Parallel 3-Sheet Nanofibers

The nanofibers formed by PAs are microns long and have a uniform diameter of approximately 6-8 nm, depending on the length of the PA molecule. Self-assembly of the nanofibers can be controlled by pH adjustment and/or addition of divalent 

Sone and Samuel (2004) continued the studies of mineralization on PA nanofibers by utilizing the same PA described above to nucleate and grow CdS nanocrystals. In this case, the negatively charged phosphate and carboxylate groups bind to Cd, and CdS was formed after diffusion of H2S gas. A low Cd to PA ratio led to the formation of CdS nanocrystals that were 3-5 nm in diameter. An intermediate ratio of 

Cd to PA produced a continuous polycrystalline CdS layer on the nanofibers. TEM analysis, which showed a lighter core surrounded by a darker layer, indicated that the hydrophilic portion of the PA was embedded in CdS whereas the hydrophobic core remained unmineralized. 

Neural progenitor cells were successfully encapsulated in vitro (Silva et al. 2004) in a manner similar to the previous case, but in this case the PA contained the 

In another case, PAs were designed to function as magnetic resonance imaging (MRI) contrast agents (Bull et al. 2005) by covalently linking the peptide portion to a derivative of l,4,7,10-tetraazacyclododecane-l,4,7,10-tetraacetic acid followed by chelation of Gd ions by this moiety. The PAs were modified such that self-assembly produce either nanofibers or spherical micelles. The application of this self-assembling system could be extended to noninvasive MRI of PA scaffolds in vivo. 

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P3ATconductive nanofibers. P3AT nanofibers are a very widely studied class of conjugated polymer nanostructures." "" Upon fiber formation, the lamellar sheets of P3HT often package parallel to each other, thus forming a... 

Figure 7.19. Schematics of nanofiber collecting systems for forming different nanofiber assembly structures (A) rotating drum for continuous nanofiber filament and aligned nano-fiber sheet (B) parallel electrodes for aligned nanofiber array (C) counter-electrodes for cross-bar nanofiber array (D) blades for nanofiber yam (E) parallel rings for twisted nano-fiber yam and (F) hquid bath for continuous nanofiber yam.

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