Biomimetic Chemical Sensing by Fluorescence Signals Using a Virus-like Particle-Based Platform.

The chemical receptors present in living organisms are promising tools for developing biomimetic chemical sensors. However, these receptors require lipid membranes for functioning under physiological conditions, which prevents their utilization in the production of cell-free in vitro chemical sensing systems. Here, we report the development of a cell-free biomimetic sensing platform using virus-like particles (VLPs) with intact ligand-gated Ca channels and genetically encoded Ca indicator (GECI).

Quantitative and Single-step Enzyme Immunosensing Based on an Electrochemical Detection Coupled with Lateral-flow System.

A single-step electrochemical immunochromatography has been developed: the device was based on two pieces of nitrocellulose membrane, a sample pad with anti-mouse IgG antibody labeled with glucose oxidase (GOx-labeled antibody), a conjugate pad with glucose, and a Pt working electrode. Either antibody or antigen was immobilized on the membrane. The addition of a solution containing mouse IgG, a model target, allows for the dissolution of GOx-labeled antibody in the sample pad to form an immunocomplex.

Extracellular Recordings of Patterned Human Pluripotent Stem Cell-Derived Cardiomyocytes on Aligned Fibers.

Human induced pluripotent stem cell (hiPSC) derived cardiomyocytes (CMs) hold high potential for use in drug assessment and myocardial regeneration. To create tissue-like constructs of CMs for extracellular monitoring, we placed aligned fibers (AFs) on the surface of a microelectrode array and then seeded hiPSC-CMs for subsequent monitoring for 14 days. As expected, the CMs organized into anisotropic and matured tissue and the extracellular recordings showed reduced premature beating higher signal amplitude and a higher probability of T-wave detection as compared to the culture without fibers.

Improvement of Electrochemical Response of Cocaine Sensors Based on DNA Aptamer by Heat Treatment.

We report on a biosensor for cocaine based on the conformation change of DNA aptamer by capturing the cocaine molecules. The oxidation current of ferrocene conjugated on the terminal end of aptamer immobilized on an Au electrode increased with increasing cocaine concentration. The sensor response has been improved by a simple heat treatment after immobilization, since the aggregates of DNA aptamer generated during the immobilization step could be dissociated and rearranged on the electrode.

Deciphering the Receptor Repertoire Encoding Specific Odorants by Time-Lapse Single-Cell Array Cytometry.

Mammals can recognize a vast number of odorants by using olfactory receptors (ORs) known as G protein-coupled receptors. The OR gene family is one of the most diverse gene families in mammalian genomes. Because of the vast combinations of ORs and odorants, few ORs have thus far been linked to specific odorants.

Compromised maturation of GABAergic inhibition underlies abnormal network activity in the hippocampus of epileptic Ca2+ channel mutant mice, tottering.

Cholinergically induced network activity is a useful analogue of theta rhythms involved in memory processing or epileptiform activity in the hippocampus, providing a powerful tool to elucidate the mechanisms of synchrony in neuronal networks. In absence epilepsy, although its association with cognitive impairments has been reported, the mechanisms underlying hippocampal synchrony remain poorly investigated. Here we simultaneously recorded electrical activities from 64 sites in hippocampal slices of CaV2.

Urinary volatile compounds as biomarkers for lung cancer.

Lung cancer is a leading cause of deaths in cancer. Hence, developing early-stage diagnostic tests that are non-invasive, highly sensitive, and specific is crucial. In this study, we investigated to determine whether biomarkers derived from urinary volatile organic compounds (VOCs) can be used to discriminate between lung cancer patients and normal control patients.

Analysis of volatile organic compounds released from human lung cancer cells and from the urine of tumor-bearing mice.

Backgrounds: A potential strategy for the diagnosis of lung cancer is to exploit the distinct metabolic signature of this disease by way of biomarkers found in different sample types. In this study, we investigated whether specific volatile organic compounds (VOCs) could be detected in the culture medium of the lung cancer cell line A549 in addition to the urine of mice implanted with A549 cells.

Results: Several VOCs were found at significantly increased or decreased concentrations in the headspace of the A549 cell culture medium as compared with the culture medium of two normal lung cell lines.

Pacemaker phase shift in the absence of neural activity in guinea-pig stomach: a microelectrode array study.

Gastrointestinal (GI) motility is well organized. GI muscles act as a functional syncytium to achieve physiological functions under the control of neurones and pacemaker cells, which generate basal spontaneous pacemaker electrical activity. To date, it is unclear how spontaneous electrical activities are coupled, especially within a micrometre range.

Dephosphorylation and internalization of cell adhesion molecule L1 induced by theta burst stimulation in rat hippocampus.

The neural cell adhesion molecule L1 may participate in initiating and maintaining synaptic changes during learning in the hippocampus. One prominent form of synaptic change in the hippocampus is long-term potentiation (LTP) that occurs following specific patterns of synaptic activity. We present evidence that Y1176 of the YRSL motif within L1 cytoplasmic domain is dephosphorylated in LTP-induced hippocampus.

Long-term recording of LTP in cultured hippocampal slices.

Long-term potentiation (LTP) was elicited by high frequency stimulation in hippocampal slices cultured on multi-electrode arrays. LTP lasting more than 1 h was recorded in 75% of slices, and a significant number of slices exhibited a non-decaying LTP that lasted more than 48 h. LTP induction was completely and reversibly blocked by an antagonist of the NMDA receptor, APV.

Chronic multichannel recordings from organotypic hippocampal slice cultures: protection from excitotoxic effects of NMDA by non-competitive NMDA antagonists.

In vitro neuronal damage has traditionally been evaluated by biochemical or anatomical but not by electrophysiological techniques. In the present study, we combined two newly developed technologies, an 8 x 8 multi-electrode array (MED-64) and cultured hippocampal slices, to demonstrate the potential use of electrophysiological measures as index of neuronal damage. We first demonstrated the stability of electrophysiological recordings over prolonged periods of time (up to 14 days) in field CA1 of cultured hippocampal slices following electrical stimulation of the Schaffer collateral pathway.

Asymmetrical distribution of the Schaffer projections within the apical dendrites of hippocampal field CA1.

Continuous current source densities were calculated in two dimensions (proximo-distal vs. medio-lateral) from slices of hippocampal field CA1 placed on a 64-electrode array in the presence of GABA blockers. The synaptic sink generated by stimulation of the Schaffer-commissural fibers spread across the extent of field CA1 within the same sublamina of the stratum radiatum as the stimulation electrode.