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1.
Drug Des Devel Ther ; 15: 4559-4574, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34764638

RESUMO

Background: Prunella vulgaris L. (PV) has been used to treat autoimmune thyroiditis (AIT), but the underlying mechanism remains unknown. The present study was designed to evaluate the effect of PV on AIT and explore the role of high-mobility group box-1 (HMGB1) signaling in PV-mediated effects in vivo and in vitro. Methods: In the present study, bioactive components of PV were identified using UPLC-ESI-MS. The protective effects and potential mechanisms critical for the anti-inflammatory and immunomodulatory effects of PV in AIT were investigated in a rat model of thyroglobulin-induced experimental autoimmune thyroiditis (EAT) and in lipopolysaccharide (LPS)-induced thyroid follicular cells (TFCs). Results: The main bioactive compound identified in PV was rosmarinic acid. The thyroid volume, thyroiditis inflammation score and serum thyroglobulin antibody levels of EAT rats were attenuated by PV treatment (P<0.01). In addition, PV significantly reduced the elevated levels of the proinflammatory cytokines TNF-α, IL-6, IL-1ß and monocyte chemoattractant protein-1 (MCP-1) both in vivo (P<0.01) and in vitro (P<0.05). PV downregulated HMGB1 mRNA and protein expression, reduced HMGB1 secretion, and inhibited TLR9 signaling pathways (TLR9 and MyD88) in PV-treated EAT rats and TFCs. Moreover, PV reversed the increases in the numbers of splenic Th1, Th2, and Th17 cells. Finally, our results acquired following administration of ethyl pyruvate, an HMGB1 inhibitor, to splenocytes cultured in vitro supported the hypothesis that the HMGB1/TLR9 pathway is involved in the PV-mediated reductions in Th1, Th2 and Th17 cells. Conclusion: PV decreased the activity of the TLR9/MyD88 pathway and proinflammatory cytokines through HMGB1. In addition, we are the first to show that PV attenuated the HMGB1-induced increases in Th1, Th2 and Th17 cells in AIT models. These findings provide new evidence for the potential therapeutic value of PV as a treatment for AIT and other autoimmune diseases.

2.
Thromb Haemost ; 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34758489

RESUMO

BACKGROUND: As inpatients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) are at increased risk for venous thromboembolism (VTE), identifying high-risk patients requiring thromboprophylaxis is critical to reduce the mortality and morbidity associated with VTE. This study aimed to evaluate and compare the validities of the Padua Prediction Score and Caprini risk assessment model (RAM) in predicting the risk of VTE in inpatients with AECOPD. METHODS: The inpatients with AECOPD were prospectively enrolled from seven medical centers of China between September 2017 and January 2020. Caprini and Padua scores were calculated on admission, and the incidence of 3-month VTE was investigated. RESULTS: Among the 3277 eligible patients with AECOPD, 128 patients (3.9%) developed VTE within 3 months after admission. The distribution of the study population by the Caprini risk level was as follows: high, 53.6%; moderate, 43.0%; and low, 3.5%. The incidence of VTE increased by risk level as high, 6.1%; moderate, 1.5%; and low, 0%. According to the Padua RAM, only 10.9% of the study population was classified as high risk and 89.1% as low risk, with the corresponding incidence of VTE 7.9% and 3.4%, respectively. The Caprini RAM had higher area under curve (AUC) compared with the Padua RAM (0.713  0.021 vs 0.644 ± 0.023, P = 0.029). CONCLUSION: The Caprini RAM was superior to the Padua RAM in predicting the risk of VTE in inpatients with AECOPD and might better guide thromboprophylaxis in these patients.

3.
Anal Chem ; 93(46): 15493-15500, 2021 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-34752060

RESUMO

Depending on the reaction between walkers and tracks, DNA walker is able to output signals continuously, which has attracted great attention from the bioanalytical community. Therefore, how to improve its reaction kinetics for efficient signal readout is of great significance. Herein, a quadrilateral DNAzyme walker was fabricated by colocalizing one walker and three DNA tracks in the quadrilateral nucleic acid frame to form a reaction unit (abbreviated as qDNA walker). Impressively, in contrast to the common free DNAzyme walker, the reaction kinetics of the qDNA walker was 2.3 times faster, which could achieve microRNA detection within 30 min. Meanwhile, an electrochemiluminescence (ECL) emitter of anthracene-cucurbituril supramolecular nanocrystals (Ant-CB SNCs) was obtained based on the self-assembly of cucurbituril (CB, host molecule) and anthracene (Ant, guest molecule). Benefiting from the host-guest recognition effect, the prepared Ant-CB SNCs exhibited enhanced ECL efficiency due to the supramolecular interaction between CB and Ant, which could inhibit vibration and rotation of the Ant molecules. We defined this new enhanced ECL phenomenon as "host-guest recognition-enhanced ECL." As a proof of concept, an ECL biosensor for microRNA-21 (miRNA-21) was constructed by combining the high-efficiency DNAzyme walker and the advanced ECL emitter of Ant-CB SNCs, which showed a linear range from 50 aM to 50 pM with a low limit of detection (11 aM), highlighting the great potential in clinical diagnosis.


Assuntos
Técnicas Biossensoriais , DNA Catalítico , MicroRNAs , DNA , Técnicas Eletroquímicas , Cinética , Limite de Detecção , Medições Luminescentes
4.
Org Biomol Chem ; 19(44): 9723-9731, 2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34727149

RESUMO

Nickel-catalyzed cross-electrophile coupling of aryl chlorides with allylic alcohols proceeds readily under mild conditions in the presence of zinc powder and MgCl2 to produce allylarenes in 25-92% yields. The reaction shows high regioselectivity and E/Z-selectivity, giving linear allylation products with an E configurated double bond when 1- or 3-arylallyl alcohols were used as the substrates. Functional groups including F, CF3, COOEt, NMe2, OMe, SiMe3, OH and vinyl groups as well as nitrogen-containing heterocycles were tolerated.

5.
Adv Sci (Weinh) ; : e2102614, 2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34716671

RESUMO

Ferroelectrics usually exhibit temperature-triggered structural changes, which play crucial roles in controlling their physical properties. However, although light is very striking as a non-contact, non-destructive, and remotely controlled external stimuli, ferroelectric crystals with light-triggered structural changes are very rare, which holds promise for optical control of ferroelectric properties. Here, an organic molecular ferroelectric, N-salicylidene-2,3,4,5,6-pentafluoroaniline (SA-PFA), which shows light-triggered structural change of reversible photoisomerization between cis-enol and trans-keto configuration is reported. SA-PFA presents clear ferroelectricity with the saturate polarization of 0.84 µC cm-2 , larger than those of some typical organic ferroelectrics with thermodynamically structural changes. Benefit from the reversible photoisomerization, the dielectric real part of SA-PFA can be reversibly switched by light. More strikingly, the photoisomerization enables SA-PFA to show reversible optically induced ferroelectric polarization switching. Such intriguing behaviors make SPFA a potential candidate for application in next-generation photo-controlled ferroelectric devices. This work sheds light on further exploration of more excellent molecular ferroelectrics with light-triggered structural changes for optical control of ferroelectric properties.

6.
Chem Commun (Camb) ; 57(90): 11988-11991, 2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34709257

RESUMO

Synthesis of 1,4-enynes was performed via nickel-catalyzed cross-coupling of allylic alcohols with alkynylzinc reagents. The reaction features high regio- and E/Z-selectivity when aryl-substituted allylic alcohols were employed. The method also exhibits a wide scope of substrates and good compatibility of functional groups.

7.
Inorg Chem ; 60(21): 16871-16877, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34689557

RESUMO

Organic-inorganic hybrid metal halide perovskites possessing unique two-dimensional (2D)-layered structures have been demonstrated with excellent molecular tunability and stability, especially the promising semiconductor properties for solar cell applications. In this work, three 2D lead halide organic-inorganic hybrid perovskites (IAA)2PbX4 (IAA = isoamylammonium cation and X = Cl, Br, and I) were synthesized by employing a solution processing method and demonstrate distinct tuning solid-state phase transitions coupled with dielectric responses, as well as light absorption properties. Among the title perovskites, the phase transition temperature decreases gradually, and their band gap also indicates a narrowing trend. The results are mainly derived from slight changes in the crystal structure by halogen regulation. These findings might provide an effective crystal engineering strategy for exploring high-performance functional perovskite materials.

8.
Anal Chem ; 93(41): 13928-13934, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34609848

RESUMO

Herein, a new field-free and highly ordered spherical nucleic acid (SNA) nanostructure was self-assembled directly by ferrocene (Fc)-labeled DNA tweezers and DNA linkers based on the Watson-Crick base pairing rule, which was employed as an electrochemiluminescence (ECL) quenching switch with improved recognition efficiency due to the high local concentration of the ordered nanostructure. Moreover, with a collaborative strategy combined with the advantages of both self-accelerated approach and pore confinement-enhanced ECL effect, the mesoporous silica nanospheres (mSiO2 NSs) were prepared to be filled with rubrene (Rub) as ECL emitters and Pt nanoparticles (PtNPs) as coreaction accelerators (Rub-Pt@mSiO2 NSs), which demonstrated high ECL response in the aqueous media (dissolved O2 as coreactant). When the SNA nanostructure was immobilized on the Rub-Pt@mSiO2 NSs-modified electrode, it presented a "signal off" state owing to the quenching effect of the Fc molecules. As a proof of concept, the SNA-based ECL switch platform was applied in the detection of microRNA let-7b (let-7b). Impressively, in the presence of the target let-7b, a deconstruction of the SNA nanostructure was actuated, causing the Fc to leave the electrode surface and achieved an extremely high ECL recovery ("signal on" state). Hence, a sensitive determination for let-7b was realized with a low detection limit of 1.8 aM ranging from 10 aM to 1 nM by employing the Rub-Pt@mSiO2 NSs-based ECL platform combined with the target-triggered SNA deconstruction, which also offered an ingenious method for the further applications of biomarker analyses.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , MicroRNAs , Ácidos Nucleicos , Técnicas Eletroquímicas , Limite de Detecção , Medições Luminescentes
9.
Circulation ; 2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34503349

RESUMO

Background: Doxycycline was demonstrated in a retrospective study to be associated with greater survival in patients with light chain (AL) amyloidosis. Therefore, we prospectively compared the efficacy of bortezomib-cyclophosphamide-dexamethasone (CyBorD) and CyBorD combined with doxycycline for cardiac AL amyloidosis. Methods: This was a multicenter, open-label randomized controlled trial. Patients with Mayo 2004 stage II-III AL amyloidosis were included. Patients were randomized to doxycycline 100 mg twice daily along with 9 cycles of CyBorD (doxycycline group) or to 9 cycles of CyBorD alone (control group). The primary outcome was 2-year progression-free survival (PFS). PFS was defined as the time from randomization to death, hematologic progression or organ progression (heart, kidney or liver). Hematologic progression was defined based on substantial increase in free light chain. Increase in either N-terminal pro B-type natriuretic peptide or cardiac troponin was the main criterion for defining cardiac progression. Cardiac PFS, defined as the time from randomization to cardiac progression or death, was compared between groups in an exploratory analysis. The corresponding treatment hazard ratio was estimated using a Cox regression model. Results: 140 patients underwent randomization, with 70 in each group. The median age was 61 (range, 33-78) years with a male: female ratio of 1.75:1. Stage II disease was present in 34 (48.6%) and 33 (47.1%) patients in the doxycycline and control groups, respectively. After a median follow-up duration of 24.4 months, 32/70 (45.7%) of patients in the doxycycline group and 30/70 (42.9%) of patients in the control group experienced progression. PFS was not significantly different between groups (hazard ratio 0.97, 95% CI, 0.59-1.60, p=0.91). Cardiac progression occurred in 29/70 (41.4%) of patients in the doxycycline group and 26/70 (37.1%) of patients in the control group. The death rates for both groups by the end of follow-up was the same, 25/70 (35.7%). There were no significant differences observed for either cardiac PFS (hazard ratio 0.91, 95% CI, 0.54-1.55, p=0.74) or overall survival (hazard ratio 1.04, 95% CI, 0.60-1.81, p=0.89). Conclusions: Our trial demonstrated that doxycycline combined with CyBorD failed to prolong PFS or cardiac PFS compared with CyBorD alone in cardiac AL amyloidosis. Clinical Trial Registration: URL: https://clinicaltrials.gov Unique Identifier: NCT03401372.

10.
Chem Sci ; 12(29): 9991-9997, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34377393

RESUMO

Efficient asymmetric synthesis of a collection of small molecules with structural diversity is highly important to drug discovery. Herein, three distinct types of chiral cyclic compounds were accessible by enantioselective catalysis and sequential transformations. Highly regio- and enantioselective [2+2] cycloaddition of (E)-alkenyloxindoles with the internal C[double bond, length as m-dash]C bond of N-allenamides was achieved with N,N'-dioxide/Ni(OTf)2 as the catalyst. Various optically active spirocyclobutyl oxindole derivatives were obtained under mild conditions. Moreover, formal [4+2] cycloaddition products occurring at the terminal C[double bond, length as m-dash]C bond of N-allenamides, dihydropyran-fused indoles, were afforded by a stereospecific sequential transformation with the assistance of a catalytic amount of Cu(OTf)2. In contrast, performing the conversion under air led to the formation of γ-lactones via the water-involved deprotection and rearrangement process. Experimental studies and DFT calculations were performed to probe the reaction mechanism.

11.
Chemistry ; 27(60): 14831-14835, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34453371

RESUMO

Since the discovery of the first ferroelectric Rochelle salt, most ferroelectrics have been investigated showing thermally triggered symmetry-breaking phase transition. Although photochromism arising from geometrical isomerization was reported as early as 1867, such photoswitchable ferroelectric crystals have scarcely been developed to date. Herein, we report that salicylideneaniline is a photochromic ferroelectric crystal. Upon photoirradiation, the dielectric constant shows obvious switching between high and low dielectric states, and more importantly, the ferroelectric polarization demonstrates quick and reversible switching. This work opens the gate to developing photoswitchable ferroelectrics, which holds great potential for applications in optically controlled smart devices.

12.
Phytomedicine ; 90: 153627, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34247115

RESUMO

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disorder prevalent in the aged population. Tetrandrine is a natural metabolite isolated from herbal medicine Stephania tetrandra with various activities. PURPOSE: In this study, we investigated the therapeutic role of tetrandrine in 5XFAD mouse, a transgenic model of AD. METHODS: 5XFAD mice were intraperitoneally injected with saline or different doses of tetrandrine (10, 20, and 40 mg/kg per 2 days) from the age of 5 months to 7 months followed by the determination of cognitive ability, amyloid plaque load, cell apoptosis, and inflammation in the brain. In vitro, the protective roles of tetrandrine against inflammatory activation of microglia and the resulting neurotoxicity were studied in BV2 cells and differentiated PC12 cells, respectively. RESULTS: Morris water maze test showed that two months of tetrandrine treatment dose-dependently improved the cognitive ability of 5XFAD mice. Immunostaining against Aß 1-42 demonstrated reduced amyloid plaque deposition in the brain of tetrandrine-treated 5XFAD mice. TUNEL assay revealed decreased cell apoptosis in the hippocampus after tetrandrine treatment. Further, RT-PCR showed that the ectopic transcription of inflammation-associated genes including TNFα, IL-1ß, IL-6, COX-2, iNOS, and p65 was reversed in 5XFAD mice treated with tetrandrine. In vitro, Aß 1-42 stimulated the secretion of inflammatory cytokines TNFα and IL-1ß in microglial BV2 cells as determined by ELISA, which was suppressed by tetrandrine pre-treatment. Tetrandrine pre-treatment also inhibited the expression of TLR4, p65, iNOS, and COX-2 in BV2 cells induced by Aß 1-42. Most importantly, treatment of PC12-derived neuron-like cells with conditional medium from Aß 1-42-stimulated BV2 cells remarkably impaired cell viability and promoted cell apoptosis, which was attenuated by the conditional medium from BV2 cells with tetrandrine pre-treatment. CONCLUSION: Collectively, findings in this study demonstrated that tetrandrine ameliorates AD by suppressing microglia-mediated inflammation and neurotoxicity.


Assuntos
Doença de Alzheimer , Benzilisoquinolinas/farmacologia , Microglia/efeitos dos fármacos , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides , Animais , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , Fragmentos de Peptídeos
13.
Chem Sci ; 12(12): 4353-4360, 2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-34163698

RESUMO

A new strategy of asymmetric carbonyl catalysis via a chiral Lewis acid-bonded aldehyde has been developed for the direct Mannich/condensation cascade reaction of glycine ester with aromatic aldimines. The co-catalytic system of 2-picolinaldehyde and chiral YbIII-N,N'-dioxides was identified to be efficient under mild conditions, providing a series of trisubstituted imidazolidines in moderate to good yields with high diastereo- and enantioselectivities. Enantiodivergent synthesis was achieved via changing the sub-structures of the chiral ligands. The reaction could be carried out in a three-component version involving glycine ester, aldehydes, and anilines with equally good results. Based on control experiments, the X-ray crystal structure study and theoretical calculations, a possible dual-activation mechanism and stereo-control modes were provided to elucidate carbonyl catalysis and enantiodivergence.

14.
Analyst ; 146(14): 4566-4575, 2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34152330

RESUMO

p-Nitrophenol and its derivatives can cause serious harm to the health of mankind and the earth's ecosystem. Therefore, it is necessary to develop a novel and rapid detection technology for p-nitrophenol and its derivative. Herein, excellent water-soluble, large-size and dual-emissive neuron cell-analogous carbon-based probes (NCNPs) have been prepared via a solvothermal approach, using o-phenylenediamine as the only precursor, which exhibit two distinctive fluorescence (FL) peaks at 420 and 555 nm under 345 nm excitation. The NCNPs show a neuron cell-like branched structure, are cross-connected, and are in the range of 10-20 nm in skeleton diameter. Interestingly, their blue-green dual-colour fluorescence is quenched by p-nitrophenol or its derivative due to the specific mechanism of the ππ stacking interactions or internal filtration effect. Accordingly, a simple, rapid, direct and free-label ratiometric FL detection of p-nitrophenol is proposed. An excellent linear relationship shows linear regions over the range of 0.1-50 µM between the ratio of the FL intensity (FL555 nm/FL420 nm) and the concentrations of p-nitrophenol. The detection limit is as low as 43 nM (3σ). Importantly, the NCNP-based probe also shows acceptable repeatability and reproducibility for the detection of p-nitrophenol and its derivatives, and the recovery results for p-nitrophenol in real wastewater samples are favourable.


Assuntos
Pontos Quânticos , Ecossistema , Corantes Fluorescentes , Neurônios , Nitrofenóis , Reprodutibilidade dos Testes
15.
Org Biomol Chem ; 19(23): 5082-5086, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34037055

RESUMO

Ni(PEt3)Cl2-catalyzed silylation of alkyl aryl sulfoxides with silylzinc reagents was carried out. This protocol allows alkyl aryl sulfoxides to convert to arylsilicon compounds under mild reaction conditions, tolerates a range of functional groups and is suitable for a wide scope of substrates.

16.
J Phys Chem Lett ; 12(21): 5221-5227, 2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-34043361

RESUMO

Organic-inorganic hybrid lead halide perovskites have attracted great interest for their use in promising optoelectronic applications. However, reports of photoluminescent perovskite molecular ferroelastic semiconductors with sequential high-Tc phase transitions have been scarce. In this work, a one-dimensional lead bromide hybrid perovskite [N,N-dimethylethanolammonium]PbBr3 has been synthesized, undergoing high-Tc sequential phase transitions at around 351 and 444 K, higher than those of most previously discovered hybrid perovskite phase transition materials. The specific intermolecular hydrogen bond between cationic molecules provides the greatest contribution to its high Tc by increasing the barrier of molecular motion under the temperature stimuli. The prominent ferroelastic domain evolution is visually observed under orthogonally polarized light. In addition, [N,N-dimethylethanolammonium]PbBr3 exhibits semiconducting and orange light emission characteristics. This finding opens up an avenue for designing high-performance ferroelastic materials and provides great motivation for discovering new multifunctional materials for the next generation of smart devices.

17.
Biol Pharm Bull ; 44(5): 714-723, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33952827

RESUMO

Ischemia-reperfusion injury (IRI) is the major cause of acute kidney injury (AKI). The previous studies demonstrated that Oridonin can protect kidney against IRI-induced AKI, but the underlying molecular mechanism is unclear. In this study, it showed that Oridonin significantly improved kidney damage, and inhibited the expression of interleukin (IL)-1ß, IL-6, tumor necrosis factor (TNF)-α and MCP-1, as well as macrophage marker F4/80 in kidney and the secretion of inflammatory cytokins in serum of AKI mice in vivo. In addition, Oridonin also effectively reduced the expression and secretion of lipopolysaccharide (LPS)-induced inflammatory factors in macrophage cell line RAW264.7 in vitro. Notably, Oridonin strongly downregulated Mincle and AKT/nuclear factor-kappaB (NF-κB) signaling both in vivo and in vitro, and the results of cellular recovery experiments of overexpression of Mincle in macrophage suggested that Oridonin suppressed inflammatory response of macrophage through inhibiting Mincle, which may be the underlying mechanism of Oridonin improving injury in kidney of AKI mice. In summary, the above results indicated that Oridonin can protect kidney from IRI-induced inflammation and injury by inhibiting the expression of Mincle in macrophage.


Assuntos
Injúria Renal Aguda/prevenção & controle , Diterpenos do Tipo Caurano/farmacologia , Macrófagos/efeitos dos fármacos , Traumatismo por Reperfusão/tratamento farmacológico , Injúria Renal Aguda/imunologia , Injúria Renal Aguda/patologia , Animais , Modelos Animais de Doenças , Diterpenos do Tipo Caurano/uso terapêutico , Humanos , Mediadores da Inflamação/antagonistas & inibidores , Mediadores da Inflamação/metabolismo , Rim/irrigação sanguínea , Rim/efeitos dos fármacos , Rim/imunologia , Rim/patologia , Lectinas Tipo C/antagonistas & inibidores , Lectinas Tipo C/metabolismo , Lipopolissacarídeos/administração & dosagem , Lipopolissacarídeos/imunologia , Macrófagos/imunologia , Masculino , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/metabolismo , Camundongos , Células RAW 264.7 , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/imunologia
18.
Talanta ; 226: 122067, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33676643

RESUMO

The preparation of boron-carbon-oxygen (BCO)-based heterostructure needs commonly high temperature, high pressure and/or auxiliary strong oxidant. And the BCO-based probe for the sensing application is still rare owing to their few active groups, low quantum yield or missing specificity. Exploring BCO-based heterostructured probe via simple routes and application in sensing, therefore, is highly challenging. Herein, we proposed a novel boron-carbon-phosphorus-oxygen (BCPO) nanodot with phosphate tunable near-ultraviolet emission performance and narrow full width at half maximum by a facile, green and gentle synthesis process. The BCPO not only exhibits a distinctive colorimetric response to 6-mercaptopurine (6-MP), but also displays 6-MP-sensitive photoluminescence quenching. Thus, dual detection channels for 6-MP based on BCPO probe have been developed, and the mechanism has been speculated. Enrichment-electron of the 6-MP can be adsorbed at the boron vacancy orbits of the BCPO by the chemical action. The formation of 6-MP/BCPO complexes trigger the efficient photoluminescence quenching and light-absorbing enhancing of the BCPO, owing to the synergistic effect of the acceptor-excited photo-induced electron/energy transfer, inner filter effect and p/π-π conjugated stacking. Furthermore, the presence of ClO- anion efficaciously sparks the release of the 6-MP molecule from the 6-MP/BCPO complexes, thereby a rapid photo-switch of the BCPO for the 6-MP has been developed. Thus, this study can not only guide the further rational design of the BCPO probe, but also inspire the in-depth application of the BCPO and other nanomaterial-based probes.


Assuntos
Carbono , Pontos Quânticos , Boro , Mercaptopurina , Fosfatos
19.
Anal Chem ; 93(12): 5301-5308, 2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33739818

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are regarded as promising electrochemiluminescent (ECL) emitters owing to their high quantum efficiency and inexpensive production. Despite the fact that the ECL properties of the pure PAH microcrystal (such as rubrene microcrystals, Rub MCs) have gained extensive attention, it is a challenge in controlling the morphology and size to reduce the inner filter effect. Herein, an advanced ECL emitter of palladium nanoparticle-functionalized hollow PAH-metal nanocubes was prepared by an in situ redox deposition method (the resultant nanocomposites were abbreviated as Pd-Rub-Ag@Au nanocubes). Specifically, the rubrene-decorated Ag@Au nanocubes (Rub-Ag@Au nanocubes) were prepared using the Ag@Au nanocubes as a template and a rubrene cation radical (Rub•+) as a reductant, and then Pd nanoparticles (Pd NPs) were in situ reduced on the surface of Rub-Ag@Au nanocubes. Impressively, compared with the Rub MCs, Pd-Rub-Ag@Au nanocubes showed uniform size and significantly enhanced ECL efficiency and intensity in the aqueous media. As a proof-of-concept, the Pd-Rub-Ag@Au nanocube-based ECL biosensing platform combined with a multisite-anchored DNA nanomachine was constructed for ochratoxin A (OTA, a type of mycotoxin) detection. The DNA nanomachine covered with high-density recognizing sequences could operate toehold-mediated strand displacement amplification on the sensing platform and promote the movement efficiency and velocity greatly. Due to the advanced performance of Pd-Rub-Ag@Au nanocubes and high recognition efficiency of the DNA nanomachine, the proposed biosensor for OTA detection can achieve a detection limit of 4.7 fg/mL ranging from 0.01 to 100 pg/mL, which offers an ingenious method for the further application of PAHs.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Micotoxinas , DNA , Técnicas Eletroquímicas , Ouro , Limite de Detecção , Medições Luminescentes
20.
Angew Chem Int Ed Engl ; 60(19): 10730-10735, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33645889

RESUMO

Chiral perovskites have emerged as a significant class of materials showing promising optoelectronic and spintronic applications. Reports of chiral perovskite ferroelectrics, however, have been scarce. In this work, we have successfully synthesized homochiral lead-iodide perovskite ferroelectrics [(R)-N-(1-phenylethyl)ethane-1,2-diaminium]PbI4 and [(S)-N-(1-phenylethyl)ethane-1,2-diaminium]PbI4 by introducing a methyl group into the organic cation of the parent (N-benzylethane-1,2-diaminium)PbI4 . Vibrational circular dichroism spectra identify the chiral mirroring relationship. They both undergo 222F2-type paraelectric-ferroelectric behavior at around 378 K coupled with clear ferroelastic domain "ON/OFF" switching. Besides, they exhibit an evident thermochromism with color change from orange-yellow to orange-red. To our knowledge, the discovery of integrated ferroelectricity, ferroelasticity, and reversible thermochromism in chiral perovskites is unprecedented.

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