Single amino acids (phenylalanine, tyrosine and glycine) have been evaluated for fibrillar structure under neutral, aqueous conditions using scanning electron microscopy, transmission electron microscopy, circular dichroism, FTIR, and Congo red and thioflavin T histological dye assays. All these techniques prove that aromatic amino acids, such as phenylalanine and tyrosine, do in fact form distinct fibrillar structures albeit without any secondary structural characteristics such as an a-helix or a b-sheet. The nature of the interactions between neighbouring amino acids in the fibrillar structures are purported to simply be non-covalent p-p interactions.

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Porous anodic alumina template has been employed, in the presence of a precipitation reaction involving Ca(OH) 2 and H 3 PO 4 , to form calcium phosphate based tubular structures. These structures are amorphous in nature and can be recovered by etching the sacrificial alumina membrane. Full characterization of these structures has been done using X-ray diffraction, electron microscopy and FTIR. In addition, their biocompatibility has been tested on L929 mouse fibroblast cells using MTT assay and the cellular internalization of these nanotubes has also been evaluated using rhodamine 6G dye tagged nanotubes in the presence of fibroblast cells. The studies also suggest that the nanotubes are non-toxic to fibroblasts and can be taken up easily by mammalian cells. Such tubes may serve as vehicles for drugs and growth factors, and for tissue repair including bone regeneration.

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