Rebuttal : Carbon Nanotube Chirality Edson P. Bellido Sosa

1. G1 Rebuttal: Carbon NanotubeChirality Edson P. Bellido Sosa

2. Thanks for all your comments, I will try to correct all the mistakes that you point out. I will try to speak slow as many of you suggested. I was the first presenter and I did not have the presentation format, that’s why I did not include further research on my presentation but I will correct this for the next presentation. Comment: Did not mention some of the major problems with CNT’s. I did not mentioned some of them on the slides but I mentioned about the present manufacturing limitations and purification methods on the talk.

3. G2 Review Controlling carbon nanotubechirality by Alfredo Bobadilla

4. Review of “Process to control carbon nanotubechirality” Nanotech course – Alfredo Bobadilla One option is taking a single (n,m) type SWCNT sample, then cutting those carbon nanotubes to get a higher number of CNTs but smaller ones. Those nanotubes would be used as template to mass produce that particular type of CNT. To grow the CNTs a vapor liquid solid (VLS) amplification growth can be performed. Fe salts can be used to act as the growth catalysts An additional tool is using NixFe1-x catalytic nanoparticles to changes or control the chirality of the grown CNT. Precise tuning of the nanocatalyst composition at constant size can be achieved by following a gas-phase synthesis route based on an atmospheric-pressure microplasma. The composition-dependent crystal structure of the nanocatalysts determines the carbon nanotubechirality.

5. G3 Review:Process to control carbon nanotubeschirality By Mary Coan 2/9/2010

6. Review • Overall the presentation was very good • Described • the properties of CNT’s • Methods for obtaining SWCNT’s • Cloning Method • Did not mention some of the major problems with CNT’s • Today’s manufacturing limitations • Carbon nanotube network films instead of single CNT’s • Purification methods for Single walled CNT’s • Formation of complex and entangled bundles

7. G4Summary ‘Controlling carbon nanotubechirality’ Diego A. Gómez-Gualdrón

8. Chirality in nanotubes Geometry-wise a nanotube can be formed by rolling over a graphene sheet to form the nanotube wall The chirality denotes the amount of twisting in the nanotube (see Fig 1) Since nanotube properties are chiral-dependant, fine control during production is desired • Diego A. Gómez-Gualdrón

9. Approach 1 Nanotube ‘cloning’ • A piece of nanotube of given chirality is extracted from a previous process • Using organic-metallic chemistry catalytic particles are added at both nanotube ends (fig a) • Growth occurs and chirality is maintained (fig b). Low number of nanotubes produced • Diego A. Gómez-Gualdrón

10. Approach 2 Altering nanocatalyst structure FCC Ni BCC Fe Metals with different structure are alloyed to form a nanoparticle whose structure is concentration-dependant • Diego A. Gómez-Gualdrón

11. Approach 2 Panels a,b,c, and d illustrate how the chirality distribution is affected by concentration-dependant changes in the nanoparticle structure • Diego A. Gómez-Gualdrón

12. CONCLUSIONS • Approach 1 is 100% selective but amount produced is minimal and procedure time consuming. (not a good alternative) • Approach 2 although not 100% effective does show that altering the catalyst structure affects the chirality distribution. It encourages further research, since success would lead to a cost effective process by eliminating post synthesis treatment • Diego A. Gómez-Gualdrón

13. Recomendations • Study the relationship between particular catalyst structures and chirality obtained • Study how effectively the catalyst structure can be controlled during synthesis • Diego A. Gómez-Gualdrón

14. G5 Review Controlling carbon nanotubechirality by Norma Rangel

15. Good presentation Covered also fabrication and few applications I think the material was covered with enough information He gave an introduction about the properties, fabrication methods. Probably something missing was the economic information about the control of CNTs chirality and viability to introduce this methods in industry or high volume fabrication. CNTs chiralityEdson Bellido Taken from wikipedia Norma Rangel

16. Process to Control Carbon nanotubes Chirality, by Edson P. Bellido Sosa • Edson gave a good introduction of CNTs and chirality, including a few interesting methods to separate CNTs with different chiralitiessuch as Selective chemistry: Selective destruction, dielectrophoretic separation, ultracentrifugation and selective growth. • Some applications of CNTs of different chirality would have complemeted great his presentation.

17. G6 Review Controlling carbon nanotubechirality by Jung Hwan Woo

18. Review for Edson’s Presentation • The electronic properties of CNT is of great interest • metallic CNT is 1000 times more conductive than copper. • MWCNT are superconductive • What are the problems for electronic applications of CNTs? • What can a research scientist do to resolve these issues? • Showing an example of the efforts that IBM made (as Dr. Seminario mentioned) to improve on this aspect. • An additional point to ask is the time needed before a practically cost-effective CNTs can be produced. This may determine the commercialization of CNTs. Jung Hwan Woo

19. G2 Rebuttal:Nano electromechanical oscillators Alfredo Bobadilla

20. Nano electromechanical oscillators – ‘Rebuttal’ • Comment: “Did not describe the theoretical part of the presentation” • Answer: The theoretical part was explained during the lecture. In essence, the “beam equation” (classical mechanics) is still useful for analyzing bending-mode vibrations in a carbon nanotube longer than ~0.5um. Research work in the nonlinear regime and the quantum regime has just began very recently. • Comment: “Text was small and hard to locate on each slide” • Answer: I’ll improve that next presentation. • Comment: “current or potential applications of such ‘nano’ electromechanical oscillators should have been shown” • Answer: The potential applications of nano electromechanical oscillators is shown in the slides and was described during the lecture. It was shown nanotube resonators can be incorporated as the sensing element for improving the performance in mass spectrometry and in calorimetry. Alfredo D. Bobadilla

21. G1Electro-Mechanical OscillatorsReview Edson P. Bellido Sosa

22. The presenter describe how a EM oscillator works and the basic equations that rules its movement . He explain how a change in a parameter, lets say the voltage on the system, can affect the overall functioning of the device, and how researcher are taking advantage of these behavior to fabricate consumer devices

23. He has explained the fabrication process and how a carbon nanotube based oscillator works, and how they can tune the bending mode vibration by changing the gate applied voltage and how they can measure the bending modes using changes in the conductivity of the carbon nanotube A comparison of the carbon nanotube oscillator and the current oscillator used on the industry, in terms of performance and cost would have been helpful. Further research is needed specially in the large scale integration process since there is no an high throughput technique to create arrays of carbon nanotube oscillators and other nano-devices.

24. G3Review: Electromechanical Oscillators By Mary Coan 2/12/2010

25. Review • Overall the presentation was decent • Described • Current applications of EN oscillators • CNT EM oscillator using various sources and diagrams • Improvements to the performance • Did not describe the theoretical part of the presentation • Showed many equations with out listing parameters • No physical description of the diagrams

26. Review • Overall style of the Presentation was lacking • Text was small and hard to locate on each slide • Some of these things may have been addressed during the actual presentation. However just looking at the presentation online I had a hard time understanding what each slide represented and the contents of each slide.

27. G4Summary and review ‘Electromechanical oscillators’ Diego A Gomez-Gualdron

28. An electromechanical oscillator circuit The distance between the plates of the capacitor varies with time, therefore changing the capacitance, which in turn affect the behavior of the circuit giving it an oscillatory behavior Figure .1

29. Promising application of a nanotube in a nanocircuit • A voltage in generates a charge in • As a result the nanotube is pushed downwards. • Bending the nanotube alter the charge once again, ending up in oscillatory motion with a frequency depending on the tension forces in the nanotube. Nature431, 284-287 (16 September 2004) | doi:10.1038/nature02905 The oscillatory motion of the nanotube, alterates the capacitance in cyclic-fashion analogous to the macroscale circuit in the fig 1.

30. Additional Review • A number of applications were shown for electromechanical oscillators. However, I am not sure if the scale of those examples is in the nanorange. If so, current or potential applications of such ‘nano’ electromechanical oscillators should have been shown.

31. G5 Review Electromechanical Oscillators by Norma Rangel

32. Electromechanical oscillatorsby Alfredo D. Bobadilla • Alfredo show the basic concepts of electromechanical oscillators , with examples of how these devices are being implemented in current technologies in the market, alternative applications and a couple of papers about state of the art electromechanical oscillators using nanotubes and origami DNA. • My suggestion for Alfred presentation is to put more emphasis on the experimental work than being too deep on the theoretical framework

33. G6 Review Electromechanical Oscillators by Jung Hwan Woo

34. Review • Overall, the presentation needs improvements • Improved presentation skill will help deliver the idea in a more effective manner • The use of larger fonts and images will make it easier for the audience to better visualize and understand the concept • A better introduction may attract the audience into the subject and the presentation. • The pace can be increased to contain more information. The information on the subject was a bit too little for a 30-minute presentation Jung Hwan Woo

35. Application • What NEMS applications are there, which take advantage of the electromechanical oscillator other than the carbon nanotube application? • What are the advantage of reducing the size of the device in MEMS/NEMS applications? Is there any downside to it? Jung Hwan Woo

36. G3Rebuttal: Nanosensors Microtubules Mary Coan

37. Rebuttal • “An additional interesting point not discussed during the presentation is how can we exploit the ‘dynamic’ self-assembling properties intrinsic to microtubules for nanosensing and nano-engineering.” • This was not discussed due to time. However it was briefly mentioned that research into the topic was done but many of the papers found only discussed the targeting the MT’s instead of using the MT’s as nanosensors. For an example, a lot of research has been conducted to inhibit the dynamic instability of MT’s. • “Nonetheless, it was perhaps too much material for a short time” and “There was a lot of material covered in the slides, perhaps to fast to comprehend in the amount of time given. It became hard to follow at some points.” • You are correct, there was a lot of information presented in a short time. I wanted the audience to understand the dynamic instability of MT’s, which is one of the most important details about MT’s. Without MT’s mitosis would not occur. I also wanted the audience to fully understand how the MT’s transported nanosensors, which is the first nanotransporter using only biological materials. • I did limit some of the information presented. This may have caused the audience to become confused or lost at certain points in the presentation.

38. Rebuttal • “I could see that the time frames relevant to the technique are quite large, which would create inconveniences for real time measurements and monitoring and quick action expected from point-of-care approaches.” • You are correct. However, I did mention that the authors proposed removing the separate regions, ie capture and tag regions, to decrease the amount of time needed to detect the analyte. Another point to mention is that the same amount of time, if not more, is required to perform the traditional double-antibody-sandwich (DAS) assays. • “The graphics and text were well balanced, and the graphics aided a great deal in trying to understand the content of the presentation.” • Thank you. I try to include motion into my presentation to help the audience.

39. Rebuttal • “The speaker covered all relevant topics from an introduction of the research to how it can be furthered. It might have been nice to have heard some of the opposition to such research and or more research in the same field, but overall the presentation was well balanced and informative.” • Thank you, I was struggling to keep the information too excessive and thus did not include more research in the same field or others points of view

40. G1 Review Nanosensing, Microtubules by EdsonBellido

41. The presenter described what are bio-nanosensors and microtubules. She described how the microtubules are formed within the cell. She explained what is the dynamic instability and what molecules affect this behavior of the microtubules. She explained how the microtubules are being used as bio-nanosensor transporter. She explained how the kinase moves the microtubule to the cell boundaries and allow us to detect analytes captured within the cell. Something missing was the details about the experimental procedures, most likely because of the short time for the presentation. those details are very important factor to analyze and determine the accuracy and reproducibility of the system. Other factor to study will be how the addition of those functionalized MTs and the quantum dots will affect the cellular response. If it affects; quantitatively how this response change the accuracy of the measure?. http://www.cancerquest.org/images/microtubules.gif

42. G2 Review Nanosensing, Microtubules by Alfredo Bobadilla

43. Review of Nanosensing & Microtubules • Microtubules are biological nanostructures. They are part of the cytoskeleton which actually look like the nervous system of the biological cell and they indeed transmit vibrational signals, perform mechanotransduction, own a highly dynamic behavior because of self-assembly dynamic process (dynamic instability) and have been found to be involved in cell decision-process mechanisms as well as in memory & learning functions. • It was shown in the lecture how functionalized microtubules can be used for nanosensing purposes and as a nanotransporter. • An additional interesting point not discussed during the presentation is how can we exploit the ‘dynamic’ self-assembling properties intrinsic to microtubules for nanosensing and nano-engineering. Alfredo D. Bobadilla

44. G4Microtubules Summary and review Diego A Gomez-Gualdrón

45. Microtubules • Microtubules (MT) are part of the cytoskeleton and posses a diameter of ~ 25 nm, and a length of ~ 250 nm • Microtubules (MT) can transmit signals as well as transport substances within the cells • They are formed by a ‘polymerization mechanism’ Functionalizing a microtubule can make it suitable as a fully-biologically-constituednanosensor

46. Sensing Mechanism • It was shown that functionalizing a MT with an antibody allows for specific binding of the analyte. • The interaction of kinesin with the MT enables the transport of the analyte to tagging and detection stages Detection occurs through fluorescence MT

47. Comments • The presentation used a lot of didactic elements to convey the information and it was general a very good presentation. Nonetheless, it was perhaps too much material for a short time • I could see that the time frames relevant to the technique are quite large, which would create inconveniences for real time measurements and monitoring and quick action expected from point-of-care approaches.

48. G5 Review Nanosensing, Microtubules by Norma Rangel

49. Nanosensors: MicrotubulesBy Mary Coan • Mary presented the use of microtubules as nanosensors, basic concepts, production of MTs, stability and alternative applications were shown. Also • Mary used great animations that helped for a better understanding of the Bio-Nanosensor Transporter concept. • I particularly like the criticism given to the paper, where she mentioned some missing details in the paper about the stability of the MTs and of course the toxicity of the MTs, but also including potential future work to further develop portable, cheap and more sensitive and stronger sensors.

50. G6 Review Nanosensing, Microtubules by Jung Hwan Woo