Over the past several years, massively parallel DNA sequencing platforms have been developed that are able to acquire approximately 3 gigabases of nucleotide sequences of the human genome from an individual. Furthermore, the next-generation DNA sequencer, which is based on single-molecule and real-time DNA sequencing technology, has just been developed. Here, we introduce these technologies in detail and discuss how our future lives and society may be enriched by new biological and medical technologies.

We describe an imaging technology by which the phosphorylation and dephosphorylation processes of signal transduction molecules can be analyzed at the single-cell level using a fluorescence resonance energy transfer-based homogeneous sandwich immunoassay method developed by authors. Glutathione S-transferase (GST)-fused mitogen-activated protein kinase (MAPK) was chosen as a molecule of model MAPK. Two types of fluorescent protein-labeled antibody probe were prepared by conjugating (Fab’)s of the anti-GST antibody and antiphosphorylated MAPK antibody labeled with enhanced cyan fluorescent protein-Jun and enhanced yellow fluorescent protein-Jun, respectively. GST-fused MAPK solution containing these probes was introduced into the cytoplasm of HeLa cells by a microinjection method, and signal transduction of the MAPK pathway was activated by stimulating the cells with epidermal growth factor. As a result, time-lapse imaging of the change in FRET ratio resulting from GST-fused MAPK phosphorylation and dephosphorylation at the single-cell level was successfully performed.

The most important advantage of optical microscopy is the capability of observing a living specimen without causing significant damage to the specimen. The recent use of vibrational spectroscopy for imaging biological samples further emphasizes this advantage because it allows us to analyze material in a specimen without having to treat the specimen such as by fluorescence staining. In this article, we introduce the recent development of molecular imaging techniques using Raman scattering and surface-enhanced Raman scattering for observing biological specimens at the micro/nanometer scale.

The goal of the present research is to identify and isolate individual human antigen-specific immune cells such as T and B cells and to screen immune-cell-related genes (TCR or antibody genes) comprehensively and efficiently in each cell. We have established technology including the efficient staining of antigen-specific immune cells, the identification and isolation of labeled single cells on a cell sorter and immune cell-related gene PCR cloning based on mRNA isolated from a single immune cell. This innovative fundamental technology will enable us to develop a novel method of producing human monoclonal antibody medicine.

More than 15 years have passed since the discovery of the single-wall carbon nanotube. Since then, high-purity and large quantity production has been achieved and the excellent physical properties of the nanotube have been revealed. However, the use of single-wall carbon nanotubes in common applications is still very limited. One of the main reasons for this is the difficulty of separating semiconducting and metallic phases from the as-grown mixture phase. In this manuscript, the recent significant progress in metal-semiconductor separation technology and a method for optical evaluation of the products are discussed.

The function of genes can be monitored by assaying transcription products known as messenger(m)-RNA. We have been assaying m-RNA in whole peripheral human blood, which we refer to as RNA Check, under various physiological conditions of the host. The results thus obtained can be used as a state-of-the-art method of monitoring the host physiology.

The behavior of water molecules at a solid/liquid interface has been intensively studied in relation to industrial technologies and phenomena in life science. The molecular-level understanding of phenomena occurring at a solid/liquid interface requires the direct measurement of interfacial phenomena with molecular-scale resolution. Such measurement has recently become possible owing to the development of liquid-environment frequency modulation atomic force microscopy (FM-AFM). Here we discuss the basic principle of FM-AFM and its application to the molecular-level study of the interface between a model biological membrane and a physiological solution.

The label-free detection of biomolecules has attracted great attention in many life science fields. In this article, we review amperometric and potentiometric biosensors based on carbon nanotubes (CNTs). The potentiometric biosensors are based on aptamer-modified CNT field-effect transistors (CNTFETs). Since aptamers are artificial oligonucleotides and thus are smaller than the Debye length, proteins are detected with high sensitivity. In contrast, in amperometric detection, CNT-modified electrodes are used as working electrodes to significantly enhance the electroactive surface area. In this review, we discuss the technology, characteristics and commercial development of label-free CNT-based biosensors.

A method of realizing the “fourth circuit element” following resistors, capacitors, and inductors, is discussed. If this element can be realized, it would produce a magnetic flux for a given input charge and produce a charge for a given input flux. One promising way of realizing such an element is through the use of spin-polarized electrons. In a semiconductor injected with spin-polarized electrons, the magnetic flux is directly proportional to the density of electrons. Therefore, such a semiconductor can operate as the fourth element, a device that relates magnetic flux to electric charge.

Gallium oxide (Ga₂O₃) is a wide-band-gap semiconductor with a band-gap energy of as high as 5 eV and is one of the oxide semiconductors capable of being grown by safe and inexpensive process. Owing to the earlier development of bulk Ga₂O₃ substrates, research with the aim of realizing device applications has been accelerated by utilizing the high-quality bulk itself or by the homoepitaxial growth. In this paper we show our recent achievements such as deep-ultraviolet photosensors and the step-flow growth of homoepitaxial Ga₂O₃ layers and heterostructures. Alloying and the formation of multilayer structures with other oxides with unique functions are expected to lead to the development of novel devices with integrated functions.

When a semiconductor is irradiated with light having greater energy than the band-gap energy, the light is absorbed and electron-hole pairs are created. In the case of a p-n junction, electrons and holes are separated at the junction, resulting in the formation of photovoltage. The photocurrent, which is proportional to the power, can be detected in an external circuit. This is the principle of operation of photodiodes. Charge-coupled device (CCD) cameras consist of a two dimensional array of p-n junctions as charge storage elements. In this article, the principles and basic performance of semiconductor photodetectors and imaging devices are reviewed.