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1.
Angew Chem Int Ed Engl ; 57(32): 10142-10147, 2018 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-29873167

RESUMO

Vesicles exchange their contents through membrane fusion processes, kiss-and-run and full-collapse fusion. Indirect observation of these fusion processes using artificial vesicles enhanced our understanding on the molecular mechanisms involved. Direct observation of the fusion processes in a real biological system, however, remains a challenge owing to many technical obstacles. We report a ratiometric two-photon probe offering real-time tracking of lysosomal ATP with quantitative information for the first time. By applying the probe to two-photon live-cell imaging, the lysosomal membrane fusion process in cells has been directly observed and the concentration of its content, lysosomal ATP, has been measured. Results show that the kiss-and-run process between lysosomes proceeds through repeated transient interactions with gradual content mixing, whereas the full-fusion process occurs at once. Furthermore, it is confirmed that both the fusion processes proceed with conservation of the content. Such a small-molecule probe exerts minimal disturbance and hence has potential for studying various biological processes associated with lysosomal ATP.


Assuntos
Trifosfato de Adenosina/análise , Corantes Fluorescentes/química , Membranas Intracelulares/química , Lisossomos/química , Fótons , Trifosfato de Adenosina/metabolismo , Células HeLa , Humanos , Membranas Intracelulares/metabolismo , Lisossomos/metabolismo , Estrutura Molecular , Imagem Óptica
2.
Sci Rep ; 6: 27142, 2016 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-27283889

RESUMO

Multiphoton microscopy (MPM) is a nonlinear fluorescence microscopic technique widely used for cellular imaging of thick tissues and live animals in biological studies. However, MPM application to human tissues is limited by weak endogenous fluorescence in tissue and cytotoxicity of exogenous probes. Herein, we describe the applications of moxifloxacin, an FDA-approved antibiotic, as a cell-labeling agent for MPM. Moxifloxacin has bright intrinsic multiphoton fluorescence, good tissue penetration and high intracellular concentration. MPM with moxifloxacin was demonstrated in various cell lines, and animal tissues of cornea, skin, small intestine and bladder. Clinical application is promising since imaging based on moxifloxacin labeling could be 10 times faster than imaging based on endogenous fluorescence.


Assuntos
Meios de Contraste/metabolismo , Fluoroquinolonas/metabolismo , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Animais , Córnea/metabolismo , Células HT29 , Humanos , Intestino Delgado/metabolismo , Camundongos , Moxifloxacina , Células NIH 3T3 , Pele/metabolismo , Distribuição Tecidual , Bexiga Urinária/metabolismo
3.
Chem Commun (Camb) ; 52(53): 8287-90, 2016 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-27292365

RESUMO

'Smart' gold nanoparticles can respond to mild acidic environments, rapidly form aggregates, and shift the absorption to red and near-infrared. They were used as a photoacoustic imaging agent responsive to the cancer microenvironment, and have demonstrated the cancer-specific accumulation at the cellular level and an amplified signal which is twice higher than the control in vivo.


Assuntos
Meios de Contraste/química , Ouro/química , Nanopartículas Metálicas/química , Neoplasias/diagnóstico , Técnicas Fotoacústicas/métodos , Microambiente Tumoral , Animais , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Células NIH 3T3 , Neoplasias/metabolismo
4.
ACS Nano ; 9(10): 9678-90, 2015 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-26348606

RESUMO

Gold nanoparticles (AuNPs) have been extensively studied for photothermal cancer therapy because AuNPs can generate heat upon near-infrared irradiation. However, improving their tumor-targeting efficiency and optimizing the nanoparticle size for maximizing the photothermal effect remain challenging. We demonstrate that mesenchymal stem cells (MSCs) can aggregate pH-sensitive gold nanoparticles (PSAuNPs) in mildly acidic endosomes, target tumors, and be used for photothermal therapy. These aggregated structures had a higher cellular retention in comparison to pH-insensitive, control AuNPs (cAuNPs), which is important for the cell-based delivery process. PSAuNP-laden MSCs (MSC-PSAuNPs) injected intravenously to tumor-bearing mice show a 37-fold higher tumor-targeting efficiency (5.6% of the injected dose) and 8.3 °C higher heat generation compared to injections of cAuNPs after irradiation, which results in a significantly enhanced anticancer effect.


Assuntos
Agregação Celular , Sistemas de Liberação de Medicamentos , Ouro/uso terapêutico , Células-Tronco Mesenquimais/citologia , Nanopartículas Metálicas/uso terapêutico , Neoplasias/terapia , Animais , Feminino , Ouro/administração & dosagem , Ouro/farmacocinética , Hipertermia Induzida/métodos , Nanopartículas Metálicas/administração & dosagem , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Fototerapia/métodos
5.
Nanoscale ; 7(21): 9433-7, 2015 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-25959856

RESUMO

A DNA hydrogel is reported as a delivery vehicle for gold nanorods and doxorubicin. The two photothermal and chemo cancer agents were co-loaded using electrostatic and DNA binding interactions, respectively. Light-triggered and highly synergistic combination cancer therapy was demonstrated in cellular and animal models.


Assuntos
DNA/química , Portadores de Fármacos/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/administração & dosagem , Linhagem Celular Tumoral , Doxorrubicina/administração & dosagem , Ouro/química , Humanos , Luz , Camundongos , Nanotubos/química , Nanotubos/ultraestrutura , Eletricidade Estática
6.
J Mater Chem B ; 3(8): 1537-1543, 2015 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32262426

RESUMO

Assembled AuNPs in a DNA hydrogel (Dgel) showed strongly coupled plasmon modes, and the Dgel vehicle can co-load anticancer drugs such as doxorubicin (Dox) as a light-controlled releasing cargo by DNA intercalations. Upon laser excitation, local heat shock generation was accompanied by the release of Dox. A highly synergistic combination of thermo- and chemotherapy was demonstrated in cellular and animal models. Our Dgel vehicle can be fragmented after the excitation-induced heat generations, which subsequently causes the dispersion of the AuNPs. Our system may be less toxic because it uses small sizes of AuNPs, and the inherently biocompatible scaffold may reduce the long-term toxicity by rapid clearance.

7.
Nanomedicine (Lond) ; 9(13): 2003-22, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25343350

RESUMO

Gold nanoparticles (AuNPs) are attractive photothermal agents for cancer therapy because they show efficient local heating upon excitation of surface plasmon oscillations. The strong absorption, efficient heat conversion, high photostability, inherent low toxicity and well-defined surface chemistry of AuNPs contribute to the growing interest in their photothermal therapy (PTT) applications. The facile tunability of gold nanostructures enables engineering of AuNPs for superior near-infrared photothermal efficacy and target selectivity, which guarantee efficient and deep tissue-penetrating PTT with mitigated concerns regarding side effects by nonspecific distributions. This article discusses the current research findings with representative near-infrared-active AuNPs, which include nanoshell, nanorod, nanocage, nanostar, nanopopcorn and nanoparticle assembly systems. AuNPs successfully demonstrate potential for use in PTT, but several hurdles to clinical applications remain, including long-term toxicity and a need for sophisticated control over biodistribution and clearance. Future research directions are discussed, especially regarding the clinical translation of AuNP photosensitizers.


Assuntos
Ouro/uso terapêutico , Nanopartículas Metálicas/uso terapêutico , Neoplasias/terapia , Fototerapia , Humanos , Nanoconchas/uso terapêutico , Neoplasias/patologia , Fármacos Fotossensibilizantes/uso terapêutico , Ressonância de Plasmônio de Superfície , Distribuição Tecidual
8.
ACS Nano ; 8(9): 8896-910, 2014 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-25188899

RESUMO

The detection of colon cancer using endoscopy is widely used, but the interpretation of the diagnosis is based on the clinician's naked eye. This is subjective and can lead to false detection. Here we developed a rapid and accurate molecular fluorescence imaging technique using antibody-coated quantum dots (Ab-QDs) sprayed and washed simultaneously on colon tumor tissues inside live animals, subsequently excited and imaged by endoscopy. QDs were conjugated to matrix metalloproteinases (MMP) 9, MMP 14, or carcinoembryonic antigen (CEA) Abs with zwitterionic surface coating to reduce nonspecific bindings. The Ab-QD probes can diagnose tumors on sectioned mouse tissues, fresh mouse colons stained ex vivo and also in vivo as well as fresh human colon adenoma tissues in 30 min and can be imaged with a depth of 100 µm. The probes successfully detected not only cancers that are readily discernible by bare eyes but also hyperplasia and adenoma regions. Sum and cross signal operations provided postprocessed images that can show complementary information or regions of high priority. This multiplexed quantum dot, spray-and-wash, and endoscopy approach provides a significant advantage for detecting small or flat tumors that may be missed by conventional endoscopic examinations and bestows a strategy for the improvement of cancer diagnosis.


Assuntos
Colo/patologia , Neoplasias do Colo/diagnóstico , Endoscopia/métodos , Imunoconjugados/química , Pontos Quânticos/química , Adsorção , Animais , Catéteres , Linhagem Celular Tumoral , Neoplasias do Colo/patologia , Humanos , Masculino , Camundongos , Microscopia de Fluorescência , Fatores de Tempo
9.
ACS Appl Mater Interfaces ; 6(8): 5619-28, 2014 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-24660776

RESUMO

The metal-enhanced fluorescence (MEF) by metal nanoparticles is a useful technique for fluorescence detections in biological systems. The MEF effects with gold nanorods (AuNRs) and nanocubes (AuNCs) for fluorescence enhancements of sulfonated aluminum phthalocyanine (AlPcS), a commonly used and clinical approved photosensitizer for photodynamic therapy of cancers, were studied in this work. For the AuNRs which have the low aspect ratios with the corresponding longitudinal surface plasma resonance (LSPR) band in the region of 600-750 nm, the fluorescence quenching of conjugated AlPcS was found. Whereas for the AuNRs that have the LSPR bands of 800-900 nm, the MEF of AlPcS was obtained with the enhancing factor of 2-6 times, respectively. Using AuNCs, a great enhancement of AlPcS fluorescence was achieved with an enhancing factor of 150 times. Using two cancer cell lines as in vitro models, an outstanding fluorescence enhancement of AlPcS-AuNCs conjugates in cells, relative to AlPcS alone, was obtained under one-photon excitation (OPE) of 405 nm. Moreover, the bright fluorescence image of AlPcS-AuNCs in cells was also achieved under the two-photon excitation (TPE) of an 800 nm femtosecond laser. The high-quality cell imaging with either OPE or TPE demonstrated the potential of AlPcS-AuNCs in cancer cell detections.


Assuntos
Ouro/química , Indóis/química , Nanotubos/química , Neoplasias/diagnóstico , Neoplasias/fisiopatologia , Compostos Organometálicos/química , Linhagem Celular Tumoral , Movimento Celular , Diagnóstico por Imagem/instrumentação , Fluorescência , Humanos
10.
Opt Lett ; 38(21): 4429-32, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-24177111

RESUMO

We report the feasibility of a novel contrast agent, namely "smart" gold nanoparticles (AuNPs), in the detection of cancer cells with photothermal optical coherence tomography (PT-OCT). "Smart" AuNPs form aggregation in low pH condition, which is typical for cancer cells, and this aggregation results in a shift of their absorption spectrum. A PT-OCT system was developed to detect this pH-induced aggregation by combining an OCT light source and a laser with 660 nm in wavelength for photothermal excitation. Optical detection of pH-induced aggregation was tested with solution samples at two different pH conditions. An increase in optical path length (OPL) variation was measured at mild acidic condition, while there was not much change at neutral condition. Detection of cancer cells was tested with cultured cell samples. HeLa and fibroblast cells, as cancer and normal cells respectively, were incubated with "smart" gold nanoparticles and measured with PT-OCT. An elevated OPL variation signal was detected with the HeLa cells while not much of a signal was detected with the fibroblast cells. With the novel optical property of "smart" AuNPs and high sensitivity of PT-OCT, this technique is promising for cancer cell detection.


Assuntos
Meios de Contraste/química , Ouro/química , Nanopartículas Metálicas , Temperatura , Tomografia de Coerência Óptica/métodos , Animais , Separação Celular , Estudos de Viabilidade , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Células NIH 3T3
12.
J Biomed Opt ; 18(8): 80502, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23922122

RESUMO

A combined two-photon microscopy (TPM) and angiographic optical coherence tomography (OCT) is developed, which can provide molecular, cellular, structural, and vascular information of tissue specimens in vivo. This combined system is implemented by adding an OCT vasculature visualization method to the previous combined TPM and OCT, and then is applied to in vivo tissue imaging. Two animal models, a mouse brain cranial window model and a mouse ear cancer model, are used. Both molecular, cellular information at local regions of tissues, and structural, vascular information at relatively larger regions are visualized in the same sections. In vivo tissue microenvironments are better elucidated by the combined TPM and angiographic OCT.


Assuntos
Angiografia/métodos , Neoplasias da Orelha/irrigação sanguínea , Neoplasias da Orelha/patologia , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Imagem Multimodal/métodos , Neovascularização Patológica/patologia , Tomografia de Coerência Óptica/métodos , Animais , Linhagem Celular Tumoral , Neoplasias da Orelha/complicações , Interpretação de Imagem Assistida por Computador/métodos , Camundongos , Neovascularização Patológica/complicações , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Técnica de Subtração
13.
Anal Chem ; 85(16): 7674-81, 2013 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-23883363

RESUMO

We report a nanoparticle-based probe that can be used for a "turn-on" theragnostic agent for simultaneous Raman imaging/diagnosis and photothermal therapy. The agent consists of a 10 nm spherical gold nanoparticle (NP) with pH-responsive ligands and Raman probes on the surface. They are engineered to exhibit the surface with both positive and negative charges upon mildly acidic conditions, which subsequently results in rapid aggregations of the gold NPs. This aggregation simultaneously provides hot spots for the SERS probe with the enhancement factor reaching 1.3 × 10(4) and shifts the absorption to far-red and near-infrared (which is optimal for deep tissue penetration) by the coupled plasmon resonances; this shift was successfully exploited for low-threshold photothermal therapy. The theragnostic gold NPs are cancer-specific because they aggregate rapidly and accumulate selectively in cancerous cells. As the result, both Raman imaging and photothermal efficacy were turned on under a cancerous local environment. In addition, the relatively small hydrodynamic size can have the potential for better access to targeted delivery in vivo and facilitated excretion after therapy.


Assuntos
Ouro/química , Concentração de Íons de Hidrogênio , Hipertermia Induzida , Nanopartículas Metálicas , Neoplasias/terapia , Fototerapia/métodos , Análise Espectral Raman/métodos , Animais , Linhagem Celular Tumoral , Camundongos , Microscopia Eletrônica de Transmissão , Propriedades de Superfície
14.
ACS Nano ; 7(4): 3388-402, 2013 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-23530622

RESUMO

A challenge in using plasmonic nanostructure-drug conjugates for thermo-chemo combination cancer therapy lies in the huge size discrepancy; the size difference can critically differentiate their biodistributions and hamper the synergistic effect. Properly tuning the plasmonic wavelength for photothermal therapy typically results in the nanostructure size reaching ∼100 nm. We report a new combination cancer therapy platform that consists of relatively small 10 nm pH-responsive spherical gold nanoparticles and conjugated doxorubicins. They are designed to form aggregates in mild acidic environment such as in a tumor. The aggregates serve as a photothermal agent that can selectively exploit external light by their collective plasmon modes. Simultaneously, the conjugated doxorubicins are released. The spatiotemporal concertion is confirmed at the subcellular, cellular, and organ levels. Both agents colocalize in the cell nuclei. The conjugates accumulate in cancer cells by the rapid phagocytic actions and effective blockage of exocytosis by the increased aggregate size. They also effectively accumulate in tumors up to 17 times over the control because of the enhanced permeation and retention. The conjugates exhibit a synergistic effect enhanced by nearly an order of magnitude in cellular level. The synergistic effect is demonstrated by the remarkable reductions in both the therapeutically effective drug dosage and the photothermal laser threshold. Using an animal model, effective tumor growth suppression is demonstrated. The conjugates induce apoptosis to tumors without any noticeable damage to other organs. The synergistic effect in vivo is confirmed by qRT-PCR analysis over the thermal stress and drug-induced growth arrest.


Assuntos
Preparações de Ação Retardada/administração & dosagem , Doxorrubicina/administração & dosagem , Ouro/uso terapêutico , Hipertermia Induzida/métodos , Nanocápsulas/administração & dosagem , Neoplasias Experimentais/terapia , Animais , Antineoplásicos/administração & dosagem , Linhagem Celular Tumoral , Terapia Combinada , Concentração de Íons de Hidrogênio , Camundongos , Camundongos Nus , Nanocápsulas/química , Neoplasias Experimentais/patologia , Ressonância de Plasmônio de Superfície/métodos , Resultado do Tratamento
15.
Sci Rep ; 3: 1282, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23412432

RESUMO

DNA nanostructures have been attractive due to their structural properties resulting in many important breakthroughs especially in controlled assemblies and many biological applications. Here, we report a unique energy storage device which is a supercapacitor that uses nanostructured DNA hydrogel (Dgel) as a template and layer-by-layer (LBL)-deposited polyelectrolyte multilayers (PEMs) as conductors. Our device, named as PEM-Dgel supercapacitor, showed excellent performance in direct contact with physiological fluids such as artificial urine and phosphate buffered saline without any need of additional electrolytes, and exhibited almost no cytotoxicity during cycling tests in cell culture medium. Moreover, we demonstrated that the PEM-Dgel supercapacitor has greater charge-discharge cycling stability in physiological fluids than highly concentrated acid electrolyte solution which is normally used for supercapacitor operation. These conceptually new supercapacitors have the potential to be a platform technology for the creation of implantable energy storage devices for packageless applications directly utilizing biofluids.


Assuntos
DNA/química , Capacitância Elétrica , Fontes de Energia Elétrica , Hidrogéis/química , Células Cultivadas , Meios de Cultura , Eletrólitos , Humanos , Nanoestruturas/química , Polímeros
16.
Langmuir ; 28(50): 17530-6, 2012 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-23186248

RESUMO

Gold nanoparticle (Au NP)-mixed metal oxide (MMO) nanocomposite photocatalysts for efficient self-sensitized dye degradations under visible light were prepared by an electrostatically driven self-assembly. Dihydrolipoic acid (DHLA)-capped Au NPs (building block I) were synthesized through a room temperature reaction. Their hydrodynamic size was determined as being around 4.9 nm by dynamic light scattering measurements. MMO nanoplates with lateral dimensions of 100-250 nm (building block II) were prepared by a calcination of zinc aluminum layered double hydroxides at 750 °C for 2 h in air. In a pH 7.0 aqueous solution, the DHLA-capped Au NPs had a negative zeta potential (-22 ± 3 mV); on the other hand, the MMO nanoplates had a positive zeta potential (15 ± 2 mV). Electrostatic self-assembly was achieved by stirring an aqueous solution (pH 7.0) containing DHLA-capped Au NPs and MMO nanoplates at room temperature for 1 h. The self-assembled and sequentially calcined nanocomposites exhibited the superior self-sensitized dye degradation efficiency under visible light to that of ZnO, TiO(2) (P25), or pure MMO nanoplates. The enhanced degradation efficiency could be attributed to strong coupling interactions of ZnO and ZnAl(2)O(4) phases of the MMO and the role of Au as an electron sink and mediator for formations of reactive oxidation species and as a light concentrator.

17.
Chemphyschem ; 13(18): 4105-9, 2012 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-23132778

RESUMO

Hot gold: The photothermal response upon pulsed laser irradiation is studied for pH-responsive gold-nanoparticle aggregates and compared to that of gold nanorods. The aggregates show a slight red shift in the absorption spectrum and retain the photothermal effect, whereas the nanorods lose the photothermal effect and exhibit a stark blue shift in the absorption.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Concentração de Íons de Hidrogênio , Luz , Terapia com Luz de Baixa Intensidade/métodos , Processos Fotoquímicos , Fótons
18.
Org Lett ; 14(10): 2598-601, 2012 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-22564078

RESUMO

For fluorescent imaging of mercury ions in living species, two-photon probes with dual optical windows are in high demand but remain unexplored. Several dithioacetals were evaluated, and a probe was found, which, upon reaction with mercury species, yielded a two-photon dye; this conversion accompanies ratiometric emission changes with a 97-nm shift, enabling fluorescent imaging of both the probe and mercury ions in cells by one- and two-photon microscopy for the first time.


Assuntos
Corantes Fluorescentes/química , Mercúrio/análise , Fluorescência , Estrutura Molecular , Fótons
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