probe-based deposition techniques are amenable to high-resolution, nanoscale and flexible patterns in which the desired structure can be easily altered at any time. Dip-pen nanolithography (DPN), in which a commercial AFM probe is coated with molecules to be deposited, is capable of making high-resolution patterns of many chemicals and biological materials. However, standard DPN techniques have not been able to deposit suspensions of solid nanoparticles.
"The nanofountain probe is not only capable of delivering such solutions but can do so continuously because the inks are contained in reservoirs on the chip," said Andrea Ho, a co-author and graduate student in Espinosa's group.
Because NFPs are batch-fabricated using standard micromachining processes, they can easily be mass-produced. The current NFPs produce nanoscale patterns with a linear array of 12 writing tips, but their design allows for straightforward scaling up to 2D arrays of tips. This would allow for the high-throughput, parallel deposition of nanoparticles with high resolution.
Northwestern University
The NFP is a cantilevered probe chip that can be mounted on commercial atomic force microscopy (AFM) equipment. On-chip reservoirs hold liquid inks such as nanoparticle solutions, which are delivered through enclosed channels to ring-shaped apertured tips. High throughput microfluidic transport of molecular inks to AFM tips is of great interest since fluid is a very effective medium for the direct delivery of molecules, which self-assemble on substrates with very specific nanoscale architectures.
"The ultimate goal of this project is to develop a robust microsystem platform for the mass production of nanoscale devices, sensors and structures using chemicals, biomolecules, nanoparticles, nanotubes and nanowires," said Espinosa.
Previous versions of the nanofountain probes were shown to be capable of depositing solutions of fluorescent dyes, alkanethiols and DNA. Among several design changes, the latest nanofountain probes have deeper microchannels to allow the facile delivery of larger particles such as gold nanoparticles 15 nanometers in diameter.
Probe-based deposition techniques are amenable to high-resolution, nanoscale and flexible patterns in which the desired structure can be easily altered at any time. Dip-pen nanolithography (DPN), in which a commercial AFM probe is coated with molecules to be deposited, is capable of making high-resolution patterns of many chemicals and biological materials. However, standard DPN techniques have not been able to deposit suspensions of solid nanoparticles.
"The nanofountain probe is not only capable of delivering such solutions but can do so continuously because the inks are contained in reservoirs on the chip," said Andrea Ho, a co-author and graduate student in Espinosa's group.
Because NFPs are batch-fabricated using standard micromachining processes, they can easily be mass-produced. The current NFPs produce nanoscale patterns with a linear array of 12 writing tips, but their design allows for straightforward scaling up to 2D arrays of tips. This would allow for the high-throughput, parallel deposition of nanoparticles with high resolution.
Northwestern University
Nanoparticles News and Current Nanoparticles Events RSSNew oral angiogenesis inhibitor offers potential nontoxic therapy for a wide range of cancers
The first oral, broad-spectrum angiogenesis inhibitor, specially formulated through nanotechnology, shows promising anticancer results in mice, report researchers from Children's Hospital Boston.
Metals Shape Up with a Little Help from Friends
For 5,000 years the only way to shape metal has been by the "heat and beat" technique. Even with modern nanotechnology, metalworking involves carving metals with electron beams or etching them with acid.
Laser Surgery Probe Targets Individual Cancer Cells
Mechanical engineering Assistant Professor Adela Ben-Yakar at The University of Texas at Austin has developed a laser "microscalpel" that destroys a single cell while leaving nearby cells intact, which could improve the precision of surgeries for cancer, epilepsy and other diseases.
New ORNL process brings nanoparticles into focus
Scientists can study the biological impacts of engineered nanomaterials on cells within the body with greater resolution than ever because of a procedure developed by researchers at the Department of Energy's Oak Ridge National Laboratory.
Ability to track stem cells in tumors could advance cancer treatments
Using noninvasive molecular imaging technology, a method has been developed to track the location and activity of mesenchymal stem cells (MSCs) in the tumors of living organisms.
A promising step towards more effective hydrogen storage
An international research team led by Swedish Professor Rajeev Ahuja, Uppsala University, has demonstrated an atomistic mechanism of hydrogen release in magnesium nanoparticles - a potential hydrogen storage material. The findings have been published in the online edition of Proceedings of the National Academy of Science (PNAS).
Secret ingredient: nanoparticles aid bone growth
In the first study of its kind, bioengineers and bioscientists at Rice University and Radboud University in Nijmegen, Netherlands, have shown they can grow denser bone tissue by sprinkling stick-like nanoparticles throughout the porous material used to pattern the bone.
Research measures movement of nanomaterials in simple model food chain
New research shows that while engineered nanomaterials can be transferred up the lowest levels of the food chain from single celled organisms to higher multicelled ones, the amount transferred was relatively low and there was no evidence of the nanomaterials concentrating in the higher level organisms.
Nanoparticles assemble by millions to encase oil drops
In a development that could lead to new technologies for cleaning up oil spills and polluted groundwater, scientists at Rice University have shown how tiny, stick-shaped particles of metal and carbon can trap oil droplets in water by spontaneously assembling into bag-like sacs.
Gene therapy increases survival for end-stage head and neck cancer
A gene therapy invented at The University of Texas M. D. Anderson Cancer Center is the first to succeed in a U.S. phase III clinical trial for cancer, as announced today at the American Society of Gene Therapy annual meeting in Boston.
More Nanoparticles News Articles
| © 2008 BrightSurf.com |