Self-assembling peptide assemblies bound to ZnS nanoparticles and their interactions with mammalian cells.

Self-assembling peptide sequences (both synthetic and natural) have emerged as a new group of building blocks for diverse applications. In this work we investigated the formation of assemblies of three diverse peptide sequences derived from the crustacean cardioactive peptide CCAP (1-9), a cardioaccelerator and neuropeptide transmitter in crustaceans, atrial natriuretic hormone ANP (1-28), a powerful vasodilator secreted by heart muscle cells of mammals, as well as adamstsostatin peptide ADS (1-17), which functions as an inhibitor of angiogenesis. The formation of assemblies was found to be dependent upon the sequences as well as the pH in which the assemblies were grown. The secondary structural transformation of the peptides was studied by circular dichroism as well as FTIR spectroscopy. In order to render the sequences luminescent, we conjugated the assemblies with ZnS nanoparticles. Finally the interactions of the peptide bound ZnS nanoparticles with mammalian normal rat kidney cells were explored. In some cases the nanoconjugates were found to adhere not only to the cellular membranes but also extend into the cytoplasm. Thus, such nanocomposites may be utilized for cell penetration and have the potential to serve as coercive multifunctional vectors for bioimaging and cellular delivery.