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1.
Small ; 15(43): e1902485, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31468663

RESUMO

Substantial progress has been made in applying nanotubes in biomedical applications such as bioimaging and drug delivery due to their unique architecture, characterized by very large internal surface areas and high aspect ratios. However, the biomedical applications of organic nanotubes, especially for those assembled from sequence-defined molecules, are very uncommon. In this paper, the synthesis of two new peptoid nanotubes (PepTs1 and PepTs2) is reported by using sequence-defined and ligand-tagged peptoids as building blocks. These nanotubes are highly robust due to sharing a similar structure to those of nontagged ones, and offer great potential to hold guest molecules for biomedical applications. The findings indicate that peptoid nanotubes loaded with doxorubicin drugs are promising candidates for targeted tumor cell imaging and chemo-photodynamic therapy.

2.
Angew Chem Int Ed Engl ; 58(35): 12223-12230, 2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31211884

RESUMO

Herein we show that by appending bulky ß-cyclodextrin (CD) groups onto sheet-forming peptoids, we obtain cylindrical micelles that further assembly into membranes and intertwined ribbons on substrates in aqueous solution, depending on the choice of solution and substrate conditions. In situ atomic force microscopy (AFM) shows that micelle assembly occurs in two steps, starting with "precursor" particles that transform into worm-like micelles, which extend and coalesce to form the higher order structures with a rate and a degree of cooperativity dependent on pH and Ca2+ concentration. After co-assembly with hydrophobic 4-(2-hydroxyethylamino)-7-nitro-2,1,3-benzoxadiazole (NBD) donors that occupy the hydrophobic core, followed by exposure to hydrophilic Rhodamine B as acceptors that insert into cyclodextrin, the micelles exhibit highly efficient Förster resonance energy transfer efficiency in aqueous solution, thereby mimicking natural light harvesting systems.

3.
Biopolymers ; 110(4): e23258, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30676654

RESUMO

Due to the branched structure feature and unique properties, a variety of star-shaped polymers have been designed and synthesized. Despite those advances, solid-phase synthesis of star-shaped sequence-defined synthetic polymers that exhibit hierarchical self-assembly remains a significant challenge. Hence, we present an effective strategy for the solid-phase synthesis of three-armed star-shaped peptoids, in which ethylenediamine was used as the centric star pivot. Based on the sequence of monomer addition, a series of AA'A''-type and ABB'-type peptoids were synthesized and characterized by UPLC-MS (ultrahigh performance liquid chromatography-mass spectrometry). By taking advantage of the easy-synthesis and large side-chain diversity, we synthesized star-shaped peptoids with tunable functions. We further demonstrated the aqueous self-assembly of some representative peptoids into biomimetic nanomaterials with well-defined hierarchical structures, such as nanofibers and nanotubes. These results indicate that star-shaped peptoids offer the potential in self-assembly of biomimetic nanomaterials with tunable chemistries and functions.


Assuntos
Peptoides/síntese química , Cromatografia Líquida de Alta Pressão , Etilenodiaminas/química , Espectrometria de Massas , Microscopia de Força Atômica , Nanofibras/química , Nanotubos/química , Peptoides/química , Técnicas de Síntese em Fase Sólida
4.
J Phys Chem Lett ; 10(3): 663-671, 2019 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-30682888

RESUMO

In this work, we successfully prepare two-dimensional ultrathin single-crystalline platinum nanodendrites (PtNDs) with precisely controlled generation (size) through a surfactant-directed solution-phase synthesis. The amphiphilic surfactant of C22H45-N+(CH3)2CH2COOH (Br-) acts as the structure-directing template and facet-capping agent simultaneously to kinetically engineer in-the-plane epitaxial growth of Pt nanocrystals along selectively exposed {111} facets into ultrathin PtNDs. A novel formation mechanism defined as crystalline facet-directed step-by-step in-the-plane epitaxial growth, similar to the synthesis of organic dendrimers, is proposed on the basis of the nanostructure and crystalline evolution of PtNDs. The generation growth process is readily extended to precisely engineer the generation of PtNDs (from 0 to 25) and can also be utilized to grow other noble metal NDs (e.g., PdNDs and AuNDs) and core-shell Pt-Pd NDs. Because of the structural advantages, ultrathin PtNDs exhibit enhanced electrocatalytic performance toward hydrogen evolution reaction.

5.
Small ; 14(52): e1803544, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30565848

RESUMO

The design and synthesis of biocompatible nanomaterials as cargoes for the intracellular delivery of therapeutic proteins or genes have attracted intense attention because of their potential for use in therapeutics. Despite the advances in this area, very few nanomaterials can be efficiently delivered to the cytosol. To address these challenges, crystalline nanoflower-like particles are designed and synthesized from fluorinated sequence-defined peptoids; the crystallinity and fluorination of these particles enable highly efficient cytosolic delivery with minimal cytotoxicity. A cytosol delivery rate of 80% has been achieved for the fluorinated peptoid nanoflowers. Furthermore, these nanocrystals can carry therapeutic genes, such as mRNA and effectively deliver the payload into the cytosol, demonstrating the universal delivery capability of the nanocrystals. The results indicate that self-assembly of crystalline nanomaterials from fluorinated peptoids paves a new way toward development of nanocargoes with efficient cytosolic gene delivery capability.


Assuntos
Citosol/metabolismo , Nanoestruturas/química , Peptoides/química , Halogenação , Humanos
6.
J Am Chem Soc ; 140(43): 14178-14184, 2018 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-30234298

RESUMO

A series of secondary amine-modified cyclodextrin (CD) derivatives was synthesized with diverse exterior terminal groups (i.e., hydroxyl, methyl, methoxyl, and primary amine). Subsequent reaction with nitric oxide (NO) gas under alkaline conditions yielded N-diazeniumdiolate-modified CD derivatives. Adjustable NO payloads (0.6-2.4 µmol/mg) and release half-lives (0.7-4.2 h) were achieved by regulating both the amount of secondary amine precursors and the functional groups around the NO donors. The bactericidal action of these NO-releasing cyclodextrin derivatives was evaluated against Pseudomonas aeruginosa, a Gram-negative pathogen, with antibacterial activity proving dependent on both the NO payload and exterior modification. Materials containing a high density of NO donors or primary amines exhibited the greatest ability to eradicate P. aeruginosa. Of the materials prepared, only the primary amine-terminated heptasubstituted CD derivatives exhibited toxicity against mammalian L929 mouse fibroblast cells. The NO donor-modified CD was also capable of delivering promethazine, a hydrophobic drug, thus demonstrating potential as a dual-drug-releasing therapeutic.


Assuntos
Antibacterianos/farmacologia , Ciclodextrinas/farmacologia , Fibroblastos/efeitos dos fármacos , Óxido Nítrico/química , Pseudomonas aeruginosa/efeitos dos fármacos , Animais , Antibacterianos/síntese química , Antibacterianos/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ciclodextrinas/síntese química , Ciclodextrinas/química , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Testes de Sensibilidade Microbiana , Estrutura Molecular
7.
Nanotechnology ; 29(40): 405602, 2018 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-29998852

RESUMO

TiO2-based nanomaterials are demonstrated to be a promising candidate for next generation lithium ion batteries due to their stable performance and easy preparation. However, their inherent low capacity impedes their wide application compared to commercial carbon nanomaterials. Here we present a unique in situ grafting-graphitization method to achieve a ternary nanocomposite of C/SiO x /TiO2 ultrathin nanobelts with a core-shell heterostructure. The obtained ternary nanocomposite integrates the merits of high specific capacity of SiO x , the excellent mechanical stability of graphite-like carbon and the high reactivity of TiO2. Cyclic voltammetric curves and cycling performance manifest the optimal ternary nanocomposite and deliver a very high initial specific capacity of ∼1196 mA h g-1 with both good rate capability (∼200 mA h g-1 up to 10 C) and especially enhanced cycle stability. Our work demonstrates that building hierarchical core-shell heterostructures is an effective strategy to improve capacity and cycling performance in other composite anodes for electrochemical energy storage materials.

8.
Nanoscale ; 10(26): 12445-12452, 2018 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-29926884

RESUMO

Nanostructured materials present new opportunities to achieve sustainable catalytic reactivity. Fabrication and organization of these catalytic particles for enhanced reactivity remain challenging due to limited synthetic and organization strategies. Biomimetic approaches represent new avenues to address such challenges. Here we report the tunable assembly of sequence-defined peptoids as templates to control the formation of highly reactive Pd nanostructures of different arrangements. In this regard, peptoid 2D membranes and 1D fibers were assembled and used to template Pd nanoparticles in specific orientations. Catalytic analysis of the resulting materials demonstrated enhanced reactivity from the fiber-based system due to changes in inorganic material display. These results suggest that the morphology of peptoid-based templates plays an important role in controlling material properties, which could open a new direction of using peptoid assemblies for applications in optics, plasmonics, sensing, etc.


Assuntos
Materiais Biomiméticos , Nanopartículas/química , Peptoides/química , Catálise
9.
Nat Commun ; 9(1): 270, 2018 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-29348551

RESUMO

Despite recent advances in the assembly of organic nanotubes, conferral of sequence-defined engineering and dynamic response characteristics to the tubules remains a challenge. Here we report a new family of highly designable and dynamic nanotubes assembled from sequence-defined peptoids through a unique "rolling-up and closure of nanosheet" mechanism. During the assembly process, amorphous spherical particles of amphiphilic peptoid oligomers crystallize to form well-defined nanosheets before folding to form single-walled nanotubes. These nanotubes undergo a pH-triggered, reversible contraction-expansion motion. By varying the number of hydrophobic residues of peptoids, we demonstrate tuning of nanotube wall thickness, diameter, and mechanical properties. Atomic force microscopy-based mechanical measurements show peptoid nanotubes are highly stiff (Young's Modulus ~13-17 GPa). We further demonstrate the precise incorporation of functional groups within nanotubes and their applications in water decontamination and cellular adhesion and uptake. These nanotubes provide a robust platform for developing biomimetic materials tailored to specific applications.


Assuntos
Nanotubos/química , Peptoides/química , Dobramento de Proteína , Multimerização Proteica , Células A549 , Cristalografia por Raios X , Humanos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Microscopia de Força Atômica , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Nanotubos/ultraestrutura , Peptidomiméticos/química , Água/química
10.
Nat Commun ; 7: 12252, 2016 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-27402325

RESUMO

An ability to develop sequence-defined synthetic polymers that both mimic lipid amphiphilicity for self-assembly of highly stable membrane-mimetic 2D nanomaterials and exhibit protein-like functionality would revolutionize the development of biomimetic membranes. Here we report the assembly of lipid-like peptoids into highly stable, crystalline, free-standing and self-repairing membrane-mimetic 2D nanomaterials through a facile crystallization process. Both experimental and molecular dynamics simulation results show that peptoids assemble into membranes through an anisotropic formation process. We further demonstrated the use of peptoid membranes as a robust platform to incorporate and pattern functional objects through large side-chain diversity and/or co-crystallization approaches. Similar to lipid membranes, peptoid membranes exhibit changes in thickness upon exposure to external stimuli; they can coat surfaces in single layers and self-repair. We anticipate that this new class of membrane-mimetic 2D nanomaterials will provide a robust matrix for development of biomimetic membranes tailored to specific applications.


Assuntos
Membrana Celular/química , Nanoestruturas/química , Peptoides/química , Materiais Biomiméticos , Cristalização , Lipídeos , Simulação de Dinâmica Molecular
11.
Chem Commun (Camb) ; 51(33): 7234-7, 2015 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-25813408

RESUMO

This work reports the self-assembly of anion-exchangeable vesicles from an amphiphilic hyperbranched polymeric ionic liquid (HBPIL). By a simple one-step anion exchange with methyl orange, the obtained HBPILs could self-assemble into pH-indicative and colorful vesicles in water with color changes directly visible to the naked eye in response to solution pH. In addition, by another step of anion exchange with bovine serum albumin (BSA), the BSA-coated vesicles could also be readily prepared.

12.
Chem Asian J ; 9(8): 2281-8, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24850132

RESUMO

Hyperbranched multiarm copolymers (HMCs) have been shown to hold great potential as precursors in self-assembly, and many impressive supramolecular structures have been prepared through the self-assembly of HMCs in solution. However, theoretical studies on the corresponding self-assembly mechanism have been greatly lagging behind. Herein, we report the self-assembly of normal or reverse vesicles from amphiphilic HMCs by dissipative particle dynamics (DPD) simulation. The simulation disclosed both the self-assembly mechanisms and dynamics of vesicles. It indicates that the self-assembly of HMCs involves several steps, from randomly distributed unimolecular micelles to small spherical micelles, to membrane-like micelles, to finally small vesicles. The membranes are formed through the direct aggregation and lateral fusion of small micelles, and the bending and closing of the membranes give rise to small vesicles. Finally, large and steady vesicles are formed through the fusion of small vesicles. In addition, the bilayer or monolayer molecular packing modes as well as the mircrophase separation behaviors of HMCs in normal or reverse vesicles have also been studied. These simulation results explore details that cannot be observed in the experiments to a certain degree, and have extended the understanding of the vesicular self-assembly process of HMCs.

13.
Chem Commun (Camb) ; 50(46): 6157-60, 2014 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-24777118

RESUMO

Large-scale and robust vesicle aggregates were obtained through molecular recognition among cell-sized polymer vesicles, carbon nanotubes and AuNPs, driven by adhesion interactions between Au and polydopamine. Vesicle fusion was effectively avoided in this three-component vesicle aggregation process.


Assuntos
Ouro/química , Indóis/química , Nanopartículas Metálicas/química , Nanotubos/química , Polímeros/química , Tamanho da Partícula , Propriedades de Superfície
14.
J Am Chem Soc ; 135(12): 4765-70, 2013 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-23464832

RESUMO

Herein, we report a novel Janus particle and supramolecular block copolymer consisting of two chemically distinct hyperbranched polymers, which is coined as Janus hyperbranched polymer. It is constructed by the noncovalent coupling between a hydrophobic hyperbranched poly(3-ethyl-3-oxetanemethanol) with an apex of an azobenzene (AZO) group and a hydrophilic hyperbranched polyglycerol with an apex of a ß-cyclodextrin (CD) group through the specific AZO/CD host-guest interactions. Such an amphiphilic supramolecular polymer resembles a tree together with its root very well in the architecture and can further self-assemble into unilamellar bilayer vesicles with narrow size distribution, which disassembles reversibly under the irradiation of UV light due to the trans-to-cis isomerization of the AZO groups. In addition, the obtained vesicles could further aggregate into colloidal crystal-like close-packed arrays under freeze-drying conditions. The dynamics and mechanism for the self-assembly of vesicles as well as the bilayer structure have been disclosed by a dissipative particle dynamics simulation.

15.
Chem Soc Rev ; 41(18): 5986-97, 2012 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-22797315

RESUMO

Self-assembly of amphiphilic hyperbranched polymers (HBPs) is a newly emerging research area and has attracted increasing attention due to the great advantages in biomedical applications. This tutorial review focuses on the self-assembly of biocompatible or biodegradable amphiphilic HBPs and their cytomimetic applications, and specialities or advantages therein owing to the hyperbranched structure have also been summarized. As shown here, various supramolecular structures including micelles, vesicles, tubes, fibers and films have been prepared through the primary self-assembly processes. The primary self-assemblies can be further assembled into more complex structures through hierachical self-assembly processes. Besides, the hyperbranched polymer vesicles have demonstrated great potential to be used as model membranes to mimic cellular behaviors, such as fusion, fission and cell aggregation. Other biomedical applications of HBPs as well as their self-assemblies are also briefly summarized.


Assuntos
Materiais Biocompatíveis/química , Materiais Biomiméticos/química , Polímeros/química , Tensoativos/química , Animais , Humanos , Micelas , Modelos Moleculares , Nanoestruturas/química , Nanoestruturas/ultraestrutura
16.
Nanotechnology ; 23(32): 325602, 2012 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-22825396

RESUMO

Herein, we report a new and facile method for fabricating TiO(2)@mesoporous carbon hybrid materials. Uniform polydopamine (PDA) layers were coated onto the surface of titanate nanotubes (TNTs) and TiO(2) nanorods (TNDs) through the spontaneous adhesion and self-polymerization of dopamine during the dipping process. Core-shell mesoporous carbon nanotubes with TiO(2) nanorods or nanoparticles encapsulated inside (TiO(2)@MC) were then obtained by transforming PDA layers into carbonaceous ones through calcination in nitrogen at 800 °C. The thickness of the mesoporous carbon layers is tens of nanometers and can be controlled by adjusting the coated PDA layers through the self-polymerization reaction time. In addition, three-layered nanocomposites of TiO(2)@MC@MO (MO, metal oxide) can be readily prepared by utilizing PDA layers in TNTs@PDA or TNDs@PDA to adsorb the metal ions, followed by the calcination process.

17.
Chemistry ; 18(28): 8641-6, 2012 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-22678989

RESUMO

Vesicle-vesicle aggregation to mimic cell-cell aggregation has attracted much attention. Here, hyperbranched polymer vesicles (branched-polymersomes, BPs) with a cell-like size were selected as model membranes, and the vesicle aggregation process, triggered by click chemistry of the copper-catalysed azide-alkyne cycloaddition reaction, was systematically studied. For this purpose, azide and alkynyl groups were loaded on the membranes of BPs through the co-assembly method to obtain N(3)-BPs and Alk-BPs, respectively. Subsequently, macroscopic vesicle aggregates were obtained when these two kinds of functional BPs were mixed together with the ratio of azide to alkynyl groups of about 1:1. Both the vesicle fusion events and lateral phase separation on the vesicle membrane occurred during such a vesicle aggregation process, and the fusion rate and phase-separation degree could be controlled by adjusting the clickable group content. The vesicle aggregation process with N(3) -micelles as desmosome mimics to connect with Alk-BPs through click-chemistry reaction was also studied, and large-scale vesicle aggregates without vesicle fusion were obtained in this process. The present work has extended the controllable cytomimetic vesicle aggregation process with the use of covalent bonds, instead of noncovalent bonds, as the driving force.


Assuntos
Alquinos/química , Azidas/química , Química Click , Cobre/química , Polímeros/química , Catálise , Agregação Celular
18.
Macromol Rapid Commun ; 33(9): 767-72, 2012 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-22415982

RESUMO

A polyhedral oligomeric silsesquioxane (POSS)-based supramolecular amphiphile is prepared from the host-guest inclusion complexation between a mono adamantane-functionalized POSS (AD-POSS) and a ß-cyclodextrin oligomer (P(ß-CD)). Assisted by the interface of H(2)O/toluene, the obtained supramolecular hybrids self-assemble into stable hollow nanospheres with thick walls. These hollow nanospheres aggregate together into a sphere layer through a spin coating technique, which then further transforms into a thin porous film containing nanometer-scale holes. The hollow nanospheres have a low cytotoxicity. The in vitro cell culture indicates the nanoporous films promote adhesion and proliferation of cells. The self-assembly morphologies and structures have been carefully characterized by SEM, TEM, AFM, DLS, XPS and water-contact angle measurements, and the self-assembly mechanism has also been discussed.


Assuntos
Compostos de Organossilício/síntese química , Polímeros/síntese química , Tensoativos/síntese química , Adamantano/química , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Epicloroidrina/química , Membranas Artificiais , Camundongos , Nanosferas/química , Nanosferas/ultraestrutura , Compostos de Organossilício/química , Compostos de Organossilício/farmacologia , Tamanho da Partícula , Polimerização , Polímeros/química , Polímeros/farmacologia , Porosidade , beta-Ciclodextrinas/química
19.
Langmuir ; 28(4): 2066-72, 2012 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-22129210

RESUMO

Herein, we have shown a large-scale cell-mimetic (cytomimetic) aggregation process by using cell-sized polymer vesicles as the building blocks and intervesicular host-guest molecular recognition interactions as the driving force. We first prepared the hyperbranched polymer vesicles named branched polymersomes (BPs) around 5-10 µm through the aqueous self-assembly of a hyperbranched multiarm copolymer of HBPO-star-PEO [HBPO = hyperbranched poly(3-ethyl-3-oxetanemethanol); PEO = poly(ethylene oxide)]. Subsequently, adamantane-functionalized BPs (Ada-BPs) or ß-cyclodextrin-functionalized BPs (CD-BPs) were prepared through the coassembly of HBPO-star-PEO and Ada-modified HBPO-star-PEO (HBPO-star-PEO-Ada), or of HBPO-star-PEO and CD-modified HBPO-star-PEO (HBPO-star-PEO-CD), respectively. Macroscopic vesicle aggregates were obtained by mixing CD-BPs and Ada-BPs. The intervesicular host-guest recognition interactions between ß-CD units in CD-BPs and Ada units in Ada-BPs, which were proved by (1)H nuclear Overhauser effect spectroscopy (NOESY) spectrum and the fluorescence probe method, are responsible for the vesicle aggregation. Additionally, the vesicle fusion events happened frequently in the process of vesicle aggregation, which were certified by double-labeling fluorescent assay, real-time observation, content mixing assay, and component mixing assay.


Assuntos
Biomimética/métodos , Polímeros/química , Adamantano/química , Agregação Celular , beta-Ciclodextrinas/química
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