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1.
EBioMedicine ; 51: 102603, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31901862

RESUMO

BACKGROUND: Tumor necrosis factor α-induced protein 1 (TNFAIP1) is frequently downregulated in cancer cell lines and promotes cancer cell apoptosis. However, its role, clinical significance and molecular mechanisms in hepatocellular carcinoma (HCC) are unknown. METHODS: The expression of TNFAIP1 in HCC tumor tissues and cell lines was measured by Western blot and immunohistochemistry. The effects of TNFAIP1 on HCC proliferation, apoptosis, metastasis, angiogenesis and tumor formation were evaluated by Cell Counting Kit-8 (CCK8), Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL), transwell, tube formation assay in vitro and nude mice experiments in vivo. The interaction between TNFAIP1 and CSNK2B was validated by liquid chromatography-tandem mass spectrometry (LC-MS/MS), Co-immunoprecipitation and Western blot. The mechanism of how TNFAIP1 regulated nuclear factor-kappaB (NF-κB) pathway was analyzed by dual-luciferase reporter, immunofluorescence, quantitative Real-time polymerase chain reaction (RT-qPCR) and Western blot. FINDINGS: The TNFAIP1 expression is significantly decreased in HCC tissues and cell lines, and negatively correlated with the increased HCC histological grade. Overexpression of TNFAIP1 inhibits HCC cell proliferation, metastasis, angiogenesis and promotes cancer cell apoptosis both in vitro and in vivo, whereas the knockdown of TNFAIP1 in HCC cell displays opposite effects. Mechanistically, TNFAIP1 interacts with CSNK2B and promotes its ubiquitin-mediated degradation with Cul3, causing attenuation of CSNK2B-dependent NF-κB trans-activation in HCC cell. Moreover, the enforced expression of CSNK2B counteracts the inhibitory effects of TNFAIP1 on HCC cell proliferation, migration, and angiogenesis in vitro and in vivo. INTERPRETATION: Our results support that TNFAIP1 can act as a tumor suppressor of HCC by modulating TNFAIP1/CSNK2B/NF-κB pathway, implying that TNFAIP1 may represent a potential marker and a promising therapeutic target for HCC.

2.
Clin Chim Acta ; 2019 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-31821791

RESUMO

BACKGROUND: Urinary proteins could be useful as markers for the detection of non-small-cell lung cancer (NSCLC). We investigated the levels of two different proteins in urine samples from NSCLC patients and assessed their diagnostic value. METHODS: Urinary plasminogen (PLG) and fibrinogen gamma chain (FGG) levels in 112 NSCLC patients and 197 controls were detected using enzyme linked immunosorbent assay (ELISA). The expression of FGG and PLG in 20 NSCLC tissues and paired adjacent non-tumour tissues were detected through immunohistochemistry. The diagnostic value of FGG and PLG for NSCLC was evaluated through a receiver operating characteristic curve (ROC). RESULTS: PLG and FGG were significantly elevated in NSCLC tissues vs paired adjacent non-tumour tissues (p=0.000) and in urinary samples from NSCLC patients vs healthy controls (p=0.000). The expression level of PLG in urinary samples was related only to the histological type (p=0.001). Further, ROC curve analysis revealed that PLG, FGG, and their combination could distinguish NSCLC and its subtypes from healthy controls with an AUC ranging from 0.827 to 0. 947. By comparing urine samples with matching plasma CEA from NSCLC stage I-IV patients (n=81) and healthy controls (n=31), the combination of CEA with PLG or FGG showed that the AUC was 0.889 and 0.806, respectively, which is superior to a single biomarker alone. CONCLUSIONS: These two urinary proteins could serve as potential markers for the diagnosis of NSCLC.

3.
Chemosphere ; 244: 125498, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31812049

RESUMO

BACKGROUND: Heavy metal exposure induces oxidative stress, which is critical for adverse male reproductive health. OBJECTIVE: To explore the mediating effect of oxidative stress on the relationship of heavy metal exposure with semen quality. METHODS: Urinary levels of three oxidative stress markers, semen quality, and urinary arsenic, cadmium and lead were examined among 1020 men. Multivariate linear regression was applied to explore cross-sectional associations, and the role of oxidative stress as mediators was investigated. RESULTS: Quartiles of metals showed significant dose-dependent relationships with increasing levels of 8-hydroxy-2deoxyguanosine (8-OHdG), 8-iso-prostaglandin F2α (8-isoPGF2α) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA). Significant or suggestive associations were also found between urinary 8-OHdG levels and the percentage of normal sperm morphology (ptrend < 0.001), between urinary 8-isoPGF2α levels and total motility (ptrend = 0.052), progressive motility (ptrend = 0.050) respectively. The mediation analysis showed that about 14.59%, 18.06%, 15.35% or 16.49% of the association between arsenic/cadmium exposure and the decreased total motility/progressive motility was mediated by 8-isoPGF2α, respectively. In addition, about 16.47% of the relationship between lead exposure and the decreased percentage of normal sperm morphology was mediated by 8-OHdG. CONCLUSIONS: Our findings suggest that higher urinary arsenic, cadmium and lead levels were associated with increased oxidative stress markers, which also related with altered semen quality. 8-isoPGF2α and 8-OHdG might be the possible mediators of the associations between urinary heavy metals and total motility, progressive motility or the proportion of normal sperm morphology.

4.
Metabolites ; 9(12)2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31817331

RESUMO

Apocynum plants, especially A. venetum and A. hendersonii, are rich in flavonoids. In the present study, a whole genome survey of the two species was initially carried out to optimize the flavonoid biosynthesis-correlated gene mining. Then, the metabolome and transcriptome analyses were combined to elucidate the flavonoid biosynthesis pathways. Both species have small genome sizes of 232.80 Mb (A. venetum) and 233.74 Mb (A. hendersonii) and showed similar metabolite profiles with flavonols being the main differentiated flavonoids between the two specie. Positive correlation of gene expression levels (flavonone-3 hydroxylase, anthocyanidin reductase, and flavonoid 3-O-glucosyltransferase) and total flavonoid content were observed. The contents of quercitrin, hyperoside, and total anthocyanin in A. venetum were found to be much higher than in A. hendersonii, and such was thought to be the reason for the morphological difference in color of A. venetum and A. hendersonii. This study provides valuable genomic and metabolome information for understanding of A. venetum and A. hendersonii, and lays a foundation for elucidating Apocynum genus plant flavonoid biosynthesis.

5.
Int J Mol Sci ; 20(24)2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31817350

RESUMO

Our laboratory and others previously showed that Annexin A2 knockout (A2KO) mice had impaired blood-brain barrier (BBB) development and elevated pro-inflammatory response in macrophages, implying that Annexin A2 (AnxA2) might be one of the key endogenous factors for maintaining homeostasis of the neurovascular unit in the brain. Traumatic brain injury (TBI) is an important cause of disability and mortality worldwide, and neurovascular inflammation plays an important role in the TBI pathophysiology. In the present study, we aimed to test the hypothesis that A2KO promotes pro-inflammatory response in the brain and worsens neurobehavioral outcomes after TBI. TBI was conducted by a controlled cortical impact (CCI) device in mice. Our experimental results showed AnxA2 expression was significantly up-regulated in response to TBI at day three post-TBI. We also found more production of pro-inflammatory cytokines in the A2KO mouse brain, while there was a significant increase of inflammatory adhesion molecules mRNA expression in isolated cerebral micro-vessels of A2KO mice compared with wild-type (WT) mice. Consistently, the A2KO mice brains had a significant increase in leukocyte brain infiltration at two days after TBI. Importantly, A2KO mice had significantly worse sensorimotor and cognitive function deficits up to 28 days after TBI and significantly larger brain tissue loss. Therefore, these results suggested that AnxA2 deficiency results in exacerbated early neurovascular pro-inflammation, which leads to a worse long-term neurologic outcome after TBI.

6.
ISA Trans ; 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31818487

RESUMO

Visual servoing is an effective strategy for autonomous flight of quadrotor. However, it faces the requirement of visibility constraint, i.e., holding the observed object inside the field of view (FOV) of camera. To accomplish this goal, we present an attitude restricted back-stepping anti-disturbance controller. Before the controller design, proper perspective moment features are selected to establish an uncoupled vision-quadrotor model without image singularity from a novel image plane, i.e., virtual image plane. Considering the structured vision-quadrotor model, an attitude restricted anti-disturbance control strategy is developed via back-stepping, where the unknown uncertainties are estimated via designing a model-assisted ESO and compensated in feedforward loop, and the drastic attitude motions are restricted by the designed saturation compensated integral barrier Lyapunov function(iBLF) control law. Its superiorities lie in: (1) by designing strong anti-disturbance mechanism and strict attitude limitation arithmetic, the controller can guarantee the observed object in the FOV of camera, (2) considering the deterioration of transient-state behavior due to the strict attitude constraints, a saturation compensator is constructed to improve the system transient-state performance, (3) by incorporating the model information into observer design, the estimation burden of ESO relieves greatly. Stability analysis based on the Lyapunov theory proves the boundedness of attitude states and the convergence of closed-loop system. And we design many simulations to confirm the controller performance.

7.
Sci China Life Sci ; 2019 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-31820200

RESUMO

Staurosporine, belonging to indolocarbazole compounds, is regarded as an excellent lead compound for synthesizing antitumor agents as a potent inhibitor against various protein kinases. In this study, two separate clusters (cluster A and cluster B), corresponding to biosyntheses of K-252c (staurosporine aglycone) and sugar moiety, were identified in Streptomyces fradiae CGMCC 4.576 and heterologously expressed in Streptomyces coelicolor M1146 separately or together. StaR, a cluster-situated LAL family regulator, activates staurosporine biosynthesis by binding to the promoter regions of staO-staC and staG-staN. The conserved sequences GGGGG and GCGCG were found through gradually truncating promoters of staO and staG, and further determined by mutational experiments. Overexpression of staR with the supplementation of 0.01 g L-1 FeSO4 increased staurosporine production to 5.2-fold compared with that of the parental strain Streptomyces fradiae CGMCC 4.576 in GYM medium. Our results provided an approach for improvement of staurosporine production mediated by a positive regulator and established the basis for dissecting the regulatory mechanisms of other indolocarbazole compounds with clinical application value.

8.
Inorg Chem ; 58(24): 16326-16329, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31793291

RESUMO

A new strategy for a G-quadruplex fluorescent probe based on a nitro-substituted ruthenium complex is described. G-quadruplex DNA can be distinguished from double- or single-strand DNA by the naked eye. This ability originates from variation of the degree of protection of the nitro group on the complex from water by G-quadruplex and other structure DNAs.

9.
Artigo em Inglês | MEDLINE | ID: mdl-31799699

RESUMO

Telomeres are specialized genomic structures that protect chromosomal ends to maintain genomic stability. Telomeric length is primarily regulated by the telomerase complex, essentially consisting of an RNA template (TERC), an enzymatic subunit (telomerase reverse transcriptase, TERT). In humans, telomerase activity is repressed during embryonic differentiation and is absent in most somatic cells. However, it is upregulated or reactivated in 80-90% of the primary tumors in humans. The human TERT (hTERT) plays a pivotal role in cellular immortality and tumorigenesis. However, the molecular mechanisms of telomerase functioning in cancer have not been fully understood beyond the telomere maintenance. Several research groups, including ours have demonstrated that hTERT possesses vital functions independent of its telomere maintenance, including angiogenesis, inflammation, cancer cell stemness, and epithelial-mesenchymal transformation (EMT). All these telomere-independent activities of hTERT may contribute to the regulation of the dynamics and homeostasis of tumor microenvironment (TME), thereby promoting tumor growth and development. Cancer progression and metastasis largely depend upon the interactions between cancer cells and their microenvironment. In this review, the involvement of TERT in tumor microenvironment and the underlying implications in cancer therapeutics have been summarized.

10.
Animals (Basel) ; 9(12)2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31835576

RESUMO

Follicular atresia is closely related to both apoptosis and autophagy of granulosa cells (GCs) in ovarian follicles. In the present study, GCs were isolated from pig ovaries in small, medium and large antral follicles, and the current results showed that the proliferation of GCs was higher in medium follicles, and lower in large follicles compared to small follicles. The Bax and Caspase 3 mRNA levels were significantly higher, but the ratio of Bcl-2/Bax was lower in GCs of large follicles. The marker genes of autophagy, Atg3, Atg7 and LC3 mRNA levels were higher in GCs from medium follicles. Apoptosis- and autophagy-related proteins had a similar expression pattern to the mRNA level. Our results showed that phosphorylated ERK (p-ERK) was activated in GCs of large follicles, while phosphorylated AKT (p-AKT) and phosphorylated mTOR (p-mTOR) were inhibited in GCs of medium follicles. Labeling of autophagic vesicles with 4',6-diamidino-2-phenylindole (DAPI) and monodansylcadaverine (MDC) confirmed the results of gene transcription and protein expression in GCs of different size follicles. We conclude that autophagy and apoptosis of GCs occurred in different size follicles during follicular development, and autophagy was mainly found in GCs of medium follicles, while apoptosis was mainly found in GCs of large follicles.

11.
Micromachines (Basel) ; 10(12)2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31835793

RESUMO

The clinical characteristics of excreted tumor cells can be found in the urine of bladder cancer patients, meaning the identification of tumor cells in urine can assist in bladder cancer diagnosis. The presence of white blood cells and epithelial cells in the urine interferes with the recognition of tumor cells. In this paper, a technique for detecting cancer cells in urine based on microfluidics provides a novel approach to bladder cancer diagnosis. The bladder cancer cell line (T24) and MeT-5A were used as positive bladder tumor cells and non-tumor cells, respectively. The practicality of the tumor cell detection system based on microfluidic cell chip detection technology is discussed. The tumor cell (T24) concentration was around 1 × 104 to 300 × 104 cells/mL. When phosphate buffer saline (PBS) was the diluted solution, the tumor cell detected rate was 63-71% and the detection of tumor cell number stability (coefficient of variation, CV%) was 6.7-4.1%, while when urine was the diluted solution, the tumor cell detected rate was 64-72% and the detection of tumor cell number stability (CV%) was 6.3-3.9%. In addition, both PBS and urine are tumor cell dilution fluid solutions. The sample was analyzed at a speed of 750 microns per hour. Based on the above experiments, a system for detecting bladder cancer cells in urine by microfluidic analysis chip technology was reported. The rate of recognizing bladder cancer cells reached 68.4%, and the speed reached 2 mL/h.

12.
Metab Brain Dis ; 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31840202

RESUMO

The present study was performed to examine the effect of oxymatrine (OMT) on motor functions and histopathologic changes after spinal cord injury and the mechanism underlying its neuroprotective effects. Results suggested that, OMT causes regain of lost motor function near to normal via attenuating oxidative stress, inflammatory response and cellular apoptosis. These observations were further supported by histological examination of spinal cord of rats. It also showed to regulate pro-inflammatory cytokines, Bcl2 family proteins and reduces the level of toll like receptor (TLR-4) and nuclear factor-kappa B (NF-ĸB) in concentration dependent manner. The mitogen-activated protein kinase (MAPK) pathway was also regulated by OMT after SCI. It has been suggested that, OMT promotes the recovery of motor function after SCI in rats via multiple mechanism, and this effect may be related to its anti-oxidant, anti-inflammatory and anti-apoptotic effects.

13.
Sci Rep ; 9(1): 18734, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31822737

RESUMO

A novel cerium doped compounds Mn3Gd7-xCex(SiO4)6O1.5 with an apatite structure was found and used to achieve high-efficiency degradation of tetracycline in aqueous solution. The catalysts were characterized by XRD, XPS, EDS and other techniques. The characteristic results indicated that the catalytic activity of the compound was improved due to the introduction of Ce in the structure, because Ce3+ which was stably present in the apatite structure can serve as an active site for the reaction, and in addition, there was a high presence between Ce4+ and Ce3+ on the surface of the catalyst. The redox potential and high oxygen storage capacity were also beneficial for the catalytic reaction. The results of free radical capture indicated that both superoxide radicals and hydroxyl radicals participated in the catalytic oxidation process and played an important role in the reaction. The decomposition of tetracycline followed the pseudo second-order reaction kinetics. In addition, the catalyst exhibited long-term stability and low metal leaching during the reaction, which indicated that the novel cerium-doped apatite structure material could be a promising wastewater treatment material.

14.
Artigo em Inglês | MEDLINE | ID: mdl-31826322

RESUMO

Astrocytes are more resistant to ischemia and hypoxia in the acute phase of brain injury after traumatic brain injury (TBI). Previous study showed that gap junction Alpha 1 (GJA1) phosphorylation can increase the survival of damaged astrocytes. The GJA1-20k expression in neurons co-culture with astrocytes was positively correlated with exosomes uptake. This study aims to explore the effect of exogenous GJA1-20k carried by astrocyte-derived exosomes on neurons apoptosis and mitochondrial function after TBI. Astrocytes were co-cultured with the neuron with/without damage from air pressure. Exosomes were isolated, extracted from the culture medium by differential ultra-centrifugation and verified by electron microscopy. Immunofluorescence staining, Tunnel, Western blot to detect exosomes marker CD60, apoptosis and mitochondrial function related protein expression and GJA1-20k in cell culture. A rat model of hydraulic injury TBI was built and exosomes was transferred. 2,3,5-triphenyltetrazolium chloride (TTC) staining and immunohistochemistry staining of Nissl and MAP 2 were used to detect the brain damage. A transwell stereo culture model of astrocytes and TBI-like injured neuron was constructed. The exosomes derived from astrocytes promoted the recovery of damaged neuron by in vitro exosome treatment. Compared to GJA1-20k KO exosome control group, GJA1-20k exosomes were up-taken by neuron and down-regulated the apoptosis rate and up-regulated mitochondrial function to promote neuronal recovery. Finally, the results were validated by TTC-staining and damaged tissue sections of rat TBI model. This study contributes to a better understanding of the astrocyte-neuron protection mechanism in TBI and provides a potential new target for the treatment of TBI.

15.
Chin Med J (Engl) ; 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31880746

RESUMO

BACKGROUND: Previously, dihydroceramide (d18:0/24:0) (dhCer (d18:0/24:0)) was reported to be a potential biomarker for acute-on-chronic liver failure (ACLF) prognosis. In this study, we further explored the role of dhCer (d18:0/24:0) in the progression of ACLF to validate the biomarker using ACLF rat model. METHODS: ACLF rats were sacrificed at 4 and 8 h post-D-galactosamine (D-gal)/lipopolysaccharide (LPS) administration to investigate the liver biochemical markers, prothrombin time and liver histopathology. Change in dhCer and other sphingolipids levels were investigated by high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). Rats were treated with N-(4-hydroxyphenyl) retinamide (4-HPR) to examine the mortality rate and its role in improving ACLF. RESULTS: LPS/D-gal administration resulted in significant elevation in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Prothrombin time was prolonged and histopathological examination showed abnormality. HPLC-MS/MS results showed total dhCer levels in ACLF group (64.10 ±â€Š8.90 pmol/100 µL, 64.22 ±â€Š6.78 pmol/100 µL for 4 and 8 h, respectively) were decreased significantly compared with control group (121.61 ±â€Š23.09) (P < 0.05). In particular, dhCer (d18:0/24:0), dhCer (d18:0/20:0), and dhCer (d18:0/22:0) levels were decreased. Treatment with 4-HPR significantly increased the levels of dhCers, including dhCer (d18:0/24:0) compared with ACLF group, for the level of dhCer (d18:0/24:0) in 4-HPR group was 20.10 ±â€Š8.60 pmol/100 µL and the level of dhCer (d18:0/24:0) in ACLF group was 9.74 ±â€Š2.99 pmol/100 µL (P < 0.05). This was associated with reduced mortality rate and prolonged survival time. The ALT and AST in 4-HPR group were significantly decreased compared with ACLF group. The prothrombin time of 4-HPR group (41.49 s) was significantly lower than the prothrombin time of ACLF group (57.96 s) (P < 0.05). 4-HPR also decreased plasma ammonia levels slightly, as the plasma ammonia levels in 4-HPR group and ACLF group were 207.37 ±â€Š60.43, 209.15 ±â€Š60.43 µmol/L, respectively. Further, 4-HPR treatment improved histopathological parameters. CONCLUSIONS: DhCer, especially dhCer (d18:0/24:0), is involved in the progression of ACLF. Increasing the levels of dhCer can reduce the mortality rate of ACLF rats and alleviate liver injury.

17.
Aging (Albany NY) ; 11(24): 12568-12580, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31881008

RESUMO

Previous studies investigated the prognostic role of programmed death-ligand 1 (PD-L1) expression in patients with biliary tract cancer (BTC); however, the results remained controversial. Therefore, we conducted the current meta-analysis with the aim of clarifying the association between PD-L1 expression and prognosis as well as with several important clinicopathological features of BTC. We searched PubMed, Embase, and Web of Science for relevant studies. Studies that detected PD-L1 expression in tumor cells by using immunohistochemistry (IHC) were selected. Pooled hazard ratios (HRs) and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the correlations. In total, 15 independent studies with 1,776 patients were included in this meta-analysis. The pooled data demonstrated that high PD-L1 expression was associated with poor overall survival (n=15, HR=1.79, 95% CI=1.55-2.07, p<0.001). The correlation between PD-L1 expression and disease-free survival was not significant (n=6, HR=1.38, 95% CI=1.00-1.91, p=0.051). In addition, no significant correlation was observed between PD-L1 expression and clinical features in patients with BTC. Our study results showed that PD-L1 expression could play a pivotal role as an effective factor of poor prognosis in patients with BTC.

18.
Int J Biol Macromol ; 144: 690-697, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31857169

RESUMO

Artemisia sphaerocephala Krasch. polysaccharide (ASKP) has attracted growing attention in the field of food and medical engineering due to its biological activity and colloidal property. In this study, the binding between ASKP and ferric ions was found and the binding mechanism was explored. The results showed that ASKP could form a hydrogel with three-dimensional network structure in the presence of ferric ions. Ferric ions could specifically bind with the carboxyl and hydroxyl groups of the high molecular weight fraction of 60P with the binding stoichiometry of [M3+]/[repeating unit] = 2.5. The possible mechanism of the formation of ASKP-Fe3+ complex was proposed as two binding modes of monodentate and bridging binding. ASKP-Fe3+ complex exhibited higher thermal stability than ASKP revealed with DSC thermograms. The study indicated that ASKP would be a novel gelation biopolymer and the ASKP-Fe3+ complex hydrogel could be exploited as a new iron fortifier.

19.
ACS Nano ; 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31841305

RESUMO

The low penetration depth of UV light in mammalian tissue is the critical limitation for the use of TiO2-based photocatalysis in biomedical applications. In this work, we develop an effective near-infrared (NIR)-active photocatalytic platform that consists of a shell structure of upconversion nanocrystals decorated on a core of Au/dark-TiO2. The heart of this system is the strong photocatalytic activity in the visible region enabled by the gold surface-plasmon resonance on dark TiO2 (D-TiO2). Simulation and experiment demonstrate for an optimized Au/D-TiO2 combination a highly enhanced light absorption in the visible range. Using ampicillin sodium (AMP) as model drug, we exemplify the effective use of this principle by demonstrating a NIR light-triggered photocatalytic payload release. Importantly, the photocatalytically generated reactive oxygen species can effectively inactivate AMP-resistant bacteria strains, thus maintaining an antibacterial effect even after all drug is released. Overall, we anticipate that the here-introduced NIR-light-active photocatalytic cascade can considerably widen TiO2-based photocatalysis and its applications into the infrared range.

20.
Biosens Bioelectron ; : 111862, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31740256

RESUMO

Salmonella is the leading risk factor in food safety. Rapid, sensitive and accurate detection of Salmonella is a key to prevent and control the outbreaks of foodborne diseases caused by Salmonella. In this study, we reported a colorimetric biosensor for ultrasensitive detection of Salmonella Typhimurium using a magnetic grid separation column to efficiently separate target bacteria from large volume of sample and platinum loaded zeolitic imidazolate framework-8 (Pt@ZIF-8) nanocatalysts to effectively amplify biological signal. The target Salmonella cells in large volume of sample were first separated and concentrated using the magnetic grid separation column with immune magnetic particle chains, then conjugated with the immune Pt@ZIF-8 nanocatalysts to mimic peroxidase for catalysis of hydrogen peroxide-3,3',5,5'-tetramethylbenzidine, and finally determined by measuring the catalysate at characteristic wavelength of 450 nm. This proposed biosensor was able to separate ∼70% of target Salmonella cells from 50 mL of bacterial sample and quantitatively detect Salmonella from 101 to 104 CFU/mL in 2.5 h with the lower detection limit of 11 CFU/mL. The mean recovery for Salmonella in spiked chicken carcass was about 109.8%. This new magnetic grid separation method was first time reported for efficient separation of target bacteria from very large volume of sample to greatly improve the sensitivity of this biosensor and could be used with various biosensing assays for practical applications in routine detection of foodborne pathogens without any bacterial pre-enrichment.

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