Visualization for Active learning:

Understanding NanomachinesCLT ExemplarsByAdham RamadanDepartment of Chemistry

Flash animations by Reham TallawiCLT

ScopeNano science and technology is one of the most rapidly developing areas in scientific research today. A particular interest within this area is concerned with nano machines. However, the notion of how they operate can be challenging to conceptualize, particularly with regards to their motion. Visual learning objects can be very useful in this regard.

The Nano" Dimension Nano meter = 10-9 meter= 10-6 mm i.e. a 1/1,000,000 of a mmA human hair is 10-5 m(10,000 nm) thick

The Nano" Dimension

Time Line4th century1661Roman glass containing nano metallic clustersBoyle suggests the existence of corpuscles minute masses / clusters that are not easily dissipable into particles that compose them18th & 19th centuriesDevelopment of photography based on emulsions of silver halides, with photochemical reactions resulting in Ag nanoparticles composing the pixels of the image1908Mie publishes a paper explaining the dependence of glass colour on metallic clusters size and type1950s & 1960s: Experimental activities on inorganic nano particles1960: Feymans lecture to the American Physical Society speculating on possibilities & potentials of nano sized materials1970s: Fabrication of 2D quantum wells at Bell and IBM labs1980s:Fabrication of metallic clusters using laser in 1981Synthesis of Fullerene in 1985Development of 1st nanomachineDevelopment of techniques for synthesizing and observing nanostructures (laser techniques, electron beam lithography, STM) Observing of some of the special properties of nanoparticles1990s:Fabrication CNTsDiscovering superconductivity & ferromagnetism in C60 structuresGrowing research in self assembliesWidespread use of STM and AFMResearch in inkjet lithographyMid 1990s: Widespread recognition of full potential of nanotechnology and realization of its interdisciplinary nature

NanomachinesA machine is an assembly of interconnected components arranged to transmit or modify force to perform useful workCollins English Dictionary

A nanomachine is one which does that on the nano dimension

Nanomachines:

What they are not!

Nanomachines:What they areNanomachines are atomic and molecular assemblies which have been constructed to perform organized work/motion at the nano-scale, which is analogous to that on the macro-scale.Ellenbogen J.C., Love J.C. in Handbook of nanoscience and Technology, Goddard W.A. , Brenner D.W., Lyskevski S.E., Lafrate G.J., eds, CRC Press, 2002, 7-12. Vicario J., Meestma A., Feringa B.L., Chem. Comm., 2005, 5910-5912

Nanomachineswhy are they so exciting?They represent a scientific curiosity and and experimental challenge at this development phase.

Possible immediate applications:Medial technology: diagnosis as well as targeted drug deliverySensor technology: toxicological sensors

Envisaged future applications:Bottom-up building of novel devices: used as components for building more ellaborate devices on these small scales.

NanomachinesReporting on their motionThis is usually carried out in publications through textual descriptions + 2 D diagrams.This is effective in relaying information about WHAT LEADS to their motion.However it is not effective in relaying a clear picture of the actual motion.

ExamplesSelf-propelled nanorods: a nano-submarineNano-rods of Platinum and gold.Catalytic decomposition of hydrogen peroxide to generate oxygen gas on the Pt side causes the motion, pushing the platinum part forward.Motion is due to the change in polarity of the liquid around the nano-rod and the interaction of the gold surface with it.Paxton, W.F., Kistler, K.C., Olmeda, C.C., Sen, A., St. Agenlo, S.K., Cao, Y., Mallouk, T.E., Lammert, P.E., Cresi, V.H., J. Am. Chem. Soc., 2004, 126, 13424-13431.Fournier-Bidoz, S., Arsenault, A.C., Manners, I., Ozin, G.A., Chem. Commun., 2005, 441-443.

ExamplesA nano bio-machine: a nano-locomotiveKinesin is a motor protein which can move along filamentous structures called microtubules.Kinesin has two head which alternately undergo a chemical reaction that releases them, then re-attaches them to the microtubule. Kinesin is fixed to a glass surface with its heads pointing upward.A microtubule can then move on these heads due to the chemical reaction.The microtubule carries enzymes which generate the chemicals needed for the reaction, i.e. a source for its own fuel.Vale, R.D., Milligan, R.A., Science, 2000, 288, 88-95.Du, Y.Z., Hiratsuka, Y., Taira, S., Eguchi, M., Uyeda, T.Q.P., Ymoto, N., Kodaka, M., Chem. Comm., 2005, 2080-2082.

ExamplesThe nano-carThese are single organic molecules synthesized with 4 bucky balls (C60).When placed on a gold surface, and heated, the C60 roll on the surfaceThe bucky balls move independently, allowing the turning and pivoting of the nano-car.Shirai, Y., Osgood, A.J., Zhao, T., Kelly, K.F., Tour, J.M., Nano Lett., 2005, 5, 2330-2334.

Understanding Nanomachines in Motion IFeedback

Examples (Again!)Self-propelled nanorods: a nano-submarineNano-rods of Platinum and gold.Catalytic decomposition of hydrogen peroxide to generate oxygen gas on the Pt side causes the motion, pushing the platinum part forward.Motion is due to the change in polarity of the liquid around the nano-rod and the interaction of the gold surface with it.

Examples (Again!)Self-propelled nanorods: a nano-submarine

Examples (Again!) A nano bio-machine: a nano-locomotiveKinesin is a motor protein which can move along filamentous structures called microtubules.Kinesin has two head which alternately undergo a chemical reaction that releases them, then re-attaches them to the microtubule. An Animated Model for Processive Motility by Conventional Kinesin, Vale, R.D., Milligan, R.A., Johnson, G., http://www.scripps.edu/cb/milligan/

Examples (Again!) A nano bio-machine: a nano-locomotiveKinesin is fixed to a glass surface with its heads pointing upward.A microtubule can then move on these heads due to the chemical reaction.The microtubule carries enzymes which generate the chemicals needed for the reaction, i.e. a source for its own fuel.

Examples (Again!) The nano-carThese are single organic molecules synthesized with 4 bucky balls (C60).When placed on a gold surface, and heated, the C60 roll on the surfaceThe bucky balls move independently, allowing the turning and pivoting of the nano-car.

Examples (Again!) The nano-carhttp://www.rice.edu/media/nanocar.html

Understanding Nanomachines in Motion IIFeedback

Student FeedbackAnimations, as visual learning objects, are very useful for demonstrating movement.They are best as complementing text or narrative explanation.They are most useful for complex cases difficult to demonstrate using 2D diagrams and textual description.They are most effective as learning objects when offered after the challenge of textual description and 2 D diagrams. In these cases they are effective because they clarify ambiguities and/or confirm ideas.They are useful for group learning as they ensure that all develop a similar understanding.They have the drawback of possibly being limiting to the imagination.

Conclusions

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