We report the first in situ quantitative visualization and characterization of electro-induced chitosan hydrogel growth an aqueous environment. This was enabled with a pair sidewall electrodes within transparent fluidic system, which allowed us to resolve electrogelling mechanism interpret dominant causes responsible for formation density distribution deposited hydrogel. The pH time-dependent profiles were directly visualized, analyzed, characterized. results indicate that gelation...

Abstract DNA demonstrates a remarkable capacity for creating designer nanostructures and devices. A growing number of these structures utilize Förster resonance energy transfer (FRET) as part the device's functionality, readout or characterization, and, device sophistication increases so do concomitant FRET requirements. Here we create multi-dye cascades assess how well can marshal organic dyes into nanoantennae that focus excitonic energy. We evaluate 36 increasingly complex designs...

The unique properties provided by hybrid semiconductor quantum dot (QD) bioconjugates continue to stimulate interest for many applications ranging from biosensing energy harvesting. Understanding both the structure and function of these composite materials is an important component in their development. Here, we compare architecture that results using two common self-assembly chemistries attach DNA QDs. modified display either a terminal biotin or oligohistidine peptidyl sequence was...

We examine the effect of electronic coupling on optical properties Cy3 dimers attached to DNA duplexes as a function base pair (bp) separation using steady-state and time-resolved spectroscopy. For close Cy3-Cy3 separations, 0 1 bp between dyes, intermediate strong is revealed by modulation absorption fluorescence including spectral band shape, peak wavelength, excited-state lifetime. Using vibronic exciton model, we estimate strengths 150 266 cm-1 for respectively, which are comparable...

Because of their ease design and assembly, DNA scaffolds provide a valuable means for organizing fluorophores into complex light harvesting antennae. However, as the size complexity DNA–fluorophore network grows, it can be difficult to fully understand energy transfer properties because large number dipolar interactions between fluorophores. Here, we investigate simple networks that represent elements more insight Förster Resonance Energy Transfer (FRET) processes in presence multiple...

Photonic wires were constructed by sequentially arranging up to 7 fluorophores along a concatenated DNA scaffold. This yielded nanostructures displaying from one- six-energy transfer steps where end-to-end efficiency reflected the multiple underlying photophysical processes and ability of long-range interactions compensate for localized non-ideal dye behaviour.

Assembling DNA-based photonic wires around semiconductor quantum dots (QDs) creates optically active hybrid architectures that exploit the unique properties of both components. DNA hybridization allows positioning multiple, carefully arranged fluorophores can engage in sequential energy transfer steps while QDs provide a superior harvesting antenna capacity drives Förster resonance (FRET) cascade through structures. Although first generation these composites demonstrated four-sequential...

The growing maturity of DNA-based architectures has raised considerable interest in applying them to create photoactive light harvesting and sensing devices. Toward optimizing efficiency such structures, resonant energy transfer was systematically examined a series dye-labeled DNA duplexes where donor-acceptor separation incrementally changed from 0 16 base pairs. Cyanine dyes were localized on the using double phosphoramidite attachment chemistry. Steady state spectroscopy, single-pair...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTChemoenzymatic Sensitization of DNA Photonic Wires Mediated through Quantum Dot Energy Transfer RelaysChris L. Dwyer†, Sebastián A. Díaz‡, Scott Walper‡, Anirban Samanta‡, Kimihiro Susumu§, Eunkeu Oh§, Susan Buckhout-White‡, and Igor Medintz*‡View Author Information† Department Electrical Computer Engineering, Duke University, Durham, North Carolina 27708, United States‡ ‡Center for Bio/Molecular Science Code 6900 §Optical Sciences Division,...

Abstract DNA‐based photonic wires that exploit Förster resonance energy transfer (FRET) between pendant fluorophores to direct and focus excitonic have high research interest due their potential applications in light harvesting, biocomputing, biosensing. One important goal with these structures is increase ability harvest then it over multiple steps both across extended portions of the spectra physical space. Toward goals, incorporating homogeneous or homoFRET sections into three unique FRET...

Molecular photonic wires (MPWs) precisely position dyes using structural DNA methodologies where they exploit Förster resonance energy transfer (FRET) to direct over nm distances with potential applications in light harvesting, biosensing, and molecular electronics. Although versatile, the number of donor–acceptor dye pairs available downhill nature FRET combine limit size efficiency current MPWs. HomoFRET between identical should provide zero loss but at cost random directionality. Here, it...

Semiconductor nanocrystals or quantum dots (QDs) should act as excellent Förster resonance energy transfer (FRET) acceptors due to their large absorption cross section, tunable emission, and high yields. Engaging this type of FRET can be complicated direct excitation the QD acceptor along with its longer excited-state lifetime. Many cases QDs acting are within time-gated from long-lifetime lanthanides, which allow decay before observing FRET. Efficient sensitization requires lanthanide in...

Structural DNA nanotechnology has developed profoundly in the last several years allowing for creation of increasingly sophisticated devices capable discrete sensing, locomotion, and molecular logic. The latter research field is particularly attractive as it provides information processing capabilities that may eventually be applied situ, example cells, with potential even further coupling to an active response such drug delivery. Rather than design a new assembly each intended logic...

DNA nanostructures provide a reliable and predictable scaffold for precisely positioning fluorescent dyes to form energy transfer cascades. Furthermore, these structures their attendant dye networks can be dynamically manipulated by biochemical inputs, with the changes reflected in spectral response. However, complexity of that have undergone such types manipulation direct biosensing applications is quite limited. Here, we investigate four different modification strategies effect dynamic...

DNA-scaffolded molecular photonic wires (MPWs) displaying prearranged donor–acceptor chromophore pairs that engage in extended Förster resonance energy transfer (FRET) cascades represent an emerging nanoscale material with numerous potential applications data storage, encryption, and communications. For translation to such applications, these devices must first demonstrate robust performance high efficiencies over distances. Here, we report the optimization of FRET a 6-helix DNA origami...

Designer DNA structures have garnered much interest as a way of assembling novel nanoscale architectures with exquisite control over the positioning discrete molecules or nanoparticles. Exploiting this potential for variety applications such light-harvesting, molecular electronics, biosensing is contingent on degree to which various nanoarchitectures desired functionalizations can be realized, and depends critically characterization. Many techniques exist analyzing DNA-organized...

DNA scaffolds offer advantages for biomolecular devices capable of generating and controlling energy flow. Through attachment the bioluminescent protein luciferase precise positioning organic fluorophores, these structures form efficient self‐illuminating transfer cascades. Luciferase initiates a resonance step, which is then propagated by Förster (FRET) through rest structure. Two related dendrimeric nanostructures are investigated; first funnels inward toward center, while second radiates...

Nanoparticle (NP) display potentially offers a new way to both stabilize and, in many cases, enhance enzyme activity over that seen for native protein solution. However, the large, globular and sometimes multimeric nature of enzymes limits their ability attach directly surface NPs, especially when latter are colloidally stabilized with bulky PEGylated ligands. Engineering extended linkers into achieve direct attachment through PEG often detrimentally alters catalytic ability. Here, we...

Dynamic rearrangement of DNA nanostructures provides a straightforward yet powerful mechanism for sequence-specific sensing and potential signaling such interactions.

Abstract DNA can process information through sequence‐based reorganization but cannot typically receive input from most biological processes and translate that into compatible language. Coupling to a substrate responsive events address this limitation. A two‐component sensor incorporating chimeric peptide‐DNA is evaluated here as protease‐to‐DNA signal convertor which transduces protease activity gates discriminate between different proteases. Acceptor dye‐labeled peptide‐DNAs are assembled...

DNA nanostructures have been shown viable for the creation of complex logic-enabled sensing motifs. To date, most these types devices limited to interaction with strictly DNA-type inputs. Restriction endonuclease represents a class enzyme endogenous specificity DNA, and we hypothesize that can be integrated structure use as inputs trigger structural transformation rearrangement. In this work, reconfigured three-arm switch, which utilizes cyclic Förster resonance energy transfer between three...

The polysaccharide chitosan is a versatile scaffold for assembly and conjugation of biomolecules, including nucleic acids, proteins, viruses. It provides unique value in bioMEMS that it can be electrodeposited on demand at specific locations closed microfluidic systems, enabling spatial temporal programmability biomolecular binding reaction sites bio-microfluidic networks. In anticipating the scaling such systems to smaller dimensions, we have investigated resolution which electrodeposition...

We demonstrate a method for imaging unstained DNA nanostructures with transmission electron microscopy via suspended graphene supports. Central to the technique is sacrificial silicon membrane beneath that provides mechanical support during aqueous sample deposition but then eliminated in final step using XeF2 dry etch.

Surface-enhanced Raman scattering (SERS) has grown dramatically as an analytical tool for the sensitive and selective detection of molecules adsorbed on nano-roughened noble metal structures. Quantification with SERS based signal intensity remains challenging due to complicated fabrication process obtain well-dispersed nanoparticles well-ordered substrates. We report a new biofabrication strategy substrates that enable quantification through newly discovered spectroscopic shift resulting...

Light harvesting quantum dot-dye-labeled DNA dendrimer structures are assembled yielding end-to-end energy transfer efficiencies approaching 25% over 4 FRET steps.