Plasmonic circular dichroism-based metal ion detection using gold nanorod-DNA complexes.

We report that complexes formed between gold nanorods (AuNRs) and metal-mediated DNA exhibit plasmonic circular dichroism (CD) signals up to ∼400 times stronger than the molecular CD signal of DNA. This substantial enhancement enables the detection of metal ions, offering a promising approach to analytical applications in chiral biochemistry.

Ultrasensitive Surface-Enhanced Raman Scattering Platform for Protein Detection via Active Delivery to Nanogaps as a Hotspot.

Surface-enhanced Raman scattering (SERS) is an attractive technique in molecular detection with high sensitivity and label-free characteristics. However, its use in protein detection is limited by the large volume of proteins, hindering its approach to the narrow spaces of hotspots. In this study, we fabricated a Au nanoTriangle plate Array on Gel (AuTAG) as an SERS substrate by attaching a Au nanoTriangle plate (AuNT) arrangement on a thermoresponsive hydrogel surface.

Reversible changes in the orientation of gold nanorod arrays on polymer brushes.

Nanoparticles exhibit a number of unique properties such as localized surface plasmon resonance (LSPR). As this LSPR is sensitive to geometrical or spatial conditions, the arrangement of nanoparticles, in particular the active arrangement of plasmonic structures, is an important issue. In this study, gold nanorod (GNR) arrays were prepared by GNR attachment on anionic polymer (DNA) brushes electrostatic interactions and their stimuli-responsive changes in orientation were investigated.

Spatiotemporal monitoring of intracellular metabolic dynamics by resonance Raman microscopy with isotope labeling.

Cellular metabolites are valuable in a diverse range of applications. For example, the unicellular green alga produces as a secondary metabolite the carotenoid pigment astaxanthin (AXT), which is widely used in nutraceutical, cosmetic, and food industries due to its strong antioxidant activity. In order to enhance the productivity of , spatial and temporal understanding of its metabolic dynamics is essential.

Homogeneous Oligomeric Ligands Prepared via Radical Polymerization that Recognize and Neutralize a Target Peptide.

Abiotic ligands that bind to specific biomolecules have attracted attention as substitutes for biomolecular ligands, such as antibodies and aptamers. Radical polymerization enables the production of robust polymeric ligands from inexpensive functional monomers. However, little has been reported about the production of monodispersed polymeric ligands.

Isolating Single Cells by Glass Microfluidics for Raman Analysis of Paramylon Biogenesis.

Time-course analysis of single cells is important to characterize heterogeneous activities of individual cells such as the metabolic response to their environment. Single-cell isolation is an essential step prior to time-course analysis of individual cells by collecting, culturing, and identifying multiple single-cell targets. Although single-cell isolation has been performed by various methods previously, a glass microfluidic device with semiclosed microchannels dramatically improved this process with its simple operation and easy transfer for time-course analysis of identified single cells.

High-throughput label-free molecular fingerprinting flow cytometry.

Flow cytometry is an indispensable tool in biology for counting and analyzing single cells in large heterogeneous populations. However, it predominantly relies on fluorescent labeling to differentiate cells and, hence, comes with several fundamental drawbacks. Here, we present a high-throughput Raman flow cytometer on a microfluidic chip that chemically probes single live cells in a label-free manner.

Conformation Manipulation and Motion of a Double Paddle Molecule on an Au(111) Surface.

The molecular conformation of a bisbinaphthyldurene (BBD) molecule is manipulated using a low-temperature ultrahigh-vacuum scanning tunneling microscope (LT-UHV STM) on an Au(111) surface. BBD has two binaphthyl groups at both ends connected to a central durene leading to anti/syn/flat conformers. In solution, dynamic nuclear magnetic resonance indicated the fast interexchange between the anti and syn conformers as confirmed by density functional theory calculations.

Monitoring Photosynthetic Activity in Microalgal Cells by Raman Spectroscopy with Deuterium Oxide as a Tracking Probe.

Microalgae offer great potential for the production of biofuel, but high photosynthetic activity is demanded for the practical realisation of microalgal biofuels. To this end, it is essential to evaluate the photosynthetic activity of single microalgal cells in a heterogeneous population. In this study, we present a method to monitor the photosynthetic activity of microalgae (in particular Euglena gracilis, a microalgal species of unicellular, photosynthetic, flagellate protists as our model organism) at single-cell resolution by Raman spectroscopy with deuterium from deuterium oxide (D O) as a tracking probe.

A polymer nanoparticle with engineered affinity for a vascular endothelial growth factor (VEGF).

Protein affinity reagents are widely used in basic research, diagnostics and separations and for clinical applications, the most common of which are antibodies. However, they often suffer from high cost, and difficulties in their development, production and storage. Here we show that a synthetic polymer nanoparticle (NP) can be engineered to have many of the functions of a protein affinity reagent.

Mechanically Induced Opening-Closing Action of Binaphthyl Molecular Pliers: Digital Phase Transition versus Continuous Conformational Change.

Reversible dynamic control of structure is a significant challenge in molecular nanotechnology. Previously, we have reported a mechanically induced continuous (analog) conformational variation in an amphiphilic binaphthyl, where closing of molecular pliers was achieved by compression of a molecular monolayer composed of these molecules at the air-water interface. In this work we report that a phase transition induced by an applied mechanical stress enables discontinuous digital (1/0) opening of simple binaphthyl molecular pliers.

Supramolecular 1-D polymerization of DNA origami through a dynamic process at the 2-dimensionally confined air-water interface.

In this study, a Langmuir-Blodgett (LB) system has been utilized for the regulation of polymerization of a DNA origami structure at the air-water interface as a two-dimensionally confined medium, which enables dynamic condensation of DNA origami units through variation of the film area at the macroscopic level (ca. 10-100 cm(2)). DNA origami sheets were conjugated with a cationic lipid (dioctadecyldimethylammonium bromide, 2C18N(+)) by electrostatic interaction and the corresponding LB-film was prepared.

In situ 2D-extraction of DNA wheels by 3D through-solution transport.

Controlled transfer of DNA nanowheels from a hydrophilic to a hydrophobic surface was achieved by complexation of the nanowheels with a cationic lipid (2C12N(+)). 2D surface-assisted extraction, '2D-extraction', enabled structure-persistent transfer of DNA wheels, which could not be achieved by simple drop-casting.

Mechanochemical Tuning of the Binaphthyl Conformation at the Air-Water Interface.

Gradual and reversible tuning of the torsion angle of an amphiphilic chiral binaphthyl, from -90° to -80°, was achieved by application of a mechanical force to its molecular monolayer at the air-water interface. This 2D interface was an ideal location for mechanochemistry for molecular tuning and its experimental and theoretical analysis, since this lowered dimension enables high orientation of molecules and large variation in the area. A small mechanical energy (<1 kcal mol(-1) ) was applied to the monolayer, causing a large variation (>50 %) in the area of the monolayer and modification of binaphthyl conformation.

Nanoarchitectonics of molecular aggregates: science and technology.

The field of making, studying and using molecular aggregates, in which the individual molecules (monomers) are arranged in a regular fashion, has come a long way. Taking control over the aggregation of small molecules and polymers in bulk, on surfaces and at interfaces pose a considerable challenge for their utilization in modern high tech applications. In this review, we provide a detailed insight into recent trends in molecular aggregates from the perspectives of nanoarchitectonics.

Epitope discovery for a synthetic polymer nanoparticle: a new strategy for developing a peptide tag.

We describe a novel epitope discovery strategy for creating an affinity agent/peptide tag pair. A synthetic polymer nanoparticle (NP) was used as the "bait" to catch an affinity peptide tag. Biotinylated peptide tag candidates of varied sequence and length were attached to an avidin platform and screened for affinity against the polymer NP.

Polymer nanoparticle-protein interface. Evaluation of the contribution of positively charged functional groups to protein affinity.

Cationic-functionalized polymer nanoparticles (NPs) show strikingly distinct affinities to proteins depending on the nature of the cationic functional group. N-Isopropylacrylamide (NIPAm) polymer NPs incorporating three types of positively charged functional groups (guanidinium, primary amino, and quaternary ammonium groups) were prepared by precipitation polymerization. The affinities to fibrinogen, a protein with an isoelectric point (pI) of 5.

ELISA-mimic screen for synthetic polymer nanoparticles with high affinity to target proteins.

Synthetic polymer nanoparticles (NPs) that display high affinity to protein targets have significant potential for medical and biotechnological applications as protein capture agents or functional replacements of antibodies ("plastic antibodies"). In this study, we modified an immunological assay (enzyme-linked immunosorbent assay: ELISA) into a high-throughput screening method to select nanoparticles with high affinity to target proteins. Histone and fibrinogen were chosen as target proteins to demonstrate this concept.

Light-triggered charge reversal of organic-silica hybrid nanoparticles.

A functional nanoparticle with light-triggered charge reversal based on a protected amine-bridged polysilsesquioxane was designed. An emulsion- and amine-free sol-gel synthesis was developed to prepare uniform nanospheres. Photolysis of suspensions of these nanoparticles results in a reversal of the ζ potential.

Radical carbonylation of ω-alkynylamines leading to α-methylene lactams. Synthetic scope and the mechanistic insights.

Tin hydride mediated radical carbonylation and cyclization reaction was investigated using a variety of ω-alkynyl amines as substrates. In this reaction α-methylene and α-stannylmethylene lactams having five to eight membered rings were obtained as principal products. In cases where the nitrogen has a substituent capable of giving stable radicals, such as an α-phenethyl group, the lactam ring formation again took place with extrusion of an α-phenethyl radical.