Successfully reported this slideshow.

Self Assembly

3,354 views

Published on

Published in: Technology
  • Thanks a lot for this ppt. It's really well elaborated!!!!
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here

Self Assembly

  1. 1. Self Assembly  Definition.  Characterization.  Examples and Applications  ...to go. © JP Carbajal 05. 2008 1
  2. 2. Self Assembly: Definition  Q&A: what is self-assembly. © JP Carbajal 05. 2008 2
  3. 3. Self Assembly: Definition Answers from the experts  “...refers to aggregation of particles into an organized structure without external assistance”. D. J. Campbell 2002.  “...we limit the term to processes that involve pre-existing com- ponents, are reversible, and can be controlled by the proper design of the components”. G. M. Whitesides 2002.  “...is the ubiquitous process by which objects autonomously as- semble into complexes”. C. Aggarwal 2005.  “...we limit SA to the spontaneous formation of organized structures from many discrete components that interact with one another dir- ectly and/or indirectly through their environment. In addition, the assembling components may also be subject to various global poten- tials such as externally imposed electromagnetic field or chemical potentials”. B. A. Grzybowski 2006. © JP Carbajal 05. 2008 3
  4. 4. Self Assembly: Definition  Self-assembly refers to spontaneous formation of organized structures through a stochastic process that involves pre-ex- isting components, are reversible, and can be controlled by the proper design of the components, the environment, and the driving force. Ilya Prigogine Video  Static SA refers to that subclass of self-assembly processes that leads to structures in local or global equilibrium.  Dynamic SA refers to that subclass of self-assembly processes that leads to stable non-equilibrium structures. These struc- tures persist only as long as the system is dissipating energy.  Programmable SA refers to that subclass of self-assembly pro- cesses where the components of the system carry informa- tion about the final desired structures or its function. from: J. A. Pelesko. Self Assembly: The science of things that put themselves together. Chapman & Hall / CRC. 2007 © JP Carbajal 05. 2008 4
  5. 5. Self Assembly: Examples  Snow crystals & Amphiphilic molecules. (static SA. Lyotropic)  Graph Grammar SA.  Diffusion-limited aggregation & Flumini's tiles.  Protein folding & Chain Tribolon.  Magnetofluids (dynamic) © JP Carbajal 05. 2008 5
  6. 6. Self Assembly: Examples Snow Crystals snowcrystals.com © JP Carbajal 05. 2008 6
  7. 7. Self Assembly: Examples Snow Crystals snowcrystals.com © JP Carbajal 05. 2008 7
  8. 8. Self Assembly: Examples Amphiphilic molecules © JP Carbajal 05. 2008 8
  9. 9. Self Assembly: Examples Amphiphilic molecules. Lyotropic liquid crystals Lyotropic states © JP Carbajal 05. 2008 9
  10. 10. Self Assembly: Potential Applications V. P. Torchilin (2007). Micellar Nanocarriers: Pharmaceutical Perspectives. Pharmaceutical Research, vol 24, no. 1, pp 1-16. N. Maurer et al. (2001).Developments in liposomal drug delivery systems. Expert Opinion on Biological Therapy, v. 1, no. 6, pp 923-947. © JP Carbajal 05. 2008 10
  11. 11. Self Assembly  Definition.  Characterization.  Examples and Applications  ...to go. © JP Carbajal 05. 2008 11
  12. 12. Self Assembly: Characterization The four essential features of SA  Units.  Interaction.  Environment.  Driving Forces. The mechanism of SA  Energy minimization.  Thermodynamic hypothesis.  Folding funnel theory. © JP Carbajal 05. 2008 12
  13. 13. Self Assembly: Characterization Units  Simple or structured particles.  The internal structure, that may be changed by external stimuli is called conformation of the unit.  Passive or active conformational changes. Actuation intensity © JP Carbajal 05. 2008 13
  14. 14. Self Assembly: Characterization Interaction Force field - driven interaction: the energy is provided by the interaction mechanism itself. Electromagnetic interaction, gravitational interaction, surface tension interaction, ... Information-based interaction: the information is the trigger of physical/chemical processes, but has no relationship with the energy or energy flows needed by the latter to unfold. Chemical signals, signal on waves (EM or mechanical), electric signals, ... J. G. Roederer, “Information, life and brains”, in J. Chela-Flores, G. Lemarchand and J. Oró, eds., Astrobiology (Kluwer Acad, Publ., Dordrecht, The Netherlands, 2000), pp. 179-194. © JP Carbajal 05. 2008 14
  15. 15. Self Assembly: Unit + Interaction D. Fazio, C. Mongin, B. Donnio, Y. Galerne, D. Guillon, and D. W. Bruce J. Mater. Chem 11 Curvature arising from a large head group (A) and a small head group (B). Unit “shape” defines structure Carbohydrate liquid crystals designed to show particular phases. A large head group example (A,C) and a small head group case (B,D). © JP Carbajal 05. 2008 15
  16. 16. Self Assembly: Examples  Snow crystals & Amphiphilic molecules.  Graph Grammar SA.(information-based. Programmable SA)  Diffusion-limited aggregation & Flumini's tiles.  Protein folding & Chain Tribolon.  Magnetofluids (dynamic) © JP Carbajal 05. 2008 16
  17. 17. Self Assembly: Examples Graph Grammar SA E. Klavins (2007). Programmable self-assembly. IEEE control systems vol. 27, no 4, pp. 3 -56 © JP Carbajal 05. 2008 17
  18. 18. Self Assembly: Examples Graph Grammar SA E. Klavins (2007). Programmable self-assembly. IEEE control systems vol. 27, no 4, pp. 3 -56 © JP Carbajal 05. 2008 18
  19. 19. Self Assembly: Examples Graph Grammar SA  Set of rules, transitions.  Uniqueness given by natural dynamics. E. Klavins (2007). Programmable self-assembly. IEEE control systems vol. 27, no 4, pp. 3 -56 © JP Carbajal 05. 2008 19
  20. 20. Self Assembly: Characterization Environment  Static or dynamic environments  Provides a way to control the system. Isign model applet J. Bishop, E. Klavins (2006). Collective Sensing with Self-Organizing Robots. Proc. 45th IEEE Conf. on Decision & Control. © JP Carbajal 05. 2008 20
  21. 21. Self Assembly: Examples  Snow crystals & Amphiphilic molecules.  Graph Grammar SA.  Diffusion-limited aggregation & Flumini's tiles. (Environment, external fields. Passive conformational switches)  Protein folding & Chain Tribolon.  Magnetofluids (dynamic) © JP Carbajal 05. 2008 21
  22. 22. Self Assembly: Examples (Reminder) © JP Carbajal 05. 2008 22
  23. 23. Self Assembly: Examples DLA Cluster grown from a copper sulfate solution in an electrodeposition cell. Simulated 3D DLA with external fields. DLA movie http://www.andylomas.com/ © JP Carbajal 05. 2008 23
  24. 24. Self Assembly: Examples Flumini's tiles Shaking table movie © JP Carbajal 05. 2008 24
  25. 25. Self Assembly: Examples Flumini's tiles ➔ Can we obtain the phase diagram? ➔ What are the parameters to study? © JP Carbajal 05. 2008 25
  26. 26. Self Assembly: Characterization Driving Forces  Could be induced by the interaction.  Independent of the system to avoid clamping. natural dynamics © JP Carbajal 05. 2008 26
  27. 27. Self Assembly: Characterization Thermodynamic Hypothesis  Proposed in relation to protein folding: A protein as- sumes a particular conformation because that state is thermodynamically the most favorable. The con- formation is a global minimum of the free energy of the system. The protein samples the energy space, eventually winding up at a global minimum. Random conformational search  Critics ... Stochastic assembly © JP Carbajal 05. 2008 27
  28. 28. Self Assembly: Characterization Folding Pathway Hypothesis  Time needed to explore the possibilities is astronomical, “Levinthal paradox”. The folding sequence is “predefined” in the dynamics of structure. C. Levinthal (1968). quot;Are there pathways for protein folding?quot;. J. Chimie Phys. Phys.-Chimie Biol. 65: 44-45 Folding Funnel Hypothesis  The energy minimum is extremely deep and with steep walls. © JP Carbajal 05. 2008 28
  29. 29. Self Assembly: Characterization Folding Funnel Hypothesis Conformational entropy is the entropy associated with the geometrical arrangement of a chain of units. The concept is most commonly ap- plied to biological macromolecules such as proteins and RNA. To cal- culate the conformational entropy, the possible conformations as- sumed by the chain may be discretized into a finite number of states, usually characterized by unique combinations of certain structural parameters, each of which has been assigned an energy level. The conformational entropy associated with a particular conformation is then dependent on the probability associated with the system taking that state, as determined by the sum of the energies associated with the parameters describing the state. © JP Carbajal 05. 2008 29
  30. 30. Self Assembly: Examples  Snow crystals & Amphiphilic molecules.  Graph Grammar SA.  Diffusion-limited aggregation & Flumini's tiles.  Protein folding & Chain Tribolon.(search space)  Magnetofluids (dynamic) © JP Carbajal 05. 2008 30
  31. 31. Self Assembly: Examples Protein Folding  A given amino acid takes on roughly the same route and pro- ceeds through roughly the same intermediates and transition states.  Alpha helices and beta sheets then tertiary structure. Forma- tion of quaternary structure usually involves the assembly of subunits that have already folded.  The amino acid sequence of each protein contains the inform- ation that specifies both the native structure and the pathway to attain that state.  Conformations differ based on environmental factors. © JP Carbajal 05. 2008 31
  32. 32. Self Assembly: Examples Chain Tribolon Conformational entropy ... ~ 242 © JP Carbajal 05. 2008 32
  33. 33. Self Assembly: Examples  Snow crystals & Amphiphilic molecules.  Graph Grammar SA.  Diffusion-limited aggregation & Flumini's tiles.  Protein folding & Chain Tribolon.  Ferrofluids. (dynamic SA) © JP Carbajal 05. 2008 33
  34. 34. Self Assembly: Examples Ferrofluids Ferrofluid demostration K. Butter et al. (2003). Direct observation of dipolar chains in iron ferrofluids by cryogenic electron microscopy. Nature Materials no. 2, pp 88 - 91. © JP Carbajal 05. 2008 34
  35. 35. Self Assembly: Potential Applications Self-repair /self-healing: Reconstruction of skin from a suspension of skin cells from a 15-day embryonic mouse. (B) t=0 (D) Migration (E) t=72 hr (A) intact embryonic skin (C) t=24 hr self-healing robot Monroy, A. and A. A. Moscona. Introductory Concepts in Developmental Biology. University of Chicago Press, Chicago. 1979. © JP Carbajal 05. 2008 35
  36. 36. Self Assembly: ...to go  Functionality  How to endow our engineered systems with func- tionality?  Theory  What are the underlying principles of SA?  Can we generalize to different scales? © JP Carbajal 05. 2008 36
  37. 37. Self Assembly: Questions? the end...? © JP Carbajal 05. 2008 37

×