Atomic force microscopy nanofibers

Oroudjev E, Soares J, Arcdiacono S, Thompson JB, Fossey SA, Hansma HG. Segmented nanofibers of spider dragline silk atomic force microscopy and single-molecule force spectroscopy. Proc Natl Acad Sci USA 2002 99 6460-6465. 

The dimension of the resultant structure was visualized by atomic force microscopy (AFM). Indeed, the width of the fibers was reduced compared to that of SAF peptides however, its length was much more heterogeneous. Most fibers were also shown to be shorter than that of previously described coiled coil nanofibers. Fiber shortening could be related to the 1) weak association between sticky-ended coiled coils and 2) salt effects. It was found that sodium chloride and ammonium sulfate have a distinct effect on the fibril lateral aggregation, leading to short fibers in NaCl and long fibers in ammonium sulfate. 

Figure 8.1 Nanofibers from p6P on muscovite mica, (a) Fluorescence microscopy image, (b) Atomic force microscopy image height scale 70 nm. p6P clusters are visible between the fibers, (c) Needles consist of lying molecules with the (1-1-1) plane facing the substrate the long needle axis (arrow) is parallel to the grooved mica direction. Dr. Frank Balzer is thanked for providing the images.

Oroudjev, E., Soares, J., Arcdiacono, S., Thompson, J.B., Fossey, S.A., and Hansma, H.G. "Segmented nanofibers of spider dragline silk atomic force microscopy and singlemolecule force spectroscopy". Proc. Natl. Acad. Sci. U.S.A. 99(14), 6460-6465 (2002). 

Weronski KJ et al (2010) Time-lapse atomic force microscopy observations of the morphology, growth rate, and spontaneous alignment of nanofibers containing a peptide-amphiphile from the hepatitis G vims (NS3 protein). J Phys Chem B 114(l) 620-625... 

Liu, D. Zhang, H. Grim. P.C.M. De Feyter. S. Wiesler. U.-M. BeiTesheim, X.J. Mullen. K. De Schryver. F.C. Self-assembl> of polyphenylene dendrimers into micrometer long nanofibers An atomic force microscopy study. Langmuir 2002. 18. 2385-2391. 

F. Hang, et al.. In situ tensile testing of nanofibers by combining atomic force microscopy and scanning electron microscopy. Nanotechnology 22 (36) (2011) 365708. 

Figure 12.12 Atomic force microscopy (AFM) images of uncoated (left) and PEDOT-PSS-coated (right) TiO nanofiber. Reproduced with permission from Ref. [66], Copyright 2013 Elsevier.

Cheng et al. produced chemically activated carbon nanofibers based on a novel solvent-free co extrusion and melt-spinning of polypropylene-based core/sheath pol5mier blends and their morphological and microstructure characteristics analyzed by scaiming electron microscopy, atomic force microscopy (ATM), Raman spectroscopy, and X-ray dififractometry [139]. 

The mechanical moduli and dependency on the content of the hydroxyapatite nanoparticles could be analyzed using three point bending with a tipless atomic force microscopy cantilever (12). An increase of the hydroxyapatite content up to 20% increased the mechanical properties of the composite scaffolds. But a further increase above 20% disrupted the polymer chain networks within silk fibroin nanofibers and weakened the mechanical strength (10). 

Besides the conditions of acid hydrolysis, the morphology and dimensions of the NCC also depend on the source from which they were extracted. Some of the main techniques used in the investigation of size and/or morphology of these nanofibers are dynamic light scattering (DLS), scanning electron microscopy with a field emission gun (FESEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM) [22,25,67,68,69]. 

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