Following the trend towards smaller channel inner diameter for better separation performance and shorter channel length for shorter transport time, a modular construction of a miniaturized 'total chemical analysis system' is proposed. The theoretical performances of such systems based on flow injection analysis, chromatography and electrophoresis, are compared with those of existing chemical sensors and analysis systems.

Miniaturized total chemical analysis systems: A novel concept for chemical sensing

Biomaterials have played an enormous role in the success of medical devices and drug delivery systems. We discuss here new challenges and directions in biomaterials research. These include synthetic replacements for biological tissues, designing materials for specific medical applications, and materials for new applications such as diagnostics and array technologies.

Designing materials for biology and medicine

Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production). This article selectively reviews recent advances in graphene-based electrochemical sensors and biosensors. In particular, graphene for direct electrochemistry of enzyme, its electrocatalytic activity toward small biomolecules (hydrogen peroxide, NADH, dopamine, etc.), and graphenebased enzyme biosensors have been summarized in more detail; Graphene-based DNA sensing and environmental analysis have been discussed. Future perspectives in this rapidly developing field are also discussed.

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Graphene Based Electrochemical Sensors and Biosensors: A Review

The seminal importance of DNA sequencing to the life sciences, biotechnology and medicine has driven the search for more scalable and lower-cost solutions. Here we describe a DNA sequencing technology in which scalable, low-cost semiconductor manufacturing techniques are used to make an integrated circuit able to directly perform non-optical DNA sequencing of genomes. Sequence data are obtained by directly sensing the ions produced by template-directed DNA polymerase synthesis using all-natural nucleotides on this massively parallel semiconductor-sensing device or ion chip. The ion chip contains ion-sensitive, field-effect transistor-based sensors in perfect register with 1.2 million wells, which provide confinement and allow parallel, simultaneous detection of independent sequencing reactions. Use of the most widely used technology for constructing integrated circuits, the complementary metal-oxide semiconductor (CMOS) process, allows for low-cost, large-scale production and scaling of the device to higher densities and larger array sizes. We show the performance of the system by sequencing three bacterial genomes, its robustness and scalability by producing ion chips with up to 10 times as many sensors and sequencing a human genome.

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An integrated semiconductor device enabling non-optical genome sequencing

An analyte monitor includes a sensor, a sensor control unit, and a display unit. The sensor has, for example, a substrate, a recessed channel formed in the substrate, and conductive material disposed in the recessed channel to form a working electrode. The sensor control unit typically has a housing adapted for placement on skin and is adapted to receive a portion of an electrochemical sensor. The sensor control unit also includes two or more conductive contacts disposed on the housing and configured for coupling to two or more contact pads on the sensor. A transmitter is disposed in the housing and coupled to the plurality of conductive contacts for transmitting data obtained using the sensor. The display unit has a receiver for receiving data transmitted by the transmitter of the sensor control unit and a display coupled to the receiver for displaying an indication of a level of an analyte. The analyte monitor may also be part of a drug delivery system to alter the level of the analyte based on the data obtained using the sensor.

Analyte Monitoring Device And Methods Of Use

In recent years, various isothermal amplification techniques have been developed as alternatives to polymerase chain reaction (PCR). The integration of isothermal amplification with electrical or electrochemical devices has enabled high-throughput nucleic acid-based assays with high sensitivity. We performed solid-phase rolling circle amplification (RCA) on the surface of a Au electrode, and detected RCA products in situ using chronocoulometry (CC) with [Ru (NH3)6]3+ as the signaling molecule. Detection sensitivity for DNA and a microRNA (miR-143) was 100 fM and 1 pM, respectively. Furthermore, we conducted potentiometric DNA detection using an ethidium ion (Et+)-selective electrode (Et+ISE) for real-time monitoring of isothermal DNA amplification by primer-generation RCA (PG-RCA). The Et+ISE potential enabled real-time monitoring of the PG-RCA reaction in the range of 10 nM-1 μM of initial target DNA. Devices based on these electrochemical techniques represent a new strategy for replacing conventional PCR for on-site detection of nucleic acids of viruses or microorganisms.

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Electrochemical Biosensors Combined with Isothermal Amplification for Quantitative Detection of Nucleic Acids

A glucose-responsive polymer brush was designed on a gold electrode and exploited as an extended gate for a field effect transistor (FET) based biosensor. A permittivity change at the gate interface due to the change in hydration upon specific binding with glucose was detectable. The rate of response was markedly enhanced compared to the previously studied cross-linked or gel-coupled electrode, owing to its kinetics involving no process of the polymer network diffusion. This finding may offer a new strategy of the FET-based biosensors effective not only for large molecules but also for electrically neutral molecules such as glucose with improved kinetics.

Chemo-Electrical Signal Transduction by Using Stimuli-Responsive Polymer Gate-Modified Field Effect Transistor

PURPOSE:To remove obstruction material from a sample, to prevent the surface absorption of protein and to make it possible to perform highly accurate analysis by modifying a moleculate separating film or adsorption removing film directly or at a specified interval on the surface of a total-reflection attenuation prism. CONSTITUTION:A sample is introduced into a film 18 which is formed with an injector 16 on a total-reflection attenuation ATR prism 17 through a sample injecting port 15. A supporting body 20 having a step 19 in conformity with the shape of the ATR is provided so that the film 18 is readily fixed on the ATR. The ATR prism 17 is fixed to a supporting body 22 having a step 21 so that the film 18 can be tightly brought into contact with the surfaces of the ATR. The edge of the ATR is machined at the angle of 45 deg. so that infrared rays 2 are introduced and emitted after the repetition of multiple reflections. Thus, the highly accurate analysis can be performed.

Cell for total-reflection attenuation prism

The adsorption of positively charged supported lipid bilayers (SLBs) on field-effect devices was studied using various salt solutions to make it possible to understand the signal generation mechanisms of the devices. The flat-band voltage change that occurred with SLB formation was dependent on the type of monovalent cations contained in the solution. Zeta potential data showed that the intrinsic charge of the bilayers was almost constant in the presence of any of the examined alkali ions. The results suggest that the lipid charge does not solely determine the flat-band voltage. The binding affinity of alkali ions to silicon nitride showed a similar trend to the dependence of the flat-band voltage change on alkali ions. The results indicate that the specific interaction of small inorganic ions with the device surface has a significant influence on the magnitude of the signal response that occurs with SLB formation. It appears that salt ions specifically bound to the device surface and the charge of the bilayers both contribute to the signal generation mechanisms.

Mechanisms of supported bilayer detection using field-effect devices

The purpose of the present invention is to provide an improved device capable of releasing a drug dependent on stimulation by glucose concentration and the like. Provided is a drug delivery device characterized in comprising: a porous body such as hollow yarn that is biocompatible and drug-permeable; a stimulation-responsive gel composition filled into the inner surface side of the porous body; and a drug that is surrounded by the gel composition, on the inner surface side of the porous body.

Yuji Miyahara

Papers

Electrochemical Biosensors Combined with Isothermal Amplification for Quantitative Detection of Nucleic Acids

Chemo-Electrical Signal Transduction by Using Stimuli-Responsive Polymer Gate-Modified Field Effect Transistor

Cell for total-reflection attenuation prism

Mechanisms of supported bilayer detection using field-effect devices

Drug delivery device