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1.
J Org Chem ; 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31886664

RESUMO

Copper-catalyzed multicomponent borylacylation of imines with acid chlorides and bis(pinacolato)diboron was developed for the preparation of synthetically useful and pharmacologically relevant α-amino boronic acid derivatives. Starting from a range of acid chlorides and imines with aryl, heteroaryl, and alkyl substituents, most of these ligand-free reactions proceeded smoothly at room temperature in moderate to good yields. Furthermore, a facile and convenient one-pot, multistep access to the direct synthesis of α-amino boronic acid derivatives from available aldehydes and amines was also developed.

2.
Arch Anim Breed ; 62(1): 125-133, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31807622

RESUMO

Keratin-associated proteins (KAPs) are a structural component of cashmere fibre, and variation in some KAP genes (KRTAPs) has been associated with a number of caprine fibre traits. In this study, we report the identification of KRTAP15-1 in goats. Sequence variation in the gene was detected using the polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) technique in 250 Longdong goats, and six variants (named A to F) containing eight single nucleotide polymorphisms (SNPs) were identified. Five of the SNPs were non-synonymous and would lead to putative amino acid changes. Reverse-transcription polymerase chain reaction (RT-PCR) analysis revealed that KRTAP15-1 was expressed in secondary hair follicles but not in heart tissue, liver tissue, lung tissue, kidney tissue or the longissimus dorsi muscle. Despite being rich in cysteine, the caprine KAP15-1 protein possesses a high content of serine and moderate content of glycine and phenylalanine. Association analyses revealed that KRTAP15-1 variant A was associated with decreased mean fibre diameter (MFD), and this effect appeared to be dominant; while variant C was found to be associated with increased MFD, the effect being recessive. The findings suggest that caprine KRTAP15-1 is highly polymorphic and that variation in this gene affects cashmere MFD.

3.
Arch Anim Breed ; 62(2): 509-515, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31807662

RESUMO

Variation in KRTAP6-1 has been reported to affect wool fibre traits in Merino cross-breed sheep and Chinese Tan sheep, but little is known about whether these effects persist in other breeds. In this study, variation in KRTAP6-1 was investigated in 290 New Zealand (NZ) Romney ewes sired by 16 different rams. Polymerase chain reaction single-stranded conformational polymorphism (PCR-SSCP) analysis revealed four variants ( A , B , E and F ) of KRTAP6-1, and nine genotypes (AA, AB, AE, AF, BB, BE, BF, EE and FF) in these ewes. Among the 243 ewes that had genotypes with a frequency of over 5 % (i.e. AA, AB and BB), the presence of A was found to be associated with reduced mean fibre diameter (MFD) and increased coefficient of variation in fibre diameter (CVFD), whereas the presence of B had a trend of association with decreased coarse edge measurement (CEM). A genotype effect was also detected for MFD and CVFD. No associations were detected for fibre diameter standard deviation (FDSD), mean fibre curvature (MFC) and medulation. These results suggest that variation in KRTAP6-1 affects wool fibre diameter in NZ Romney ewes, confirming the finding in Merino cross-breed sheep.

4.
Genomics ; 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31866420

RESUMO

CircRNA is a specific type of non-coding RNA that has been shown to have an important role in mammary gland (MG) activity, but no study of MG circRNA activity in sheep so far. In this study, the expression profile of circRNAs was investigated using RNA-Seq in MG parenchyma at peak lactation from Small-Tailed Han sheep and Gansu Alpine Merino sheep with phenotypic differences in milk yield and components. A total of 4, 906 circRNAs were found and 33 of these were differentially expressed between breeds. GO and KEGG results showed that the parental genes of differentially expressed circRNAs were mainly enriched in heterocyclic compound binding, kinase activity, adherens junction, the TGF-ß signaling pathway, and the MAPK signaling pathway. This study provides an overview of circRNA expression in the ovine MG and the interaction between some key circRNAs and their target miRNAs. It improves our knowledge of the role of circRNA in sheep milk synthesis.

5.
Genes (Basel) ; 10(11)2019 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-31717789

RESUMO

The keratin-associated proteins (KAPs) are structural components of hair/wool fibres. All of the KAPs identified to date contain cysteine, which is thought to form disulphide bonds cross-linking the keratin intermediate filaments. Here, we report the identification of a KAP gene in sheep that would produce a protein that contains a high proportion (63.2 mol%) of glycine and tyrosine, but would not contain any cysteine. This suggests that other forms of intra- and inter-strand interaction may occur with this KAP, such as interactions via ring-stacking and hydrogen-bonding. The gene was dissimilar to any previously reported KAP gene, and was therefore assigned to a new family, and named KRTAP36-1. The KRTAP36-1 genome sequence was almost identical to some EST sequences from sheep and goat skin follicles, suggesting that it is present and expressed in sheep and goats. A BLAST search of the human genome assembly sequence did not reveal any human homologue. Three variant sequences (named A to C) of ovine KRTAP36-1 were identified and four single nucleotide polymorphisms (SNPs) were detected. One SNP was located 32 bp upstream of the coding region, and all of the others were in the coding region and were nonsynonymous. After correcting for potential linkage to the proximal KRTAP20-1, variant B of KRTAP36-1 was found to be associated with increased prickle factor (PF) in wool, suggesting that variation in the gene may have the potential to be used as gene marker for breeding sheep with lower PF.

6.
Genes (Basel) ; 10(10)2019 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-31597369

RESUMO

The mammary gland is a crucial tissue for milk synthesis and plays a critical role in the feeding and growth of mammalian offspring. The aim of this study was to use RNA-sequencing (RNA-Seq) technology to provide a transcriptome profile of the ovine mammary gland at the peak of lactation. Small-Tailed Han (STH) sheep (n = 9) and Gansu Alpine Merino (GAM) sheep (n = 9), breeds with phenotypic differences in milk production traits, were selected for the RNA-Seq analysis. This revealed 74 genes that were more highly expressed in the STHs than in the GAMs. Similarly, 143 genes that were expressed at lower levels in the STHs than in the GAMs, were identified. Gene ontogeny (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that these differentially expressed genes (DEGs) were associated with binding and catalytic activities, hematopoietic cell lineages, oxytocin signaling pathway and neuroactive ligand-receptor interaction. This is the first study of the transcriptome profile of the ovine mammary gland in these Chinese breeds at peak lactation. The results provide for a better understanding of the genetic mechanisms involved in ovine lactation.

7.
Chemphyschem ; 20(23): 3177-3180, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31639248

RESUMO

Herein, we report ultrasound-propelled graphene-oxide coated gold nanowire motors, functionalized with fluorescein-labeled DNA aptamers (FAM-AIB1-apt), for qualitative detection of overexpressed AIB1 oncoproteins in MCF-7 breast cancer cells. The movement of nanomotors under the ultrasound field facilitated intracellular uptake and resulted in a faster aptamer binding with the target protein and thus faster fluorescence recovery. The propulsion behavior of the aptamer functionalized nanomotors greatly enhanced the fluorescence intensity compared to static conditions. The new aptamer@nanomotor-based strategy offers considerable potential for further development of sensing methodologies towards diagnosis of breast cancer.

8.
Sci Rep ; 9(1): 14154, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31578355

RESUMO

This study aimed to evaluate the disparity in the under-five mortality rate (U5MR) between minority and non-minority areas in Sichuan Province in Western China. Data for this study was obtained from the National Health Statistics Survey System. The Cochran-Armitage trend test was used to analyze the time trend of the U5MR. We conducted Poisson regression model to compare the differences of U5MRs between minority and non-minority areas. The U5MR in Sichuan province was reduced by 62.19% from 2008 to 2017, with the minority and non-minority areas reduced by 60.48% and 65.39%, respectively. The under-five mortality risk in minority areas was approximately 1.791 times (95% CI: 1.790-1.793; P < 0.01) that in non-minority areas. The primary cause of death of children under-five years old in minority areas was the respiratory disease, which was significantly higher than that in non-minority areas (P all < 0.01). The U5MR significantly declined both in minority and non-minority areas in Sichuan Province in Western China from 2008 to 2017. However, disparities still existed between minority and non-minority areas. Respiratory diseases were the main causes of death in minority areas and corresponding rates were higher than those in non-minority areas.

9.
Pharm Biol ; 57(1): 507-513, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31401919

RESUMO

Context: Bladder cancer, which has high recurrence, is one of the most deadly cancers in the world. Astragalus propinquus Schischkin (Fabaceae) and Sagittaria sagittifolia L. (Alismataceae) are important herbs reported to be effective in cancer therapy. Objective: The efficacy of QCSL (Qici Sanling decoction) in bladder cancer treatment was examined. Materials and methods: T24 cells were injected into the flanks of nude mice and the mice were randomly divided into five groups: control; 20 mg/kg XAV-939 (an inhibitor of the WNT/ß-catenin pathway); QCSL (100, 200, or 400 mg/kg). After 7 weeks, the mice were anaesthetised using isoflurane and the xenografts were excised to perform further experiments. Results: Both XAV-939 (tumour volume: 379.67 ± 159.92 mm3) and QCSL (796.18 ± 101.6 mm3) dramatically suppressed tumour growth comparing with control group (3612.12 ± 575.03 mm3). XAV-939 and QCSL treatments decreased cell proliferation from 56.3 ± 0.05% to 29.02 ± 0.07% and 37.51 ± 0.04%, respectively. In agreement, more infiltration of immune cells and pyknotic cells upon XAV-939 (apoptosis rates: 43.92 ± 0.03%) and QCSL (34.57 ± 0.04%) treatment comparing with control group (15.59 ± 0.03%) were observed. Furthermore, TUNEL staining of xenograft tumours illustrated more apoptotic cells upon XAV-939 and QCSL treatment. Mechanistically, XAV-939 and QCSL treatments significantly inhibited WNT/ß-catenin pathway in T24 xenograft tumours. Discussion and conclusions: Our findings give new insights into the role of QCSL in bladder cancer and explore potential mechanisms contributing to the therapeutic effects of QCSL in bladder cancer.

10.
Animals (Basel) ; 9(7)2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31315271

RESUMO

Keratin-associated proteins (KAPs) are key constituents of wool and hair fibers. In this study, an ovine KAP gene encoding a HGT-KAP protein was identified. The gene was different from all of the HGT-KAP genes identified in sheep, but was closely related to the human KAP21-1 gene, suggesting that it represented the unidentified ovine KRTAP21-1. Four variants (named A to D) of ovine KRTAP21-1 were found in 360 Merino × Southdown-cross lambs from four sire lines. Three sequence variations were detected among these variants. Two of the sequence variations were located upstream of the coding region and the remaining one was a synonymous variation in the coding sequence. Six genotypes were found in the Merino-cross lambs, with only two of the genotypes (AA and AC) occurring at a frequency of over 5%. Wool from sheep of genotype AA had a higher yield than that from AC sheep (p = 0.014), but tended to have a lower greasy fleece weight (GFW) than that of genotype AC (P = 0.078). This suggests that variation in KRTAP21-1 affects wool yield and the gene may have potential for use as a genetic maker for improving wool yield.

11.
Environ Pollut ; 252(Pt B): 1439-1447, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31265954

RESUMO

Arsenic (As) and antimony (Sb) are considered as priority environmental pollutants and their accumulation in crop plants particularly in rice has posed a great health risk. This study endeavored to investigate As and Sb contents in paired soil-rice samples obtained from Xikuangshan, the world largest active Sb mining region, situated in China, and to investigate As speciation and location in rice grains. The soil and rice samples were analyzed by coupling the wet chemistry, laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), synchrotron-based micro X-ray fluorescence mapping (µ-XRF) and micro X-ray absorption near-edge structure (µ-XANES) spectroscopy. The results of field survey indicated that the paddy soil in the region was co-polluted by Sb (5.91-322.35 mg kg-1) and As (0.01-57.21 mg kg-1). Despite the higher Sb concentration in the soil, rice accumulated more As than Sb indicating the higher phytoavailability of As. Dimethylarsinic acid (DMA) was the predominant species (>60% on average) in the rice grains while the percentage of inorganic As species was 19%-63%. The µ-XRF mapping of the grain section revealed that the most of As was distributed and concentrated in rice husk, bran and embryo. Sb was distributed similarly to As but was not in the endosperm of rice grain based on LA-ICP-MS. The present results deepened our understanding of the As/Sb co-pollution and their association with the agricultural-product safety in the vicinity of Sb mining area.


Assuntos
Antimônio/análise , Arsênico/análise , Poluição Ambiental/análise , Oryza/química , Poluentes do Solo/análise , China , Mineração , Solo/química , Espectroscopia por Absorção de Raios X
12.
Bull Environ Contam Toxicol ; 103(1): 199-205, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31147729

RESUMO

Metal dioxide nanoparticles (NPs) are produced in ever-increasing amounts and widely used in industrial, medical and consumer products. They may pose potential risks to the environment. In this study we quantitatively evaluated the phytoavailability of CeO2NPs, ZrO2NPs and SiO2NPs to wheat (Triticum aestivum L.). Metal dioxide NPs showed distinct differences in uptake, with uptake rate constants of 90.2 ± 9.9, 12.2 ± 2.5, 0.4 ± 0.02 and 0.9 ± 0.1 L kg-1 h-1 for ZrO2NPs, CeO2NPs, SiO2NPs (13 nm) and SiO2NPs (25 nm), respectively. However, such difference cannot be generalized by single factor of NP characteristics and/or root damage. This study provides fundamental information for NP uptake by crop plants.


Assuntos
Nanopartículas Metálicas/análise , Dióxido de Silício/metabolismo , Poluentes do Solo/metabolismo , Triticum/metabolismo , Zircônio/metabolismo , Raízes de Plantas
13.
Anal Chem ; 91(11): 7418-7425, 2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31056901

RESUMO

This work demonstrates for the first time the creation of microchip electrophoresis devices with ∼50 µm cross-sectional dimensions by stereolithographic 3D printing and their application in the analysis of medically significant biomarkers related to risk for preterm birth (PTB). We determined that device current was linear with applied potential up to 800 V (620 V/cm). We optimized device and separation conditions using fluorescently labeled amino acids as a model system and compared the performance in our 3D printed microfluidic devices to that in other device materials commonly used for microchip electrophoresis analysis. We demonstrated for the first time microchip electrophoresis in a 3D printed device of three PTB biomarkers, including peptides and a protein, with suitable separation characteristics. Limits of detection for microchip electrophoresis in 3D printed microfluidic devices were also determined for PTB biomarkers to be in the high picomolar to low nanomolar range.

14.
Adv Mater ; 31(27): e1901828, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31070278

RESUMO

Magnesium (Mg)-based micromotors are combined with live macrophage (MΦ) cells to create a unique MΦ-Mg biohybrid motor system. The resulting biomotors possess rapid propulsion ability stemming from the Mg micromotors and the biological functions provided by the live MΦ cell. To prepare the biohybrid motors, Mg microparticles coated with titanium dioxide and poly(l-lysine) (PLL) layers are incubated with live MΦs at low temperature. The formation of such biohybrid motors depends on the relative size of the MΦs and Mg particles, with the MΦ swallowing up Mg particles smaller than 5 µm. The experimental results and numerical simulations demonstrate that the motion of MΦ-Mg motors is determined by the size of the Mg micromotor core and the position of the MΦ during the attachment process. The MΦ-Mg motors also perform biological functions related to free MΦs such as endotoxin neutralization. Cell membrane staining and toxin neutralization studies confirm that the MΦs maintain their viability and functionality (e.g., endotoxin neutralization) after binding to the Mg micromotors. This new MΦ-Mg motor design can be expanded to different types of living cells to fulfill diverse biological tasks.


Assuntos
Macrófagos/citologia , Magnésio/química , Animais , Linhagem Celular , Membrana Celular/metabolismo , Sobrevivência Celular , Endotoxinas/metabolismo , Camundongos , Microesferas , Polilisina/química , Poliestirenos/química , Titânio/química
15.
Animals (Basel) ; 9(4)2019 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-30987059

RESUMO

Keratin-associated proteins (KAPs) are a diverse group of proteins and form a matrix that cross-links keratin intermediate filaments in hair and wool fibres. From over 100 KAP genes (KRTAPs) identified in mammalian species, KRTAP25-1 is a high sulphur (HS)-KAP gene, which has recently been described in humans. Here, we report the absence of KRTAP25-1 in sheep, and describe a new HS-KRTAP (named KRTAP28-1) in the chromosome region where KRTAP25-1 was expected to be found. Six variants (A-F) of KRTAP28-1 containing eight single nucleotide polymorphisms (SNPs) and a TG repeat polymorphism were detected. One was positioned 30 bp upstream of the transcription start codon and all the others were non-synonymous SNPs, including a nonsense SNP. The TG repeat polymorphism would lead to a reading frame shift at the carboxyl-terminal end. The effect of KRTAP28-1 on wool traits was investigated with 383 Southdown × Merino-cross lambs from seven sire lines. Of the four genotypes with a frequency of over 5%, lambs of genotypes AB and BD produced wool of a smaller MFD than lambs of genotype BC. This shows that KRTAP28-1 is associated with wool fibre diameter, and that variation in this gene might have potential for use as a gene marker for reducing wool fibre diameter.

16.
Med Sci Monit ; 25: 3090-3099, 2019 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-31026254

RESUMO

BACKGROUND In the pathogenesis and progression of prostate cancer, cell proliferation and cell migration results in tumor invasion and metastasis that is associated with patient morbidity and mortality. Rho-associated protein kinase (ROCK) has previously been shown to be upregulated in prostate cancer, but its biological role remains poorly understood. This study aimed to investigate the role of ROCK in the proliferation and migration of PC-3 and DU145 prostate cancer cells and to identify the possible targets involved by knockdown of ROCK1 and ROCK2 RNA expression. MATERIAL AND METHODS An RNA interference (RNAi) assay was performed to silence the expression of ROCK1 and ROCK2 in the PC-3 and DU145 human prostate cancer cell lines. Cells were also treated with a specific ROCK inhibitor, Y27632. A cell counting kit-8 (CCK-8) assay was used to determine the proliferation rate of prostate cancer cells, and cell migration and invasion assays were performed. Western blot and polymerase chain reaction were used to measure protein and RNA expression levels. RESULTS In PC-3 and DU145 prostate cancer cells, knockdown of ROCK1 and ROCK2 reduced cell migration and invasion. ROCK1 and ROCK2 regulated cell proliferation in PC-3 and DU145 prostate cancer cells. Protein levels of phosphorylated LIM kinase 1 (p-LIMK1) and matrix metalloproteinase-2 (MMP-2) were reduced in ROCK1 and ROCK2 siRNA transfected cells. CONCLUSIONS In PC-3 and DU145 human prostate cancer cells, ROCK promoted cell proliferation and migration by targeting LIMK1 and MMP-2.


Assuntos
Quinases Lim/metabolismo , Metaloproteinase 2 da Matriz/metabolismo , Neoplasias da Próstata/enzimologia , Quinases Associadas a rho/metabolismo , Adenocarcinoma/enzimologia , Adenocarcinoma/patologia , Animais , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Técnicas de Silenciamento de Genes , Humanos , Neoplasias Pulmonares/enzimologia , Neoplasias Pulmonares/secundário , Masculino , Camundongos , Camundongos Nus , Células PC-3 , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/genética , Transdução de Sinais , Quinases Associadas a rho/genética
17.
Zhongguo Gu Shang ; 32(1): 22-27, 2019 Jan 25.
Artigo em Chinês | MEDLINE | ID: mdl-30813663

RESUMO

OBJECTIVE: To explore clinical efficacy of limited external fixation with plastic paperboard in treating senile proximal comminuted humeral fracture. METHODS: From June 2015 to December 2017, 32 senile patients with proximal comminuted fracture of humerus were treated with plasticized cardboard after manual external fixation. Among them, including 13 males and 19 females aged from 55 to 85 years old with an average of(68.22±8.36) years old; 18 patients on the left side and 14 patients on the right side; all patients were regularly review shoulder X-rays and performed appropriate functional exercises. Constant-Murley shoulder joint scoring was used to evaluate clinical effects. RESULTS: Thirty-two patients were followed up for 3 to 12 months with an average of (4.97±2.39) months. All patients were underwent functional exercise under guidance of physicians. Nine patients were treated with topical Chinese herbal moist heat compresses to promote shoulder function recovery. Thirty-one patients were obtained fracture healing, the time ranged from 5 to 12 weeks with an average of(7.44±1.72)weeks. One patient was not healed due to comminuted fracture of fracture end and the separation was large, the blood supply to humeral head was insufficient for necrosis absorption. Postoperative Constant-Murley shoulder score at 3 months was 87.56±6.93; 15 patients got excellent results, 14 good, 2 fair and 1 poor. CONCLUSIONS: Limited external fixation with plastic paperboard for the treatment of senile proximal comminuted humeral fracture could ensure biomechanical stability of fracture, promote early recovery of shoulder joint function and shorten recovery time.


Assuntos
Fraturas Cominutivas , Fraturas do Úmero , Fraturas do Ombro , Idoso , Idoso de 80 Anos ou mais , Feminino , Fixação Interna de Fraturas , Fraturas Cominutivas/cirurgia , Humanos , Fraturas do Úmero/cirurgia , Masculino , Pessoa de Meia-Idade , Plásticos , Resultado do Tratamento
18.
PeerJ ; 7: e6555, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30886771

RESUMO

Background: Adrenocortical carcinoma (ACC) is a rare and aggressive malignant cancer in the adrenal cortex with poor prognosis. Though previous research has attempted to elucidate the progression of ACC, its molecular mechanism remains poorly understood. Methods: Gene transcripts per million (TPM) data were downloaded from the UCSC Xena database, which included ACC (The Cancer Genome Atlas, n = 77) and normal samples (Genotype Tissue Expression, n = 128). We used weighted gene co-expression network analysis to identify gene connections. Overall survival (OS) was determined using the univariate Cox model. A protein-protein interaction (PPI) network was constructed by the search tool for the retrieval of interacting genes. Results: To determine the critical genes involved in ACC progression, we obtained 2,953 significantly differentially expressed genes and nine modules. Among them, the blue module demonstrated significant correlation with the "Stage" of ACC. Enrichment analysis revealed that genes in the blue module were mainly enriched in cell division, cell cycle, and DNA replication. Combined with the PPI and co-expression networks, we identified four hub genes (i.e., TOP2A, TTK, CHEK1, and CENPA) that were highly expressed in ACC and negatively correlated with OS. Thus, these identified genes may play important roles in the progression of ACC and serve as potential biomarkers for future diagnosis.

19.
ACS Nano ; 13(3): 3714-3722, 2019 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-30831025

RESUMO

The efforts of detecting bioactive targets with complex, dynamic, and unknown molecular profiles have inspired the development of various biosensor platforms. Herein, we report a cell-membrane-modified field effect transistor (FET) as a function-based nanosensor for the detection and quantitative measurement of numerous toxins and biological samples. By coating carbon nanotube FETs with natural red blood cell membranes, the resulting biomimetic nanosensor can selectively interact with and absorb broad-spectrum hemolytic toxins regardless of their molecular structures. Toxin-biomembrane interactions alter the local charge distribution at the FET surface in an ultrasensitive and concentration-dependent manner, resulting in a detection limit down to the femtomolar (fM) range. Accurate and quantitative measurements are enabled via a built-in calibration mechanism of the sensor, which overcomes batch-to-batch fabrication variations, and are demonstrated using three distinct toxins and various complex bacterial supernatants. The measured signals of bacterium-secreted proteins correlate linearly with the actual bacterial numbers, making the biosensor a nontraditional approach to rapidly detecting bacterial concentrations without a need to count bacterial colonies.

20.
Biomicrofluidics ; 13(1): 014106, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30766649

RESUMO

In this paper, we demonstrate the ability to 3D print tightly integrated structures with active valves, pumps, and mixers, and we use our compact chip-to-chip interconnects [Gong et al., Lab Chip 18, 639-647 (2018)] to move bulky world-to-chip connections to separate interface chips for both post-print flushing and post-cure device operation. As example devices, we first examine 3D printed pumps, followed by two types of selectable ratio mixer pumps, a linear dilution mixer pump (LDMP) and a parallelized dilution mixer pump (PDMP), which occupy volumes of only 1.5 mm 3 and 2.6 mm 3 , respectively. The LDMP generates a selectable dilution ratio from a linear set of possibilities, while the PDMP generates a denser set of possible dilutions with a maximum dilution ratio of 1/16. The PDMP also incorporates a new 4-to-1 valve to simultaneously control 4 inlet channels. To characterize LDMP and PDMP operation and performance, we present a new, low-cost video method to directly measure the relative concentration of an absorptive dye on a pixel-by-pixel basis for each video frame. Using this method, we find that 6 periods of the active mixer that forms the core of the LDMP and PDMP are sufficient to fully mix the fluid, and that the generated concentrations track the designed dilution ratios as expected. The LDMP mixes 20 nl per 4.6 s mixer pump period, while the PDMP uses parallelized input pumps to process the same fluid volume with greater choice of dilution ratios in a 3.6 s period.

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