Sonal Padalkar

Natural biopolymers: Novel templates for the synthesis of nanostructures

Biological systems such as proteins, viruses, and DNA have been most often reported to be used as templates for the synthesis of functional nanomaterials, but the properties of widely available biopolymers, such as cellulose, have been much less exploited for this purpose. Here, we report for the first time that cellulose nanocrystals (CNC) have the capacity to assist in the synthesis of metallic nanoparticle chains. A cationic surfactant, cetyltrimethylammonium bromide (CTAB), was critical to nanoparticle stabilization and CNC surface modification. Silver, gold, copper, and platinum nanoparticles were synthesized on CNCs, and the nanoparticle density and particle size were controlled by varying the concentration of CTAB, the pH of the salt solution, and the reduction time.

Biotemplated synthesis of metallic nanoparticle chains on an alpha-synuclein fiber scaffold.

Biomolecular templates provide an excellent potential tool for bottom-up device fabrication. Self-assembling alpha-synuclein protein fibrils, the formation of which has been linked to Parkinsons disease, have yet to be explored for potential device fabrication. In this paper, alpha-synuclein fibrils were used as a template for palladium (Pd), gold (Au) and copper (Cu) nanoparticle chains synthesis. Deposition over a range of conditions resulted in metal-coated fibers with reproducible average diameters between 50 and 200 nm. Active elemental palladium deposited on the protein fibrils is used as a catalyst for the electroless deposition of Au and Cu. Nanoparticle chains were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectrometry (XEDS), and electron energy loss spectrometry (EELS).

Alpha-synuclein as a template for the synthesis of metallic nanowires

Exploiting the concepts learnt from nature to build new nanomaterials from the bottom up is critical for the efficient design of complex nanodevices. We demonstrate for the first time that the capacity of the α-synuclein protein to assemble into nanofibres can be used for the synthesis of metallic nanowires. Silver and platinum nanowires with controlled diameters, ranging from 15 to 125 nm, have been synthesized on an α-synuclein protein fibre scaffold.

Electrodeposition of Gold Nanostructures Having Controlled Morphology

Gold (Au) nanostructures exhibit unique electronic, optoelectronic and plasmonic properties. This makes them potential candidates for applications in areas including biosensing, catalysis, optics, and electronics. These unique properties are governed by the precise control over their morphologies and size. The present work investigates the electrodeposition process of Au nanostructures. Additionally, the influence of applied potential, electrolyte pH and presence of L-cysteine on the morphology, size, distribution and density of Au nanostructured was studied. The observations elucidated the relationship between the process parameters and the formation mechanism of the Au nanostructures. The morphology and composition of these Au nanostructures were characterized by scanning electron microscopy and X-ray diffraction respectively.

Metallic nanowires on a new protein template

Exploiting the concepts learnt from nature to build new nanomaterials from the bottom-up is critical for the efficient design of complex nanodevices. We demonstrate for the first time that the capacity of the &agr;-synuclein protein to assemble into nanofibers can be used for the synthesis of metallic nanowires. Silver and platinum nanowires with controlled diameters, ranging from 15 to 125nm, have been synthesized on an &agr;-synuclein protein fiber scaffold.