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1.
Langmuir ; 2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-33823595

RESUMO

Detection of bovine serum albumin (BSA) is an important issue in the sense of medical applications and enzymatic reactions; however, the recently developed fluorescent probes require the involvement of dimethyl sulfoxide (DMSO), which may be detrimental to proteins. In this study, we demonstrated a DMSO-free and water-soluble fluorescent probe prepared by ionic co-assembly of amphiphiles. The cationic amphiphile is a newly designed molecule (denoted by DPP-12) bearing a conjugated diketopyrrolopyrrole (DPP) and two tetraphenylethylene groups. It turns out that the fluorescence emission of DPP-12 depends on the amount of anionic amphiphilic sodium dodecyl benzene sulfonate (SDBS). The fluorescence intensity first increases and then decreases with the concentration of SDBS, and each branch presents a linear relationship. BSA consumes SDBS by the formation of complexes, thus leading to an increase of fluorescence intensity of the mixed solution of DPP-12 and SDBS. Therefore, the mixed solution of DPP-12 and SDBS was applied as a fluorescent probe to detect the low concentration of BSA by back-titration. This fluorescent probe does not require DMSO and has good tolerance to metal ions in blood and good photostability. The limit of detection is as low as 940 nM, almost 3 orders of magnitude lower than the content in organisms.

2.
Nanotechnology ; 2021 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33831851

RESUMO

Graphene, as a typical two-dimensional material, is popular in the design of nanodevices. The interlayer relative sliding of graphene sheets can significantly affect the effective bending stiffness of the few-layered graphene. For restricting the relative sliding, we adopted the atomic shot peening method to bond the graphene sheets together by ballistic C60 fullerenes from its two surfaces. Collision effects are evaluated via molecular dynamics simulations. Results obtained indicate that the fullerenes' incident velocity has an interval, in which the graphene sheet can be bonded after collision while no atoms on the fullerenes escaping from the graphene ribbon after collision. The limits of the interval increase with the layer number. Within a few picoseconds of collision, a stable carbon network is produced at an impacted area. The graphene sheets are bonded via the network and cannot slide relatively anymore. Conclusions are drawn to show the way of potential applications of the method in manufacturing a new graphene-based two-dimensional material that has a high out-of-plane bending stiffness.

3.
J Am Chem Soc ; 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33794093

RESUMO

The synthesis of highly luminescent colloidal CsSnX3 (X = halogen) perovskite nanocrystals (NCs) remains a long-standing challenge due to the lack of a fundamental understanding of how to rationally suppress the formation of structural defects that significantly influence the radiative carrier recombination processes. Here, we develop a theory-guided, general synthetic concept for highly luminescent CsSnX3 NCs. Guided by density functional theory calculations and molecular dynamics simulations, we predict that, although there is an opposing trend in the chemical potential-dependent formation energies of various defects, highly luminescent CsSnI3 NCs with narrow emission could be obtained through decreasing the density of tin vacancies. We then develop a colloidal synthesis strategy that allows for rational fine-tuning of the reactant ratio in a wide range but still leads to the formation of CsSnI3 NCs. By judiciously adopting a tin-rich reaction condition, we obtain narrow-band-emissive CsSnI3 NCs with a record emission quantum yield of 18.4%, which is over 50 times larger than those previously reported. Systematic surface-state characterizations reveal that these NCs possess a Cs/I-lean surface and are capped with a low density of organic ligands, making them an excellent candidate for optoelectronic devices without any postsynthesis ligand management. We showcase the generalizability of our concept by further demonstrating the synthesis of highly luminescent CsSnI2.5Br0.5 and CsSnI2.25Br0.75 NCs. Our findings not only highlight the value of computation in guiding the synthesis of high-quality colloidal perovskite NCs but also could stimulate intense efforts on tin-based perovskite NCs and accelerate their potential applications in a range of high-performance optoelectronic devices.

4.
Infect Dis Poverty ; 10(1): 37, 2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33761984

RESUMO

BACKGROUND: The COVID-19 has caused significant toll over the globe. Pregnant women are at risk of infection. The present study examined the frequency of washing hands with soap and wearing face mask when going out, prevalence of depression and anxiety, and identified their associated factors among pregnant women during the early phase of COVID-19 outbreak in China. METHODS: A cross-sectional online survey was conducted between 24 February and 3 March 2020. A total of 15 428 pregnant women who were using maternal health care services in China completed a questionnaire which assessed their socio-demographic and pregnancy-related characteristics, contextual, cognitive and social factors related to COVID-19, frequency of washing hands and wearing face masks, and depression and anxiety. Logistics regression analyses were performed to identify the associated factors of preventive behaviours and mental health. RESULTS: The prevalence of probable anxiety and depression was 28.2% and 43.6% respectively. 19.8% reported always wearing face mask when going out, and 19.1% reported washing hands with soap for more than 10 times per day. Results from logistic regression analyses showed that older age was associated with lower levels of depression and anxiety (OR = 0.42-0.67) and higher frequency of washing hands (OR = 1.57-3.40). Higher level of education level was associated with probable depression (OR = 1.31-1.45) and higher frequency of wearing face mask (OR = 1.50-1.57). After adjusting for significant socio-demographic and pregnancy-related factors, place of residence being locked down (aOR = 1.10-1.11), being quarantined (aOR = 1.42-1.57), personally knowing someone being infected with COVID-19 (aOR = 1.80-1.92), perception that COVID-19 would pose long term physical harm to human (aOR = 1.25-1.28) were associated with higher levels of depression and anxiety, while the perception that the disease will be under control in the coming month was associated with lower levels of depression and anxiety (aOR = 0.59-0.63) and lower tendency of always wearing face mask (aOR = 0.85). Social support was associated with lower levels of depression and anxiety (aOR = 0.86-0,87) and higher frequency of washing hands (aOR = 1.06). CONCLUSIONS: The mental health and preventive behaviours of pregnant women during COVID-19 outbreak was associated with a range of socio-demographic, pregnancy-related, contextual, cognitive and social factors. Interventions to mitigate their mental health problems and to promote preventive behaviours are highly warranted.


Assuntos
/prevenção & controle , Comportamentos Relacionados com a Saúde , Saúde Mental , Complicações Infecciosas na Gravidez/prevenção & controle , Adulto , Fatores Etários , China , Depressão/epidemiologia , Escolaridade , Feminino , Desinfecção das Mãos/tendências , Humanos , Modelos Logísticos , Serviços de Saúde Materna/estatística & dados numéricos , Razão de Chances , Equipamento de Proteção Individual , Gravidez , Complicações Infecciosas na Gravidez/psicologia , Cuidado Pré-Natal , Prevalência , Fatores de Risco , Apoio Social , Inquéritos e Questionários , Adulto Jovem
5.
Commun Biol ; 4(1): 372, 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33742112

RESUMO

Phytophthora sojae is a pathogen that causes stem and root rot in soybean (Glycine max [L.] Merr.). We previously demonstrated that GmBTB/POZ, a BTB/POZ domain-containing nuclear protein, enhances resistance to P. sojae in soybean, via a process that depends on salicylic acid (SA). Here, we demonstrate that GmBTB/POZ associates directly with soybean LIKE HETEROCHROMATIN PROTEIN1 (GmLHP1) in vitro and in vivo and promotes its ubiquitination and degradation. Both overexpression and RNA interference analysis of transgenic lines demonstrate that GmLHP1 negatively regulates the response of soybean to P. sojae by reducing SA levels and repressing GmPR1 expression. The WRKY transcription factor gene, GmWRKY40, a SA-induced gene in the SA signaling pathway, is targeted by GmLHP1, which represses its expression via at least two mechanisms (directly binding to its promoter and impairing SA accumulation). Furthermore, the nuclear localization of GmLHP1 is required for the GmLHP1-mediated negative regulation of immunity, SA levels and the suppression of GmWRKY40 expression. Finally, GmBTB/POZ releases GmLHP1-regulated GmWRKY40 suppression and increases resistance to P. sojae in GmLHP1-OE hairy roots. These findings uncover a regulatory mechanism by which GmBTB/POZ-GmLHP1 modulates resistance to P. sojae in soybean, likely by regulating the expression of downstream target gene GmWRKY40.

6.
J Med Internet Res ; 23(4): e24053, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33729983

RESUMO

BACKGROUND: COVID-19 is an emerging infectious disease that has created health care challenges worldwide. Pregnant women are particularly affected by this disease. OBJECTIVE: The aims of this study are to assess the levels of perceived threat (susceptibility, severity, impact), negative emotions (fear, worry), and self-efficacy of pregnant women in China related to COVID-19 and to examine their associations with mental health (depression and anxiety) and personal protective behavior (wearing a face mask). METHODS: A total of 4087 pregnant women from China completed a cross-sectional web-based survey between March 3 and 10, 2020. RESULTS: The prevalence of probable depression and anxiety was 48.7% (1989/4087) and 33.0% (1347/4087), respectively; 23.8% participants (974/4087) reported always wearing a face mask when going out. Of the 4087 participants, 32.1% (1313) and 36.4% (1490) perceived themselves or their family members to be susceptible to COVID-19 infection, respectively; 3216-3518 (78.7%-86.1%) agreed the disease would have various severe consequences. Additionally, 2275 of the 4087 participants (55.7%) showed self-efficacy in protecting themselves from contracting COVID-19, and 2232 (54.6%) showed efficacy in protecting their family members; 1303 (31.9%) reported a high level of fear of the disease, and 2780-3056 (68.0%-74.8%) expressed worry about various aspects of COVID-19. The results of the multivariate multinominal logistic regression analyses showed that perceived severity, perceived impact, fear, and worry were risk factors for probable depression and anxiety, while self-efficacy was a protective factor. The results of the multivariate logistic regression analysis showed that perceived susceptibility was associated with always wearing a face mask. CONCLUSIONS: Chinese pregnant women showed high levels of mental distress but low levels of personal protective behavior during the COVID-19 pandemic. Interventions are needed to promote the mental health and health behavior of pregnant women during the pandemic.

7.
Huan Jing Ke Xue ; 42(3): 1461-1468, 2021 Mar 08.
Artigo em Chinês | MEDLINE | ID: mdl-33742943

RESUMO

Due to the shortage of phosphate and the eutrophication caused by phosphorus pollution, it is urgent to recover phosphate from wastewater. Given their high adsorption capacity and convenient separation from water to which a magnetic field is applied, ferrite composites have received increasing attention for phosphate recovery. In this study, Spinel La@MgFe2O4 was prepared using a one-step co-precipitation method. La3+ loading on grain boundary defects of MgFe2O4, and phosphorus absorption capacity were examined using X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM). The structure of La@MgFe2O4 involved La3+ loading on grain boundary defects of MgFe2O4 in the form of La(OH)3. The addition of La changed the crystallinity and morphology of MgFe2O4, which greatly improved the capacity of MgFe2O4 for phosphorus adsorption. Saturation magnetization remained at 14 emu·g-1, which was easily separated from water using an external magnetic field. The maximum adsorption capacity was 143.156 mg·g-1 at pH 6 and 10℃, which was comparable to that achieved at 25℃. Kinetic observations showed that a low phosphorus concentration (10 mg·L-1) could result in extremely low phosphorus adsorption by La@MgFe2O4 after 30 min. The adsorption mechanism shows that phosphorus is removed through ligand exchange and the formation of inner spherical complexes. La@MgFe2O4 has highly selective adsorption with respect to phosphate, and the adsorbent can be reused many times after desorption. Based on addition of 1 g·L-1 of La@MgFe2O4 in the treatment of low temperature municipal wastewater in Northern China, phosphate concentrations could be reduced to less than 0.5 mg·L-1 an hour, offering a promising means of phosphate adsorption even in cold regions.

9.
Eur J Med Chem ; 217: 113361, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33740546

RESUMO

Diosgenin (DSG) has attracted attention recently as a potential anticancer therapeutic agent due to its profound antitumor activity. To better utilize DSG as an antitumor compound, two series of DSG-amino acid ester derivatives (3a-3g and 7a-7g) were designed and synthesized, and their cytotoxic activities against six human cancer cell lines (K562, T24, MNK45, HepG2, A549, and MCF-7) were evaluated. The results obtained showed that a majority of derivatives exhibited cytotoxic activities against these six human tumor cells. Structure-activity relationship analysis revealed that the introduction of l-tryptophan to the C-3 position of DSG and the C-26 position of derivative 5 was the preferred option for these compounds to display significant cytotoxic activities. Among them, compound 7g exhibited significant cytotoxicity against the K562 cell line (IC50 = 4.41 µM) and was 6.8-fold more potent than diosgenin (IC50 = 30.04 µM). Further cellular mechanism studies in K562 cells elucidated that compound 7g triggered mitochondrial-related apoptosis by increasing the generation of intracellular reactive oxygen species (ROS) and decreasing mitochondrial membrane potential (MMP), which was associated with upregulation of the gene and protein expression levels of Bax, downregulation of the gene and protein expression levels of Bcl-2 and activation of the caspase cascade. The above results suggested that compound 7g might be considered a promising scaffold for further modification of more potent anticancer agents.

10.
Nat Prod Res ; : 1-6, 2021 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-33678090

RESUMO

Two new alkaloids, phranisines A-B (1-2), along with two known compounds, N-p-Coumaroyl serotonin (3) and N-p-coumaroyl-tryptamine (4), were isolated from the roots of Phragmites australis. The structures of 1-4 were established on the basis of extensive spectroscopic. The absolute configuration of compounds 1-2 were identified through quantum-chemical electronic circular dichroism (ECD) calculation compared with their experimental CD. All the isolated compounds were tested for their cytotoxic activities against HeLa and MCF-7 human cancer cell lines, and compounds 2-4 showed moderate cytotoxic activities against HeLa cell lines with IC50 values ranging from 13.2 to 18.6 µM.

11.
Proc Natl Acad Sci U S A ; 118(10)2021 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-33649213

RESUMO

Various neuromodulation approaches have been employed to alter neuronal spiking activity and thus regulate brain functions and alleviate neurological disorders. Infrared neural stimulation (INS) could be a potential approach for neuromodulation because it requires no tissue contact and possesses a high spatial resolution. However, the risk of overheating and an unclear mechanism hamper its application. Here we show that midinfrared stimulation (MIRS) with a specific wavelength exerts nonthermal, long-distance, and reversible modulatory effects on ion channel activity, neuronal signaling, and sensorimotor behavior. Patch-clamp recording from mouse neocortical pyramidal cells revealed that MIRS readily provides gain control over spiking activities, inhibiting spiking responses to weak inputs but enhancing those to strong inputs. MIRS also shortens action potential (AP) waveforms by accelerating its repolarization, through an increase in voltage-gated K+ (but not Na+) currents. Molecular dynamics simulations further revealed that MIRS-induced resonance vibration of -C=O bonds at the K+ channel ion selectivity filter contributes to the K+ current increase. Importantly, these effects are readily reversible and independent of temperature increase. At the behavioral level in larval zebrafish, MIRS modulates startle responses by sharply increasing the slope of the sensorimotor input-output curve. Therefore, MIRS represents a promising neuromodulation approach suitable for clinical application.

12.
Asian J Surg ; 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33581945

RESUMO

BACKGROUND: In this study, we investigated the impact of concomitant coronary artery bypass grafting (CABG) on operative and midterm mortality in patients with acute type A aortic dissection (ATAAD) undergoing surgical repair. METHODS: From January 2012 to December 2014, among 489 patients (mean age: 47.6 ± 10.4 years, 77.1% male) with ATAAD who received surgical repair at our institute, 21 patients (4.3%) underwent concomitant CABG. Isolated aortic repair was performed in the remaining 468 cases (95.7%). Coronary dissection was indicated in 15 patients (Neri classification type B in 2, type C in 13), concomitant coronary artery disease in five and coronary artery compression in one. The follow-up time was 97.3% at 44.1 ± 13.9 months. RESULTS: A total of 44 patients (9%) died from surgery, and operative mortality in the concomitant CABG group was significantly higher than that in the isolated aortic repair group (47.6%, 10/21 vs. 7.3%, 34/468; P < 0.001). Among the 11 survivors in the concomitant CABG group, no deaths occurred during the follow-up. Cox regression indicated that concomitant CABG increased the operative mortality risk by 9.2 times (HR, 9.26; 95% CI, 4.31-19.89; P < 0.001). Although it predicted a 5.2-fold increase in overall mortality (HR, 5.20; 95% CI, 2.55-10.61; P < 0.001), concomitant CABG did not affect midterm death (P = 0.996). CONCLUSIONS: Concomitant CABG carries a significant operative risk in ATAAD patients undergoing surgical repair. However, survivors may benefit from concomitant CABG and had similar midterm mortality compared with the other cases.

13.
JMIR Ment Health ; 8(2): e24162, 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33570500

RESUMO

BACKGROUND: Mental health problems are prevalent among pregnant women, and it is expected that their mental health will worsen during the COVID-19 pandemic. Furthermore, the underutilization of mental health services among pregnant women has been widely documented. OBJECTIVE: We aimed to identify factors that are associated with pregnant women's intentions to seek mental health services. We specifically assessed pregnant women who were at risk of mental health problems in mainland China. METHODS: A web-based survey was conducted from February to March, 2020 among 19,515 pregnant women who were recruited from maternal health care centers across various regions of China. A subsample of 6248 pregnant women with probable depression (ie, those with a score of ≥10 on the 9-item Patient Health Questionnaire) or anxiety (ie, those with a score of ≥5 on the 7-item General Anxiety Disorder Scale) was included in our analysis. RESULTS: More than half (3292/6248, 52.7%) of the participants reported that they did not need mental health services. Furthermore, 28.3% (1770/6248) of participants felt that they needed mental health services, but had no intentions of seeking help, and only 19% (1186/6248) felt that they needed mental health services and had intentions of seek help. The results from our multivariate logistic regression analysis showed that age, education level, and gestational age were factors of not seeking help. However, COVID-19-related lockdowns in participants' cities of residence, social support during the COVID-19 pandemic, and trust in health care providers were protective factors of participants' intentions to seek help from mental health services. CONCLUSIONS: Interventions that promote seeking help for mental health problems among pregnant women should also promote social support from health care providers and trust between pregnant women and their care providers.

14.
Micron ; 143: 103012, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33524916

RESUMO

The electronic structure of GaN and GaN:Zn was investigated by electron energy loss spectroscopy and first-principles calculations. In the low-loss spectrum, the interband transitions are assigned to the observed energy loss peaks. After Zn doping, impurity levels are introduced to the density of states and hybrid orbitals of N 2p and Zn 3d are formed around the Fermi level. In the nitrogen K-edge, an additional peak was observed due to the formation of donor defect states. A core-hole effect is believed to be significant for simulation of the N K-edge for both GaN and GaN:Zn.

15.
J Am Chem Soc ; 143(7): 2886-2895, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33577309

RESUMO

The charge transport in single-molecule junctions depends critically on the chemical identity of the anchor groups that are used to connect the molecular wires to the electrodes. In this research, we report a new anchoring strategy, called the electrostatic anchor, formed through the efficient Coulombic interaction between the gold electrodes and the positively charged pyridinium terminal groups. Our results show that these pyridinium groups serve as efficient electrostatic anchors forming robust gold-molecule-gold junctions. We have also observed binary switching in dicationic viologen molecular junctions, demonstrating an electron injection-induced redox switching in single-molecule junctions. We attribute the difference in low- and high-conductance states to a dicationic ground state and a radical cationic metastable state, respectively. Overall, this anchoring strategy and redox-switching mechanism could constitute the basis for a new class of redox-activated single-molecule switches.

16.
Artigo em Inglês | MEDLINE | ID: mdl-33529006

RESUMO

For the stability and commercial development of the perovskite solar cells (PVK-SCs), synthesizing high-efficiency dopant-free hole-transport materials (DF-HTMs) and exploring how the DF-HTM structure affects the photovoltaic performance is inevitable. Two small-molecule DF-HTMs based on 2,2'-bithiophene as a central part (denoted by BT-MTP and DFBT-MTP) were designed and synthesized. DFBT-MTP, with two more fluorine atoms substituted on the 2,2'-bithiophene group, exhibited enhanced photovoltaic property as DF-HTMs, including larger backbone planarity, declining highest occupied molecular orbit (HOMO) energy level, increasing hole transportation, more effective passivation, and efficient charge extraction. With fluorinated DFBT-MTP being applied as DF-HTMs in p-i-n PVK-SCs, an efficiency of 20.2% was achieved, showing ∼35% efficiency increase compared with the nonfluorinated BT-MTP-based devices. The leading power conversion efficiency (PCE) indicates that the fluorinated compounds should be a promising direction for exploring high-performance DF-HTMs in the p-i-n PVK-SCs.

17.
Arthroscopy ; 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33539982

RESUMO

PURPOSE: The purpose of the present study was to analyze the anatomic landmarks of Schöttle's point and establish a locating method for identification. METHODS: From 2013 to 2016, patients undergoing medial patellofemoral ligament (MPFL) reconstruction for patellofemoral instability were enrolled. INCLUSION CRITERIA: at least 2 episodes of patellar dislocation. EXCLUSION CRITERIA: previous knee surgeries, open physes, severe trochlear dysplasia, tibial tuberosity lateralization, or patella alta. Group A: From January 2013 to December 2013, preoperative 3-dimensional computed tomography (3D-CT) images were obtained. Anatomic features of Schöttle's point were measured on the 3D-CT images. A Schöttle's point locating method with 2 distinct landmarks was established. Group B: From January 2014 to January 2016, consecutive MPFL reconstructions were performed. The placement of Schöttle's point was following the established method without fluoroscopy. The accuracy of femoral tunnel positions was assessed on the 3D-CT images postoperatively. RESULTS: CT images of 53 knees were obtained in group A. Forty-seven MPFL reconstructions were performed in group B. No significant difference was found between the 2 groups regarding to demographic characteristics. The intraclass correlation coefficients were excellent for all measures (r = 0.97). In group A, Schöttle's point was 8.1 ± 0.2 mm (95% confidence interval [CI], 7.7-8.5) distal to the apex of the adductor tubercle and 8.0 ± 0.3 mm (95% CI, 7.4-8.6) anterior to the posterior edge. Apex of the adductor tubercle was defined as the most convex point, and posterior edge was defined as the edge of the posteromedial cortex in the transition area between the medial condyle and femoral shaft. In group B, 44 of 47 femoral tunnels (93.6%) were considered localized in the proper zone. CONCLUSIONS: Schöttle's point was approximately 8 mm distal to the apex of the adductor tubercle and 8 mm from the posterior edge. Schöttle's point locating method without fluoroscopy had high accuracy. LEVEL OF EVIDENCE: Level IV, case series.

18.
J Org Chem ; 2021 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-33599126

RESUMO

Two organic cages have been prepared in situ in water through the 2 + 3 hydrazone coupling of two pyridinium-derived trialdehydes and oxalohydrazide. The highly water-soluble cages encapsulate and solubilize linear neutral molecules. Such encapsulation has been applied for the promotion of both two- or three-component hydrazone condensation in water. For two-component reactions, the yields of the resulting monohydrazones are increased from 5-10 to 90-96%. For three-component reactions of hydrazinecarbohydrazide with 11 aromatic aldehydes, in the presence of the organic cages, the bihydrazone products can be produced in 88-96% yields. In contrast, without the promotion of the organic cages, 9 of the reactions do not afford the corresponding dihydrazone product.

19.
Anal Chim Acta ; 1145: 114-123, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33453872

RESUMO

The development of reliable bioanalytical probes for sensitive and specific detection of hydrogen sulfide (H2S) plays important role for better understanding the roles of this biomolecule in living cells and organisms. Taking advantages of unique photophysical properties of ruthenium(II) (Ru(II)) complex, this work presents the development of a responsive Ru(II) complex probe, Ru-PNBD, for colorimetric and luminescent analysis of H2S in living cells and organisms. In aqueous solution, Ru-PNBD is yellow color and non-luminescent because of the photoinduced electron transfer (PET) process from Ru(II) complex luminophore to NBD moiety. The H2S-triggered specific nucleophilic substitution reaction with Ru-PNBD cleaves the NBD moiety to form pink NBD-SH and highly luminescent Ru-PH. The color of the solution thus changes from yellow to pink for colorimetric analysis and the emission intensity is about 65-fold increased for luminescent analysis. Ru-PNBD has high sensitivity and selectivity for H2S detection, low cytotoxicity and good permeability to cell membrane, which allow the application of this probe for H2S imaging in living cells, Daphnia magna, and larval zebrafish. Collectively, this work provides a useful tool for H2S analysis and expands the scope of transition metal complex probes.

20.
Bioengineered ; 12(1): 392-401, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33472509

RESUMO

This study developed a novel method for the rapid detection of Escherichia coli (E. coli) O157:H7 on a microfluidic platform. First, the concentration of bacteria in a sample was determined with the adenosine triphosphate (ATP) method. Then, the specific detection of E. coli was achieved in a microfluidic chip by the immune-microsphere technique. The influences of the culture time, flow rate and capture time on the detection of the target bacteria were investigated systematically. Generally, with increasing capture time, more bacteria could be captured by the microspheres, which had a positive effect on bacterial detection. Furthermore, the sensitivity and specificity of the method were also tested. The results showed that this method could specifically detect E. coli with a sensitivity as high as 49.1 cfu/µL; the consumption of bacteria was 1 µL, and the reagent was at the microliter level. The testing time can be controlled within one and a half hours, and the cost of testing was approximately RMB 10. The method described in this article is simple and accurate and has great application value in bacterial detection for medical diagnostics.

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