A templating approach for monodisperse self-assembled organic nanostructures.
Ontology highlight
ABSTRACT:
SUBMITTER: Bull SR
PROVIDER: S-EPMC2538364 | biostudies-literature | 2008 Mar
REPOSITORIES: biostudies-literature
Publications
A templating approach for monodisperse self-assembled organic nanostructures.
Bull Steve R SR Palmer Liam C LC Fry Nathaniel J NJ Greenfield Megan A MA Messmore Benjamin W BW Meade Thomas J TJ Stupp Samuel I SI
Journal of the American Chemical Society 20080212 9
The precise structural control is known for self-assembly into closed spherical structures (e.g., micelles), but similar control of open structures is much more challenging. Inspired by natural tobacco mosaic virus, we present the use of a rigid-rod template to control the size of a one-dimensional self-assembly. We believe that this strategy is novel for organic self-assembly and should provide a general approach to controlling size and dimension. ...[more]
Similar Datasets
Project description:The high optical and chemical activity of nanoparticles (NPs) signifies the possibility of converting the spin angular momenta of photons into structural changes in matter. Here, we demonstrate that illumination of dispersions of racemic CdTe NPs with right- (left-)handed circularly polarized light (CPL) induces the formation of right- (left-)handed twisted nanoribbons with an enantiomeric excess exceeding 30%, which is ?10 times higher than that of typical CPL-induced reactions. Linearly polarized light or dark conditions led instead to straight nanoribbons. CPL 'templating' of NP assemblies is based on the enantio-selective photoactivation of chiral NPs and clusters, followed by their photooxidation and self-assembly into nanoribbons with specific helicity as a result of chirality-sensitive interactions between the NPs. The ability of NPs to retain the polarization information of incident photons should open pathways for the synthesis of chiral photonic materials and allow a better understanding of the origins of biomolecular homochirality.
| S-EPMC4387888 | biostudies-literature
Project description:Zinc telluride (ZnTe) quantum dots (QDs) were synthesized by a unique supersaturation-controlled aqueous route. For a given pH, increasing the degree of initial supersaturation led to a decrease in the average diameter (d avg) of the QDs and increased monodispersity. Three samples of ZnTe QDs having average sizes of 0.8, 1.7, and 2.2 nm were synthesized (hence named ZnTe_0.8, ZnTe_1.7, and ZnTe_2.2). Nonlinear absorption (NLA) and nonlinear refraction (NLR) of these colloidal ZnTe QDs of different sizes were investigated by the Z-scan technique using a continuous He-Ne laser (632.8 nm, 15 mW). Isotropic assembly of ZnTe_2.2 leads to the formation of nanoballs (hence named ZnTe_NB). The NLA profile of smaller QDs, ZnTe_1.7 and ZnTe_0.8, was found to follow a three-photon absorption (3PA) model, while relatively bigger QDs, ZnTe_2.2, followed a two-photon absorption (2PA) model. On moving from ZnTe_0.8 to ZnTe_1.7, the three-photon absorption coefficient (γ) decreases by 26% (3.00 × 10-4 → 2.21 × 10-4 cm3/MW2). The two-photon absorption coefficient (β) for ZnTe_2.2 is 0.3 cm/MW. For a 63% decrease in average diameter (2.2 → 0.8 nm), the refractive index (n 2) increases by 45% (2.48 × 10-2 → 3.6 × 10-2 cm2/MW). Overall, the NLR coefficient shows a decreasing trend with size. Upon isotropic self-assembly, ZnTe_NB, there is a significant increase in the NLR coefficient by 40% (2.48 × 10-2 → 3.48 × 10-2 cm2/MW) and a simultaneous decrease in the NLA coefficient by 45% (0.3 → 0.166 cm/MW). The figure of merit was also determined for all of the samples, and it was found that ZnTe_2.2 and ZnTe_0.8 were best suited for all-optical device applications. Further, the self-assembled nanostructures are promising for making optical waveguides for supercontinuum generation (SCG).
| S-EPMC8613852 | biostudies-literature
Project description:Porous vaterite crystals of CaCO? are extensively used for the fabrication of self-assembled polymer-based microparticles (capsules, beads, etc.) utilized for drug delivery and controlled release. The nature of the polymer used plays a crucial role and discovery of new perspective biopolymers is essential to assemble microparticles with desired characteristics, such as biocompatibility, drug loading efficiency/capacity, release rate, and stability. Glycoprotein mucin is tested here as a good candidate to assemble the microparticles because of high charge due to sialic acids, mucoadhesive properties, and a tendency to self-assemble, forming gels. Mucin loading into the crystals via co-synthesis is twice as effective as via adsorption into preformed crystals. Desialylated mucin has weaker binding to the crystals most probably due to electrostatic interactions between sialic acids and calcium ions on the crystal surface. Improved loading of low-molecular-weight inhibitor aprotinin into the mucin-containing crystals is demonstrated. Multilayer capsules (mucin/protamine)? have been made by the layer-by-layer self-assembly. Interestingly, the deposition of single mucin layers (mucin/water)? has also been proven, however, the capsules were unstable, most probably due to additional (to hydrogen bonding) electrostatic interactions in the case of the two polymers used. Finally, approaches to load biologically-active compounds (BACs) into the mucin-containing microparticles are discussed.
| S-EPMC6187553 | biostudies-literature
Project description:The multivalent presentation of glycans leads to enhanced binding avidity to lectins due to the cluster glycoside effect. Most materials used as scaffolds for multivalent glycan arrays, such as polymers or nanoparticles, have intrinsic dispersity: meaning that in any sample, a range of valencies are presented and it is not possible to determine which fraction(s) are responsible for binding. The intrinsic dispersity of many multivalent glycan scaffolds also limits their reproducibility and predictability. Here we make use of the structurally programmable nature of self-assembled metal coordination cages, with polyhedral metal-ion cores supporting ligand arrays of predictable sizes, to assemble a 16-membered library of perfectly monodisperse glycoclusters displaying valencies from 2 to 24 through a careful choice of ligand/metal combinations. Mono- and trisaccharides are introduced into these clusters, showing that the synthetic route is tolerant of biologically relevant glycans, including sialic acids. The cluster series demonstrates increased binding to a range of lectins as the number of glycans increases. This strategy offers an alternative to current glycomaterials for control of the valency of three-dimensional (3-D) glycan arrays, and may find application across sensing, imaging, and basic biology.
| S-EPMC10401570 | biostudies-literature
Project description:Chemically self-assembled antibody nanorings (CSANs) displaying multiple copies of single-chain variable fragments can be prepared from dihydrofolate reductase (DHFR) fusion proteins and bis-methotrexate (bisMTX). We have designed and synthesized a bisMTX chemical dimerizer (bisMTX-NH(2)) that contains a third linker arm that can be conjugated to fluorophores, radiolabels, and drugs. Monovalent, divalent, and higher-order AntiCD3 CSANs were assembled with a fluorescein isothiocyanate (FITC)-labeled bis-methotrexate ligand (bisMTX-FITC) and found to undergo rapid internalization and trafficking by HPB-MLT, a CD3+ T-leukemia cell line, to the early and late endosome and lysosome. Because the fluorescence of bisMTX-FITC when incorporated into CSANs was found to be significantly greater than that of the free ligand, the stability of the endocytosed AntiCD3 CSANs could be monitored. The internalized CSANs were found to be stable for several hours, while treatment with the nontoxic DHFR inhibitor trimethoprim resulted in a rapid loss (>80%) of cellular fluorescence within minutes, consistent with efficient intracellular disassembly of the nanorings. Over longer time periods (24 h), cellular fluorescence decreased by 75-90%, regardless of whether cells had been treated with DMSO or trimethoprim. Although bisMTX is a potent inhibitor of DHFR, it was found to be nontoxic (GI(50) > 20 ?M) to HPB-MLT cells. In contrast, AntiCD3 CSANs prepared with bisMTX were found to be at least 13-fold more cytotoxic (GI(50) = 0.5-1.5 ?M) than bisMTX at 72 h. Consistent with our findings from CSAN stability studies, no increase in cytotoxicity was observed upon treatment with trimethoprim. Taken together, our results suggest that cell receptor targeting CSANs prepared with trifunctional bisMTX could be used as potential tissue selective drug carriers.
| S-EPMC3549309 | biostudies-literature
Project description:A facile ferroelectric nanostructures preparation method is developed based on the self-assembly of poly(2-vinylpyridine)-b-poly(vinylidene fluoride-co-trifluoroethylene)-b-poly(2-vinylpyridine) triblock copolymers (P2VP-b-P(VDF-TrFE)-b-P2VP), and the effect of morphological characteristics of the block copolymers on the ferroelectric response has been investigated for the first time. By simple adjustment of the ratio between the blocks, lamellar, cylindrical, and spherical morphologies are obtained in the melt and preserved upon crystallization of P(VDF-TrFE). However, at high P(VDF-TrFE) content, crystallization becomes dominant and drives the self-assembly of block copolymers. The crystallization study of the block copolymers reveals the preservation of the high degree of crystallinity inside the confined nanodomains as well as the reduction of the crystalline size and the Curie transition temperature with the confinement level. Only a small difference in the coercive field and the shape of the hysteresis loop is observed for block copolymers with a lamellar morphology produced either by crystallization-driven self-assembly or by confinement inside preformed lamellar domains. In contrast, delayed spontaneous polarization or the absence of dipole switching is demonstrated for the confinement of ferroelectric crystals inside both isolated cylindrical and spherical domains, exemplifying the influence of dimensionality on the critical size for ferroelectric order.
| S-EPMC6328973 | biostudies-literature
Project description:A number of cyclic peptides including [FR]4, [FK]4, [WR]4, [CR]4, [AK]4, and [WK]n (n = 3-5) containing L-amino acids were produced using solid-phase peptide synthesis. We hypothesized that an optimal balance of hydrophobicity and charge could generate self-assembled nanostructures in aqueous solution by intramolecular and/or intermolecular interactions. Among all the designed peptides, [WR]n (n = 3-5) generated self-assembled vesicle-like nanostructures at room temperature as shown by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and/or dynamic light scattering (DLS). This class of peptides represents the first report of surfactant-like cyclic peptides that self-assemble into nanostructures. A plausible mechanistic insight into the self-assembly of [WR]5 was obtained by molecular modeling studies. Modified [WR]5 analogues, such as [WMeR]5, [WR(Me)2]5, [WMeR(Me)2]5, and [WdR]5, exhibited different morphologies to [WR]5 as shown by TEM observations. [WR]5 exhibited a significant stabilizing effect for generated silver nanoparticles and glyceraldehyde-3-phosphate dehydrogenase activity. These studies established a new class of surfactant-like cyclic peptides that self-assembled into nanostructures and could have potential applications for the stabilization of silver nanoparticles and protein biomolecules.
| S-EPMC3811951 | biostudies-literature
Project description:Synthetic nucleic acids have shown great potential in the treatment of various diseases. Nevertheless, the selective delivery to a target tissue has proved challenging. The coupling of nucleic acids to targeting peptides, proteins, and antibodies has been explored as an approach for their selective tissue delivery. Nevertheless, the preparation of covalently coupled peptides and proteins that can also undergo intracellular release as well as deliver more than one copy of the nucleic acid has proved challenging. Recently, we have developed a novel method for the rapid noncovalent conjugation of nucleic acids to targeting single chain antibodies (scFv) using chemically self-assembled nanostructures (CSANs). CSANs have been prepared by the self-assembly of two dihydrofolate reductase molecules (DHFR(2)) and a targeting scFv in the presence of bis-methotrexate (bis-MTX). The valency of the nanorings can be tuned from one to eight subunits, depending on the length and composition of the linker between the dihydrofolate reductase molecules. To explore their potential for the therapeutic delivery of nucleic acids as well as the ability to expand the capabilities of CSANs by incorporating smaller cyclic targeting peptides, we prepared DHFR(2) proteins fused through a flexible peptide linker to cyclic-RGD, which targets ?v?3 integrins, and a bis-MTX chemical dimerizer linked to an antisense oligonucleotide (bis-MTX-ASO) that has been shown to silence expression of eukaryotic translation initiation factor 4E (eIF4E). Monomeric and multimeric cRGD-CSANs were then prepared with bis-MTX-ASO and shown to undergo endocytosis in the breast cancer cell line, MDA-MB-231, which overexpresses ?v?3. The bis-MTX-ASO was shown to undergo endosomal escape resulting in the knock down of eIF4E with at least the same efficiency as ASO delivered by oligofectamine. The modularity, flexibility, and common method of conjugation may prove to be a useful general approach for the targeted delivery of ASOs, as well as other nucleic acids to cells.
| S-EPMC5568898 | biostudies-literature
Project description:Natural polymers are able to self-assemble into versatile nanostructures based on the information encoded into their primary structure. The structural richness of biopolymer-based nanostructures depends on the information content of building blocks and the available biological machinery to assemble and decode polymers with a defined sequence. Natural polypeptides comprise 20 amino acids with very different properties in comparison to only 4 structurally similar nucleotides, building elements of nucleic acids. Nevertheless the ease of synthesizing polynucleotides with selected sequence and the ability to encode the nanostructural assembly based on the two specific nucleotide pairs underlay the development of techniques to self-assemble almost any selected three-dimensional nanostructure from polynucleotides. Despite more complex design rules, peptides were successfully used to assemble symmetric nanostructures, such as fibrils and spheres. While earlier designed protein-based nanostructures used linked natural oligomerizing domains, recent design of new oligomerizing interaction surfaces and introduction of the platform for topologically designed protein fold may enable polypeptide-based design to follow the track of DNA nanostructures. The advantages of protein-based nanostructures, such as the functional versatility and cost effective and sustainable production methods provide strong incentive for further development in this direction.
| S-EPMC3938474 | biostudies-literature
Project description:Aqueous sodium-ion battery of low cost, inherent safety, and environmental benignity holds substantial promise for new-generation energy storage applications. However, the narrow potential window of water and the enlarged ionic radius because of hydration restrict the selection of electrode materials used in the aqueous electrolyte. Here, inspired by the efficient redox reaction of biomolecules during cellular energy metabolism, a proof of concept is proposed that the redox-active biomolecule alizarin can act as a novel electrode material for the aqueous sodium-ion battery. It is demonstrated that the specific capacity of the self-assembled alizarin nanowires can reach as high as 233.1 mA h g-1, surpassing the majority of anodes ever utilized in the aqueous sodium-ion batteries. Paired with biocompatible and biodegradable polypyrrole, this full battery system shows excellent sodium storage ability and flexibility, indicating its potential applications in wearable electronics and biointegrated devices. It is also shown that the electrochemical properties of electrodes can be tailored by manipulating naturally occurring 9,10-anthroquinones with various substituent groups, which broadens application prospect of biomolecules in aqueous sodium-ion batteries.
| S-EPMC5867053 | biostudies-literature