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A novel method of Surface Enhanced Raman Scattering (SERS) based molecular detection was developed using self-assembled DNA nanostructures. Molecule detection using rigid, shape-controllable DNA nanostructures provides significant advantages such as accurate control of the particle distance and geometrical programmability of the DNA nanostructure. We successfully detected the Cy3 dye, a Raman-active molecule, at 1461, 1590, and 1619 cm −1 using a Ag-enhanced Au-DNA nanostructure. Consequently, DNA-guided SERS detection is expected to contribute significantly to molecular detecting systems in the near future.

Surface-enhanced Raman scattering (SERS) is a promising technology owing to its single-molecular sensitivity and molecular specificity. However, producing strong and stable SERS signal from plasmonic nanostructures remains a challenge. Herein, we present a facile generation of SERS-active nanomaterials by organizing metallic nanoparticles onto dye-labeled three-dimensional DNA nanostructures. Stable formations of metal clusters with the dye located in hot spots enabled detection of SERS signals. SERS signals were further regulated via interaction of pyramidal DNA scaffold with target biomolecules. We believe our SERS-active nanomaterials with controllable geometry and reversible SERS effects meet significant requirements for practical SERS-based sensors. By integrating versatile properties of DNA and introducing various Raman dyes into plasmonic nanostructures, the emergence of powerful and multiplexed biosensors should be possible. Keywords: DNA nanostructures, Surface-enhanced Raman scattering, Plasmonic nanostructures, DNA pyramid

The present study was designed to examine fathers` awareness and practice of picture book reading with toddlers. The subjects were 221 fathers who have toddlers, and the data collected by questionnaires were analysed by mean and standard deviation, and frequency analysis. As a result, approximately 59% of fathers stated that it is essential to read to their children who are 12 month old or less, and 36% of fathers answered that they read books as much as their children wanted. The majority considered the emotional aspect of picture book reading as being significant. Also, nearly half (46%) of the fathers read books to their children 1-2 times per week, and 37% of them spent 6-10 minutes at a time reading books. While reading books, 60% of the fathers explained text and pictures to their children and a fourth of the fathers answered their children`s questions. Also, while reading books, fathers tried to accept their toddlers` responses positively. However, they did not have much time to read books to their children and had little knowledge on how to read books to infants. Further research and education programs on picture book reading for fathers are needed.

New zwitterionic polymer-coated immunoaffinity beads were developed to resist nonspecific protein adsorption from undiluted human serum for diagnostic applications of exosomes. A zwitterionic sulfobetaine monomer with an amine functional group was employed for simple surface chemistry and antifouling properties. An exosomal biomarker protein, epithelial cell adhesion molecule (EpCAM), was selected as a target molecule in this work. The beads were coated with polyacrylic acids (PAA) for increasing biorecognition sites, and protein G was then conjugated with carboxylic acid groups on the surfaces for controlling EpCAM antibody orientation. The remaining free carboxylic acid groups were modified with sulfobetaine moieties, and anti-EpCAM antibody was finally introduced. The amount of anti-EpCAM on the beads was increased by 40% when compared with PAA-uncoated beads. The surfaces of the beads exhibited near-net-zero charge, and nonspecific protein adsorption was effectively suppressed by sulfobetaine moieties. EpCAM was captured from undiluted human serum with almost the same degree of efficiency as from PBS buffer solution using the newly developed immunoaffinity beads.

We studied the physical characteristics of modified-DNA (M-DNA) double crossover crystals fabricated via substrate-assisted growth with various concentrations of four different divalent metallic ions, Cu(2+), Ni(2+), Zn(2+), and Co(2+). Atomic force microscopy (AFM) was used to test the stability of the M-DNA crystals with different metal ion concentrations. The AFM images show that M-DNA crystals formed without deformation at up to the critical concentrations of 6 mM of [Cu(2+)], 1.5 mM of [Ni(2+)], 1 mM of [Zn(2+)], and 1 mM of [Co(2+)]. Above these critical concentrations, the M-DNA crystals exhibited deformed, amorphous structures. Raman spectroscopy was then used to identify the preference of the metal ion coordinate sites. The intensities of the Raman bands gradually decreased as the concentration of the metal ions increased, and when the metal ion concentrations increased beyond the critical values, the Raman band of the amorphous M-DNA was significantly suppressed. The metal ions had a preferential binding order in the DNA molecules with G-C and A-T base pairs followed by the phosphate backbone. A two-probe station was used to measure the electrical current-voltage properties of the crystals which indicated that the maximum currents of the M-DNA complexes could be achieved at around the critical concentration of each ion. We expect that the functionalized ion-doped M-DNA crystals will allow for efficient devices and sensors to be fabricated in the near future.

Recombinant mouse tryptophan hydroxylase (TPH) was expressed in Escherichia coli, using a bacterial expression vector and has been purified to homogeneity by sonication followed by Sepharose 4B column chromatography and native slab gel electrophoresis. This purified enzymatically active TPH protein was used for production of a specific antiserum. This antiserum identified the predicted TPH band (molecular weight, 54 kDa) on Western blot of crude extracts from the rat and mouse dorsal raphe, and the rat pineal gland. However, this antiserum recognized an additional protein band of lower molecular weight (48 kDa) in pineal extract. It is not clear whether the 48 kDa TPH band represents an isozyme or a protease cleavage product of TPH. Since the pineal gland contains higher TPH mRNA and lower TPH activity when it is compared with dorsal raphe nucleus enzyme, this lower molecular weight TPH may participate in the reduced TPH specific activity. In addition, there are no specific TPH inhibitors in the pineal gland and this lower molecular weight TPH is inactive or has a very low specific activity. This antiserum specifically immunostained serotonergic cell bodies in the dorsal raphe nuclei, some large caliber serotonergic processes in the dorsal raphe area as well as terminals in the olfactory bulb. It also immunolabeled the pineal gland and immunoprecipitated equally well TPH protein from the dorsal raphe nucleus and the pineal gland in a concentration-dependent manner.

This paper describes a novel microchip filter device incorporating slit arrays and 3-dimensional flow that can separate rare cells with high efficiency and throughput. The proposed device has several tens of times increased throughput, and has a unique pressure distribution along the filter pore, inducing target cells to be captured and gently lined up at the end of the slit in relatively low shear stress condition. With the enhanced capture yield and throughput, the proposed device can be used as an efficient rare-cell-analyzing tool for blood-based diagnostics.

We present a novel method for separating circulating tumor cells (CTCs) with high recovery and purity at the same time using a micro-slit filter chip and a fully automated fluidic system. Considering white blood cells (WBCs) as big as CTCs are also captured with CTCs during filtration, we amplified the size of CTCs specifically using microbeads (3 μm) coated with anti-Epithelial Cell Adhesion Molecule (anti-EpCAM) to increase the size difference between WBCs and CTCs. The average diameter of MCF-7 cells was increased from 16.5 μm to 23.1 μm. A micro filter chip having an extremely high aspect ratio (AR=3488) rectangular slit was designed to prevent clogging which induces unwanted aggregation, capturing of other small blood cells and consequently decreasing purity. A fully automated fluid control system was implemented for the better reproducibility and the minimization of handling errors. The procedures from blood loading to staining, prior to analysis, were performed automatically. With the optimized condition, separation experiments using 5ml of normal whole blood spiked with 100 MCF-7 cells have demonstrated the reduction of clogging, high recovery (91.1 %) and high purity (52.0 %) at the same time.

A direct extraction method was developed for exosomal microRNAs. After isolation of exosomes from human serum by immunoaffinity magnetic beads, microRNAs were extracted by just mixing beads with a lysis solution and heating without further purification. The lysis solution was composed of a nonionic detergent and salt (NaCl). The concentration of each component was optimized to maximize lysis efficiency and to inhibit adsorption of extracted microRNAs on beads. MicroRNAs extracted by this method could be quantitatively analyzed by qRT-PCR, indicating that the method could replace conventional methods for extracting microRNAs from immunobead-captured exosomes.