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1.
Trends Analyt Chem ; 157: 116750, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36060607

ABSTRACT

Rapid, highly sensitive, and accurate virus circulation monitoring techniques are critical to limit the spread of the virus and reduce the social and economic burden. Therefore, point-of-use diagnostic devices have played a critical role in addressing the outbreak of COVID-19 (SARS-CoV-2) viruses. This review provides a comprehensive overview of the current techniques developed for the detection of SARS-CoV-2 in various body fluids (e.g., blood, urine, feces, saliva, tears, and semen) and considers the mutations (i.e., Alpha, Beta, Gamma, Delta, Omicron). We classify and comprehensively discuss the detection methods depending on the biomarker measured (i.e., surface antigen, antibody, and nucleic acid) and the measurement techniques such as lateral flow immunoassay (LFIA), enzyme-linked immunosorbent assay (ELISA), reverse transcriptase-polymerase chain reaction (RT-PCR), reverse transcription loop-mediated isothermal amplification (RT-LAMP), microarray analysis, clustered regularly interspaced short palindromic repeats (CRISPR) and biosensors. Finally, we addressed the challenges of rapidly identifying emerging variants, detecting the virus in the early stages of infection, the detection sensitivity, selectivity, and specificity, and commented on how these challenges can be overcome in the future.

2.
Data Brief ; 43: 108393, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35781980

ABSTRACT

Data in this article is associated with our research article "Enhanced wireless cell stimulation using soft and improved bipolar electroactive conducting polymer templates" Qin et al. (2022). Primarily, the present article shows the data of PPy-PMAS/FTO, PPy-PMAS-collagen/FTO and PPy-PMAS-DS-collagen/FTO in conventional electrochemical process and bipolar electrochemical process along with in situ spectrometry for comprehensive supplement and comparison to help with better developing modified conducting polymers based bipolar electrochemistry. Secondly, the presented the complete dataset useful for modelling the soft and improved bipolar electroactive conducting polymers focusing on wireless cell (animal and human) stimulation, which are reported in the main article. All data reported were analysed using Origin 2019b 64Bit.

3.
Bioelectrochemistry ; 146: 108150, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35550256

ABSTRACT

The detection of a key biomarker in epilepsy, miR-134, using an environmentally sensitive electrochemiluminescent luminophore, [Ru(DPPZ)2 PIC]2+, is reported, DPPZ is dipyrido[3,2-a:2',3'-c]phenazine) and PIC is (2,2'-bipyridyl)-2(4-carboxy phenyl) imidazo [4,5][1,10] phenanthroline. A thiolated capture strand is first labelled with [Ru(DPPZ)2 PIC]2+ and then adsorbed onto a gold electrode. No significant electrochemiluminescence, ECL, is observed for immobilised Ru-labelled capture strands which is consistent with the light-switch dye being exposed to the aqueous solution. In sharp contrast, binding of the target turns on ECL. The ECL intensity, IECL, depends on the number of adenine "spacer" bases between the end of the capture sequence and the dye. The ECL intensity for the optimised system increases linearly with increasing miR-134 concentration from 100 nM to approximately 20 µM. Single and double base mismatches produce IECL that are only approximately 30% and 8% respectively of that observed for the fully complementary target reflecting differences in their association constants. Significantly, the presence of BSA protein causes IECL to increase by less 5% in either the single or duplex circumstances. Finally, the ability of the sensor to quantify miR-134 in unprocessed plasma samples from healthy volunteers and people with epilepsy is reported.


Subject(s)
Biosensing Techniques , Coordination Complexes , Epilepsy , MicroRNAs , Biomarkers , Electrochemical Techniques , Epilepsy/diagnosis , Humans , Luminescent Measurements , Phenanthrolines
4.
Biomedicines ; 9(7)2021 Jun 22.
Article in English | MEDLINE | ID: mdl-34206405

ABSTRACT

Emerging and validated biomarkers promise to revolutionize clinical practice, shifting the emphasis away from the management of chronic disease towards prevention, early diagnosis and early intervention. The challenge of detecting these low abundance protein and nucleic acid biomarkers within the clinical context demands the development of highly sensitive, even single molecule, assays that are also capable of selectively measuring a small number of defined analytes in complex samples such as whole blood, interstitial fluid, saliva or urine. Success relies on significant innovations in nanomaterials, bioreceptor engineering, transduction strategies and microfluidics. Primarily using examples from our work, this article discusses some recent advance in the selective and sensitive detection of disease biomarkers, highlights key innovations in sensor materials and identifies issues and challenges that need to be carefully considered especially for researchers entering the field.

5.
Front Chem ; 9: 662810, 2021.
Article in English | MEDLINE | ID: mdl-34113601

ABSTRACT

The fabrication and electrochemical properties of a 3D printed titanium electrode array are described. The array comprises 25 round cylinders (0.015 cm radius, 0.3 cm high) that are evenly separated on a 0.48 × 0.48 cm square porous base (total geometric area of 1.32 cm2). The electrochemically active surface area consists of fused titanium particles and exhibits a large roughness factor ≈17. In acidic, oxygenated solution, the available potential window is from ~-0.3 to +1.2 V. The voltammetric response of ferrocyanide is quasi-reversible arising from slow heterogeneous electron transfer due to the presence of a native/oxidatively formed oxide. Unlike other metal electrodes, both [Ru(bpy)3]1+ and [Ru(bpy)3]3+ can be created in aqueous solutions which enables electrochemiluminescence to be generated by an annihilation mechanism. Depositing a thin gold layer significantly increases the standard heterogeneous electron transfer rate constant, ko, by a factor of ~80 to a value of 8.0 ± 0.4 × 10-3 cm s-1 and the voltammetry of ferrocyanide becomes reversible. The titanium and gold coated arrays generate electrochemiluminescence using tri-propyl amine as a co-reactant. However, the intensity of the gold-coated array is between 30 (high scan rate) and 100-fold (slow scan rates) higher at the gold coated arrays. Moreover, while the voltammetry of the luminophore is dominated by semi-infinite linear diffusion, the ECL response is significantly influenced by radial diffusion to the individual microcylinders of the array.

6.
Chem Commun (Camb) ; 57(38): 4642-4645, 2021 May 11.
Article in English | MEDLINE | ID: mdl-33876176

ABSTRACT

Wireless electrochemiluminescence is generated using interdigitated, 3D printed, titanium arrays as feeder electrodes to shape the electric field. Gold microparticles (45 µm diameter), functionalised with 11-mercaptoundecanoic acid, act as micro-emitters to generate electrochemiluminescence from [Ru(bpy)3]2+, (bpy is 2,2'-bipyridine) where the co-reactant is tripropylamine. The oxide coated titanium allows intense electric fields, whose distribution depends on the geometry of the array, to be created in the absence of deliberately added electrolyte. COMSOL modelling and long exposure ECL imaging have been used to map the electric field distribution. Significantly, we demonstrate that by controlling the surface charge of the gold microparticles through the solution pH, the light intensity can be increased by a factor of more than 10.

7.
Langmuir ; 37(11): 3359-3369, 2021 03 23.
Article in English | MEDLINE | ID: mdl-33705153

ABSTRACT

A 153-mer target DNA was amplified using ethynyl ferrocene dATP and a tailed forward primer resulting in a duplex with a single-stranded DNA tail for hybridization to a surface-tethered probe. A thiolated probe containing the sequence complementary to the tail as well as a 15 polythimine vertical spacer with a (CH2)6 spacer was immobilized on the surface of a gold electrode and hybridized to the ferrocene-modified complementary strand. Potential step chronoamperometry and cyclic voltammetry were used to probe the potential of zero charge, PZC, and the rate of heterogeneous electron transfer between the electrode and the immobilized ferrocene moieties. Chronoamperometry gives three, well-resolved exponential current-time decays corresponding to ferrocene centers located within 13 Å (4 bases) along the duplex. Significantly, the apparent standard heterogeneous electron transfer rate constant, kappo, observed depends on the initial potential, i.e., the rate of electron transfer at zero driving force is not the same for oxidation and reduction of the ferrocene labels. Moreover, the presence of ions, such as Sr2+, that strongly ion pair with the negatively charged DNA backbone modulates the electron transfer rate significantly. Specifically, kappo = 246 ± 23.5 and 14 ± 1.2 s-1 for reduction and oxidation, respectively, where the Sr2+ concentration is 10 mM, but the corresponding values in 1 M Sr2+ are 8 ± 0.8 and 150 ± 12 s-1. While other factors may be involved, these results are consistent with a model in which a low Sr2+ concentration and an initial potential that is negative of the PZC lead to electrostatic repulsion of the negatively charged DNA backbone and the negatively charged electrode. This leads to the DNA adopting an extended configuration (concertina open), resulting in a slow rate of heterogeneous electron transfer. In contrast, for ferrocene reduction, the initial potential is positive of PZC and the negatively charged DNA is electrostatically attracted to the electrode (concertina closed), giving a shorter electron transfer distance and a higher rate of heterogeneous electron transfer. When the Sr2+ concentration is high, the charge on the DNA backbone is compensated by the electrolyte and the charge on the electrode dominates the electron transfer dynamics and the opposite potential dependence is observed. These results open up the possibility of electromechanical switching using DNA superstructures.


Subject(s)
DNA , Electrons , DNA/genetics , Electrodes , Electron Transport , Metallocenes , Static Electricity
8.
Microorganisms ; 10(1)2021 Dec 30.
Article in English | MEDLINE | ID: mdl-35056520

ABSTRACT

Muskox (Ovibos moschatus), as the biggest herbivore in the High Arctic, has been enduring the austere arctic nutritional conditions and has evolved to ingest and digest scarce and high lignified forages to support the growth and reproduce, implying probably harbor a distinct microbial reservoir for the deconstruction of plant biomass. Therefore, metagenomics approach was applied to characterize the rumen microbial community and understand the alteration in rumen microbiome of muskoxen fed either triticale straw or brome hay. The difference in the structure of microbial communities including bacteria, archaea, fungi, and protozoa between the two forages was observed at the taxonomic level of genus. Further, although the highly abundant phylotypes in muskoxen rumen fed either triticale straw or brome hay were almost the same, the selective enrichment different phylotypes for fiber degrading, soluble substrates fermenting, electron and hydrogen scavenging through methanogenesis, acetogenesis, propionogenesis, and sulfur-reducing was also noticed. Specifically, triticale straw with higher content of fiber, cellulose selectively enriched more lignocellulolytic taxa and electron transferring taxa, while brome hay with higher nitrogen content selectively enriched more families and genera for degradable substrates-digesting. Intriguingly, the carbohydrate-active enzyme profile suggested an over representation and diversity of putative glycoside hydrolases (GHs) in the animals fed on triticale straw. The majority of the cellulases belonged to fiver GH families (i.e., GH5, GH6, GH9, GH45, and GH48) and were primarily synthesized by Ruminococcus, Piromyces, Neocallimastix, and Fibrobacter. Abundance of major genes coding for hemicellulose digestion was higher than cellulose mainly including GH8, GH10, GH16, GH26, and GH30, and these enzymes were produced by members of the genera Fibrobacter, Ruminococcus, and Clostridium. Oligosaccharides were mainly of the GH1, GH2, GH3, and GH31 types and were associated with the genera Prevotella and Piromyces. Our results strengthen metatranscriptomic evidence in support of the understanding of the microbial community and plant polysaccharide response to changes in the feed type and host animal. The study also establishes these specific microbial consortia procured from triticale straw group can be used further for efficient plant biomass hydrolysis.

9.
Data Brief ; 33: 106406, 2020 Dec.
Article in English | MEDLINE | ID: mdl-33088881

ABSTRACT

Data in this article is associated with our research article "Bipolar Electroactive Conducting Polymers for Wireless Cell Stimulation" [1]. Primarily, the present article shows the data of PPy-pTS, PPy-DS and PPy-DS/collagen in conventional electrochemical process and bipolar electrochemical process for comprehensive supplement and comparison to help with better understanding and developing conducting polymers based bipolar electrochemistry. Secondly, the presented data of bipolar electrostimulation (BPES) protocol development constitute the complete dataset useful for modeling the bipolar electroactive conducting polymers focusing on wireless cell stimulation, which are reported in the main article. All data reported were analysed using Origin 2018b 64Bit.

10.
Molecules ; 25(17)2020 Aug 26.
Article in English | MEDLINE | ID: mdl-32858929

ABSTRACT

The properties of carbon nano-onions (CNOs) make them attractive electrode materials/additives for the development of low-cost, simple to use and highly sensitive Screen Printed Electrodes (SPEs). Here, we report the development of the first CNO-based ink for the fabrication of low-cost and disposable electrodes, leading to high-performance sensors. Achieving a true dispersion of CNOs is intrinsically challenging and a key aspect of the ink formulation. The screen-printing ink formulation is achieved by carefully selecting and optimising the conductive materials (graphite (GRT) and CNOs), the polymer binder, the organic solvent and the plasticiser. Our CNO/GRT-based screen-printed electrodes consist of an interconnected network of conducting carbon particles with a uniform distribution. Electrochemical studies show a heterogeneous electron transfer rate constant of 1.3 ± 0.7 × 10-3 cm·s-1 and a higher current density than the ferrocene/ferrocenium coupled to a commercial graphite SPEs. In addition, the CNO/GRT SPE can detect dopamine in the concentration range of 10.0-99.9 µM with a limit of detection of 0.92 µM (N = 3). They exhibit a higher analytical sensitivity than the commercial graphite-based SPE, with a 4-fold improvement observed. These results open up the possibility of using high-performing CNO-based SPEs for electrochemical applications including sensors, battery electrodes and electrocatalysis.


Subject(s)
Carbon/chemistry , Electrochemical Techniques , Nanostructures/chemistry , Printing, Three-Dimensional , Electrodes
11.
Electrochem commun ; 116: 106762, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32501391

ABSTRACT

Near patient detection of viral infection represents a powerful approach for the control of emerging threats to global health. Moreover, the ability to identify individuals who have contracted the disease and developed antibodies that confer immunity is central to a return to normal daily activities. This review presents some of the recent advances in electrochemical sensors for the detection of viruses and their associated antibody profiles. Given the speed, portability, sensitivity and selectivity achieved using electrochemical detection, these sensor systems hold the promise of transformative change in clinical practice.

12.
Int Microbiol ; 23(2): 137-148, 2020 May.
Article in English | MEDLINE | ID: mdl-31432356

ABSTRACT

The camel is known to survive in harsh environmental conditions, due to its higher digestive efficiency of high-fiber diets compared with other ruminants. However, limited data are available on the microbial community in the rumen of a camel. In this study, the Illumina sequencing of V4 region of 16S rRNA genes based on RNA isolation was employed to get insight into the bacterial and archaeal communities associated with liquid and solid rumen fractions in eight camels under different feeding systems. Camels in group C1 were fed Egyptian clover hay plus concentrates mixture and camels of group C2 were fed fresh Egyptian clover. The results showed that liquid fraction has higher operational taxonomic units (OTUs) than solid fraction, and camel group C1 showed a higher microbial diversity than C2. The UniFrac analysis indicated that the microbial communities in camel groups are distinct. Moreover, phylum Firmicutes and Bacteroidetes dominated the bacterial community and Candidatus Methanomethylophilus dominated the archaeal community with a significant difference in the relative abundance between camel groups. Dominant bacterial genera were Prevotella, Fibrobacteres, Ruminococcus, and Butyrivibrio. There were many negative and positive correlations between and within bacterial and archaeal genera. The composition of microbial community in the rumen of a camel is similar to other ruminants with differences in the abundance.


Subject(s)
Archaea , Bacteria , Camelus/microbiology , Gastrointestinal Microbiome/genetics , Rumen/microbiology , Animals , Archaea/classification , Archaea/genetics , Archaea/isolation & purification , Bacteria/classification , Bacteria/genetics , Bacteria/isolation & purification , High-Throughput Nucleotide Sequencing , Metagenomics , RNA, Ribosomal, 16S/genetics
13.
PeerJ ; 7: e6496, 2019.
Article in English | MEDLINE | ID: mdl-30863673

ABSTRACT

The taxonomy and associated nomenclature of many taxa of rumen bacteria are poorly defined within databases of 16S rRNA genes. This lack of resolution results in inadequate definition of microbial community structures, with large parts of the community designated as incertae sedis, unclassified, or uncultured within families, orders, or even classes. We have begun resolving these poorly-defined groups of rumen bacteria, based on our desire to name these for use in microbial community profiling. We used the previously-reported global rumen census (GRC) dataset consisting of >4.5 million partial bacterial 16S rRNA gene sequences amplified from 684 rumen samples and representing a wide range of animal hosts and diets. Representative sequences from the 8,985 largest operational units (groups of sequence sharing >97% sequence similarity, and covering 97.8% of all sequences in the GRC dataset) were used to identify 241 pre-defined clusters (mainly at genus or family level) of abundant rumen bacteria in the ARB SILVA 119 framework. A total of 99 of these clusters (containing 63.8% of all GRC sequences) had no unique or had inadequate taxonomic identifiers, and each was given a unique nomenclature. We assessed this improved framework by comparing taxonomic assignments of bacterial 16S rRNA gene sequence data in the GRC dataset with those made using the original SILVA 119 framework, and three other frameworks. The two SILVA frameworks performed best at assigning sequences to genus-level taxa. The SILVA 119 framework allowed 55.4% of the sequence data to be assigned to 751 uniquely identifiable genus-level groups. The improved framework increased this to 87.1% of all sequences being assigned to one of 871 uniquely identifiable genus-level groups. The new designations were included in the SILVA 123 release (https://www.arb-silva.de/documentation/release-123/) and will be perpetuated in future releases.

14.
J Basic Microbiol ; 59(1): 101-110, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30303547

ABSTRACT

Anaerobic fungi colonize the rumen and degrade cellulose and hemicellulose, which enable them to be key players in the lignocellulose fermentation. Consequently, an expansion of knowledge about rumen fungi could increase animal productivity, utilization of lignified forages like alfalfa hay, and enhance fibrolytic enzymes production. Here, we used an Internal Transcribed Spacer 1 (ITS1) clone library to investigate the anaerobic rumen fungi in camel and to investigate their ability to produce cellulase and xylanase in vitro. Rumen fluid was collected from camels fed Egyptian clover (n = 14), and wheat straw (n = 7) and fecal samples were collected from camels fed wheat straw and concentrates (n = 5), or natural grazing plants (n = 10). Neocallimastix and Cyllamyces were the most abundant anaerobic fungi in all camel groups. An anaerobic rumen fungi media containing alfalfa hay as a carbon source was inoculated by rumen and fecal samples to assess the ability of anaerobic rumen fungi in camel gut to produce cellulase and xylanase. The anaerobic gut fungi in the camel is diverse and has cellulolytic and xylanolytic activities, fungal culture from rumen samples of camel fed wheat straw (R2) exhibited highest cellulase production. In addition, many of the sequences in the current study have no equivalent cultured representative, indicating a novel diversity within the camel gut.


Subject(s)
Camelus/microbiology , Dietary Fiber/metabolism , Fungi/enzymology , Fungi/metabolism , Microbiota , Rumen/microbiology , Animal Feed/microbiology , Animals , Biodiversity , Cellulase/metabolism , Cellulose/biosynthesis , DNA, Fungal/analysis , Egypt , Feces/microbiology , Fermentation , Fungi/classification , Fungi/genetics , Lignin/metabolism , Male , Medicago sativa , Phylogeny , Polysaccharides/metabolism , Sequence Analysis, DNA , Triticum , Xylosidases/biosynthesis
15.
EBioMedicine ; 38: 127-141, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30396857

ABSTRACT

BACKGROUND: There are no blood-based molecular biomarkers of temporal lobe epilepsy (TLE) to support clinical diagnosis. MicroRNAs are short noncoding RNAs with strong biomarker potential due to their cell-specific expression, mechanistic links to brain excitability, and stable detection in biofluids. Altered levels of circulating microRNAs have been reported in human epilepsy, but most studies collected samples from one clinical site, used a single profiling platform or conducted minimal validation. METHOD: Using a case-control design, we collected plasma samples from video-electroencephalogram-monitored adult TLE patients at epilepsy specialist centers in two countries, performed genome-wide PCR-based and RNA sequencing during the discovery phase and validated findings in a large (>250) cohort of samples that included patients with psychogenic non-epileptic seizures (PNES). FINDINGS: After profiling and validation, we identified miR-27a-3p, miR-328-3p and miR-654-3p with biomarker potential. Plasma levels of these microRNAs were also changed in a mouse model of TLE but were not different to healthy controls in PNES patients. We determined copy number of the three microRNAs in plasma and demonstrate their rapid detection using an electrochemical RNA microfluidic disk as a prototype point-of-care device. Analysis of the microRNAs within the exosome-enriched fraction provided high diagnostic accuracy while Argonaute-bound miR-328-3p selectively increased in patient samples after seizures. In situ hybridization localized miR-27a-3p and miR-328-3p within neurons in human brain and bioinformatics predicted targets linked to growth factor signaling and apoptosis. INTERPRETATION: This study demonstrates the biomarker potential of circulating microRNAs for epilepsy diagnosis and mechanistic links to underlying pathomechanisms.


Subject(s)
Biomarkers , Circulating MicroRNA , Epilepsy, Temporal Lobe/genetics , MicroRNAs/genetics , Animals , Case-Control Studies , Computational Biology/methods , Disease Models, Animal , Epilepsy, Temporal Lobe/blood , Epilepsy, Temporal Lobe/diagnosis , Gene Expression Profiling , Gene Regulatory Networks , High-Throughput Nucleotide Sequencing , Humans , Mice , Transcriptome
16.
Microorganisms ; 6(3)2018 Aug 20.
Article in English | MEDLINE | ID: mdl-30127327

ABSTRACT

We studied the relationship between fiber digestion and the composition of the bacterial community in the rumen of muskoxen at the start and the end of the annual window of plant growth from spring to fall. Eight ruminally cannulated castrated males were fed brome hay or triticale straw (69.6% vs. 84.6% neutral detergent fiber, respectively) that were similar in fiber content to the sedges consumed by wild muskoxen (64.5 to 71.7% neutral detergent fiber). Muskoxen digested fiber from both forages faster and to a greater extent when straw rather than hay was consumed. Fiber digestion was therefore inducible by diet 4 in each season. We used 16S rRNA sequences from ruminal contents to study how season and diet affected the bacterial community and how the latter related to fiber digestion. We found that Bacteroidetes and Firmicutes accounted for 90% of the sequences at the level of Phylum, which is typical for the mammal gut microbiome. Using partial least square regressions, it was found that between 48% and 72% of the variation in fiber digestion was associated with 36⁻43 genera of bacteria. The main fibrolytic bacteria typical of domestic ruminants were generally not among the most important bacteria associated with fiber digestion in muskoxen. This reveals that muskoxen rely upon on a large suite of bacterial genera that are largely distinct from those used by other ruminants to digest the cell walls of plants that vary widely in both abundance and nutritional quality through the year.

17.
ACS Omega ; 3(12): 17116-17124, 2018 Dec 31.
Article in English | MEDLINE | ID: mdl-31458332

ABSTRACT

An electrochemical biosensor for the detection of cardiac troponin I, cTnI, an important cardiac biomarker, is described. A combination of a novel monoclonal antibody, mAb20B3, and a novel Ir(III)-based metal complex was used for detection using faradaic electrochemical impedance spectroscopy. A limit of detection of 10 ag/mL was achieved, which is significantly lower than established assays. The ability to detect these ultralow concentrations enables rapid and early stage detection of cardiac events and opens up the possibility of developing a point-of-care device.

18.
Langmuir ; 34(2): 715-725, 2018 01 16.
Article in English | MEDLINE | ID: mdl-29240434

ABSTRACT

Human blood platelets and SK-N-AS neuroblastoma cancer-cell capture at spontaneously adsorbed monolayers of fibrinogen-binding motifs, GRGDS (generic integrin adhesion), HHLGGAKQAGDV (exclusive to platelet integrin αIIbß3), or octanethiol (adhesion inhibitor) at planar gold and ordered 1.6 µm diameter spherical cap gold cavity arrays were compared. In all cases, arginine/glycine/aspartic acid (RGD) promoted capture, whereas alkanethiol monolayers inhibited adhesion. Conversely only platelets adhered to alanine/glycine/aspartic acid (AGD)-modified surfaces, indicating that the AGD motif is recognized preferentially by the platelet-specific integrin, αIIbß3. Microstructuring of the surface effectively eliminated nonspecific platelet/cell adsorption and dramatically enhanced capture compared to RGD/AGD-modified planar surfaces. In all cases, adhesion was reversible. Platelets and cells underwent morphological change on capture, the extent of which depended on the topography of the underlying substrate. This work demonstrates that both the nature of the modified interface and its underlying topography influence the capture of cancer cells and platelets. These insights may be useful in developing cell-based cancer diagnostics as well as in identifying strategies for the disruption of platelet cloaks around circulating tumor cells.


Subject(s)
Blood Platelets/metabolism , Cell Adhesion , Gold/chemistry , Oligopeptides/chemistry , Sulfhydryl Compounds/chemistry , Amino Acid Sequence , Cell Line, Tumor , Humans , Microscopy, Confocal , Microscopy, Electron, Scanning , Platelet Adhesiveness , Porosity
19.
Front Microbiol ; 8: 1657, 2017.
Article in English | MEDLINE | ID: mdl-28993761

ABSTRACT

Anaerobic fungi (phylum Neocallimastigomycota) are common inhabitants of the digestive tract of mammalian herbivores, and in the rumen, can account for up to 20% of the microbial biomass. Anaerobic fungi play a primary role in the degradation of lignocellulosic plant material. They also have a syntrophic interaction with methanogenic archaea, which increases their fiber degradation activity. To date, nine anaerobic fungal genera have been described, with further novel taxonomic groupings known to exist based on culture-independent molecular surveys. However, the true extent of their diversity may be even more extensively underestimated as anaerobic fungi continue being discovered in yet unexplored gut and non-gut environments. Additionally many studies are now known to have used primers that provide incomplete coverage of the Neocallimastigomycota. For ecological studies the internal transcribed spacer 1 region (ITS1) has been the taxonomic marker of choice, but due to various limitations the large subunit rRNA (LSU) is now being increasingly used. How the continued expansion of our knowledge regarding anaerobic fungal diversity will impact on our understanding of their biology and ecological role remains unclear; particularly as it is becoming apparent that anaerobic fungi display niche differentiation. As a consequence, there is a need to move beyond the broad generalization of anaerobic fungi as fiber-degraders, and explore the fundamental differences that underpin their ability to exist in distinct ecological niches. Application of genomics, transcriptomics, proteomics and metabolomics to their study in pure/mixed cultures and environmental samples will be invaluable in this process. To date the genomes and transcriptomes of several characterized anaerobic fungal isolates have been successfully generated. In contrast, the application of proteomics and metabolomics to anaerobic fungal analysis is still in its infancy. A central problem for all analyses, however, is the limited functional annotation of anaerobic fungal sequence data. There is therefore an urgent need to expand information held within publicly available reference databases. Once this challenge is overcome, along with improved sample collection and extraction, the application of these techniques will be key in furthering our understanding of the ecological role and impact of anaerobic fungi in the wide range of environments they inhabit.

20.
Anal Chem ; 89(22): 12441-12449, 2017 11 21.
Article in English | MEDLINE | ID: mdl-29083162

ABSTRACT

Damage to DNA from the metabolites of drugs and pollutants constitutes a major human toxicity pathway known as genotoxicity. Metabolites can react with metal ions and NADPH to oxidize DNA or participate in SN2 reactions to form covalently linked adducts with DNA bases. Guanines are the main DNA oxidation sites, and 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) is the initial product. Here we describe a novel electrochemiluminescent (ECL) microwell array that produces metabolites from test compounds and measures relative rates of DNA oxidation and DNA adduct damage. In this new array, films of DNA, metabolic enzymes, and an ECL metallopolymer or complex assembled in microwells on a pyrolytic graphite wafer are housed in dual microfluidic chambers. As reactant solution passes over the wells, metabolites form and can react with DNA in the films to form DNA adducts. These adducts are detected by ECL from a RuPVP polymer that uses DNA as a coreactant. Aryl amines also combine with Cu2+ and NADPH to form reactive oxygen species (ROS) that oxidize DNA. The resulting 8-oxodG was detected selectively by ECL-generating bis(2,2'-bipyridine)-(4-(1,10-phenanthrolin-6-yl)-benzoic acid)Os(II). DNA/enzyme films on magnetic beads were oxidized similarly, and 8-oxodG determined by LC/MS/MS enabled array standardization. The array limit of detection for oxidation was 720 8-oxodG per 106 nucleobases. For a series of aryl amines, metabolite-generated DNA oxidation and adduct formation turnover rates from the array correlated very well with rodent 1/TD50 and Comet assay results.


Subject(s)
Amines/pharmacology , DNA/drug effects , DNA/metabolism , Electrochemical Techniques , Luminescent Measurements , Microfluidic Analytical Techniques , Copper/chemistry , Cytochrome P-450 Enzyme System/metabolism , DNA Adducts/drug effects , DNA Damage , Electrochemical Techniques/instrumentation , Humans , Luminescent Measurements/instrumentation , Microfluidic Analytical Techniques/instrumentation , NADP/chemistry , Oxidation-Reduction
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