  Porphyrin nanotubes (PNTs) are prepared by self-assembly using meso-tetrakis
(4-sulfonatophenyl) porphyrin and Fe(III) meso-Tetra (N-Methyl-4-Pyridyl)
porphyrin in water as starting materials. Long tubes of about one micron
diameter are formed with bunches of smaller tubes attached to it, as judged
from the analysis of HRTEM images. The PNTs formed by this method are found to
exhibit good visible emission at 669 nm on excitation at 432 nm whereas both
parent porphyrin monomers do not exhibit any fluorescence. This result
highlights the scope of PNTs as functional components in the design of
biofriendly devices in medical as well as nanophotonics applications.
