Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 91
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Am Chem Soc ; 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32191463

RESUMO

Biomolecular assembly in biological systems is typically a complex dynamic process regulated by the exchange of molecular information between biomolecules such as proteins and nucleic acids. Here, we demonstrate a nucleic-acid-based system that can program the dynamic assembly process of viral proteins. Tobacco mosaic virus (TMV) genome-mimicking RNA is anchored on DNA origami nanostructures via hybridization with a series of DNA strands which also function as locks that prevent the packaging of RNA by the TMV proteins. The selective, sequential releasing of the RNA via toehold-mediated strand displacement allows us to program the availability of RNA and subsequently the TMV growth in situ. Furthermore, the programmable dynamic assembly of TMV on DNA templates also enables the production of new DNA-protein hybrid nanostructures, which are not attainable by using previous assembly methods.

2.
Small ; : e2001003, 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32162848

RESUMO

Fluorescence in the second near-infrared window (NIR-II, 900-1700 nm) has drawn great interest for bioimaging, owing to its high tissue penetration depth and high spatiotemporal resolution. NIR-II fluorophores with high photoluminescence quantum yield (PLQY) and stability along with high biocompatibility are urgently pursued. In this work, a Ag-rich Ag2 Te quantum dots (QDs) surface with sulfur source is successfully engineered to prepare a larger bandgap of Ag2 S shell to passivate the Ag2 Te core via a facile colloidal route, which greatly enhances the PLQY of Ag2 Te QDs and significantly improves the stability of Ag2 Te QDs. This strategy works well with different sized core Ag2 Te QDs so that the NIR-II PL can be tuned in a wide range. In vivo imaging using the as-prepared Ag2 Te@Ag2 S QDs presents much higher spatial resolution images of organs and vascular structures as compared with the same dose of Ag2 Te nanoprobes administrated, suggesting the success of the core-shell synthetic strategy and the potential biomedical applications of core-shell NIR-II nanoprobes.

3.
Top Curr Chem (Cham) ; 378(2): 33, 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32162028

RESUMO

Self-assembly, which is ubiquitous in living systems, also stimulates countless synthetic molecular self-assembling systems. Most synthetic self-assemblies are realized by passive processes, going from high-energy states to thermodynamic equilibrium. Conversely, living systems work out of equilibrium, meaning they are energy-consuming, dissipative and active. In recently years, chemists have made extensive efforts to design artificial active self-assembly systems, which will be pivotal to emulating and understanding life. Among various strategies, emerging approaches based on DNA nanotechnology have attracted a lot of attention. Structural- as well as dynamic-DNA-nanotechnology offer diverse tools with which to design building blocks and to shape their assembly behaviors. To achieve active self-assembly, a synergy of diverse DNA techniques is essential, including structural design, controllable assembly-disassembly, autonomous assembly, molecular circuits, biochemical oscillators, and so on. In this review, we introduce progress towards, or related to, active assembly via DNA nanotechnology. Dynamic DNA assembly systems ranging from passive assembly-disassembly systems, to autonomous assembly systems to sophisticated artificial metabolism and time-clocking oscillation systems will be discussed. We catalogue these systems from the perspective of free energy change with the reaction process. We end the review with a brief outlook and discussion.

4.
Artigo em Inglês | MEDLINE | ID: mdl-32030871

RESUMO

Activatable theranostic systems show potential for improved tumor diagnosis and therapy owing to high detection specificities, effective ablation, and minimal side-effects. Herein, a tumor microenvironment (TME)-activated NIR-II nanotheranostic system (FEAD1) for precise diagnosis and treatment of peritoneal metastases is presented. FEAD1 was fabricated by self-assembling the peptide Fmoc-His, mercaptopropionic-functionalized Ag2 S quantum dots (MPA-Ag2 S QDs), the chemodrug doxorubicin (DOX), and NIR absorber A1094 into nanoparticles. We show that in healthy tissue, FEAD1 exists in an NIR-II fluorescence "off" state, because of Ag2 S QDs-A1094 interactions, while DOX remains in stealth mode. Upon delivery of FEAD1 to the tumor, the acidic TME triggers its disassembly through breakage of the Fmoc-His metal coordination and DOX hydrophobic interactions. Release of A1094 switches on Ag2 S fluorescence, illuminating the tumor, accompanied by burst release of DOX within the tumor tissue, thereby achieving precise tumor theranostics. This TME-activated theranostic strategy holds great promise for future clinical applications.

5.
Angew Chem Int Ed Engl ; 59(1): 247-252, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31626380

RESUMO

Traumatic brain injury (TBI) is one of the most dangerous acute diseases resulting in high morbidity and mortality. Current methods remain limited with respect to early diagnosis and real-time feedback on the pathological process. Herein, a targeted activatable fluorescent nanoprobe (V&A@Ag2 S) in the second near-infrared window (NIR-II) is presented for in vivo optical imaging of TBI. Initially, the fluorescence of V&A@Ag2 S is turned off owing to energy transfer from Ag2 S to the A1094 chromophore. Upon intravenous injection, V&A@Ag2 S quickly accumulates in the inflamed vascular endothelium of TBI based on VCAM1-mediated endocytosis, after which the nanoprobe achieves rapid recovery of the NIR-II fluorescence of Ag2 S quantum dots (QDs) owing to the bleaching of A1094 by the prodromal biomarker of TBI, peroxynitrite (ONOO- ). The nanoprobe offers high specificity, rapid response, and high sensitivity toward ONOO- , providing a convenient approach for in vivo early real-time assessment of TBI.

6.
Nano Lett ; 20(2): 1154-1160, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31874042

RESUMO

The science of protein self-assembly has experienced significant development, from discrete building blocks of self-assembled nanoarchitectures to advanced nanostructures with adaptive functionalities. Despite the prominent achievements in the field, the desire of designing de novo protein-nanoparticle (NP) complexes and constructing dynamic NP systems remains highly challenging. In previous works, l-rhamnulose-1-phosphate aldolase (C98RhuA) tetramers were self-assembled into two-dimensional (2D) lattices via disulfide bond interactions. These interactions provided 2D lattices with high structural quality and a sophisticated assembly mode. In this study, we devised a rational design for RhuA building blocks to fabricate 2D functionalized protein lattices. More importantly, the lattices were used to direct the precise assembly of NPs into highly ordered and diverse nanoarchitectures. These structures can be employed as an excellent tool to adequately verify the self-assembly mode and structural quality of the designed RhuA crystals. The subsequent redesign of RhuA building blocks enabled us to predictably produce a novel protein lattice whose conformational dynamics can be controllably regulated. Thus, a dynamic system of AuNP lattices was achieved. Transmission electron microscopy and small-angle X-ray scattering indicated the presence of these diverse NP lattices. This contribution enables the fabrication of future NP structures in a more programmable manner with more expected properties for potential applications in nanoelectronics and other fields.

7.
ACS Nano ; 13(12): 13702-13708, 2019 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-31550129

RESUMO

Herein, we report self-assembled reconfigurable plasmonic diastereomers based on DNA nanotechnology. Up to three plasmonic chiral centers were organized by dynamic DNA origami platforms. Meanwhile, each chiral center could be individually controlled to switch between left-handed and right-handed states. Thus, complex and reconfigurable chiral plasmonic diastereomers with eight plasmonic stereoisomers were achieved, driven by programmed DNA reactions. With these plasmonic diastereomers, we demonstrated the existence of strong cross-talk near-field coupling among chiral centers, and the coupling of chiral centers could substantially contribute to the overall CD signals. Our work provides an important bottom-up approach for building complex and dynamic chiral plasmonics and for probing the interactions of plasmonic chiral centers.

8.
Eur J Nucl Med Mol Imaging ; 46(11): 2392-2397, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31338549

RESUMO

PURPOSE: Stem cell transplantation is promising for temporal lobe epilepsy (TLE) treatment. This study aimed to use PET imaging for the investigation of dynamic metabolic changes after transplantation of human neural stem cells (NSCs) and human GABA progenitor cells (GPCs) in a rat model of TLE. METHODS: 18F-FDG PET imaging, video-electroencephalography (EEG), whole-cell patch-clamp recordings and immunostaining were performed after transplantation of NSCs and GPCs. RESULTS: PET imaging demonstrated that glucose metabolism was gradually improved in the NSCs group, but decreased in GPCs and the control. Video-EEG manifested that seizures were suppressed after NSCs or GPCs transplantation; whole-cell patch-clamp confirmed increased inhibitory response of GPC-derived cells; immunostaining studies verified that the transplanted NSCs and GPCs could survive, migrate and differentiate into mature neuronal subtypes. CONCLUSION: 18F-FDG PET imaging could be a distinguishing approach for evaluation of dynamic glycolytic metabolic changes after transplantation of NSCs and GPCs in TLE. Whole-cell patch-clamp provides evidence for functional maturation and integration of transplanted stem cells within host circuits.

9.
Angew Chem Int Ed Engl ; 58(32): 11001-11006, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31162792

RESUMO

Fluorescence-guided cytoreductive surgery is one of the most promising approaches for facile elimination of tumors in situ, thereby improving prognosis. Reported herein is a simple strategy to construct a novel chainlike NIR-II nanoprobe (APP-Ag2 S-RGD) by self-assembly of an amphiphilic peptide (APP) into a nanochain with subsequent chemical crosslinking of NIR-II Ag2 S QDs and the tumor-targeting RGD peptide. This probe exhibits higher capability for cancer cell detection compared with that of RGD-functionalized Ag2 S QDs (Ag2 S-RGD) at the same concentration. Upon intraperitoneal injection, superior tumor-to-normal tissue signal ratio is achieved and non-vascularized tiny tumor metastatic foci as small as about 0.2 mm in diameter could be facilely eliminated under NIR-II fluorescent imaging guidance. These results clearly indicate the potential of this probe for fluorescence-guided tumor staging, preoperative diagnosis, and intraoperative navigation.

10.
Annu Rev Phys Chem ; 70: 275-299, 2019 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-31112458

RESUMO

We present a comprehensive review of recent developments in the field of chiral plasmonics. Significant advances have been made recently in understanding the working principles of chiral plasmonic structures. With advances in micro- and nanofabrication techniques, a variety of chiral plasmonic nanostructures have been experimentally realized; these tailored chiroptical properties vastly outperform those of their molecular counterparts. We focus on chiral plasmonic nanostructures created using bottom-up approaches, which not only allow for rational design and fabrication but most intriguingly in many cases also enable dynamic manipulation and tuning of chiroptical responses. We first discuss plasmon-induced chirality, resulting from the interaction of chiral molecules with plasmonic excitations. Subsequently, we discuss intrinsically chiral colloids, which give rise to optical chirality owing to their chiral shapes. Finally, we discuss plasmonic chirality, achieved by arranging achiral plasmonic particles into handed configurations on static or active templates. Chiral plasmonic nanostructures are very promising candidates for real-life applications owing to their significantly larger optical chirality than natural molecules. In addition, chiral plasmonic nanostructures offer engineerable and dynamic chiroptical responses, which are formidable to achieve in molecular systems. We thus anticipate that the field of chiral plasmonics will attract further widespread attention in applications ranging from enantioselective analysis to chiral sensing, structural determination, and in situ ultrasensitive detection of multiple disease biomarkers, as well as optical monitoring of transmembrane transport and intracellular metabolism.

11.
Adv Mater ; 31(23): e1901485, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30977207

RESUMO

Self-assembly guided by biological molecules is a promising approach for fabricating predesigned nanostructures. Protein is one such biomolecule possessing deterministic 3D crystal structure and peptide information, which acts as a good candidate for templating functional nanoparticles (fNPs). However, inadequate coordination efficacy during the establishment of interfacial interactions with fNPs makes it highly challenging to precisely fabricate designed nanostructures and functional materials. Here, a facile and robust strategy is reported for the hierarchical assembly of fNPs into ordered architectures, with unprecedentedly large sizes up to tens of micrometers, using a hollow cylinder-shaped tobacco mosaic virus coat protein (TMV disk). The rational design of the site-specific functional groups on the TMV disk not only demonstrates the powerful capability of directing various discrete fNP assemblies with high controllability but also assists in precise assembly of a TMV monolayer sheet structure for further organizing homogeneous and heterogeneous fNP periodic lattices by varying the types of fNPs. The high precision and adjustability of the pattern fashions of different fNPs unambiguously corroborate the validity of this innovative strategy, which provides a convenient route to design and assemble protein-based hierarchical ordered architectures for use in nanophotonics and nanodevices.


Assuntos
Proteínas do Capsídeo/química , Nanoestruturas/química , Vírus do Mosaico do Tabaco/química , Proteínas Virais/química , Aminoácidos/química , Sítios de Ligação , Nanopartículas/química , Tamanho da Partícula , Ligação Proteica
12.
Angew Chem Int Ed Engl ; 58(18): 6099-6103, 2019 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-30840347

RESUMO

Tuning the crystal phase of metal alloy nanomaterials has been proved a significant way to alter their catalytic properties based on crystal structure and electronic property. Herein, we successfully developed a simple strategy to controllably synthesize a rare crystal structure of hexagonal close-packed (hcp) NiFe nanoparticle (NP) encapsulated in a N-doped carbon (NC) shell (hcp-NiFe@NC). Then, we systemically investigated the oxygen evolution reaction (OER) performance of the samples under alkaline conditions, in which the hcp-NiFe@NC exhibits superior OER activity compared to the conventional face-centered cubic (fcc) NiFe encapsulated in a N-doped carbon shell (fcc-NiFe@NC). At the current densities of 10 and 100 mA cm-2 , the hcp-NiFe@NC with Fe/Ni ratio of ≈5.4 % only needs ultralow overpotentials of 226 mV and 263 mV versus reversible hydrogen electrode in 1.0 m KOH electrolyte, respectively, which were extremely lower than those of fcc-NiFe@NC and most of other reported NiFe-based electrocatalysts. We proposed that hcp-NiFe possesses favorable electronic property to expedite the reaction on the NC surface, resulting higher catalytic activity for OER. This research provides a new insight to design more efficient electrocatalysts by considering the crystal phase correlated electronic property.

13.
ACS Nano ; 13(3): 3691-3702, 2019 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-30790523

RESUMO

Image-guided photothermal therapy (PTT) is an attractive strategy to improve the diagnosis accuracy and treatment outcomes by monitoring the accumulation of photothermal agents in tumors in real-time and determining the best treatment window. Taking advantage of the superior imaging quality of NIR-II fluorescence imaging and remote-controllable phototherapy modality of PTT, we developed a facile macromolecular fluorophore (PF) by conjugating a small-molecule NIR-II fluorophore (Flav7) with an amphiphilic polypeptide. The PF can form uniform micelles in aqueous solution, which exhibit a slight negative charge. In vitro experimental results showed that the PF nanoparticles showed satisfactory photophysical properties, prominent photothermal conversion efficiency (42.3%), excellent photothermal stability, negligible cytotoxicity, and photothermal toxicity. Meanwhile, the PF can visualize and feature the tumors by NIR-II fluorescence imaging owing to prolonged blood circulation time and enhanced accumulation in tumors. Moreover, in vivo studies revealed that the PF nanoparticles achieved an excellent photothermal ablation effect on tumors with a low dose of NIR-II dye and light irradiation, and the process can be traced by NIR fluorescence imaging.

14.
Small ; 15(10): e1805543, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30706634

RESUMO

Herein, the assembly of 3D uniform gear-like architectures is demonstrated with a tobacco mosaic virus (TMV) disk as a building block. In this context, the intrinsic behavior of the TMV disk that promotes its assembly into nanotubes is altered by a synergistic effect of dual functional modifications at the 53rd arginine mutation and the introduction of lysine groups in the periphery at 1st and 158th positions of the TMV disk, which results in the formation of 3D gear-like superstructures. Therein, the 53rd arginine moiety significantly strengthens the linkage between TMV disks in the alkaline environment through hydrogen bond interactions. The charge of lysine-modified lateral surfaces is partially neutralized in the alkaline solution, which induces the TMV disk to form a gear-like architecture to maintain its structural stability by exploiting the electrostatic repulsion between neighboring TMV disks. This study not only provides explicit evidence regarding the molecular-level understanding of how the modification of site-specific amino acid affects the assembly of resultant superstructures but also encourages the fabrication of functional protein-based nanoarchitectures.

15.
Small ; 15(26): e1804044, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30645016

RESUMO

Nucleic acids and proteins are the two primary building materials of living organisms. Over the past decade, artificial DNA-protein hybrid structures have been pursued for a wide range of applications. DNA nanotechnology, in particular, has dramatically expanded nanoscale molecule engineering and contributed to the spatial arrangement of protein components. Strategies for designing site-specific coupling of DNA oligomers to proteins are needed in order to allow for precise control over stoichiometry and position. Efforts have also been focused on coassembly of protein-DNA complexes by engineering their fundamental molecular recognition interactions. This Concept focuses on the precise manipulation of DNA-protein nanoarchitectures. Particular attention is paid to site-selectivity within DNA-protein conjugates, regulation of protein orientation using DNA scaffolds, and coassembly principles upon unique structural motifs. Current challenges and future directions are also discussed in the design and application of DNA-protein nanoarchitectures.

16.
Adv Mater ; 30(51): e1804437, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30357938

RESUMO

Combined chemotherapy and immunotherapy have demonstrated great potential in cancer treatment. However, it is difficult to provide clear information of the pharmacokinetics and pharmacodynamics of chemodrugs and transplanted immune cells in vivo by traditional approaches, resulting in inadequate therapy. Here, a multiplexed intravital imaging strategy by using fluorescence in the second near-infrared window (NIR-II) is first developed to visualize the two events of chemotherapy and immunotherapy in vivo, so that a combinational administration is programed to improve the therapeutical effects against a mouse model of human breast cancer. In detail, Ag2 Se quantum dots (QDs) (λEm = 1350 nm) loaded with stromal-cell-derived factor-1α (SDF-1α) and chemodrug doxorubicin (DOX) are first administrated to deliver the SDF-1α and DOX to the tumor site. After their arrival, monitored by Ag2 Se QD fluorescence, natural killer (NK)-92 cells labeled with Ag2 S QDs (λEm = 1050 nm) are intravenously injected so that the cells are recruited to the tumor by the chemotaxis of SDF-1α, which is visualized by Ag2 S QD fluorescence. Such an imaging approach allows simultaneous evaluation of the behaviors of individual injections in vivo, and facilitates optimized administration regimens, resulting in enhanced tumor inhibition.


Assuntos
Neoplasias da Mama/terapia , Imunoterapia/métodos , Raios Infravermelhos , Imagem Óptica , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/imunologia , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Humanos , Camundongos
17.
ACS Nano ; 12(10): 9654-9659, 2018 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-30347984

RESUMO

The past decade has witnessed rapid technological development on nanoscale probes and imaging optics in the second near-infrared transparency window (NIR-II, 1000-1700 nm). These methods hold great promise for biomedical applications due to their deep penetration through tissues and high fidelity of images. However, applications of these techniques in biomedical research and translational medicine will require a number of issues to be addressed. In this Perspective, we examine the technical challenges for intravital NIR-II fluorescence imaging technology and discuss where the development of this cutting-edge technique fits in the future.


Assuntos
Pesquisa Biomédica , Corantes Fluorescentes/química , Imagem Óptica , Humanos , Raios Infravermelhos
18.
Small ; 14(40): e1802895, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30260570

RESUMO

Establishing a correlation between the crystal structure and electrocatalytic activity is crucial to the rational design of high performance electrocatalysts. In this work, taking the widely investigated nickel (Ni) based nonprecious oxygen evolution reaction (OER) catalyst as an example, for the first time, it is reported that the crystal structure plays a critical role in determining the OER performance. Similar-sized nickel nanoparticles but in different hexagonal close-packed phase and face-centered cubic phase coated with N-doped carbon shells, noted as hcp-Ni@NC and fcc-Ni@NC, are successfully prepared, respectively, in which the N-coated carbon shell structures were also similar. Surprisingly, a dramatically enhanced OER performance of hcp-Ni@NC in comparison with fcc-Ni@NC is observed. The hcp-Ni@NC only requires 305 mV overpotential to achieve the current density of 10 mA cm-2 , which is 55 mV lower than that of fcc-Ni@NC, which can be ascribed to the influence of nickel crystal phase on the electron structure of N-doped carbon shell. This finding will bring new thinking toward the rational design of high performance non-noble metal electrocatalysts.

19.
Nano Lett ; 18(10): 6563-6569, 2018 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-30182720

RESUMO

Highly permeable and precisely size-selective membranes are the subject of continuous pursuit for energy-efficient separation of fine chemicals. However, challenges remain in the fabrication of an ultrathin selective layer with homogeneous pores, in particular, with the pore sizes in the 1-10 nm range. We report the design of a free-standing porous nanosheet assembled with a single layer of proteins. Tobacco mosaic virus mutant (TMVm), a cylinder-shaped protein containing an inner pore of 4 nm in diameter, was cross-linked via a Cu2+-catalyzed disulfide-bond-forming reaction along the 2D orientation. By such a design, ultralarge single-layer TMVm nanosheets extending over tens of micrometers in width and with well-defined nanopores were successfully developed. A ∼40 nm thick ultrafiltration membrane laminated by the single-layer TMVm nanosheets through simple vacuum filtration accomplished the precise separation of ∼4 nm sized substances. Meanwhile, the membrane exhibited water permeance up to ∼7000 L m-2 h-1 bar-1, which is an order of magnitude improvement compared with traditional ultrafiltration membranes with a similar rejection profile.

20.
ACS Appl Mater Interfaces ; 10(32): 26835-26840, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30073831

RESUMO

Templated by DNA origami, plasmonic gold nanorods (AuNRs) could be assembled into complex nanostructures with strong chiroptical activities. However, it is still not clear how the plasmonic chirality of a complex nanostructure matters with its daughter structural components. Here, we rationally design and fabricate a series of AuNR trimers and their daughter AuNR dimers. Strikingly, we corroborate by circular dichroism spectroscopy that the plasmonic chirality of asymmetrical AuNR trimers is a nearly perfect summation of the chiroptical response of all their constituent dimeric components. Our results provide fundamental insight into the origin of the plasmonic chirality of complex nanostructures.


Assuntos
Nanotubos , DNA , Ouro
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA