Controlling the lattice parameters of gold nanoparticle FCC crystals with duplex DNA linkers.
Ontology highlight
ABSTRACT:
SUBMITTER: Hill HD
PROVIDER: S-EPMC8191496 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:A novel bioconjugation strategy leading to ultrastable gold nanoparticles (AuNPs), utilizing DNA linkers and diluents in place of traditional self-assembled monolayers, is reported. The protective capacity of DNA confers straightforward biomolecular attachment and multistep derivatization capabilities to these nanoparticles and, more significantly, substantially enhances their stability in demanding and complex sensing environments. The DNA/AuNPs were assembled through pH-assisted thiol-gold bonding of single stranded DNA and salt aging, with preconjugated biotin moieties facing outward from the gold surface. These nanoparticles remain a stable colloidal suspension under a wide range of buffers and ionic strengths and can endure multiple rounds of lyophilization while retaining high biological activity. Furthermore, the high stability of the DNA/AuNPs allows for multiple reactions and conjugations to be performed within the colloidal suspensions (i.e., Protein A and antibody binding) for tailored and specific recognition to take place. We have demonstrated the applications of the DNA/AuNPs for colorimetric assays and ELISA feasibility; additionally, SPR imaging analysis of a supported membrane microarray shows excellent results with DNA/AuNPs as the enhancing agent. Together, the properties imparted by this interface render the material suitable for clinical and point-of-care applications where stability, throughput, and extended shelf lives are needed.
| S-EPMC6045812 | biostudies-literature
Project description:The crystal phase-based heterostructures of noble metal nanomaterials are of great research interest for various applications, such as plasmonics and catalysis. However, the synthesis of unusual crystal phases of noble metals still remains a great challenge, making the construction of heterophase noble metal nanostructures difficult. Here, we report a one-pot wet-chemical synthesis of well-defined heterophase fcc-2H-fcc gold nanorods (fcc: face-centred cubic; 2H: hexagonal close-packed with stacking sequence of "AB") at mild conditions. Single particle-level experiments and theoretical investigations reveal that the heterophase gold nanorods demonstrate a distinct optical property compared to that of the conventional fcc gold nanorods. Moreover, the heterophase gold nanorods possess superior electrocatalytic activity for the carbon dioxide reduction reaction over their fcc counterparts under ambient conditions. First-principles calculations suggest that the boosted catalytic performance stems from the energetically favourable adsorption of reaction intermediates, endowed by the unique heterophase characteristic of gold nanorods.
| S-EPMC7335101 | biostudies-literature
Project description:Advances in self-assembly over the past decade have demonstrated that nano- and microscale particles can be organized into a large diversity of ordered three-dimensional (3D) lattices. However, the ability to generate different desired lattice types from the same set of particles remains challenging. Here, we show that nanoparticles can be assembled into crystalline and open 3D frameworks by connecting them through designed DNA-based polyhedral frames. The geometrical shapes of the frames, combined with the DNA-assisted binding properties of their vertices, facilitate the well-defined topological connections between particles in accordance with frame geometry. With this strategy, different crystallographic lattices using the same particles can be assembled by introduction of the corresponding DNA polyhedral frames. This approach should facilitate the rational assembly of nanoscale lattices through the design of the unit cell.
| S-EPMC5282967 | biostudies-literature
Project description:Understanding the interaction of molecularly assembled nanoparticles with physiological fluids is critical to their use for in vivo delivery of drugs and contrast agents. Here, we systematically investigated the factors and mechanisms that govern the degradation of DNA on the nanoparticle surface in serum. We discovered that a higher DNA density, shorter oligonucleotides, and thicker PEG layer increased protection of DNA against serum degradation. Oligonucleotides on the surface of nanoparticles were highly resistant to DNase I endonucleases, and degradation was carried out exclusively by protein-mediated exonuclease cleavage and full-strand desorption. These results enabled the programming of the degradation rates of the DNA-assembled nanoparticle system from 0.1 to 0.7 h-1 and the engineering of superstructures that can release two different preloaded dye molecules with distinct kinetics and half-lives ranging from 3.3 to 9.8 h. This study provides a general framework for investigating the serum stability of DNA-containing nanostructures. The results advance our understanding of engineering principles for designing nanoparticle assemblies with controlled in vivo behavior and present a strategy for storage and multistage release of drugs and contrast agents that can facilitate the diagnosis and treatment of cancer and other diseases.
| S-EPMC5137734 | biostudies-literature
Project description:Exciton transport in most organic materials is based on an incoherent hopping process between neighboring molecules. This process is very slow, setting a limit to the performance of organic optoelectronic devices. In this Article, we overcome the incoherent exciton transport by strongly coupling localized singlet excitations in a tetracene crystal to confined light modes in an array of plasmonic nanoparticles. We image the transport of the resulting exciton-polaritons in Fourier space at various distances from the excitation to directly probe their propagation length as a function of the exciton to photon fraction. Exciton-polaritons with an exciton fraction of 50% show a propagation length of 4.4 μm, which is an increase by 2 orders of magnitude compared to the singlet exciton diffusion length. This remarkable increase has been qualitatively confirmed with both finite-difference time-domain simulations and atomistic multiscale molecular dynamics simulations. Furthermore, we observe that the propagation length is modified when the dipole moment of the exciton transition is either parallel or perpendicular to the cavity field, which opens a new avenue for controlling the anisotropy of the exciton flow in organic crystals. The enhanced exciton-polariton transport reported here may contribute to the development of organic devices with lower recombination losses and improved performance.
| S-EPMC9306002 | biostudies-literature
Project description:The self-assembly of DNA-conjugated nanoparticles represents a promising avenue toward the design of engineered hierarchical materials. By using DNA to encode nanoscale interactions, macroscale crystals can be formed with mechanical properties that can, at least in principle, be tuned. Here we present in silico evidence that the mechanical response of these assemblies can indeed be controlled, and that subtle modifications of the linking DNA sequences can change the Young's modulus from 97 kPa to 2.1 MPa. We rely on a detailed molecular model to quantify the energetics of DNA-nanoparticle assembly and demonstrate that the mechanical response is governed by entropic, rather than enthalpic, contributions and that the response of the entire network can be estimated from the elastic properties of an individual nanoparticle. The results here provide a first step toward the mechanical characterization of DNA-nanoparticle assemblies, and suggest the possibility of mechanical metamaterials constructed using DNA.
| S-EPMC5043426 | biostudies-literature
Project description:Gold nanoparticles (gold-NPs) have lately been proposed as alternative contrast agents to iodine-based contrast agents (iodine-CA) for computed tomography (CT) angiography. The aims of this study were to confirm an appropriate environment in which to evaluate such novel contrast agents, to investigate the comparative contrast of iodine-CA versus gold-NP, and to determine optimal scanning parameters for gold-NP.Three different clinical scanners were used to acquire CT images. A range of concentrations (10 mM to 1.5 M) of gold-NP and iodine-CA were scanned with varying x-ray tube voltages and currents, reconstruction kernels, protocols, and scanner models. The different environments investigated were air, water, and water with a bone simulant (Ca3(PO4)2). Regression coefficients were derived from the attenuation values plotted against concentration and compared for statistical significance using t values.As expected, contrast was linearly related to concentrations up to 500 to 1000 mM, depending on the conditions used, whereupon a plateau of 3000 Hounsfield units was reached. Attenuation was significantly different depending on the environment used (air, water, or water and bone simulant). Contrast is dependent on the x-ray tube voltage used, with the contrast produced from iodine-CA sharply declining with increasing voltage, whereas the contrast of gold-NP varied less with tube voltage but was maximal at 120 kV in water with bone simulant. Current, reconstruction kernels, protocols, and scanner model had less effect on contrast.Water with a bone simulant is a preferable environment for evaluating novel cardiac CT contrast agents. Relative iodine-CA versus gold-NP contrast is dependent on the scanning conditions used. Optimal scanning conditions for gold-NP will likely use an x-ray tube voltage of 120 kV.
| S-EPMC3582405 | biostudies-literature
Project description:We report the synthesis of a novel trithiol-capped oligodeoxyribonucleotide and gold nanoparticle conjugates prepared from it. These DNA-gold nanoparticle conjugates exhibit substantially higher stability than analogs prepared from monothiol and cyclic disulfide-capped oligodeoxyribonucleotides, but comparable hybridization properties. A quantitative analysis of their stability under a range of conditions is provided. Significantly, this novel trithiol oligodeoxyribonucleotide can be used to stabilize particles >30 nm in diameter, which are essential for many diagnostic applications.
| S-EPMC101851 | biostudies-literature
Project description:We have determined the minimum number of base pairings necessary to stabilize DNA-Au NP aggregates as a function of salt concentration for particles between 15 and 150 nm in diameter. Significantly, we find that sequences containing a single base pair interaction are capable of effecting hybridization between 150 nm DNA-Au NPs. While traditional DNA hybridization involves two strands interacting in one dimension (1D, Z), we propose that hybridization in the context of an aggregate of polyvalent DNA-Au NP conjugates occurs in three dimensions (many oligonucleotides oriented perpendicular to the X, Y plane engage in base pairing), making nanoparticle assembly possible with three or fewer base pairings per DNA strand. These studies enabled us to compare the stability of duplex DNA free in solution and bound to the nanoparticle surface. We estimate that 4-8, 6-19, or 8-33 additional DNA bases must be added to free duplex DNA to achieve melting temperatures equivalent to hybridized systems formed from 15, 60, or 150 nm DNA-Au NPs, respectively. In addition, we estimate that the equilibrium binding constant (K(eq)) for 15 nm DNA-Au NPs (3 base pairs) is approximately 3 orders of magnitude higher than the K(eq) for the corresponding nanoparticle free system.
| S-EPMC8191498 | biostudies-literature
Project description:Nanoparticle assemblies interconnected with DNA triple helixes can be used to colorimetrically screen for triplex DNA binding molecules and simultaneously determine their relative binding affinities based on melting temperatures. Nanoparticles assemble only when DNA triple helixes form between DNA from two different particles and a third strand of free DNA. In addition, the triple helix structure is unstable at room temperature and only forms in the presence of triplex DNA binding molecules which stabilize the triple helix. The resulting melting transition of the nanoparticle assembly is much sharper and at a significantly higher Tm than the analogous triplex structure without nanoparticles. Upon nanoparticle assembly, a concomitant red-to-blue color change occurs. The assembly process and color change do not occur in the presence of duplex DNA binders and therefore provide a significantly better screening process for triplex DNA binding molecules compared to standard methods.
| S-EPMC3200552 | biostudies-literature