NIRT: Molecular NanomagnetsNIRT: Molecular Nanomagnets D.G. Naugle, G. Agnolet, F.A. Cotton, K.R. Dunbar, V. Pokrovsky, D.G. Naugle, G. Agnolet, F.A. Cotton, K.R. Dunbar, V. Pokrovsky,

J.H. Ross, Jr.J.H. Ross, Jr.Texas A&M University — DMR 0103455Texas A&M University — DMR 0103455

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Fig. B Fig. C

Fig. A. Schematics of the MMC. Levitation is provided by a very strong magnetic field gradient created by two neodymium - iron-boron magnets with opposite magnetization direction. A levitating droplet/particle (purple) is moved by current pulses through an electrode (yellow). A crystal (white) is rotated from the vertical orientation imposed by the magnetic field to a horizontal orientation imposed by an AC electrical field between the magnets.

We have developed a Magnetic Microlevitation Chip (MMC) (Fig. A) for diamagnetic levitation of droplets and/or particles of nano–femtoliter volume and demonstrated their on-chip storage and high precision manipulation (translation (see Movie), merging (see Fig B), assembling and rotation (see Fig C)). It has been used as a levitation based microfluidic processor to process droplets with up to a billion times smaller volume than in known microfluidic devices. With this microfluidic processor, literally individual solute molecules in femtoliter size droplets can be isolated for study or for initiation of chemical reactions (by merging droplets) with different individual molecules in a predefined sequence of reactions in a single femtoliter size “beaker”. Injection of individual molecules into a droplet loaded with a single cell, bacteria or virus is thus possible. The MMC may be used in detection of low concentration chemical and biological agents.

Movie

The principle of diamagnetic levitation was predicted by Michael Faraday and Lord Kelvin one and a half centuries ago. It’s most sensational demonstration was levitation of a frog by British researchers with a large, powerful magnet. Researchers in this NIRT have used the same principle to design a postage stamp size prototype device to levitate and manipulate tiny droplets, a billion times smaller in volume than the average rain droplet, which can be loaded with bacteria, cells, viruses and even a single DNA or protein molecule. Suspended in air, these droplets move on a magnetic “conveyor belt” like tiny “beakers” to be processed according to standard biochemical protocols in “Lab-On-a-Chip” devices. This work brings us much closer to the ultimate capability for the “Lab-On-a-Chip” technology.

This summer 2 high school students, 2 middle school teachers, 2 junior college teachers and 6 REU undergraduate students participated in research projects under this NIRT program. Of these 12 participants, 5 were from underrepresented categories.

The 2 high school students and 2 of the undergraduates participated in the synthesis of new asymmetrical magnetic molecules like those shown at the right. They used a building block approach to design new clusters based on addition of metal ions to the previously formed trigonal bipyramidal clusters shown in A to form new cluster molecules containing mixed Ni, Co and Fe magnetic ions like that shown in B or under different conditions to form chains of linked trigonal bipyramidal clusters like that shown in C.

Three of the outreach participants helped fabricate Magnetic Microlevitation Chips like that in the previous slide, while two learned to operate sophisticated instruments for magnetic characterization. The remaining two worked with projects to develop new techniques for growth of thin films of the new magnetic molecules for electronic applications.

NIRT: Molecular NanomagnetsNIRT: Molecular Nanomagnets D.G. Naugle, G. Agnolet, F.A. Cotton, K.R. Dunbar, V. Pokrovsky, D.G. Naugle, G. Agnolet, F.A. Cotton, K.R. Dunbar, V. Pokrovsky,

J.H. Ross, Jr.J.H. Ross, Jr.Texas A&M University — DMR 0103455Texas A&M University — DMR 0103455

A B

C

A major aspect of the NIRT program is enhancement of educational efforts across the spectrum, K-16. This NIRT has focused on bringing high school and undergraduate students and middle school, high school, community and four-year college science teachers into their research program for extended periods in the summer. This is, of course, in addition to a significant number of graduate and postdoctoral students who participate throughout the year. These teachers work with state-of-the-art, NSF funded equipment in nanoscience research. The teachers are also encouraged to design and build a simple demonstration of one of the principles used in their research. Consequently, this experience is disseminated to their students for much greater impact.