The small-sized molecules that have been developed from single hydrophobic amino acids (Phe, Trp, Tyr and Leu) by suitably protecting the -NH 2 and -CO 2 H groups generate diverse nanoscopic structures -such as nanorods, nanofi brils, nanotubes, and nanovesicles -depending upon the protection parameters and solvent polarity. The vesicular structures get disrupted in the presence of various salts, such as KCl, CaCl 2 , (NH 4 ) 2 SO 4 and N(n-Bu) 4 Br. Insertion of unnatural ( o / m / p )-aminobenzoic acids as a protecting group and the lack of conventional peptide bonds in the molecules give the nanostructures proteolytic stability. The nanostructures also show signifi cant thermal stability along with a morphological transformation upon heat treatment. Our in vitro studies reveal that the addition of micromolar concentration "curcumin" signifi cantly reduces the formation of amyloid-like fi brils. These diverse nanostructures are used as a template for fabricating silver nanoparticles on their outer surfaces as well as in the inner part, followed by calcination in air which helps to obtain a 1D silver nanostructure. Furthermore, the nanovesicles are observed to encapsulate a potent drug (curcumin) and other biologically important molecules, which could be released through salt-triggered disruption of vesicles.

Fabrication of protein-inorganic hybrid materials of innumerable hierarchical patterns plays a major role in the development of multifunctional advanced materials with their improved features in synergistic way. However, effective fabrication and applications of the hybrid structures is limited due to the difficulty in control and production cost. Here, we report the controlled fabrication of complex hybrid flowers with hierarchical porosity through a green and facile coprecipitation method by using industrial waste natural silk protein sericin. The large surface areas and porosity of the microsize hybrid flowers enable water purification through adsorption of different heavy metal ions. The high adsorption capacity depends on their morphology, which is changed largely by sericin concentration in their fabrication. Superior adsorption and greater selectivity of the Pb(II) ions have been confirmed by the characteristic growth of needle-shaped nanowires on the hierarchical surface of the hybrid flowers. These hybrid flowers show excellent thermal stability even after complete evaporation of the protein molecules, significantly increasing the porosity of the flower petals. A simple, cost-effective and environmental friendly fabrication method of the porous flowers will lead to a new solution to water pollution required in the modern industrial society.

A set of two modified tripeptides containing conformationally rigid m-aminobenzoic acid (m-ABA) as a template at the C-terminal self-assemble to form diverse micro-and nanostructure materials such as nanovesicles, nanotubes, giant microvesicles, macroporous vesicular structures including macroporous films, macro-and mesoporous materials, and organo gels-depending upon the solvent polarity. A balanced participation of the hydrogen bonding and the p-p interactions mainly between aromatic rings of m-ABA is crucial for this morphological diversity. Insertion of an aromatic amino acid instead of an aliphatic one in the peptide sequence drastically changes the morphology of the nanostructures formed from a particular solvent system. Interestingly these short hydrophobic peptides form saltresponsive multilayer vesicular structures from methanolic solutions, where the diameter of the vesicles increases with an increase of concentration. The most important property of these multilayer vesicular structures is the encapsulation of a potent natural hydrophobic drug curcumin and of a fluorescent dye rhodamine B, which can be effectively released in presence of biocompatible metal ions. Moreover, the encapsulation efficiency and release profile of drug and other biologically important guest molecules have been successfully quantified. We have developed a simple modified peptide based organogelator from chloroform, where the xerogel shows the striking property of adsorbing dye rhodamine B from water, which can be utilized in water purification by removing the toxic dye from waste water. Short peptide based macroporous vesicular structures including macroporous films have been successfully fabricated through controlled self-assembly employing solvents with different chloroform-petroleum ether ratios. Furthermore, the mesoporous structures prepared from toluene can efficiently absorb I 2 .

Facilely fabricated silk protein sericin-mediated hierarchical hydroxyapatite hybrid architectures show excellent adsorption of toxic heavy metal ions of Pb(ii), Cd(ii) and Hg(ii) and a hazardous dye, Congo red (CR), from wastewater.

Fabrication of molecular assemblies by arranging molecules through on-surface chemical reactions is an attractive way of functionalizing nanosheets chemically. Here, we study morphological changes of organometallic assemblies on a graphene oxide surface by controlling the formation of covalent bonds through on-surface chemical reactions with and without coupling agents. The difference in surface morphology originates from the different crystal growths of molecules diffusing on the surface, relating to the formation of covalent immobilization between the molecule and the surface. The molecules forming the assemblies have individual spins acquired by charge transfer between the molecule and the surface. The size and distribution of the assemblies on the surface produce morphology-related magnetism among the weakly interacting molecular spins. The present approach based on arranging simple molecules through on-surface chemical reactions provides new insights into molecular magnetism.