While environmental concentration of bisphenol A (BPA) is ubiquitously detected in effluent and surface of freshwater, BPA has also been measured in coastal and marine ecosystems. To understand the effect of waterborne BPA on the transcriptome over time, male fish of the marine medaka Oryzias javanicus were exposed to 76 μg/L of BPA for 72 h. Time-course microarray study identified differentially expressed transcripts upon BPA exposure in the liver tissues in a time-dependent manner. The primary effect of BPA treatment appears to be significantly upregulated mRNA expression of lipid metabolism (e.g. fatty acid process, lipid/lipoprotein biosynthesis and transport, cholesterol regulation), while genes involved in diverse biochemical and physiological processes were downregulated. In particular, vertebrate immunity relevant genes showed strong downregulated patterns across time-courses. This study provides preliminary insights into the transcriptional response of marine medaka male fish to waterborne BPA exposure and suggests a basis for uncovering the mode of action particularly with respect to endocrine disrupting chemicals (EDCs) such as BPA.

Changes in cell adhesion molecule (CAM) expression and miRNAs regulating them are known to be involved in malignant progression in colon cancer. We investigated expression profiles of CAM genes and non-coding RNAs in CaCo2 colon cancer cells in static culture and under dynamic flow conditions perfused in microfluidic chip emulating physiological microenvironment. We incubated monolayers of CaCo2 cells in Transwell® units either under static conditions or under flow in a microfluidic chip. We identified 7 up-regulated CAM genes (CD44, CDH7, CEACAM5, CEACAM6, CYR61, L1CAM and VCAN), 7 down-regulated genes (COL12A1, FGA, FGB, FGG, GJA1, ITGA5 and LAMA1) and 69 miRNAs targeting them under the influence of microcirculation. The revealed network comprised CAM genes known to interact with each other and 13 miRNAs simultaneously regulating more than one of them. The discovered regulatory network comprising CAM genes and miRNAs is likely involved in normal functioning of intestine epithelium as well as in cancer progression.

Nanopillar arrays have provided unique optical properties due to their multi-dimensional architectures with large surface area. Recently, surface enhanced Raman spectroscopy (SERS) has taken full benefits of nanopillar arrays for highly sensitive chemical and biosensing. This article gives an overview of hot spot engineering on nanopillar arrays for SERS. Nanopillar arrays are very beneficial for providing high density plasmonic nanostructures, which induce the oscillation of free electrons to create highly localized electric fields, i.e., electromagnetic hot spots, for highly intense SERS detection. The diverse methods have successfully demonstrated the nanofabrication of hotspot-rich nanopillar arrays on silicon or glass substrates. Tailoring hot spots enables ultrasensitive detection of biomolecules at low concentrations and even allows single-molecule level detections. This review overviews the nanofabrication methods for nanopillar array construction, the design strategies for electromagnetic hot spot generation on nanopillar arrays, and their SERS applications.

Toxicogenomics is a rapidly developing area of research which combines the understanding of molecular and cellular regulation in response to interaction of chemical stressors. Moreover, the emergence of comprehensive research method covering genomic, proteomic, and metabonomics analysis including bioinformatics has further substantiated the field of toxicogenomics. Thus, evaluation of such integrated analysis, conversing from variety of experimental techniques, along with the resulting database can decipher the importantance of such techniques in toxicogenomics. In addition, recent integration of epigenetic study (DNA Methylation, histone modification, small and noncoding RNAs) with toxicogenomics can pave the path to elucidate, highly reliable research results. The objective of the present review is to expand these understandings of toxicogenomics approach and validate the contribution of the developing research methods (genome, proteome, metabolites) to emphasize its importance in future toxicogenomics research.

Recent automated systems for the serological tests employing chemiluminescence immunoassay or electrochemiluminescent immunoassay give results within 30 minutes with high sensitivity and accuracy. However, false positive results are inevitable in serological screening for an infection due to the trade-off between sensitivity and specificity. A titration test has been used to confirm the screening results, but it is rarely performed. Instead, molecular tests are preferred in these days. Immunoassays were mostly qualitative in the past; however, quantitative kits have been developed and released on the market. The calibration step is necessary to report results quantitatively. As the calibration curve of an immunoassay is non-linear, four parameter or five parameter logistic models are adopted. analytical measurement range (AMR) verification should be performed periodically at least every six months in order to report quantitative results. Quantitative reporting is feasible only within a linear range that is verified by AMR evaluation. A new concept of quantitative measurement/qualitative reporting in immunoassays is introduced. Qualitative reporting even after the quantitative measurement has the advantage that periodic AMR verification is not required. This category can be applied if the accurate quantitative value is not clinically significant. Lately, the market of point-of-care testing (POCT) is growing rapidly due to an increasing need. Nevertheless, the performance of the serological POCT kits is much lower than that of automated systems for central laboratories. This limits the broad utilization of POCT, and thus research for enhancing its performance should continue.

Today, the application of nanomaterials has been gaining prominence in the field of biosensing technologies as it offers more and more impact studies to improve the sensitivity k]specificity k]speed of response and cost effectiveness k]Especially in electrochemical impedance spectroscopy technique k]an outstanding electrical biotransducer k]nanomaterials have been extensively used in almost all studies over the past decade k]The nanostructures used in the construction of sensing devices vary in size k]shape and physicochemical properties k]such as nanoparticles k]nanotubes k]nanosheets k]nanoelectrodes or nanochannels k]The use of nanomaterials in impedimetric biosensor involves two key principles: (1) to develop a new sensing substrate via surface modification techniques with the aim of increasing the impedimetric response and (2) to develop a compatible sensing platform to facilitate the detection based on the resemblance in size between targets and signal transducers k]Herein k]the review shows the recent trends of using engineered nanomaterials in impedimetric biosensors as a factor of signal amplification k]The detection events are diverse from biomolecular recognitions including enzymes k]proteins k]nucleic acids k]etc k]to whole cells monitoring k]Additionally k]the shortcomings of current techniques and future perspectives of impedimetric point-of-care devices are also included.

This paper presents a proof-of-concept microfluidic aptamer-based sensor for thrombin point-of-care testing using electrochemical impedance spectroscopy. The disposable biosensor is composed of a polydimethylsiloxane (PDMS) channel layer over a glass substrate. The substrate surface has an Au working electrode and a Pt reference/counter electrode. In this study, human thrombin was used as a biomarker for disease diagnosis. An unlabeled aptamer specific to thrombin was immobilized on a working electrode and electrochemical impedance was measured as thrombin was injected into the biosensor. Thrombin was detected by measuring change in impedance. The proposed biochip had a detection range of 0.1–100,000 ng mL−1 for thrombin concentration and a limit of detection of 0.1 ng mL−1. The results indicated that our biochip could be an effective tool for other molecular diagnostic systems.

Concentration polarization (CP) is an electrochemical phenomenon related to the concentration gradient (under a transversal electric field) near an ion selective membrane surface. During concentration polarization process, quantitatively investigate the background electrolyte (BGE) concentration distribution is a very challenging problem. In this study, we conducted transient simulations within 2D micro-nanochannel domain to capture the dynamic nature of concentration polarization process and compared the propagating behavior of analytes and BGE. The simulation results show that the depletion area of chloride ion and analyte are both increase with time at ohmic and limiting region. The normalized depletion area (NDA) differences increases with decreasing BGE concentration. For the high applied voltage (overlimiting region), chloride ion and analyte at the anodic side microchannel are depleted everywhere that the NDA tends to 1 after an increasing step because of the electroconvection effect. This means there is no depletion area (DA) differences between two species in this plateau region. These results tell us the fluorescent ion indicator can’t show the exact BGE concentration distribution during CP process and we need to find new technique to visualize the concentration field.

The construction of biosensors with antibodies as the biological sensing element requires the integration of antibodies into the biosensor such that their activity is reproducibly retained. In this work, a peptide ligand was identified from phage-displayed heptameric peptide libraries for the purpose of antibody immobilization on biosensor surfaces. For biopanning of peptides specific to the Fc region of the antibody, rabbit anti-goat immunoglobulin G (IgG) antibody was immobilized on a culture dish coated with goat IgG, which enabled exposure of the Fc region of rabbit antibody on the surface with the Fab region bound to the surface-adsorbed goat IgG. The library phages were added to the dish and phages displaying antibody-binding peptides were competitively eluted using the rabbit antibody. After four rounds of biopanning, 22 phage plaques were randomly selected and their nucleotide sequences corresponding to the random peptide were determined. Three enriched sequences were selected and analyzed for their rabbit antibody-binding activity. One of these sequences (KHRFNKD), which was rich in positive charge and homologous to the IgG-binding domains of Staphylococcal protein A, exhibited a high and specific affinity to rabbit antibody. This peptide was immobilized on a quartz crystal microbalance (QCM) biosensor, and the resulting QCM was found to be capable of capturing antibody and detecting antigen, with potential applications in antibody purification and enzyme immunoassay.

The rapid and accurate detection of pathogenic Escherichia coli (E. coli) poses a significant health problem in both developed and developing countries around the world. Conventional microbial detection methods can take more than 48 hours to identify a pathogenic organism. Recently new types of nucleic acid chip based methods, microfluidic devices, signal amplification methods, immunoassays and biosensors have been developed capable of detecting very low concentrations of pathogenic E. coli in a few hours. This review examines the current limitations and recent advances in methodologies employed in the rapid detection of pathogenic E. coli O157: H7.