Chandramouleeswaran Subramani

Self-assembly and cross-linking of FePt nanoparticles at planar and colloidal liquid-liquid interfaces

Terpyridine thiol functionalized FePt and Au NPs were self-assembled and cross-linked at the liquid-liquid interfaces using Fe(II) metal ion. Complexation of terpyridine with Fe(II) metal ion leads to NP network and affords stable membranes and colloidal shells at the liquid-liquid interfaces.

Nanoimprint Lithography for Functional Three-Dimensional Patterns

Nanoimprint lithography (NIL) is viewed as an alternative nanopatterning technique to traditional photolithography, allowing micrometer-scale and sub-hundred-nanometer resolution as well as three-dimensional structure fabrication. In this Research News article we highlight current activities towards the use of NIL in patterning active or functional materials, and the application of NIL in patterning materials that present both chemistry and structure/topography in the patterned structures, which provide scaffolds for subsequent manipulation. We discuss and give examples of the various materials and chemistries that have been used to create functional patterns and their implication in various fields as electronic and magnetic devices, optically relevant structures, biologically important surfaces, and 3D particles.

Stable Magnetic Colloidosomes via Click-Mediated Crosslinking of Nanoparticles at Water-Oil Interfaces

Alkyne- and azide-functionalized iron oxide nanoparticles are co-assembled at the water-oil interface and covalently linked using click chemistry under ambient conditions to create magnetic colloidosomes (see image). These colloidosomes possess high stability, size-selective permeability, and are responsive toward external magnetic stimuli.

Direct Fabrication of Functional and Biofunctional Nanostructures Through Reactive Imprinting

One-step reactive imprinting of a protected maleimide polymer provides a nanopatterned maleimide surface via a retro-Diels-Alder reaction. The patterned surfaces are used as scaffolds for the generation of functional and biofunctional structures. The biofunctional surface offers a platform for aligning the cells in the direction of patterns, demonstrating the potential for applications in the field of tissue engineering.

Gold nanoparticle-PPE constructs as biomolecular material mimics: understanding the electrostatic and hydrophobic interactions

Eleven cationic, monolayer-protected quaternary ammonium-functionalized gold nanoparticles (ANPs) were prepared and investigated for their ability to quench the fluorescence of a poly(p-phenyleneethynylene) (PPE) that features carboxylate groups to enable electrostatic interactions with the ANPs. Depending upon their structures, the ANPs displayed binding constants to the PPE from 8 × 107 to 1010 M−1, with particularly high affinity observed with aromatic functionalized ANPs capable of aromatic stacking. These binding constants were obtained by analyzing the quenching data using a modified Stern–Volmer formalism.

Chemoselective Nanoporous Membranes via Chemically Directed Assembly of Nanoparticles and Dendrimers

Chemoselective nanoporous membranes: tunably porous membranes with embedded functionalities are generated using a template-free, chemically directed nanoparticle-dendrimer (NP-Den) network assembly. This approach provides a direction in the design of post-functionalizable nanoporous membranes for distinguishing both organic molecules and proteins with excellent chemo- and bioselectivity.

Synthesis and use of self-assembled rhamnolipid microtubules as templates for gold nanoparticles assembly to form gold microstructures.

Natural unmodified rhamnolipids are thermally self-assembled into soft microtubules, which can produce gold nanoparticles onto themselves due to the presence of rhamnose sugar moieties at their surface. The loading of gold nanoparticles on composite microtubules can be controlled by varying the concentration of gold salt to rhamnolipid and the reaction temperature. The composite rhamnolipid-gold nanoparticle microtubules are then heat treated to produce porous gold microwire-like structures with fairly controlled nanostructured features, which may have interesting applications in catalysis, biosensing and electronics.

Rapid Coating of Surfaces with Functionalized Nanoparticles for Regulation of Cell Behavior

A robust monolayer of nanoparticles is formed via dip-coating of cell culture plates. These surfaces provide cell type-specific modulation of growth behavior without the uptake of nanoparticles.

Direct Patterning of Quantum Dot Nanostructures via Electron Beam Lithography

Patterned quantum dot (QD) nanostructures were prepared by direct electron beam lithography on QD films. Time resolved photoluminescence measurements show that the optical properties of these QDs were retained after cross-linking.

Direct Patterning of Engineered Ionic Gold Nanoparticles via Nanoimprint Lithography

Gold nanoparticles are engineered for direct imprinting of stable structures. This imprinting strategy provides access to new device architectures, as demonstrated through the fabrication of a prototype photoswitchable device.