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1.
Bioresour Technol ; 319: 124163, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33254444

RESUMO

Hydrothermal liquefaction (HTL) of Gracilaria corticata (GC) macroalgae was studied over a series of nickel-iron-layered double oxides (NiFe-LDO) supported on activated bio-char catalysts at 280 °C and different solvents medium. Maximum bio-oil yield (56.2 wt%) was found with 5%Ga/NiFe-LDO/AC catalyst at 280 °C under ethanol solvent. The catalytic HTL up-gradation decreased the bio-char yield significantly. However the bio-oil quality significantly improved with using the 5%Ga/NiFe-LDO/AC catalyst. Also, improved performance with higher amount of bio-oil and lower amounts of bio-char and gas were achieved, which is due the several reactions happening during the HTL process. Catalytic HTL also revealed that introducing NiFe-LDO nanosheets into the activated char could result in NiFe-LDO/AC catalysts of higher surface area and increased active sites. Being impregnated by 5%Ga, catalysts with improved acid sites and thereby, advanced deoxygenation and aromatization activities were achieved. Hence Ga/NiFe-LDO/AC could be considered as a promising catalyst HTL bio-oil upgrading.


Assuntos
Gracilaria , Alga Marinha , Biocombustíveis , Biomassa , Óleos Vegetais , Polifenóis , Temperatura , Água
2.
Amino Acids ; 2020 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-33236256

RESUMO

Protonectin was a typical amphiphilic antimicrobial peptide with potent antimicrobial activity against Gram-positive and Gram-negative bacteria. In the present study, when its eleventh amino acid in the sequence was substituted by phenylalanine, the analog named phe-Prt showed potent antimicrobial activity against Gram-positive bacteria, but no antimicrobial activity against Gram-negative bacteria, indicating a significant selectivity between Gram-positive bacteria and Gram-negative bacteria. However, when Gram-negative bacteria were incubated with EDTA, the bacteria were susceptible to phe-Prt. Next, the binding effect of phe-Prt with LPS was determined. Our result showed that LPS could hamper the bactericidal activity of phe-Prt against Gram-positive bacteria. The result of zeta potential assay further confirmed the binding effect of phe-Prt with LPS for it could neutralize the surface charge of E. coli and LPS. Then, the effect of phe-Prt on the integrity of outer membrane of Gram-negative bacteria was determined. Our results showed that phe-Prt had a much weaker disturbance to the outer membrane of Gram-negative bacteria than the parent peptide protonectin. In summary, the introduction of L-phenylalanine into the sequence of antimicrobial peptide protonectin made phe-Prt show significant selectivity against Gram-positive bacteria, which could partly be attributed to the delay effect of LPS for phe-Prt to access to cell membrane. Although further study is still needed to clarify the exact mechanism of selectivity, the present study provided a strategy to develop antimicrobial peptides with selectivity toward Gram-positive and Gram-negative bacteria.

3.
Drug Deliv ; 27(1): 1176-1187, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32762483

RESUMO

Icaritin (ICT) and hydrous icaritin (HICT) are two similar flavonoids compounds isolated from Epimedium Genus. This is the first comparative study on their in vitro and in vivo antitumor effects. Nanorods (NRs) were prepared for ICT and HICT by anti-solvent precipitation method using D-alpha tocopherol acid polyethylene glycol succinate (TPGS) as a stabilizer. The prepared ICT-NRs and HICT-NRs had similar diameter (155.5 nm and 201.7 nm), high drug loading content (43.30 ± 0.22% and 41.08 ± 0.19%), excellent stability and a similar sustaining drug release manner. Nanorods improved the in vitro toxicity against 4 different cancer cells in contrast to free ICT or free HICT; however, no significant difference was observed in this regard between ICT-NRs and HICT NRs. In the in vivo study on the anticancer efficacy on MCF-7 and PLC/PRE/5 tumor-bearing mice model, HICR-NRs displayed certain advantage over ICT NRs with higher tumor inhibition rate.

4.
J Med Virol ; 2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32691881

RESUMO

We aim to systematically review the characteristics of asymptomatic infection in the coronavirus disease 2019 (COVID-19). PubMed and EMBASE were electronically searched to identify original studies containing the rate of asymptomatic infection in COVID-19 patients before 20 May 2020. Then mate-analysis was conducted using R version 3.6.2. A total of 50 155 patients from 41 studies with confirmed COVID-19 were included. The pooled percentage of asymptomatic infection is 15.6% (95% CI, 10.1%-23.0%). Ten included studies contain the number of presymptomatic patients, who were asymptomatic at screening point and developed symptoms during follow-up. The pooled percentage of presymptomatic infection among 180 initially asymptomatic patients is 48.9% (95% CI, 31.6%-66.2%). The pooled proportion of asymptomatic infection among 1152 COVID-19 children from 11 studies is 27.7% (95% CI, 16.4%-42.7%), which is much higher than patients from all aged groups. Abnormal CT features are common in asymptomatic COVID-19 infection. For 36 patients from 4 studies that CT results were available, 15 (41.7%) patients had bilateral involvement and 14 (38.9%) had unilateral involvement in CT results. Reduced white blood cell count, increased lactate dehydrogenase, and increased C-reactive protein were also recorded. About 15.6% of confirmed COVID-19 patients are asymptomatic. Nearly half of the patients with no symptoms at detection time will develop symptoms later. Children are likely to have a higher proportion of asymptomatic infection than adults. Asymptomatic COVID-19 patients could have abnormal laboratory and radiational manifestations, which can be used as screening strategies to identify asymptomatic infection.

5.
Sci Rep ; 10(1): 8851, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32483248

RESUMO

As one of the main components of Tripterygium wilfordii Hook F, celastrol (CSL) has significant antitumor activity, but its clinical application has been limited by its poor solubility, low oral bioavailability and systemic toxicity. In this study, celastrol nanosuspensions (CSL-NSps) were prepared using an antisolvent precipitation method with poloxamer 188 (P-188) as a stabilizer at a high CSL/P-188 feeding ratio of 8:1. The resultant CSL was spherical in shape with an average particle size of 147.9 nm, a polydispersity index (PDI) of 0.12 and zeta potential of -19.2 mV. The encapsulation efficiency and drug loading content were 98.18% and 86.83%, respectively, and the X-ray diffraction (XRD) pattern showed that CSL existed in an amorphous state in the nanosuspensions. CSL-NSps were quite stable in various physiological media and plasma and were both suitable for oral and intravenous administration. Nanosuspensions greatly enhanced the in vitro dissolution, and the cumulative drug release reached approximately 69.20% within 48 h. In vivo, CSL-NSps (3 mg/kg, i.g.) displayed a significantly enhanced tumor inhibition rate (TIR) in comparison with that of CSL suspension when administered orally (TIR, 50.39%, vs. 41.16%, p < 0.05),  similar to that of PTX injection (8 mg/kg, i.v. TIR, 50.88%). CSL-NSps showed even better therapeutic efficacy than PTX injection (TIR, 64.18%, p < 0.01) when intravenously injected. This has demonstrated that, with the help of nanosuspensions, CSL is likely to be an effective and promising antitumor agent in clinic practice for the treatment of breast cancer.


Assuntos
Antineoplásicos/química , Portadores de Fármacos/química , Nanoestruturas/química , Triterpenos/química , Administração Oral , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Sobrevivência Celular , Liberação Controlada de Fármacos , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Tamanho da Partícula , Temperatura , Transplante Heterólogo , Triterpenos/farmacologia , Triterpenos/uso terapêutico
6.
Drug Deliv ; 27(1): 816-824, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32489130

RESUMO

Hydroxy genkwanin (HGK), a flavonoid compound from natural resources, showed good inhibition against the growth of breast tumor cells. However, the poor solubility restricted the further study and the in vivo drug delivery of HGK. We prepared HGK nanosuspensions by antisolvent precipitation method and investigated their characterization, stability, hemolysis probability, release behavior in vitro, antitumor activity in vitro and in vivo, and preliminary safety through acute toxicity experiments. The resultant HGK nanosuspensions (HGK-NSps) showed an average diameter of (261.1 ± 4.8 nm), a narrow particle size distribution (PDI of 0.12 ± 0.01), spherical morphology, high drug-loading content (39.9 ± 2.3%, w/w), and good stability in various physiological media. HGK-NSps was safe for intravenous injection at low concentration and HGK was slowly released from the obtained nanosuspensions. HGK-NSps showed stronger cytotoxicity than free HGK against many tumor cells in vitro. Especially against MCF-7 cells, the IC50 value was decreased to 1.0 µg/mL, 5-fold lower than the HGK solution. In the in vivo antitumor activity study HGK-NSps (40 mg/kg) displayed a similar therapeutic effect to that of the paclitaxel injection (8 mg/kg). The preliminary acute toxicity test showed that even at the highest dose of 360 mg/kg (iv), HGK-NSps had 100% of mice survival and all the mice were in a good state, suggesting a maximum tolerated dose more than 360 mg/kg. The effective antitumor effect and good tolerance showed HGK-NSps were likely to become a safe and effective antitumor drug for the treatment of breast cancer in the future.

7.
Anal Chem ; 92(11): 7940-7946, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32406677

RESUMO

Monitoring the ATP levels in lysosomes in situ is crucial for understanding their involvement in various biological processes but remains difficult due to the interference of ATP in other organelles or the cytoplasm. Here, we report a lysosome-specific fluorescent carbon dot (CD), which can be used to detect ATP in acidic lysosomes with "off-on" changes of yellow fluorescence. These CDs were successfully applied in real-time monitoring of the fluctuating concentration of lysosomal ATP induced by drug stimulation (e.g., chloroquine, etoposide, and oligomycin). Because of the excellent specificity, these CDs are promising agents for drug screening and medical diagnostics through lysosomal ATP monitoring.

8.
Water Sci Technol ; 81(4): 813-823, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32460284

RESUMO

A nitrogen-doped reduced graphene oxide/Fe3O4 composite (NGO-Fe3O4) was prepared through the simplified hydrothermal and deposition-precipitation method and characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. The degradation efficiency of oxytetracycline (OTC) by NGO-Fe3O4 activated peroxodisulfate (PDS) under visible light irradiation was studied. The degradation efficiency reached 100% within 32.5 min (the initial OTC concentration 50 mg L-1 and PDS 1 mM; [NGO-Fe3O4]:[ PDS] = 4:1; pH = 3.0). No apparent decrease in degradation efficiency was observed after five cycles. SO4-· and ·OH were the main active oxides for OTC degradation in this system. Moreover, four degradation pathways were proposed, namely hydroxylation, dehydration, decarbonylation and demethylation according to the analysis results of high-performance liquid chromatography mass spectrometry.


Assuntos
Oxitetraciclina , Luz , Microscopia Eletrônica de Varredura , Óxidos , Difração de Raios X
9.
PLoS Biol ; 18(4): e3000491, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32282798

RESUMO

Nervous systems exploit regularities in the sensory environment to predict sensory input, adjust behavior, and thereby maximize fitness. Entrainment of neural oscillations allows retaining temporal regularities of sensory information, a prerequisite for prediction. Entrainment has been extensively described at the frequencies of periodic inputs most commonly present in visual and auditory landscapes (e.g., >0.5 Hz). An open question is whether neural entrainment also occurs for regularities at much longer timescales. Here, we exploited the fact that the temporal dynamics of thermal stimuli in natural environment can unfold very slowly. We show that ultralow-frequency neural oscillations preserved a long-lasting trace of sensory information through neural entrainment to periodic thermo-nociceptive input as low as 0.1 Hz. Importantly, revealing the functional significance of this phenomenon, both power and phase of the entrainment predicted individual pain sensitivity. In contrast, periodic auditory input at the same ultralow frequency did not entrain ultralow-frequency oscillations. These results demonstrate that a functionally significant neural entrainment can occur at temporal scales far longer than those commonly explored. The non-supramodal nature of our results suggests that ultralow-frequency entrainment might be tuned to the temporal scale of the statistical regularities characteristic of different sensory modalities.


Assuntos
Encéfalo/fisiologia , Percepção da Dor/fisiologia , Dor/fisiopatologia , Estimulação Acústica , Adulto , Eletroencefalografia , Feminino , Humanos , Lasers , Masculino , Dor/psicologia , Medição da Dor , Processamento de Sinais Assistido por Computador
10.
Drug Deliv ; 27(1): 228-237, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32003229

RESUMO

Due to their various biological activities that are beneficial to human health and antitumor effect, flavonoid compounds have attracted much attention in recent years. Hydrous icaritin (HICT) was such a flavonoid that can inhibit the growth of breast cancer and cancer stem cells. In order to overcome the insolubility problem, HICT was fabricated into nanorods (NRs) through anti-solvent precipitation in this paper using D-α tocopherol acid polyethylene glycol succinate and sodium oleate as a co-stabilizer meanwhile using the mixture of ethanol and acetone (1:2, v/v) as the organic solvent. The obtained HICT NRs showed an average particle size 222.0 nm with a small polydispersity index value of 0.124 and a high zeta potential of - 49.5 mV. HICT NRs could maintain similar particle size in various physiological medium and could be directly lyophilized without the addition of any cytoprotectants and then reconstituted into a colloidal system of similar size. The resultant HICT NRs had a high drug loading content of 55.6% and released HICT in a steady and constant pattern. MTT assay indicated NRs enhanced HICT's antitumor activity to ninefold against MCF-7 breast carcinoma cells. In vivo studies demonstrated oral administration free HICT had almost no tumor inhibitory effect while HICT NRs showed a tumor inhibition rate of 47.8%. When intravenously injected, HICT NRs displayed similar therapeutic efficacy to paclitaxel injections (70.4% vs. 74.5%, TIR). This may be partly due to the high accumulation of the injected HICT NRs in tumor ranking only second to that in the liver but much higher than in other organs. These results demonstrated that HICT NRs could be a promising antitumor agent for the treatment of breast cancer in clinic.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Flavonoides/farmacologia , Nanotubos , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Estabilidade de Medicamentos , Feminino , Flavonoides/administração & dosagem , Humanos , Injeções Intravenosas , Células MCF-7 , Camundongos , Camundongos Nus , Paclitaxel/administração & dosagem , Paclitaxel/farmacologia , Tamanho da Partícula
11.
Colloids Surf B Biointerfaces ; 189: 110876, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32088559

RESUMO

Poly(methacrylate oligoethylene glycol dendron-co-citric acid) (PGCA) that is based on citric acid and oligoethylene glycol (OEG) dendrons is utilized as a nanomaterial for the removal of heavy metal ions from aqueous solution. PGCA shows excellent solubility in aqueous solution and realizes satisfactory removal efficacy for Pb2+ ions; the removal rate exceeds 95 %. In addition, PGCA can be utilized in Chinese herbal decoctions; the removal rate of Pb2+ ions in the ligusticum wallichii decoction exceeds 90 %, meanwhile the concentration of the active ingredient, namely, ferulic acid, is maintained. In this nanoadsorbent, citric acid provides the active site for the chelation of heavy metal ions, and OEG dendron serves as a protective layer that reduces the opportunity for carboxyl groups to be occupied by other ingredients. In summary, nanomaterial PGCA is designed and synthesized successfully that can be applied as a nanoadsorbent for the removal of Pb2+ ions from aqueous solution, especially in Chinese herbal decoctions that have acidic compounds as active ingredients.

12.
Mol Pharm ; 17(4): 1205-1214, 2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32073273

RESUMO

The composition of amphiphilic nanocarriers can affect the antitumor efficacy of drug-loaded nanoparticles and should be researched systematically. In this paper, to study the influence of hydrophobic chains, an amphiphilic copolymer (PEG45PCL17) and hydrophilic PEG (PEG45) were utilized as nanocarriers to prepare docetaxel-loaded nanoparticles (DTX/PEG45PCL17 nanoparticles and DTX/PEG45 nanoparticles) through an antisolvent precipitation method. The two DTX nanoparticles presented a similar drug loading content of approximately 60% and a sheet-like morphology. During the preparation procedure, the drug loading content affected the morphology of DTX nanoparticles, and the nanocarrier composition influenced the particle size. Compared with DTX/PEG45 nanoparticles, DTX/PEG45PCL17 nanoparticles showed a smaller mean diameter and better in vitro and in vivo antitumor activity. The cytotoxicity of DTX/PEG45PCL17 nanoparticles against 4T1 cells was 1.31 µg mL-1, 3.4-fold lower than that of DTX/PEG45 nanoparticles. More importantly, DTX/PEG45PCL17 nanoparticles showed significantly higher antitumor activity in vivo, with an inhibition rate over 80%, 1.5-fold higher than that of DTX/PEG45 nanoparticles. Based on these results, antitumor activity appears to be significantly affected by the particle size, which was determined by the composition of the nanocarrier. In summary, to improve antitumor efficacy, the amphiphilic structure should be considered and optimized in the design of nanocarriers.

13.
J Nanobiotechnology ; 18(1): 4, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31907045

RESUMO

Disulfiram (DSF) has been considered as "Repurposing drug" in cancer therapy in recent years based on its good antitumor efficacy. DSF is traditionally used as an oral drug in the treatment of alcoholism. To overcome its rapid degradation and instability, DSF nanosuspensions (DSF/SPC-NSps) were prepared using soybean lecithin (SPC) as a stabilizer of high drug-loaded content (44.36 ± 1.09%). Comprehensive characterization of the nanosuspensions was performed, and cell cytotoxicity, in vivo antitumor efficacy and biodistribution were studied. DSF/SPC-NSps, having a spherical appearance with particle size of 155 nm, could remain very stable in different physiological media, and sustained release. The in vitro MTT assay indicated that the cytotoxicity of DSF/SPC-NSps was enhanced remarkably compared to free DSF against the 4T1 cell line. The IC50 value decreased by 11-fold (1.23 vs. 13.93 µg/mL, p < 0.01). DSF/SPC-NSps groups administered via intravenous injections exhibited better antitumor efficacy compared to the commercial paclitaxel injection (PTX injection) and had a dose-dependent effect in vivo. Notably, DSF/SPC-NSps exhibited similar antitumor activity following oral administration as PTX administration via injection into a vein. These results suggest that the prepared nanosuspensions can be used as a stable delivery vehicle for disulfiram, which has potential application in breast cancer chemotherapy.


Assuntos
Antineoplásicos/farmacologia , Dissulfiram/farmacologia , Lecitinas/química , Nanopartículas/química , Soja/química , Animais , Varredura Diferencial de Calorimetria , Linhagem Celular Tumoral , Dissulfiram/química , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Feminino , Camundongos Endogâmicos BALB C , Nanopartículas/ultraestrutura , Tamanho da Partícula , Eletricidade Estática , Suspensões , Distribuição Tecidual/efeitos dos fármacos , Resultado do Tratamento , Difração de Raios X
14.
Colloids Surf B Biointerfaces ; 187: 110656, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31796243

RESUMO

Heavy metal ion in aqueous solutions has been a challenge to human health. Discovering efficient adsorbents to remove heavy metal ion from water can help address this problem. In this study, poly(methacrylate citric acid) (PCA) with a well-defined structure based on a hydrophilic citric acid monomer was synthesized and then applied as a nanoadsorbent to remove several heavy metal ion. PCA presented excellent solubility in aqueous solution, and after freeze-drying, a loose porous structure was observed. PCA exhibited higher adsorption capacity for all the heavy metal ions (Cu2+, Pb2+, and Cd2+) than citric acid, and had a selectivity for Pb2+ ions with a removal efficiency of >90%. PCA also showed a good selectivity for adsorption of Pb2+ in a Chinese medicine decoction, with a removal rate >50%, while the concentration of active ingredient was maintained. Cell cytotoxicity in a cell model and system toxicity in mice indicated good biosafety of PCA. These results suggested that PCA with a good biosafety could be utilized as nanoadsorbent to remove Pb2+ ion from aqueous solution and decoction.

15.
ACS Omega ; 4(10): 14162-14168, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31508537

RESUMO

Heavy metal ions in aqueous solutions are harmful to human health, but exploring and exploiting nanoadsorbents with a high adsorption capacity and low cost should be an effective method for overcoming this problem. In this study, a novel nanoadsorbent termed poly(N-isopropylacrylamide-co-citric acid) (PNCA) was designed and synthesized via free-radical polymerization. PNCA exhibits good solubility in aqueous solutions and can self-assemble into spherical nanoaggregates with a mean hydrodynamic diameter of approximately 723.1 nm. After freeze-drying, the solid powder of PNCA exhibited a loose porous structure. When PNCA is dissolved in water, the resulting copolymer solution exhibits high removal rates for Cu2+ and Pb2+ of over 80%; meanwhile, over 97% of the PNCA is precipitated with metal ions. The adsorption process of PNCA chelated with Cu2+ ions fit the Freundlich model. The adsorption capacity is independent of the media pH, but could be affected by the temperature. Except for herbal medicines with alkaloids as active ingredients, PNCA also presents good adsorption capacity for Cu2+ in herbal medicine decoctions, with a removal rate of over 80%. The cell cytotoxicity in vitro and system toxicity in vivo demonstrate the desirable biosafety of PNCA. These results suggest that PNCA with good biosafety can be utilized as a nanoadsorbent to remove the metal ions, especially Cu2+, in different media.

16.
Viruses ; 11(9)2019 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-31443406

RESUMO

Members of the interleukin 12 (IL-12) family have been known to be inflammatory factors since their discovery. The IL-12 family consists of IL-12, IL-23, IL-27, IL-35, and a new member, IL-39, which has recently been identified and has not yet been studied extensively. Current literature has described the mechanisms of immunity of these cytokines and potential uses for therapy and medical cures. IL-12 was found first and is effective in combatting a wide range of naturally occurring viral infections through the upregulation of various cytokines to clear the infected cells. IL-23 has an essential function in immune networks, can induce IL-17 production, and can antagonize inhibition from IL-12 in the presence of T helper (Th) 17 cells, resulting in type II IFN (IFN-γ) regulation. IL-27 has a competitive relationship to IL-35 because they both include the same subunit, the Epstein-Barr virus-induced gene3 (EBi3). This review provides a simple introduction to the IL-12 family and focuses on their functions relevant to their actions to counteract viral infections.


Assuntos
Citocinas , Interleucina-12 , Viroses/imunologia , Imunidade Adaptativa , Animais , Antivirais , Citocinas/biossíntese , Citocinas/imunologia , Citocinas/uso terapêutico , Humanos , Imunidade Inata , Interferon gama/metabolismo , Interleucina-12/biossíntese , Interleucina-12/imunologia , Interleucina-17/biossíntese , Interleucina-17/metabolismo , Interleucina-23/biossíntese , Interleucina-23/imunologia , Interleucina-27/biossíntese , Interleucina-27/imunologia , Interleucinas/biossíntese , Interleucinas/imunologia , Células Th1/imunologia , Células Th1/metabolismo , Células Th17/metabolismo , Viroses/tratamento farmacológico
17.
Small ; 15(48): e1901517, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31165584

RESUMO

Mitochondria play a significant role in many cellular processes. Precise long-term tracking of mitochondrial status and behavior is very important for regulating cell fate and treating mitochondrial diseases. However, developing probes with photostability, long-term tracking capability, and tunable long-wavelength fluorescence has been a challenge in mitochondrial targeting. Carbon dots (CDs) as new fluorescent nanomaterials with low toxicity and high stability show increasing advantages in bioimaging. Herein, the mitochondria tracking CDs (MitoTCD) with intrinsic mitochondrial imaging capability and tunable long-wavelength fluorescence from green to red are synthesized where the lipophilic cation of rhodamine is served as the luminescent center of CDs. Due to the excellent photostability, superior fluorescence properties and favorable biocompatibility, these MitoTCD are successfully used for mitochondrial targeting imaging of HeLa cells in vitro and can be tracked as long as six passages, which is suitable for long-term cell imaging. Moreover, these MitoTCD can also be used for zebrafish imaging in vivo.


Assuntos
Carbono/química , Mitocôndrias/metabolismo , Pontos Quânticos/química , Sobrevivência Celular , Fluorescência , Células HeLa , Humanos , Tamanho da Partícula , Pontos Quânticos/ultraestrutura
18.
Org Biomol Chem ; 17(22): 5514-5519, 2019 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-31115424

RESUMO

Pharmaceutically important compounds were synthesized through the organocatalytic 1,3-dipolar cycloaddition reaction. In the presence of a cinchonine-derived squaramide catalyst, the cycloaddition of N-2,2,2-trifluoroethylisatin ketimines with α,ß-unsaturated pyrazolones gave a spiro-pyrrolidine-linked oxindole and pyrazolone compound bearing four consecutive stereocenters and two vicinal spiroquaternary chiral centers, in excellent yields and stereoselectivities.

19.
Neuroimage ; 198: 221-230, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31085301

RESUMO

Survival in a suddenly-changing environment requires animals not only to detect salient stimuli, but also to promptly respond to them by initiating or revising ongoing motor processes. We recently discovered that the large vertex brain potentials elicited by sudden supramodal stimuli are strongly coupled with a multiphasic modulation of isometric force, a phenomenon that we named cortico-muscular resonance (CMR). Here, we extend our investigation of the CMR to the time-frequency domain. We show that (i) both somatosensory and auditory stimuli evoke a number of phase-locked and non-phase-locked modulations of EEG spectral power. Remarkably, (ii) some of these phase-locked and non-phase-locked modulations are also present in the Force spectral power. Finally, (iii) EEG and Force time-frequency responses are correlated in two distinct regions of the power spectrum. An early, low-frequency region (∼4 Hz) reflects the previously-described coupling between the phase-locked EEG vertex potential and force modulations. A late, higher-frequency region (beta-band, ∼20 Hz) reflects a second coupling between the non-phase-locked increase of power observed in both EEG and Force. In both time-frequency regions, coupling was maximal over the sensorimotor cortex contralateral to the hand exerting the force, suggesting an effect of the stimuli on the tonic corticospinal drive. Thus, stimulus-induced CMR occurs across at least two different types of cortical activities, whose functional significance in relation to the motor system should be investigated further. We propose that these different types of corticomuscular coupling are important to alter motor behaviour in response to salient environmental events.


Assuntos
Percepção Auditiva/fisiologia , Ondas Encefálicas , Encéfalo/fisiologia , Desempenho Psicomotor/fisiologia , Percepção do Tato/fisiologia , Estimulação Acústica , Adulto , Fenômenos Biomecânicos , Feminino , Mãos , Humanos , Contração Isométrica , Masculino , Atividade Motora , Estimulação Física , Córtex Sensório-Motor/fisiologia , Adulto Jovem
20.
Chemistry ; 25(34): 8043-8052, 2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-30916836

RESUMO

Tuning fluorescence colour of solid-state materials has become a topic of increasing interest for both fundamental mechanism study and practical applications such as sensors, optical recording and security printing. In this work, a fluorescent colour tuneable molecule BA-C16 is rationally designed and facilely synthesized by attaching flexible long alkyl chains to 2-hydroxybenzophenone azine (BA), which shows both aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) characteristics. Compared to BA, the simple introduction of long alkyl chains in BA-C16 leads to an emission wavelength redshift from 542 to 558 nm. This strategy of extending emission wavelength is rarely reported, and is ascribed to the enlarged through-space π-conjugation between interplanar molecules in the aggregate of BA-C16. Three crystals of BA-C16 are obtained with green, yellowish green and yellow emission. According to characterization by X-ray crystallography, X-ray powder diffraction and differential scanning calorimetry, alkyl chains play an important role in inducing different stacking modes of the three crystals, which further leads to polymorph-dependent fluorescence colour. BA-C16 exhibits tuneable solid-state fluorescence upon vapor fumigation, or annealing based on a transition between a "near-monomer" crystalline state and a "dimer" crystalline state. BA-C16 is further applied for rewritable fluorescence printing tuned by vapor- and thermal-treatment.

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