Simultaneous optical and electrical in vivo analysis of the enteric nervous system.

The enteric nervous system (ENS) is a major division of the nervous system and vital to the gastrointestinal (GI) tract and its communication with the rest of the body. Unlike the brain and spinal cord, relatively little is known about the ENS in part because of the inability to directly monitor its activity in live animals. Here, we integrate a transparent graphene sensor with a customized abdominal window for simultaneous optical and electrical recording of the ENS in vivo. The implanted device captures ENS responses to neurotransmitters, drugs and optogenetic manipulation in real time.

Electrical characteristics of multilayer MoS2 FET's with MoS2/graphene heterojunction contacts.

The electrical properties of multilayer MoS2/graphene heterojunction transistors are investigated. Temperature-dependent I-V measurements indicate the concentration of unintentional donors in exfoliated MoS2 to be 3.57 × 10(11) cm(-2), while the ionized donor concentration is determined as 3.61 × 10(10) cm(-2). The temperature-dependent measurements also reveal two dominant donor levels, one at 0.27 eV below the conduction band and another located at 0.05 eV below the conduction band. The I-V characteristics are asymmetric with drain bias voltage and dependent on the junction used for the source or drain contact. I-V characteristics of the device are consistent with a long channel one-dimensional field-effect transistor model with Schottky contact. Utilizing devices, which have both graphene/MoS2 and Ti/MoS2 contacts, the Schottky barrier heights of both interfaces are measured. The charge transport mechanism in both junctions was determined to be either thermionic-field emission or field emission depending on bias voltage and temperature. On the basis of a thermionic field emission model, the barrier height at the graphene/MoS2 interface was determined to be 0.23 eV, while the barrier height at the Ti/MoS2 interface was 0.40 eV. The value of Ti/MoS2 barrier is higher than previously reported values, which did not include the effects of thermionic field emission.

Non-Faradaic electrochemical detection of protein interactions by integrated neuromorphic CMOS sensors.

Electronic detection of the binding event between biotinylated bovine serum albumen (BSA) and streptavidin is demonstrated with the chemoreceptive neuron MOS (CnuMOS) device. Differing from the ion-sensitive field-effect transistors (ISFET), CnuMOS, with the potential of the extended floating gate determined by both the sensing and control gates in a neuromorphic style, can provide protein detection without requiring analyte reference electrodes. In comparison with the microelectrode arrays, measurements are gathered through purely capacitive, non-Faradaic interactions across insulating interfaces. By using a (3-glycidoxypropyl)trimethoxysilane (3-GPS) self-assembled monolayer (SAM) as a simple covalent link for attaching proteins to a silicon dioxide sensing surface, a fully integrated, electrochemical detection platform is realized for protein interactions through monotone large-signal measurements or small-signal impedance spectroscopy. Calibration curves were created to coordinate the sensor response with ellipsometric measurements taken on witness samples. By monitoring the film thickness of streptavidin capture, a sensitivity of 25ng/cm2 or 2A of film thickness was demonstrated. With an improved noise floor the sensor can detect down to 2ng/(cm2mV) based on the calibration curve. AC measurements are shown to significantly reduce long-term sensor drift. Finally, a noise analysis of electrochemical data indicates 1/f(alpha) behavior with a noise floor beginning at approximately 1Hz.

[Detecting poliovirus in wastewater from Armenia, Colombia]. / Detección de poliovirus en Aguas residuales de Armenia, Colombia.

OBJECTIVES: Implementing environmental surveillance for poliovirus circulating from wastewater. METHODS: Six wastewater samples were collected from each final site within a wastewater collection system in Armenia, Quindío. Virus was extracted and concentrated by a method using polyethylenglycol and sodium chloride as concentrating agent. Polioviruses were identified by polymerase chain reaction assay with group-specific, serotype-specific and Sabin vaccine-specific primers. RESULTS: It was confirmed that the viral detection method is highly efficient. Poliovirus was detected in 5 of 6 (83%) samples collected. Serotype-specific identification revealed the presence of type 1 and type 3 polioviruses in the samples. All of them were of the vaccine type, which provided evidence regarding the non-circulation of wild poliovirus in the country. CONCLUSION: Wastewater surveillance can be a sensitive tool for detecting poliovirus circulation.

Detección de Poliovirus en Aguas Residuales de Armenia, Colombia / Detecting poliovirus in wastewater from Armenia, Colombia

OBJETIVOS: Implementar un método para la vigilancia ambiental de poliovirus circulante a partir de aguas residuales. MÉTODOS: Se colectaron 6 muestras de aguas residuales en los sitios finales de descarga del acueducto de Armenia, Quindío. Los virus fueron concentrados y extraídos por un método que usa el polietilenglicol y cloruro de sodio como agentes concentradores. La identificación de poliovirus se realizó mediante la técnica de reacción en cadena de la polimerasa empleando cebadores específicos de grupo, de serotipo y de cepa vacunal sabin. RESULTADOS: Se demostró la eficiencia de los métodos de detección viral empleados. Se encontró la presencia de poliovirus en 5 de las 6 (83 %) muestras colectadas. La identificación serotipo-específica reveló la presencia de poliovirus tipo 1 y 3 en las muestras estudiadas. Todos los poliovirus detectados resultaron ser del tipo vacunal lo cual aporta una evidencia más a favor de la no circulación de poliovirus salvaje en la región. CONCLUSIÓN El sistema de vigilancia a partir de aguas residuales puede ser una herramienta sensible para la detección de la circulación de poliovirus.

Electrolyte pulse current measurements by CvMOS with microsecond and thermal voltage resolution.

Non-invasive, charge-based sensing in chemoreceptive neuron MOS (CvMOS) transistors with extended floating-gate structure has brought forth features that are beneficial to the system integration of biological sensing. This paper presents the results of fast electrolytic signal detection on silicon dioxide, which advances possible technologies for rapid DNA discrimination or external monitoring of cell action potentials.