Accurate knowledge of the kinetics complementary oligonucleotide hybridization is integral to design and understanding DNA-based biosensors. In this work, single-molecule fluorescence imaging applied measuring rates between fluorescently labeled target ssDNA unlabeled probe immobilized on glass surfaces. absence site labeling, capture surface must be highly selective avoid influence nonspecific adsorption interpretation results. This accomplished by increasing molecule densities a factor...

Simultaneous multipass resistive-pulse sensing and fluorescence imaging have been used to correlate the size intensity of individual E. coli lipid liposomes composed polar extracts labeled with membrane-bound 3,3-dioctadecyloxacarbocyanine (DiO) fluorescent molecules. Here, a nanopipet serves as waveguide direct excitation light zone at end tip. Individual DiO-labeled (>50 nm radius) were multipassed back forth through orifices glass nanopipets' 110–150 radius via potential switching obtain...

We report excited-state lifetime modification of diffusing molecules by Al nanoapertures in the UV. Lifetime reductions ∼3.5× have been observed for high quantum yield laser dye p-terphenyl a 60 nm diameter aperture. The reduction is smaller low molecule tryptophan, which maximum ∼1.7 observed. as function aperture size and native accurately predicted simulation. Simulation further predicts greater net fluorescence enhancement tryptophan compared to p-terphenyl, consistent with expectation...

Due to its high specific surface area and chemical stability, porous silica is used as a support structure in numerous applications, including heterogeneous catalysis, biomolecule immobilization, sensors, liquid chromatography. Reversed-phase chromatography (RPLC), which uses particles, has become an indispensable separations tool quality control, pharmaceutics, environmental analysis requiring identification of compounds mixtures. For complex samples, the need for higher resolution requires...

Fluorescence imaging and counting of single molecules adsorbed or bound to surfaces are being employed in a number quantitative analysis applications. Reliable molecular counts with knowledge uncertainties, both false-positive false-negative probabilities, critical these By stationary on surface, spatial criteria may be applied the image improve confidence detection, which is especially when detecting fluorescent labels. In this work, we describe simple approach incorporating for by using an...

We report modification of the ultraviolet (UV) fluorescence decay rate p-terphenyl dye molecules by magnesium (Mg) nanoapertures in free solution, comparison with aluminum (Al). Mg exhibit a lifetime reduction up to ∼7.2×, which our knowledge is largest UV reported so far literature. In comparison, Al ∼5.3×, exceeding previously value ∼3.5× due smaller aperture size employed here. Simulation results reveal large plasmon resonance frequency shifts between and nanoapertures, contributing...

Abstract Super‐resolution imaging was used to quantify organizational changes in the plasma membrane after treatment with hybrid nanoconjugates. The nanoconjugates crosslinked CD20 on surface of malignant B cells, thereby inducing apoptosis. images were analyzed by using pair‐correlation analysis determine cluster size and count average number molecules clusters. role lipid rafts investigated pre‐treating cells a cholesterol chelator actin destabilizer prevent raft formation. Lipid...

Aptamers are short nucleic-acid biopolymers selected to have high affinity and specificity for protein or small-molecule target analytes. can be engineered into split-aptamer biosensors comprising two nucleic acid strands that coassemble as they bind a target, resulting in large signal change from attached molecular probes (e.g., beacons). The kinetics of assembly their dependence on recognition largely unknown; knowledge these could help design optimization biosensors. In this work, we...

Single-molecule imaging of fluorescently labeled biomolecules is a powerful technique for measuring association interactions; however, care must be taken to ensure that the fluorescent labels do not influence system being probed. Label-free techniques are needed understand biomolecule interactions free from an attached label, but these often lack sensitivity and specificity. To solve challenges, we have developed competitive assay uses single-molecule detection track population unlabeled...

Single-molecule fluorescence imaging detects distinct hybridization events to determine rates of association and dissociation.

Preparation of new recyclable polymer-supported oxidizing reagents based on 2-iodylphenol ethers is described. The synthesis employs commercially available aminomethylated polystyrene or Merrifield resin and affords with loading up to 0.86 mmol/g respect IO2 groups. effect clean efficient conversion a wide range alcohols, including heteroatomic unsaturated structures, the corresponding carbonyl compounds. Recycling resins possible minimal loss activity after several reoxidations.

The binding of glucagon-like peptide-1 (GLP-1) to a planar phospholipid bilayer is measured using single-molecule total internal reflection fluorescence microscopy. From several reports in the literature, GLP-1 has been shown be random coil free solution, adopting folded, α-helix conformation when intercalated into membrane environments. Single-molecule measurements supported lipid bilayers show evidence two populations membrane-associated molecules having different residence times,...

Single-molecule fluorescence methods can count molecules without calibration, measure kinetics at equilibrium, and observe rare events that cannot be detected in an ensemble measurement. We employ total internal reflection microscopy to monitor hybridization between individual spatially resolved target DNA immobilized a glass interface fluorescently labeled complementary probe free solution. Using super-resolution imaging, are located with 36 nm precision, their duplex formation dissociation...

The development of high fidelity polymerases and streamlined synthesis threose nucleic acid (TNA) triphosphates phosphoramidites has made TNA accessible as a motif for generating nuclease-resistant high-affinity aptamers, antisense oligos, synthetic genetic biopolymers. Little is known, however, about the thermostability trends TNA:DNA duplexes. Here we investigate 14 duplexes with goal elucidating fundamental factors governing duplex stability. We find that purine content in significantly...

Detection of single, fluorescently labeled biomolecules is providing a powerful approach to measuring molecular transport, biomolecular interactions, and localization in biological systems. Because the molecules interest rarely exhibit sufficient intrinsic fluorescence allow observation individual molecules, they are usually with fluorescent dye proteins, semiconductor nanocrystals or quantum dots, doped silica polymer nanospheres their detection. Differences photophysical spectral...

Encapsulation of molecules in phospholipid vesicles provides unique opportunities to study chemical reactions small volumes as well the behavior individual proteins, enzymes, and ribozymes a confined region without requiring tether immobilize molecule surface. These experiments generally depend on generating predictable loading with numbers target thus raise significant measurement challenge, namely, quantify molecular occupancy at single-molecule level. In this work, we describe an imaging...

Many interfacial chemical phenomena are governed in part by electrostatic interactions between polyelectrolytes and charged surfaces; these can influence the performance of biosensors, adsorption natural (humic substances) on soils, production polyelectrolyte multilayer films. In order to understand that govern phenomena, we have investigated behavior a model polyelectrolyte, 15 kbp fluorescently labeled plasmid DNA, near polarized indium tin oxide (ITO) electrode surface. The population DNA...

Single-molecule fluorescence imaging is a powerful method to measure reversible reaction kinetics, allowing one monitor the bound state of individual probe molecules with fluorescently labeled targets. In case DNA hybridization, previous studies have shown that presence fluorescent label on target strand can exhibit significant influence stability duplex formed. this work, we developed super-resolution hybridization kinetics unlabeled compete tracer hybridize an immobilized at surface. The...

Oligonucleotide aptamers can be converted into structure-switching biosensors by incorporating a short, typically labeled oligonucleotide that is complementary to the analyte-binding region. Binding of target analyte disrupt hybridization equilibrium between aptamer and labeled-complementary oligo producing concentration-dependent signal for target-analyte sensing. Despite its importance in performance biosensor, mechanism analyte-response most not well understood. In this work, we employ...

Characterization of DNA at solid/liquid interfaces remains a challenge because most surface-sensitive techniques are unable to provide quantitative insight into the base content, length, or structure. Surface-enhanced Raman scattering measurements hybridization on plasmonic-metal substrates have been used overcome small Raman-scattering cross-sections; however, surface-enhanced spectroscopy not generally due fall-off in signal with decay electric field enhancement from surface, which also...

The heteroduplex hybridization thermodynamics of DNA with either RNA or TNA are greatly affected by pyrimidine content, where increased content leads to significantly duplex stability. Little is known, however, about the effect that purine has on kinetics these duplexes. In this work, single-molecule imaging used measure oligonucleotides having varying complementary DNA, RNA, and sequences. Results suggest change in stability from (corresponding RNA) primarily due changes dissociation rate,...

Optically transparent semiconductors allow simultaneous control of interfacial electrical potential and spectroscopic observation chemistry near the electrode surface. Care must be taken, however, to avoid unwanted photoexcitation-induced charging semiconductor that could influence results. In this work, we investigate in situ surface by photoexcitation well below band gap an optically semiconductor, indium-tin oxide (ITO) electrode. Using total-internal-reflection fluorescence microscopy,...

Abstract Advanced software can be used to enhance risk evaluations with fire and explosion simulations concerning the survivability of offshore drilling structures as well major plant structures. This article focuses on simulated heat loads from fires showing structural responses due thermal radiation fluxes, associated applied mechanical loads, different protection features. Early simulation (fires their actual region impact) allow for effective safety measures incorporated into structure,...