Abstract The chirality of (nano)structures is paramount in many phenomena, including biological processes, self-assembly, enantioselective reactions, and light or electron spin polarization. In the quest for new chiral materials, metallo-organic hybrids have been attractive candidates exploiting aforementioned scientific fields. Here, we show that carbon nanoparticles, called nanodots, can be readily prepared using hydrothermal microwave-assisted synthesis easily purified. These particles,...

Abstract Strategies for in-liquid molecular detection via Surface Enhanced Raman Scattering (SERS) are currently based on chemically-driven aggregation or optical trapping of metal nanoparticles in presence the target molecules. Such strategies allow formation SERS-active clusters that efficiently embed molecule at “hot spots” and enhance its scattering by orders magnitude. Here we report a novel scheme exploits radiation pressure to locally push gold nanorods induce their buffered solutions...

The presence of 10-13 M chiral clusters aromatic amino acids addresses aggregation opposite-charged achiral porphyrin towards the formation smart assemblies. latter supramolecular complexes are able to self-propagate and transfer their information with a 100% yield. bias occurs through correlated sequence induction, memory, amplification chirality that strongly recalls possible prebiotic scenarios.

Samples containing J-aggregates formed by the porphyrin meso-tetrakis(4-sulfonatophenyl)porphine (H2TPPS44-) were studied a combination of elastic (ELS) and dynamic (DLS) light scattering techniques. Aggregation was fostered lowering pH increasing ionic strength (I; selected experimental conditions: (i) = 0.7; (ii) 2.8, I 0.5 M; (iii) 0.7, 2 M). The ELS data suggest presence self-similar structures, whose fractal dimension are df 1.7, 2.13, 2.09 (for case i, ii, iii, respectively). DLS...

We show that percolation and structural arrest transitions coexist in different regions of the phase diagram a copolymer-micellar system relate them to short-range intermicellar attraction. The intermediate scattering function shows nonergodic transition along temperature concentration dependent line. Analyses logarithmic time dependence, attributed higher-order glass singularity predicted by mode-coupling theory, followed power law.

A structural change from fractal to nanorod J-aggregates of tetrakis(4-sulfonatophenyl)porphyrin has been obtained by acting on the intermolecular interaction potential. The size and shape these self-assembled porphyrin clusters have monitored under different experimental conditions, means polarized depolarized dynamic light scattering small wide angle elastic scattering. At sufficiently low concentration high ionic strength, shielded repulsive potential seems be responsible for structure...

We present results of analyses an extensive set static light scattering (SLS), small angle neutron (SANS), and viscoelastic (frequency dependent complex moduli) measurements aqueous solutions a triblock copolymer micellar system. investigate Pluronic L64 $({\mathrm{PEO}}_{13}{\mathrm{PPO}}_{30}{\mathrm{PEO}}_{13})$-water system in wide range composition temperature. determine phase diagram the disordered phase, including cmc-cmt curve, cloud point critical concentration, temperature by means...

Recently, we showed that J-aggregates, formed by the zwitterionic diacid form of porphyrin 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (H2TPPS44-) under acidic conditions, can be described in terms fractal geometry. We have extended investigation system strongly conditions through a combination UV/vis and fluorescence emission spectroscopy, together with static (SLS), quasi-elastic (QELS), resonant (RLS) light-scattering techniques. The experimental findings suggest J-aggregates begin to...

We have investigated in detail the self-assembly of a chiral porphyrin trimer different solvents and correlated this behavior to aggregation molecule at solid-liquid interface. In n-hexane cyclohexane, CD spectroscopy dynamic static light scattering studies showed that self-assembles already micromolar concentrations into long, supramolecular polymers, which precipitate as fibers when solution is drop-cast onto mica surface. contrast, chloroform, compound molecularly dissolved up 0.2 mM...

Self-assembled cyclodextrin (CD)–DNA nanoparticles (CDplexes) exhibiting transfection efficiencies significantly higher than PEI-based polyplexes have been prepared from homogeneous seven-fold symmetric polyaminothiourea amphiphiles constructed on a β-cyclodextrin scaffold.

Chiral porphyrin J-aggregates are confined into microemulsions, achieving a fine control of their size and optical properties. The quality the circular dichroism signal exhibits remarkable scaling on dimension from nano- up to mesoscopic regime.

Optical forces are used to aggregate plasmonic nanoparticles and create SERS–active hot spots in liquid. When biomolecules added the nanoparticles, high sensitivity SERS detection can be accomplished. Here, we pursue studies on Bovine Serum Albumin (BSA) detection, investigating BSA–nanorod aggregations a range from 100 µM 50 nM by combining light scattering, plasmon resonance SERS, correlating signal with concentration. Experimental data fitted simple model describing optical aggregation...

Positively charged, synthetic chrysotile nanotubes act as inorganic tectons supporting H- and J-type aggregates of anionic porphyrins with markedly different optical properties, making these nanohybrid materials interest for application in nanotechnology.

Complexes of cationic amphiphilic cyclodextrins heptakis[2-(ω-amino-oligo(ethylene glycol))-6-deoxy-6-hexadecylthio]-β-cyclodextrin and glycol))-6-deoxy-6-dodecylthio]-β-cyclodextrin with DNA were examined by small-angle X-ray scattering dynamic as well electrophoretic light scattering. The first cyclodextrin forms bilayer vesicles in water, which, the presence calf thymus DNA, transform to a multilamellar complex. In this complex, lies between two polar layers cyclodextrin's protonated...

J-aggregates of conjugated molecules are known to be the result π–π stacking and hydrophobic electrostatic interactions with hydrogen bonding providing stabilization. The present study on porphyrin derivatives, thanks absence chargeable groups, helps focus attention effect hydrogen-bonding interactions. Moreover, aqueous medium, causing a competitive for formation H-bonds porphyrins, strengthens role inter-porphyrin contribution in self-assembly. Herein it is proven, through UV-vis...

The kinetics of growth for chiral J-aggregates H4TPPS4 porphyrin have been investigated under different experimental conditions in the presence tartaric acid. observed rate constants and anisotropy factor g show a defined dependence on enantiomer used as templating agent.

Abstract The entanglement process between water‐soluble 5,10,15,20‐tetrakis(4‐sulfonatophenyl)‐21 H ,23 ‐porphine and the amphiphilic cyclodextrin (CD) heptakis(2‐ω‐amino‐ O ‐oligo(ethylene oxide)‐6‐hexylthio)‐β‐CD occurrence of various species at different porphyrin:CD ratios were studied by a combination UV/Vis absorption, fluorescence anisotropy, time‐resolved fluorescence, resonance light scattering, circular dichroism. effect on mean vesicle diameter was investigated over wide...

Depending on the experimental conditions, various charged water soluble porphyrins can aggregate, leading to large supramolecular assemblies whose basic building blocks are constituted by J-type aggregates or heteroaggregated species made up oppositely molecules. The mesoscopic structures resulting (i) self-aggregation of anionic porphyrin tetrakis(4-sulfonatophenyl)porphine (H2TPPS44-) and (ii) its heteroaggregates with cationic tetrakis(4-N-methylpyridinium)porphine (H2TMpyP(4)4+) some...

Water/decane/AOT microemulsions have been used to obtain J-aggregates of the anionic water soluble porphyrin tetrakis(4-sulfonatophenyl)porphyrin (TPPS4), having sizes that are controlled by dimension pool. The kinetics aggregation investigated on changing pH, ionic strength and size treated a model derived for self-assembling processes based catalytic role critical nucleus. analysis present data evidences dimer or trimer in rate determining step. exhibit resonance light scattering (RLS)...

Purpose: We investigated the concentration of riboflavin in human donor corneas during corneal cross-linking using two-photon optical microscopy and spectrophotometry. Methods: Eight tissues were de-epithelialized soaked with 20% dextran-enriched 0.1% solution for 30 minutes. After stromal soaking, three irradiated a 3 mW/cm2 UV-A device minutes 10 9 Two additional used as positive controls. A Ti:sapphire laser at 810 nm was to perform emission fluorescence (TPEF) second harmonic generation...

In this paper, the Chlorophyll a aggregation behavior is investigated in relation to nature of organic solvent, composition aqueous mixtures with different solvents, and pigment concentration. Because complexity system under investigation number parameters that can influence processes, data relative physicochemical characterization species will be discussed three sessions, corresponding ranges solvent composition. when present mainly as monomer, polymer or "micellar" species, respectively....

Resonance light scattering (RLS) is a phenomenon due to an enhancement of the scattered in close proximity absorption band. The effect easily detectable case strongly absorbing chromophores, which are able interact, thus leading large aggregates (Pasternack,R. F.; Collings, P. J. Science 1995, 269, 935). measurement spectra from solutions containing such resonant systems can lead misleading results. In this paper, simple method described obtain aggregated species with fairly good correction...

We have studied the aggregation of porphyrin $t{\ensuremath{-}\mathrm{H}}_{2}{\mathrm{P}}_{\mathrm{agg}}$ in aqueous solution by light scattering. The intensity profile elastically scattered light, exchanged wave-vector range $0.2\ensuremath{\le}q\ensuremath{\le}31.4\ensuremath{\mu}{\mathrm{m}}^{\ensuremath{-}1}$, indicates that produces large monodisperse clusters having a fractal structure, and is driven diffusion-limited kinetics. Additional measurements performed at different $q$ values...