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Rice UniversityCBEN
Center for Biological and Environmental Nanotechnology

Nanomanufacturing: Designing, Improving and Producing Nanoparticles

Optical and Magnetic Properties of Bilayer-nanocrystals

Optical and magnetic properties of bilayer-nanocrystal complexes are similar to the original materials. On the far left panels, a strong permanent magnet is able to concentrate the iron oxide materials (nMAG) much as is observed in hexanes. On the right panel, the fluorescence of quantum dots (QD) is relatively unchanged after the formation of a bilayer and the transfer of the material into water.

Since 2001, the nanomanufacturing program within CBEN has provided our engineering efforts with adaptive, responsive projects for their emerging material needs. A major strength of CBEN lies in its strong materials chemistry, particularly nanochemistry, expertise. The depth and breadth of our investigators in QD, ceramic nanocrystal, and carbon nanostructure chemistry and characterization has been widely recognized by expert reviewers as well as our own advisors since our inception. Capturing this expertise in our Center’s programs, however, presents some organizational challenges. CBEN’s chemists can be tightly coupled into our engineering efforts in Theme 2 and Theme 3, or materials chemists can be engaged in more exploratory research that provides new opportunities for engineering. We house both types of effort in this project. Materials research groups get time and funding to develop new concepts as well as support to address near-time needs for engineering collaborators. We use the term “nanomanufacturing” to describe this set of programs, which includes materials generation, scale-up production, and characterization—all of which are enabling technologies for our core engineering outcomes.

Since 2001, we have found this strategy to be effective at generating both new materials and methods, which then impact our engineering research. Some highlights from this year include:

  • Bilayer structures can be formed around water stable nanocrystals of iron oxide and quantum dots.  Colvin’s group has shown that unlike polymeric surfactants, bilayers introduce little free surface agent into aqueous dispersions – a need crucial for biomedical applications and structure-function studies in toxicology.
  • Whitmire’s efforts within CBEN in past years yielded star and cross-shaped metal oxide particles and he has effectively used these as templates for gold deposition.  The resulting structures have complex and valuable photonic properties useful in disease detection and treatment.
  • Tomson and Colvin have found a scalable and simple way to create stable dispersions of commercial magnetite for use in the Guanajuato project.
  • Colvin’s group used a heterogeneous synthetic process to deposit crystalline and size controlled quantum dots onto iron oxide nanocrystals. These materials possess both size dependent fluorescence as well as efficient magnetic capture capabilities.

This year, nanomanufacturing will continue to support efforts that improve the production, properties, and control of materials used in Theme 2 and Theme 3.  We will sustain our emphasis on the practical, economic and accessible manufacturing of materials for applications in our water treatment testbed sites.  Moreover, Theme 2 groups (Drezek, West) are active collaborators in the generation of magneto-optical materials.  We anticipate over the next year that the basic chemistry will be captured in publications, and the value of the systems for imaging will be scoped out in several limited cell and animal studies.


Figure 2. Schematic of programs within nanomanufacturing. 

Schematic of programs within nanomanufacturing.

Participating Researchers: