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1.
Artigo em Inglês | MEDLINE | ID: mdl-31593426

RESUMO

Upconversion nanoparticles (UCNPs) have become competitive materials for bioanalysis, bioimaging, and early diagnosis of diseases, especially cancers. However, traditional upconversion luminescence (UCL) nanosensors are often challenged with complicated covalent modification and relatively poor stability. As efficient energy acceptors in the luminescence resonance energy-transfer (LRET) process, organic dyes exhibit unique advantages such as easy modification and stable property. Herein, a simple and universal bioplatform is constructed for in situ imaging and quantitation of intracellular microRNA-21 (miR-21) using dual-acceptor-based upconversion nanoprobes with enhanced quenching efficiency. In this assay, UCNPs with core-shell structures are synthesized, in which the emitting ions are confined in the shell to take the energy donors and acceptors in close proximity. The complementary DNA (cDNA) that can specifically recognize target miR-21 is labeled with organic dyes TAMRA and black hole quencher as dual acceptors and easily assembled on UCNPs via electrostatic adsorption. Compared with only one acceptor for LRET, two dyes quench more luminescence of UCNPs (>60%), which thus reduce the background and improve the sensitivity. With the enhanced quenching efficiency and simple assembly process, the proposed system is readily applied to in situ imaging of miR-21 in different cancer cells, which further achieves quantification of miR-21 in MCF-7 cells. Therefore, our proposed dual-acceptor-based upconversion nanoplatform opens up new opportunities for sensitive analysis of miRNA and provides potential applications in biomedical and clinical research.

2.
Adv Mater ; : e1903796, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31573709

RESUMO

Electrocatalytic CO2 reduction (ECR) is a promising technology to simultaneously alleviate CO2 -caused climate hazards and ever-increasing energy demands, as it can utilize CO2 in the atmosphere to provide the required feedstocks for industrial production and daily life. In recent years, substantial progress in ECR systems has been achieved by the exploitation of various novel electrode materials. The anodic materials and cathodic catalysts that have, respectively, led to high-efficiency energy input and effective heterogenous catalytic conversion in ECR systems are comprehensively reviewed. Based on the differences in the nature of energy sources and the role of materials used at the anode, the fundamentals of ECR systems, including photo-anode-assisted ECR systems and bio-anode-assisted ECR systems, are explained in detail. Additionally, the cathodic reaction mechanisms and pathways of ECR are described along with a discussion of different design strategies for cathode catalysts to enhance conversion efficiency and selectivity. The emerging challenges and some perspective on both anode materials and cathodic catalysts are also outlined for better development of ECR systems.

3.
Anal Chem ; 91(19): 12298-12306, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31486639

RESUMO

A "signal-off" surface-enhanced Raman scattering (SERS) platform has been constructed for ultrasensitive detection of miRNA-21 by integrating exonuclease-assisted target recycling amplification with a plasmon coupling enhancement effect. On this platform, Raman-labeled Au nanostar (AuNS) probes can be covalently linked with the thiolated aptamer (Apt) on the Au-decorated silicon nanowire arrays (SiNWAs/Au) substrate, creating a coupled electromagnetic field between the substrate and the probes to enhance Raman signal. In the presence of miRNA-21, T7 exonuclease specifically hydrolyzed Apt on Apt/miRNA duplex to release miRNA-21. The regenerated element could then initiate another cycle of Apt/miRNA duplex formation and Apt cleavage. Correspondingly, the capture ability of substrate toward probes and the plasmon coupling effect between them were both diminished, giving a prominent attenuation of Raman intensity that can work as the detection signal. Due to the cascading integration between the target cycle process and the plasmon coupling effect, the present platform displayed a very low detection limit (0.34 fM, 3σ) for miRNA-21 detection. Furthermore, it was proven to be effective for analyzing miRNA-21 in biological samples and distinguishing the expression levels of miRNA-21 in MCF-7 cells and NIH3T3 cells, which became a promising tool to monitor miRNA-21 in cancer auxiliary diagnosis and drug screening.

4.
Langmuir ; 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31536371

RESUMO

DNA-functionalized gold nanoparticles (AuNPs) often encounter various small molecules and ions such as backfilling agents, bifunctional cross-linkers, stabilizers, and molecules from biological fluids both during and after the DNA conjugation process. Small molecules and ions can influence the stability and property of the conjugate, but such interactions are yet to be fully explored. In this work, eight important molecules were studied and compared, including tris(2-carboxyethyl)phosphine hydrochloride (TCEP), 3-(2-pyridyldithio)propionic acid N-hydroxysuccinimide ester (SPDP), 4-maleimidobutyric acid N-hydroxysuccinimide ester (GMBS), 6-hydroxy-1-hexanethiol (MCH), l-glutathione (GSH), bromide (Br-), bis(p-sulfonatophenyl)phenylphosphine (BSPP), and thiocyanate (SCN-). Depending on the size, charge, and adsorption affinity on the AuNPs, they can either stabilize or destabilize the AuNPs. Their ability to displace thiolated DNA from AuNPs follows the order of MCH > SPDP > GSH > SCN- > TCEP > Br- > BSPP > GMBS. BSPP has the best stabilization effect for the colloidal stability of AuNPs, while it does not displace the adsorbed DNA. TCEP can be adsorbed on AuNPs and enhance the adsorption of A/C rich DNA in low-salt conditions. This work indicates that the effects of small molecules and ions cannot be ignored when studying the DNA-functionalized AuNPs, which ensures optimal applications and correct interpretation of the data.

5.
Nat Chem ; 11(9): 846-851, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31444485

RESUMO

The electroreduction of CO2 is a promising technology for carbon utilization. Although electrolysis of CO2 or CO2-derived CO can generate important industrial multicarbon feedstocks such as ethylene, ethanol, n-propanol and acetate, most efforts have been devoted to promoting C-C bond formation. Here, we demonstrate that C-N bonds can be formed through co-electrolysis of CO and NH3 with acetamide selectivity of nearly 40% at industrially relevant reaction rates. Full-solvent quantum mechanical calculations show that acetamide forms through nucleophilic addition of NH3 to a surface-bound ketene intermediate, a step that is in competition with OH- addition, which leads to acetate. The C-N formation mechanism was successfully extended to a series of amide products through amine nucleophilic attack on the ketene intermediate. This strategy enables us to form carbon-heteroatom bonds through the electroreduction of CO, expanding the scope of products available from CO2 reduction.

6.
Nat Commun ; 10(1): 3849, 2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31451698

RESUMO

Measurement of electron transfer at single-molecule level is normally restricted by the detection limit of faraday current, currently in a picoampere to nanoampere range. Here we demonstrate a unique graphene-based electrochemical microscopy technique to make an advance in the detection limit. The optical signal of electron transfer arises from the Fermi level-tuned Rayleigh scattering of graphene, which is further enhanced by immobilized gold nanostars. Owing to the specific response to surface charged carriers, graphene-based electrochemical microscopy enables an attoampere-scale detection limit of faraday current at multiple individual gold nanoelectrodes simultaneously. Using the graphene-based electrochemical microscopy, we show the capability to quantitatively measure the attocoulomb-scale electron transfer in cytochrome c adsorbed at a single nanoelectrode. We anticipate the graphene-based electrochemical microscopy to be a potential electrochemical tool for in situ study of biological electron transfer process in organelles, for example the mitochondrial electron transfer, in consideration of the anti-interference ability to chemicals and organisms.

7.
Chem Soc Rev ; 48(18): 4892-4920, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31402369

RESUMO

DNA nanotechnology engineered at the solid-liquid interface has advanced our fundamental understanding of DNA hybridization kinetics and facilitated the design of improved biosensing, bioimaging and therapeutic platforms. Three research branches of DNA nanotechnology exist: (i) structural DNA nanotechnology for the construction of various nanoscale patterns; (ii) dynamic DNA nanotechnology for the operation of nanodevices; and (iii) functional DNA nanotechnology for the exploration of new DNA functions. Although the initial stages of DNA nanotechnology research began in aqueous solution, current research efforts have shifted to solid-liquid interfaces. Based on shape and component features, these interfaces can be classified as flat interfaces, nanoparticle interfaces, and soft interfaces of DNA origami and cell membranes. This review briefly discusses the development of DNA nanotechnology. We then highlight the important roles of structural DNA nanotechnology in tailoring the properties of flat interfaces and modifications of nanoparticle interfaces, and extensively review their successful bioapplications. In addition, engineering advances in DNA nanodevices at interfaces for improved biosensing both in vitro and in vivo are presented. The use of DNA nanotechnology as a tool to engineer cell membranes to reveal protein levels and cell behavior is also discussed. Finally, we present challenges and an outlook for this emerging field.

8.
Chem Commun (Camb) ; 55(73): 10892-10895, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31436766

RESUMO

Bifunctional supramolecular prodrug vesicles have been successfully constructed based on the complexation between a glutathione (GSH)-responsive prodrug guest molecule (DNS-CPT) and a water-soluble pillar[5]arene (WP5) for cancer diagnosis and therapy. Under the microenvironment of cancer cells with high GSH concentration, 7-ethyl-10-hydroxycamptothecin (SN-38) with strong yellow fluorescence can be efficiently released from the prodrug DNS-CPT for drug location and cancer therapy.

9.
Ultrason Sonochem ; 58: 104634, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31450346

RESUMO

Iron oxide nanoparticles decorated on multi-wall nanotube (MWCNTs) were successfully fabricated through a facile and rapid sonochemical method without any pre-treatment on MWCNTs. Fe3O4/MWCNTs-20 showed a uniform and fine distribution of nanoparticles in the MWCNTs. The obtained Fe3O4/MWCNTs were analysed using TEM and XPS. Notably, Fe3O4/MWCNTs were used for persulfate activation on cyanobacterial cell removal. With 20 mg/L persulfate, Fe3O4/MWCNTs showed an efficient catalytic performance after 1 h treatment. In the Fe3O4/MWCNTs hybrid catalyst, Fe3O4 helps to produce sulfate radicals and hydroxyl radicals whereas the size of the Fe3O4 clusters could affect the electron transfer for radical generation. Moreover, using high frequency low intensity ultrasound, the combination of persulfate and Fe3O4/MWCNTs-20 reduced the remaining cell number to 9.4% within 30 min treatment. In conclusion, our work demonstrated that low frequency ultrasonic devices are capable of fabricating Fe3O4/MWCNTs via a simple and time-saving route, and the obtained catalysts showed superior catalytic performance on persulfate for harmful cyanobacteria control.

10.
Dalton Trans ; 48(35): 13120-13124, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31348472

RESUMO

Near-infrared photothermal-activated nanomaterials are emerging as a promising tool in precise cancer theranostics. This Frontier article highlights the recent advances of photothermal-activated nanoagents in biomedical applications, namely photothermal-initiated drug/contrast agent release, gene silencing, programmed targeting and gas theranostics. In the end, we give a perspective on the further development of photothermal-sensitive nanomedicines.

11.
Angew Chem Int Ed Engl ; 58(40): 14100-14103, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31314934

RESUMO

We report a new strategy to prepare a composite catalyst for highly efficient electrochemical CO2 reduction reaction (CO2 RR). The composite catalyst is made by anchoring Au nanoparticles on Cu nanowires via 4,4'-bipyridine (bipy). The Au-bipy-Cu composite catalyzes the CO2 RR in 0.1 m KHCO3 with a total Faradaic efficiency (FE) reaching 90.6 % at -0.9 V to provide C-products, among which CH3 CHO (25 % FE) dominates the liquid product (HCOO- , CH3 CHO, and CH3 COO- ) distribution (75 %). The enhanced CO2 RR catalysis demonstrated by Au-bipy-Cu originates from its synergistic Au (CO2 to CO) and Cu (CO to C-products) catalysis which is further promoted by bipy. The Au-bipy-Cu composite represents a new catalyst system for effective CO2 RR conversion to C-products.

12.
Anal Chem ; 91(13): 8607-8614, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31148456

RESUMO

Low-toxic trivalent bismuth, with an isoelectronic structure (6s26p0) and a similar ionic radius to divalent lead, represents a promising candidate for constructing lead-free perovskites. Herein, cesium bismuth halide perovskite quantum dots (Cs3Bi2Br9 QDs) were synthesized via a comprehensively improved ligand-assisted reprecipitation method with the addition of γ-butyrolactone, trace distilled water, and tetrabutylammonium bromide, as well as the aid of ultrasonic technology. The as-prepared QDs displayed remarkable monodispersity, outstanding stability, and highly passivated surfaces with a near-single-component PL decay, thus affording superb optical properties with a photoluminescence quantum yield up to 37%, outperforming all the reported bismuth-based perovskites. Furthermore, Cs3Bi2Br9 QDs were first attempted for electrochemiluminescence (ECL) and exhibited a stable and efficient ECL response following either an annihilation or a coreaction ECL mechanism. Not only were the optical properties and stability of Cs3Bi2Br9 QDs greatly improved in this work, but their electrochemical behaviors and ECL natures were also investigated systematically for the first time, demonstrating the significant potential to extend this environmentally friendly bismuth-based perovskite into the ECL domain.

13.
ACS Appl Mater Interfaces ; 11(21): 18995-19005, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31058483

RESUMO

Cutting off the glucose supply by glucose oxidase (GOx) has been regarded as an emerging strategy in cancer starvation therapy. However, the standalone GOx delivery suffered suboptimal potency for tumor elimination and potential risks of damaging vasculatures and normal organs during transportation. To enhance therapeutic efficacy and tumor specificity, a site-specific activated dual-catalytic nanoreactor was herein constructed by embedding GOx and ferrocene in hyaluronic acid (HA)-enveloped dendritic mesoporous silica nanoparticles to promote intratumoral oxidative stress in cancer starvation. In this nanoreactor, the encapsulated GOx served as the primary catalyst that accelerated oxidation of glucose and generation of H2O2, while the covalently linked ferrocene worked as the secondary catalyst for converting the upstream H2O2 to more toxic hydroxyl radicals (•OH) via a classic Fenton reaction. The outmost HA shell not only offered a shielding layer for preventing blood glucose from oxidation during nanoreactor transportation, thus minimizing the probable oxidative damage to normal tissues, but also imparted the nanoreactor with targeting ability for facilitating its internalization into CD44-overexpressing tumor cells. After the nanoreactor was endocytosed by target cells, the HA shell underwent hyaluronidase-triggered degradation in lysosomes and switched on the cascade catalytic reaction mediated by GOx and ferrocene. The resulting glucose exhaustion and •OH accumulation would effectively kill cancer cells and suppress tumor growth via combination of starvation and oxidative stress enhancement. Both in vitro and in vivo results indicated the significantly amplified therapeutic effects of this synergistic therapeutic strategy based on the dual-catalytic nanoreactor. Our study provides a new avenue for engineering therapeutic nanoreactors that take effect in a tumor-specific and orchestrated fashion for cancer starvation therapy.

14.
Anal Chem ; 91(11): 7295-7303, 2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31062958

RESUMO

Rational engineering of highly stable and Raman-active nanostructured substrates is still urgently in demand for achieving sensitive and reliable surface-enhanced Raman spectroscopy (SERS) analysis in solution phase. Herein, monodisperse N-doping graphene quantum dots wrapped Au nanoparticles (Au-NGQD NPs) were facilely prepared, and further their applications as substrates in SERS-based detection and cellular imaging have been explored. The as-prepared Au-NGQD NPs exhibit superior long-term stability and biocompatibility, as well as large enhancement capability due to the integration of electromagnetic and chemical enhancements. The practical applicability of the Au-NGQD NPs was verified via the direct SERS tests of several kinds of aromatics in solution phase. Finite-difference time-domain simulations in combination with density functional theory calculation were also successfully used to explain the enhancement mechanism. Furthermore, the Au-NGQD NPs were conjugated with 4-nitrobenzenethiol (4-NBT, as reporter) and 4-mercaptophenylboronic acid (MPBA, as targeting element) to construct the MPBA/4-NBT@Au-NGQD probes, which could specifically recognize glycan-overexpressed cancer cells through SERS imaging on a cell surface. The prepared Au-NGQDs show great potential as superior SERS substrates in solution phase for on-site Raman detection.

15.
Talanta ; 201: 90-95, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31122466

RESUMO

Exploring new energy donor/acceptor pairs for constructing FRET system has important research significance. In this study, a FRET assembly by using carbon dots (CDs) as energy donor and gold nanorods (Au NRs) as energy acceptor has been proposed through covalent bond interactions by taking advantage of cysteamine as a bridge. The assembly is characterized by UV-vis absorption spectra, fluorescence spectra, FT-IR spectra and TEM images, revealing that Au NRs successfully absorbed on the surface of CDs. As for the occurrence of FRET process from CDs to Au NRs, the fluorescence signal of CDs-cysteamine-Au NRs assembly quenched significantly. Interestingly, Pb2+ ions could bind completely with cysteamine and disturbed the FRET process, which activated fluorescence signal of the system. Based on these experimental phenomena, CDs-cysteamine-Au NRs assembly was performed as an off-on FRET biosensor for Pb2+ ions. The linear range obtained is from 0 to 155 µM with the detection limit of 0.05 µM. Moreover, the FRET-based sensor exhibited high selectivity to the analyte Pb2+ ions against other interference substances. Furthermore, the present approach was successfully applied to detect Pb2+ ions in real samples, which suggested its potential applications in environmental monitoring.

16.
Angew Chem Int Ed Engl ; 58(26): 8752-8756, 2019 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-31046176

RESUMO

Tumor hypoxia, the "Achilles' heel" of current cancer therapies, is indispensable to drug resistance and poor therapeutic outcomes especially for radiotherapy. Here we propose an in situ catalytic oxygenation strategy in tumor using porphyrinic metal-organic framework (MOF)-gold nanoparticles (AuNPs) nanohybrid as a therapeutic platform to achieve O2 -evolving chemoradiotherapy. The AuNPs decorated on the surface of MOF effectively stabilize the nanocomposite and serve as radiosensitizers, whereas the MOF scaffold acts as a container to encapsulate chemotherapeutic drug doxorubicin. In vitro and in vivo studies verify that the catalase-like nanohybrid significantly enhances the radiotherapy effect, alleviating tumor hypoxia and achieving synergistic anticancer efficacy. This hybrid nanomaterial remarkably suppresses the tumor growth with minimized systemic toxicity, opening new horizons for the next generation of theranostic nanomedicines.

17.
Anal Chem ; 91(9): 6363-6370, 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-30964659

RESUMO

In this work, a potential-resolved electrochemiluminescence (ECL) method is developed and used for the apoptosis diagnosis at the single-cell level. The apoptosis of cells usually induces the decreasing expression of epidermal growth factor receptor (EGFR) and promotes phosphatidylserine (PS) eversion on the cell membrane. Here, Au@L012 and g-C3N4 as ECL probes are functionalized with epidermal growth factor (EGF) and peptide (PSBP) to recognize the EGFR and PS on the cell surface, respectively, showing two well-separated ECL signals during a potential scanning. Experimental results reveal that the relative ECL change of g-C3N4 and Au@L012 correlates with the degree of apoptosis, which provides an accurate way to investigate apoptosis without interference that solely changes EGFR or PS. With a homemade ECL microscopy, we simultaneously evaluate the EGFR and PS expression of abundant individual cells and, therefore, achieve the visualization analysis of the apoptosis rate for normal and cancer cell samples. This strategy contributes to visually studying tumor markers and pushing the application of ECL imaging for the disease diagnosis at the single-cell level.

18.
Anal Chem ; 91(10): 6829-6835, 2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-31006237

RESUMO

Investigating catalytic behavior of heterogeneous catalysts, especially at the crystal facets level, is crucial for rational catalyst design in the energy and environmental fields. Here we demonstrate an efficient approach to in situ visualize and analyze the heterogeneity of electrocatalytic activity on different facets at the subparticle level via electrochemiluminescence (ECL) microscopy. ZnO crystals with various exposed facet proportions were synthesized, and the correlation between their electrocatalytic performance toward luminol analogue degradation and the exposed facets is established. It is clearly imaged that the ZnO (002) facet has superior catalytic performance compared to the ZnO (100) facet, which is supported by theoretical computation and electrochemical experiments as the facet-induced heterogeneity of the catalytic effect on oxygen reduction into the key reactant for ECL. Accordingly, the spatial heterogeneity of electrocatalytic activity at different facets on one particle is visualized for the first time. The realization of subparticle ECL imaging and kinetic analysis could provide a special approach to visualize facet-induced spatial heterogeneity of catalytic behavior and valuable information for the catalysis study and analysis.

19.
Anal Chem ; 91(7): 4608-4617, 2019 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-30821439

RESUMO

Due to the outstanding synergistic effects and low-toxicity, combination therapy exhibits more considerable potential in antitumor activity than monotherapy. Herein, a core-shell magnetic gold nanostar (Fe3O4@GNS, MGNS)-based system for codelivery of a mitochondrial targeting amphipathic tail-anchoring peptide (ATAP) and a membrane-associated cytokine (tumor-necrosis-factor-related apoptosis-inducing ligand (TRAIL) was constructed. The magnetic core can facilitate delivery of the drug vehicle by external magnetic field, which results in accurate accumulation and enhances tumor cellular uptake for preliminary targeting. TRAIL and ATAP could sequentially target and be released toward the plasma membrane and mitochondria, initiating the extrinsic and intrinsic apoptosis pathways, respectively. The gold shell of MGNS can cause local tumor hyperthermia due to broad-band plasmon resonances in the near-infrared region, which can act as a complement with the peptide drug to further enhance apoptosis. Both in vitro and in vivo experiments revealed that rationally integrating extrinsic apoptosis, intrinsic apoptosis and hyperthermia for triplexed synergistic therapy, enabled the smart drug vehicle with pinpoint peptide drug delivery capabilities, and minimized side effects, enhancing the antitumor efficiency.

20.
Anal Chem ; 91(5): 3619-3627, 2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30735030

RESUMO

Human telomerase RNA (hTR), an important biomarker for cancer diagnosis, is the template for the synthesis of telomeric DNA repeats and is found to be 7-fold overexpressed in tumor cells. Herein, we present a photoelectrochemical (PEC) biosensor for hTR detection coupled with a novel amplification strategy based on cascades of catalytic hairpin assembly (CHA) and hyperbranched hybridization chain reaction (HB-HCR). At the electrode surface, thiolated hairpin 1 probes were immobilized on deposited CdS nanoparticles via a Cd-S bond. In the presence of target hTR, a CHA reaction was triggered and the exposing of trigger1 could further initiate an HB-HCR reaction to form abundant hemin/G-quadruplex DNAzymes containing dendritic DNA structure. The DNAzymes' catalytic precipitation of 4-chloro-1-naphthol (4-CN) by H2O2 subsequently took place on the surface of the PEC electrode and efficiently suppressed the photocurrent output. Therefore, the change of photocurrent response had a positive linear relationship with logarithmic value of hTR concentration varying from 200 fM to 20.0 nM with a limit of detection (LOD) of 17.0 fM. The LOD for CHA/HB-HCR was about 8.8-fold lower than that of CHA/linear-branched HCR (CHA/LB-HCR) and 547-fold lower than that of CHA. By coupling the feature of high signal amplification capacity for DNA nanotechnology, a prominently stable, reproducible, and selective PEC biosensor was successfully constructed and applied in hTR detection.

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