Enhancing the fluorescence of a weak emitter is important to further extend reach single-molecule imaging many unexplored systems. Here we study enhancement by isolated gold nanorods and explore role surface plasmon resonance (SPR) on observed enhancements. Gold can be cheaply synthesized in large volumes, yet find similar enhancements as literature reports lithographically fabricated nanoparticle assemblies. The emitter, crystal violet, enhanced more than 1000-fold single nanorod with its...

Tip-functionalized nanorods: Single-particle spectroscopy shows that functionalization of small gold nanorods with thiol groups leads to a broadening the plasmon resonance by chemical interface damping. By specifically functionalizing tips nanorod (see picture) this is nearly eliminated while sensing performance maintained relative fully functionalized particles. Detailed facts importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not...

The biological properties of four lanthanide complexes with phenanthroline derivatives in ovarian cancer cells.

Protein synthesis is supported by cellular machineries that ensure polypeptides fold to their native conformation, whilst eliminating misfolded, aggregation prone species. underlies pathologies including neurodegeneration. Aggregates' formation antagonised molecular chaperones, with cytoplasmic machinery resolving insoluble protein aggregates. However, it unknown whether an analogous disaggregation system exists in the Endoplasmic Reticulum (ER) where ~30% of proteome synthesised. Here we...

Cancer remains a leading cause of mortality and morbidity worldwide. Consequently, the scientific community continues to pursue improvements in diagnostic methods subsequent treatments. To enhance treatment efficacy reduce probability adverse outcomes, reliable sensitive are essential. A potential solution may lie synergy between nanotechnology optical biosensors, as they can provide exceptional sensitivity detection disease biomarkers. This review focuses on fluorescent DNA probes assembled...

We have performed atomistic molecular dynamics simulations of PAMAM dendrimers generations 0.5, 1.5, 2.5, 3.5, and 4.5. The simulated systems comprise the charged dendrimer its counterions embedded in a dielectric continuum (i.e., without explicit solvent). Structural properties these dendrimers, like radius gyration, principal moments inertia, segment density profiles, were evaluated from simulations. average gyration obtained for intermediate half-generations 4.5 follows same scaling law...

We demonstrate correlation analysis of the photothermal signal from gold nanoparticles diffusing in solution. Our experimental setup is primarily optimized for large detection volumes and therefore has a relatively low numerical aperture (0.25). This requirement limits light collection efficiency, but we can nevertheless detect particles as small 20 nm diameter 100 μs. Photothermal spectroscopy (PCS) water water:glycerol mixtures gives access to characteristic diffusion times some tens...

Gold nanorods are promising platforms for label-free biosensing. We have functionalized gold with biotin thiol linkers of increasing chain length and evaluated their ability in the molecular detection streptavidin. found an unexpected effect increase linker length, which resulted a substantial improvement plasmon response at surface saturation. The peak shift increased from 5 to 14 nm, i.e., more than twice response, between short long linkers. This is observed only site-selective tip...

Anionic meso-tetrakis(4-sulfonatophenyl)porphine (TSPP) interacts with poly(amido) amine (PAMAM) dendrimers of generations 2.0 and 4.0 in aqueous solution to form several dendrimer-associated species, which depend on the relative concentrations dendrimer porphyrin (D/P ≡ [PAMAM]/[TSPP]). At D/P ratios above isoelectric point charge balance between porphyrin, only two spectroscopic species were detected. An equilibrium model assuming a dendrimer-induced TSPP H-dimer coexisting monomer...

Porphyrins are typically weak emitters, which presents challenges to their optical detection by single-molecule fluorescence microscopy. In this contribution, we explore the enhancement effect of gold nanodimer antennas on porphyrins in order enable detection. Four meso-substituted free-base were evaluated: two cationic, one neutral, and anionic porphyrin. The able enhance emission from these a factor 105–106 increase maximum detected photon rates. This extreme is due combination an antenna...

Steady-state absorption and emission spectroscopy time-resolved fluorescence measurements were employed in the study of meso-tetrakis(4-N-methylpyridinium)porphine (TMPyP) interactions with half-generation carboxyl-terminated poly(amidoamine) (PAMAM) dendrimers water. TMPyP experiences a less polar environment strong quenching effect upon dendrimer association. The tertiary amine functional groups PAMAM are likely to be responsible for through an electron-transfer mechanism. Stern−Volmer...

The self-assembly of a neutral meso-methoxyphenylporphyrin functionalized with dipeptide glycilglycine substituent (MGG) in water and water-ethanol mixtures was studied by absorption fluorescence spectroscopy. In water, hydrophobic interactions the noncovalent intermolecular hydrogen bonding between terminal carboxylate group one porphyrin atoms pyrrolic nitrogens another originate nonspecific disorganized H- J-aggregates. addition ethanol (0.1-25% v/v) to creates small clusters within which...

Thin films of colloidal semiconductor CdSe quantum-dots (QDs) and a styrene/maleic anhydride copolymer were prepared by the Langmuir–Blodgett technique their photoluminescence was characterized confocal fluorescence lifetime microscopy. In films, dynamics are strongly affected excitation energy migration between close-packed trapping surface-defective QDs or small clusters aggregated QDs. Polymer/QD with more QD regions exhibit lower PL intensities faster decays, which we attribute primarily...

The relevance of mannosyldiinositolphosphorylceramide [M(IP)2C] synthesis, the terminal complex sphingolipid class in yeast Saccharomyces cerevisiae, for lateral organization plasma membrane, and particular sphingolipid-enriched gel domains, was investigated by fluorescence spectroscopy microscopy. We also addressed how changing profile membrane could influence compartments (MC) containing either arginine/ H+ symporter Can1p (MCC) or proton ATPase Pma1p (MCP). To achieve these goals,...

Conjugation of fluorescently-labelled DNA onto gold nanorods produces strongly emitting nano-assemblies, but only tip-selective functionalization affords an effective emission enhancement.

We report on the plasmon-enhanced fluorescence emission achieved in an organic/inorganic hybrid multilayered polyelectrolyte film incorporating aluminum tetrasulfonated phthalocyanine (AlPcTS) and gold nanoparticles (AuNPs). The induced effect can be tuned by number of layers separating AlPcTS AuNPs, reaching most favorable conditions with seven (PE) layers. increase intensity was measured steady-state as well confocal microscopy. films are optically heterogeneous, is stronger spatially...

The surface plasmon modes of metal nanoparticles provide a way to efficiently enhance the excitation and emission from fluorescent dye. We have employed DNA-directed assembly prepare dimers gold used their longitudinally coupled mode fluorescence an organic red-emitting dye, Atto-655. plasmon-enhanced this dye using 80 nm particles was measured at single-molecule detection level. top enhancement factors were above 1000-fold in 71% within total 32 measured, some cases, they reached almost...

We report on single-molecule fluorescence of an aluminum phthalocyanine dye associated with PAMAM dendrimers at a glass surface. The decays the phthalocyanine−dendrimer complex deposited from solution pH 3 are monoexponential and lifetimes closely distributed around its natural lifetime. However, in absence buffer (pH 6), distribution is broadened toward shorter decay times. Fluorescence quenching attributed to electron transfer between excited-state dendrimer's tertiary amines, which...