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1.
Artigo em Inglês | MEDLINE | ID: mdl-32337964

RESUMO

Pursuing a high catalytic selectivity is challenging but paramount for an efficient and low-cost CO2 electrochemical reduction (CO2R). In this work, we demonstrate a significant correlation between the selectivity of CO2R to formate and the duration of tin (Sn) electrodeposition over cuprous oxide (Cu2O)-derived substrate. A Sn electrodeposition of 120 s led to a cathode with a formate faradaic efficiency of around 81%, which is over 37% higher than 684 s and Sn foil at -1.1 V vs. RHE. This result highlights the significant role of interfaces between deposited Sn and cuprous-derived substrate in determining the selectivity of CO2R. High-resolution X-ray photoelectron spectra revealed that the residue cuprous species at the Cu/Sn interfaces could stabilize Sn species at oxidation states of 2+ and 4+, a mixture of which is essential for a selective formate conversion. Such modulation effects likely arise from the moderate electronegativity of the cuprous species that is lower than that of Sn2+ but higher than that of Sn4+. Our work highlights the significant role of the substrate on the selectivity of the deposited catalyst and provides a new avenue to advance selective electrodes for CO2 electrochemical reduction.

2.
Anal Chem ; 92(5): 3613-3619, 2020 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-32037803

RESUMO

Intracellular lipid metabolism occurs in lipid droplets (LDs), which is critical to the survival of cells. Imaging LDs is an intuitive way to understand their physiology in live cells. However, this is limited by the availability of specific probes that can properly visualize LDs in vivo. Here, an LDs-specific red-emitting probe is proposed to address this need, which is not merely with an ultrahigh signal-to-noise (S/N) ratio and a large Stokes shift (up to 214 nm) but also with superior resistance to photobleaching. The probe has been successfully applied to real-time tracking of intracellular LDs behaviors, including fusion, migration, and lipophagy processes. We deem that the proposed probe here offers a new possibility for deeper understanding of LDs-associated behaviors, elucidation of their roles and mechanisms in cellular metabolism, and determination of the transition between adaptive lipid storage and lipotoxicity as well.

3.
Sci Adv ; 6(4): eaat0919, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-32042891

RESUMO

Tight control on the selectivity of nanoparticles' interaction with biological systems is paramount for the development of targeted therapies. However, the large number of tunable parameters makes it difficult to identify optimal design "sweet spots" without guiding principles. Here, we combine superselectivity theory with soft matter physics into a unified theoretical framework and we prove its validity using blood brain barrier cells as target. We apply our approach to polymersomes functionalized with targeting ligands to identify the most selective combination of parameters in terms of particle size, brush length and density, as well as tether length, affinity, and ligand number. We show that the combination of multivalent interactions into multiplexed systems enable interaction as a function of the cell phenotype, that is, which receptors are expressed. We thus propose the design of a "bar-coding" targeting approach that can be tailor-made to unique cell populations enabling personalized therapies.

4.
Chem Commun (Camb) ; 56(12): 1859-1862, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-31950954

RESUMO

We present the design and synthesis of water-soluble quinoline-indole-based derivatives (IM-1, IM-2, and IM-3) with three-photon absorption activity. IM-3 can specifically target DNA and RNA accompanied by an obvious three-photon fluorescence enhancement in the second near-infrared window (1000-1700 nm). The in vitro experiments demonstrate that IM-3 can simultaneously stain mitochondria and the nucleolus both in living and fixed cells. The organelle-specific targeting behaviour is successfully visualized under stimulated emission depletion (STED) nanoscopy.


Assuntos
DNA Mitocondrial/análise , Corantes Fluorescentes/química , Indóis/química , Fótons , Quinolinas/química , RNA Neoplásico/análise , Nucléolo Celular/química , Células Hep G2 , Humanos , Estrutura Molecular , Imagem Óptica , Solubilidade , Água/química
5.
J Control Release ; 318: 124-135, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31838206

RESUMO

Functionalized drug delivery systems against malignant lung metastasis of breast cancer have been extensively studied, while metastasis remains a challenging issue. We propose a new strategy to achieve eradication of primary breast cancer cells and inhibition of pulmonary metastasis. A cathepsin B/pH dual-sensitive block copolymer with a molecular weight of 92 kDa was synthesized to conjugate with doxorubicin (DOX). The copolymer-DOX was further loaded with nifuroxazide (NFX) to self-assemble co-prodrug-loaded micelles (CLM). CLM displayed a drug release pattern in response to pH/enzyme dual stimuli and was enzymatically biodegradable. CLM was demonstrated to reduce viability and inhibit migration and invasion of 4T1 murine breast cancer cells in vitro. After i.v. injection of CLM, its nanoscale size and stimuli-responsiveness facilitated delivery of drugs to the tumor site in mice. Enhanced anti-tumor efficacy and great anti-metastatic effects were found in both orthotropic and lung metastasis 4T1 breast cancer mice models. Meanwhile, histological immunofluorescence and immunohistochemical analyses revealed a high level of apoptosis, suppressed expression of matrix metalloproteinases and reduction in MDSCs infiltration, and all these contributed to inhibit pulmonary metastasis. CLM may be explored as a potential nanomedicine against breast cancer metastasis.

6.
Chem Sci ; 10(30): 7228-7232, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31588291

RESUMO

Multiphoton bioimaging benefits from good penetration of tissue, low phototoxicity and high resolution. Hence, development of efficient multiphoton imaging agents is highly desirable but remains challenging. Herein, a novel terpyridine-based Zn(ii) complex bearing a thiophene bridge was designed rationally and fabricated. Thanks to its aggregation-induced emission (AIE), DZ1 emitted bright yellow-green fluorescence (λ em = 575 nm) under physiological conditions. The three-photon spectral changes of DZ1 when binding with RNA unambiguously reflected its RNA-specific targeting behaviour, resulting in twofold enhancement in three-photon action cross-sections located at the second near-infrared window (1700 nm).

7.
Theranostics ; 9(8): 2158-2166, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31149035

RESUMO

Platinum complexes have been used for anti-cancer propose for decades, however, their high side effects resulting from damage to healthy cells cannot be neglected and prevent further clinical utilisation. Here, we designed a cyclometalated platinum (II) complex that can bind the endogenous nuclear factor-κB (NF-κB) protein. Employing detailed colocalization studies in co-culture cell line models, we show that by binding to NF-κB, the platinum (II) complex is capable of upregulated nuclear translocation specifically in cancer but not normal cells, thereby impairing cancer proliferation without disturbing healthy cells. In a murine tumour model, the platinum (II) complex prevents tumour growth to a greater extent than cisplatin and with considerably lower side-effects and kidney damage. Considering its weak damage to normal cells combined with high toxicity to cancer cells, this NF-κB-binding platinum complex is a potential anti-cancer candidate and acts to verify the strategy of hijacking endogenous trans-nuclear proteins to achieve cancer-cell specificity and enhance therapeutic indices.

8.
Talanta ; 199: 140-146, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30952238

RESUMO

Small molecules emitting in the NIR for tracking mitochondrial pH alteration with super-resolution are expected to play an essential role in biomedical applications. Herein, two small molecules based on pyridinium salt (P1 and P2) have been synthesized and systematically investigated. It was found that pyridinium salts P1 and P2 emitted in the NIR (about 610 nm), which could detect pH changes from 2.0 to 11.0 with good linearity and high sensitivity. Importantly, P2 could precisely target cellular mitochondria in a real-time manner under stimulated emission depletion (STED). These results implied a chemical strategy with a potential application in super-resolution imaging and mitochondrial pH determination.


Assuntos
Mitocôndrias/química , Compostos de Piridínio/química , Bibliotecas de Moléculas Pequenas/química , Cristalografia por Raios X , Células Hep G2 , Humanos , Concentração de Íons de Hidrogênio , Raios Infravermelhos , Microscopia de Fluorescência , Modelos Moleculares , Estrutura Molecular , Compostos de Piridínio/síntese química , Teoria Quântica , Bibliotecas de Moléculas Pequenas/síntese química
10.
Angew Chem Int Ed Engl ; 58(21): 7087-7091, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-30912239

RESUMO

The dynamics of DNA and RNA structures in live cells are important for understanding cell behaviors, such as transcription activity, protein expression, cell apoptosis, and hereditary disease, but are challenging to monitor in live organisms in real time. The difficulty is largely due to the lack of photostable imaging probes that can distinguish between DNA and RNA, and more importantly, are capable of crossing multiple membrane barriers ranging from the cell/organelle to the tissue/organ level. We report the discovery of a cationic carbon quantum dot (cQD) probe that emits spectrally distinguishable fluorescence upon binding with double-stranded DNA and single-stranded RNA in live cells, thereby enabling real-time monitoring of DNA and RNA localization and motion. A surprising finding is that the probe can penetrate through various types of biological barriers in vitro and in vivo. Combined with standard and super-resolution microscopy, photostable cQDs allow time-lapse imaging of chromatin and nucleoli during cell division and Caenorhabditis elegans (C. elegans) growth.

11.
J Control Release ; 298: 99-109, 2019 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-30703391

RESUMO

We propose here a new approach to achieve intratumoral near-infrared (NIR) two-photon photodynamic therapy (PDT). We established a composite micellar thermosensitive hydrogel made of clinically approved methoxy poly(ethylene glycol)-polylactide copolymer (mPEG-PDLLA) and Pluronic (F127). The mPEG-PDLLA form micelles that can be loaded with two-photon absorption compound (T1) and photosensitizer (PS), The F127 micelles are liquid at room temperature and while forming an hydrogel at body temperature. This enables an in situ gelification upon injection providing long-term retentio within the tumor. The NIR light is thus upconverted into visible light by T1 and excited PS. The morphology, rheology properties and releasing profiles of hydrogel were fully characterized. The rheology properties and releasing mechanism was investigated. The composite hydrogel showed significant cytotoxicity to 4 T1 murine breast cancer cells upon NIR laser irradiation, while it showed non-significant cytotoxicity without. Time-dependent in vivo and ex vivo distribution results suggested that hydrogel administrated via intra-tumoral injection could prolong both PDT agents retention in tumor. We show here that the use of NIR radiation allows deep tissue penetration and inhibition of tumor growth of >50% even under 1 cm thick muscle tissue.

12.
Chem Asian J ; 14(4): 509-526, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30716209

RESUMO

Zinc is a biocompatible element that exists as the second most abundant transition metal ion and an indispensable trace element in the human body. Compared to traditional metal-organic complexes systems, d10 metal ZnII complexes not only exhibit a large Stokes shift and good photon stability but also possess strong emission and low cytotoxicity with a relatively small molecular weight. The use of ZnII complexes has emerged in the last decade as a versatile and convenient tool for numerous biological applications, including bioimaging, molecular and protein recognition, as well as photodynamic therapy. Herein, we review recent developments involving ZnII metal complexes applied as specific subcellular compartment imaging probes and their correlated utilizations.


Assuntos
Complexos de Coordenação/farmacologia , Corantes Fluorescentes/farmacologia , Zinco/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Meios de Contraste/química , Meios de Contraste/farmacologia , Complexos de Coordenação/química , Corantes Fluorescentes/química , Humanos , Membranas Intracelulares/metabolismo , Microscopia Confocal/métodos , Espectrometria de Fluorescência/métodos
13.
Chem Commun (Camb) ; 55(10): 1450-1453, 2019 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-30644469

RESUMO

Herein, a series of photosensitizers were constructed of α, ß and γ-isomers of terpyridine and the corresponding N-methylation derivatives. Benefiting from the tunable singlet-triplet energy gap and aggregation-induced emission characteristics, two-photon active photosensitizers L2b and L2c showed relatively strong intersystem crossing facilitating 1O2 generation and cell apoptosis with near-infrared excitation.

14.
Chem Commun (Camb) ; 55(14): 2035-2038, 2019 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-30687863

RESUMO

Telomerase is repressed stringently in normal cells but highly activated in tumours to maintain their uncontrollable growth. We report a ratiometric fluorescence strategy for visualising telomerase activity for tumour identification. Using our strategy, tumour cells and tissues can be differentiated from normal cells and tissues by the naked eye.

15.
Anal Chem ; 91(1): 977-982, 2019 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-30507133

RESUMO

Visualizing and dynamic tracking lipid droplets (LDs) are of great importance to biological research. Herein, two-photon absorption fluorescent small bioprobes based on lipophilic coumarin were developed, which exhibited high selectivity toward LDs in HeLa cells. Because of good biocompatibility and excellent photostability, the probes were applied to realize specific super-resolution visualization of the intracellular LDs in HeLa cells, offering us the quantitative results of the amount and diameters of LDs as well. Furthermore, the bioprobes were capable of monitoring the movements of the LDs in real time. We believe that bioprobes would provide new avenues to designing bioimaging and biological diagnosis.

16.
J Inorg Biochem ; 192: 1-6, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30544075

RESUMO

Compared to organotin (IV) compounds with biochemical activity, two-photon absorption (2PA) organotin (IV) complexes for targeting nuclear with anticancer activities are rarely reported. Here, two novel 2PA organotin (IV) cyano carboxylate complexes (C1Sn-1, C1Sn-2) are synthesized and characterized. The two-photon absorption cross section values (δ) in the near-infrared region are significantly enhanced for C1Sn-2 compared to C1Sn-1, thus developing for targeting nuclear by two-photon fluorescence microscopy (2PFM). C1Sn-2 could specifically target nuclear DNA in vitro. The mechanism demonstrated that there are abundant hydrogen bond interactions between hydroxy group of C1Sn-2 and DNA. The animal mode studies are first proposed that C1Sn-2 displayed a certain anti-cancer efficiency with non-significant toxicity.

17.
Angew Chem Int Ed Engl ; 58(8): 2261-2265, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30589211

RESUMO

Enzyme activity in live cells is dynamically regulated by small-molecule transmitters for maintaining normal physiological functions. A few probes have been devised to measure intracellular enzyme activities by fluorescent imaging, but the study of the regulation of enzyme activity via gasotransmitters in situ remains a long-standing challenge. Herein, we report a three-channel imaging correlation by a single dual-reactive fluorescent probe to measure the dependence of phosphatase activity on the H2 S level in cells. The two sites of the probe reactive to H2 S and phosphatase individually produce blue and green fluorescent responses, respectively, and resonance energy transfer can be triggered by their coexistence. Fluorescent analysis based on the three-channel imaging correlation shows that cells have an ideal level of H2 S to promote phosphatase activity up to its maximum. Significantly, a slight deviation from this H2 S level leads to a sharp decrease of phosphatase activity. The discovery further strengthens our understanding of the importance of H2 S in cellular signaling and in various human diseases.

18.
Inorg Chem ; 57(22): 14134-14143, 2018 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-30376316

RESUMO

It is currently challenged that nonlinear optical (NLO) properties in the near-infrared region (NIR) of metal complexes can be tunable with an assistant ligand. Herein, the linear and nonlinear photophysical properties of the novel C^N^C cyclometalated Pt(II) complexes with different substituents as auxiliary ligands are presented. The complexes displayed intense triplet metal/ligand-to-ligand charge-transfer (3MLCT/3LLCT) and intraligand 3π, π* emission at low-temperature. The excited-state characteristics are further confirmed over the TD-DFT calculations, transient absorption, and emission lifetimes. The Pt-3 possesses a relatively high quantum yield (9.1%), a moderate triplet excited-state lifetime (5.32 µs), and a broad excited-state absorption from the visible to the near-IR region. Interestingly, it was found that Pt-3 exhibited high 2PA cross section values (σ2 up to 367 GM at 820 nm), as well as good optical limiting properties over a tunable femtosecond laser. The relationships between the structures and properties were systematically investigated on the basis of crystal structural information. Hence, cyclometalated Pt(II) complexes would become candidates for the application of the NIR NLO materials.

19.
Chem Commun (Camb) ; 54(80): 11288-11291, 2018 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-30232472

RESUMO

We present a thiophene-based terpyridine Zn(ii) complex (namely LC) which could specifically target live cell mitochondria via binding with mitochondrial DNA (mtDNA). Due to its high biocompatibility, red emission and photo-stability, mtDNA distribution within mitochondrial cristae and inner matrix in living cells was successfully visualized using stimulated emission depletion (STED) nanoscopy with unprecedented resolution.


Assuntos
DNA Mitocondrial/análise , DNA Mitocondrial/química , Nanotecnologia , Compostos Organometálicos/química , Piridinas/química , Tiofenos/química , Zinco/química , Células HeLa , Humanos , Microscopia de Fluorescência , Estrutura Molecular
20.
ACS Appl Mater Interfaces ; 10(38): 31959-31964, 2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-30130086

RESUMO

Neuronal nuclei (NeuN) protein is a key RNA-associated protein to guide the transcription of RNA and regulate mRNA splicing in neurons. However, the lack of effective labeling and tracking method has hindered the elucidation of the biological mechanism of NeuN operation in living neurons to understand correlated central nervous system disorders. Here, we report a molecular probe that can be inserted into a neighboring hydrophobic-hydrophilic region in NeuN, which upon binding becomes capable of emitting light in red region. The NeuN specificity enables the probe imaging neuronal cells in primary brain regions including hippocampus, cerebellum, midbrain, and cingulate gyrus. The probes' optical properties are such to enable stimulated emission depletion imaging showing for the first time the 3D structure of RNA tangling into NeuN in a living neuron with tens of nanometer resolution.


Assuntos
Antígenos Nucleares/metabolismo , Corantes Fluorescentes/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/patologia , Núcleo Celular/metabolismo , Núcleo Celular/patologia , Corantes Fluorescentes/química , Hipocampo/diagnóstico por imagem , Humanos , Microscopia de Fluorescência , Neurônios/citologia , Ligação Proteica , RNA/química
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