Neat Protein-Polymer Surfactant Bioconjugates as Universal Solvents.

Solvents, particularly those having low volatility, are of great interest for the biocatalytic synthesis of utility chemicals and fuels. We show novel and universal solvent-like properties of a neat and water-less polymer surfactant-bovine serum albumin (BSA) conjugated material (WL-PS pBSA). This highly viscous, nonvolatile material behaves as a liquid above its solid-liquid transition temperature (∼25-27 °C) and can be used as a solvent for variety of completely dry solutes of different sizes and surface chemistries.

NIR-emitting chiral gold nanoclusters coated with γ-cyclodextrin are pH sensitive: Application as biomarker.

Unlabelled: Change in cellular pH due to onset of certain malfunctions needs to be tracked quickly so that treatment to cure such incidents may be started immediately. For example, microenvironment of a developing tumor is acidic due to high metabolic rate as well as low oxygen supply. Hence biomarkers that can sharply sense transition in pH could be of great use in the early detection of tumor formation.

Modulation of energy/electron transfer in gold nanoclusters by single walled carbon nanotubes and further consequences.

Semiconductor or metallic character in single-walled carbon nanotubes (SWCNTs) is developed because of their chirality and diameter. Depending upon the extent of these characters in a particular sample of SWCNT, various electronic and mechanical applications are formulated. In this work we used protein protected red emitting gold nanoclusters (AuNCs) to enhance the metallic character in SWCNTs through electron transfer induced by photonic excitation.

Promoting the "water-wire" mechanism of double proton transfer in [2,2'-bipyridyl]-3,3'-diol by porous gold nanoparticles.

The effect of nanopores in porous gold nanoparticles (Au NPs) on excited-state double proton transfer (DPT) in [2,2'-bipyridyl]-3,3'-diol (BP(OH)2) in an aqueous environment is the main focus of the present work. DPT in BP(OH)2 is known to take place through two mechanisms. In a bulk environment, an open solvated molecule facilitates the process and emits at 460 nm whereas, in a confined situation, formation of a "water wire" between the prototropic centers leads to the transfer of protons.

FRET-based characterisation of surfactant bilayer protected core-shell carbon nanoparticles: advancement toward carbon nanotechnology.

Surfactant bilayer protected core-shell carbon nanoparticles (CNPs) have been synthesised. Förster resonance energy transfer (FRET) between the core-shell CNPs and two strategically chosen organic dyes has been exploited to characterise the protective surfactant bilayer.

Protein-templated gold nanoclusters: size dependent inversion of fluorescence emission in the presence of molecular oxygen.

Gold nanoclusters are promising candidates as biological markers without having toxic effects like fluorescent quantum dots. Herein, bovine serum albumin (BSA) protein stabilized gold nanoclusters of two different sizes emitting at 410 and 645 nm have been synthesized. These nanoclusters have been shown to interact with molecular oxygen differentially.

"Extra stabilisation" of a pyrene based molecular couple by γ-cyclodextrin in the excited electronic state.

Two thiosemicarbazide and semicarbazide functionalized pyrene labeled Schiff base compounds have been synthesized. The pyrene moieties in the compounds result in formation of π-π coupled complexes in aqueous medium in the excited electronic state. Added γ-cyclodextrin allows incorporation of the pyrene head inside its less polar core and promotes hydrogen bonding of the thio and oxo groups of the compounds with its rim hydroxyl groups to "stabilise" the monomers.

Förster resonance energy transfer between pyrene and bovine serum albumin: effect of the hydrophobic pockets of cyclodextrins.

The phenomenon of Förster resonance energy transfer (FRET) between pyrene and bovine serum albumin (BSA) protein in presence of cyclodextrins (CDs) is explored in the present work. CDs provide hydrophobic environment and thus the aromatic molecules get encapsulated in them depending on the relative size and space. In this work we revealed that along with pyrene monomer, the side chains of amino acids in BSA can get trapped partly in the hydrophobic cavities of CDs if space permits.

Interaction of a new surface sensitive probe compound with anionic surfactants of varying hydrophobic chain length.

The amide derivative of a bis-phenylethynyl compound meta linked to 2,6-pyridine (BPEAP) poses inherent equilibrium between its neutral and zwitterionic forms in the excited state. BPEAP has been found to bind to the surface of anionic micelles instead of penetrating inside. This phenomenon has been exploited to attempt controlling the process of equilibrium using sodium dodecyl sulfate (SDS) at its pre-micellar and near-micellar aggregation concentrations.

Interaction of a "nido"-ruthenium terpyridylamine complex with charged elongated micellar scaffolds.

Influence on ionic surfactants by a specially designed terpyridylamine ligand and the ruthenium(II) complex formed with it has been studied in aqueous solution. The ligand coordinates to Ru(2+) into an octahedral geometry in such a way that the final form takes a "nido" or nest-like structure. The substitution on the pyridinyl moiety is kept at the ortho position to acquire the specified geometry.

Orientation of a TICT probe trapped in the peripheral confined water created by ionic surfactant envelope around silver nanoparticles.

Ionic surfactants are known to aggregate around the surface of a nanoparticle as a single layer in premicellar and a double layer in micellar concentrations. This motif of arrangement indicates the development of a layer of confined water of lower polarity than bulk water around the surface of the nanoparticle. We have demonstrated the behavior of a twisted intramolecular charge transfer (TICT) probe, trans-2-[4-(dimethylamino)styryl]benzothiazole (DMASBT), in the confined aqueous layer developed at the surface of spherical silver nanoparticles (Ag NPs) at and above the critical micellar concentrations (CMC) of a cationic and an anionic surfactant, namely, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS).