Infections caused by various known and emerging pathogenic microorganisms, including antibiotic-resistant strains, are a major threat to global health and well-being. This highlights the urgent need for detection systems for microbial identification, quantification and characterization towards assessing infections, prescribing therapies and understanding the dynamic cellular modifications. Current state-of-the-art microbial detection systems exhibit a trade-off between sensitivity and assay time, which could be alleviated by selective and label-free microbial capture onto the sensor surface from dilute samples. AC electrokinetic methods, such as dielectrophoresis, enable frequency-selective capture of viable microbial cells and spores due to polarization based on their distinguishing size, shape and sub-cellular compositional characteristics, for downstream coupling to various detection modalities. Following elucidation of the polarization mechanisms that distinguish bacterial cells from each other, as well as from mammalian cells, this review compares the microfluidic platforms for dielectrophoretic manipulation of microbials and their coupling to various detection modalities, including immuno-capture, impedance measurement, Raman spectroscopy and nucleic acid amplification methods, as well as for phenotypic assessment of microbial viability and antibiotic susceptibility. Based on the urgent need within point-of-care diagnostics towards reducing assay times and enhancing capture of the target organism, as well as the emerging interest in isolating intact microbials based on their phenotype and subcellular features, we envision widespread adoption of these label-free and selective electrokinetic techniques.

Selective trapping of nanoscale bioparticles (size <100 nm) is significant for the separation and high-sensitivity detection of biomarkers. Dielectrophoresis is capable of highly selective trapping of bioparticles based on their characteristic frequency response. However, the trapping forces fall steeply with particle size, especially within physiological media of high-conductivity where the trapping can be dissipated by electrothermal (ET) flow due to localized Joule heating. Herein, we investigate the influence of device scaling within the electrodeless insulator dielectrophoresis geometry through the application of highly constricted channels of successively smaller channel depth, on the net balance of dielectrophoretic trapping force versus ET drag force on bioparticles. While higher degrees of constriction enable dielectrophoretic trapping of successively smaller bioparticles within a short time, the ETflow due to enhanced Joule heating within media of high conductivity can cause a significant dissipation of bioparticle trapping. This dissipative drag force can be reduced through lowering the depth of the highly constricted channels to submicron sizes, which substantially reduces the degree of Joule heating, thereby enhancing the range of voltages and media conductivities that can be applied toward rapid dielectrophoretic concentration enrichment of silica nanoparticles (∼50 nm) and streptavidin protein biomolecules (∼5 nm). We envision the application of these methodologies toward nanofabrication, optofluidics, biomarker discovery, and early disease diagnostics.

BackgroundExaggerated postprandial spikes in blood glucose and lipids induce proportional increases in oxidative stress, which acutely trigger impairment endothelial, inflammation and increased risk of future cardiovascular events. In this research, we have investigated acute effects of vinegar intake on some of the biochemical atherosclerosis risk factors in high cholesterol fed rabbits to see if we can find a probable protective value for it.MethodsThe rabbits were randomly divided into four groups: normal diet, high cholesterol diet (%1cholesterol), %1 cholesterol with 5 ml vinegar (low dose), %1 cholesterol with 10 ml vinegar (high dose). After fasting for 12-15 hours, blood samples were taken to determine baseline values. Three hours after feeding, blood samples were collected again to investigate acute effects of vinegar intake on the measured factors.ResultsUsing high-dose vinegar with cholesterolemic diet caused significant reduce in LDL-cholesterol (LDL-C), oxidized-LDL (ox-LDL), malondialdehyde (MDA), total cholesterol (TC) and apolipoprotein B (ApoB) in comparison with hypercholesterolemic diet. Consumption low-dose vinegar with cholesterolemic diet induced a significant decrease in fibrinogen and glucose compared to hypercholesterolemic diet. Level of serum nitrite, nitrate, triacylglycerol (TAG), HDL-cholesterol (HDL-C), apolipoprotein A (ApoA), serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetate transaminase (SGOT) and C-reactive protein (CRP) were not significantly difference in low and high doses vinegar with cholesterolemic diet compared to hypercholesterolemic diet. A significant difference was observed for LDL-C, ApoB100 and TC between low and high doses vinegar.ConclusionThis study suggest that vinegar, might have some acute effects on biochemical risk factors of atherosclerosis and a probable protective value can be considered for its postprandial use.

Heterogeneous immunoassays usually require long incubation times to promote specific target binding and several wash steps to eliminate non-specific binding. Hence, signal saturation is rarely achieved at detection limit levels of analyte, leading to significant errors in analyte quantification due to extreme sensitivity of the signals to incubation time and methodology. The poor binding kinetics of immunoassays at detection limit levels can be alleviated through creating an enriched analyte plug in the vicinity of immobilized capture probes to enable signal saturation at higher levels and at earlier times, due to higher analyte association and its faster replenishment at the binding surface. Herein, we achieve this by coupling frequency-selective dielectrophoretic molecular dam enrichment of the target biomarker in physiological media to capture probes immobilized on graphene-modified surfaces in a nanoslit to enable ultrafast immunoassays with near-instantaneous (<2 minutes) signal saturation at dilute biomarker levels (picomolar) within ultra-low sample volumes (picoliters). This methodology is applied to the detection of Prostate Specific Antigen (PSA) diluted in serum samples, followed by validation against a standard two-step immunoassay using three de-identified patient samples. Based on the ability of dielectrophoretic molecular dam analyte enrichment methods to enable the detection of PSA at 1-5 pg mL(-1) levels within a minute, and the relative insensitivity of the signals to incubation time after the first two minutes, we envision its application for improving the sensitivity of immunoassays and their accuracy at detection limit levels.

The aim of the present study is to evaluate the protective effect of manganese chloride against carbon tetrachloride (CCl4)-induced liver injury in rats. Manganese chloride (0.001, 0.01, 0.05 and 0.1 g/kg bw) was administered intragastrically for 28 consecutive days to male CCl4-treated rats. The hepatoprotective activity was assessed using various biochemical parameters such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), γ-glutamyltransferase (GGT) and superoxide dismutase (SOD). Histopathological changes in the liver of different groups were also studied. Administration of CCl4 increased the serum ALT, AST, ALP and GGT but decreased SOD levels in rats. Treatment with manganese chloride significantly attenuated these changes to nearly normal levels. The animals treated with manganese chloride have shown decreased necrotic zones and hepatocellular degeneration when compared to the liver exposed to CCl4 intoxication alone. Thus, the histopathological studies also supported the protective effect of manganese chloride. Therefore, the results of this study suggest that manganese chloride exerts hepatoprotection via promoting antioxidative properties against CCl4-induced oxidative liver damage.