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Flexible gas sensors with high-sensitivity and good stability are essential components of wearable electronic devices. In this paper, we present a novel graphene fabric gas sensor composed of reduced graphene oxide (RGO) nanosheets and electrospun nylon-6 nanofibers. By combination the RGO with nanofiber, the graphene electronic fabrics show sensitive response to NO 2 (13.6%@1 ppm) at room temperature, and excellent mechanical reliability against repeated deformation during 5000 bending cycles with an extreme bending radius of 1.0 mm.

Molybdenum disulfide (MoS2) field-effect transistor (FET)-based biosensors have attracted significant attention as promising candidates for highly sensitive, label-free biomolecule detection devices. In this paper, toward practical applications of biosensors, we demonstrate reliable and quantitative detection of a prostate cancer biomarker using the MoS2 FET biosensor in a nonaqueous environment by reducing nonspecific molecular binding events and realizing uniform chemisorption of anti-PSA onto the MoS2 surface. A systematic and statistical study on the capability of the proposed device is presented, and the biological binding events are directly confirmed and characterized through intensive structural and electrical analysis. Our proposed biosensor can reliably detect various PSA concentrations with a limit of 100 fg/mL. Moreover, rigorous theoretical simulations provide a comprehensive understanding of the operating mechanism of the MoS2 FET biosensors, and further suggests the enhancement of the sensitivity through engineering device design parameters.

Silica–polystyrene (Si–PS) nanocomposite latex particles were prepared by emulsion polymerization using Hwangtoh clay as the silica source and blending with polyethylene terephthalate (PET) by melt extrusion. The Hwangtoh clay was mechanically grounded as nanoscale. XRD measurements showed more crystallized Hwangtoh clay in nano-dimension than that of raw material with crystallite sizes (t) of 108.52 and 126.7 nm, respectively. SEM (scanning electron microscope) measurements showed that the dispersed Si–PS hybrid nanocomposite had a D h of ~350 nm within the PET matrix. FTIR (Fourier transform infrared spectroscopy) measurements exhibited the characteristic absorption peaks of Si–O–Si stretching vibrations and Al–O–Si bending vibrations from both the Si–PS hybrid structure and PET/Si–PS composite. X-ray diffraction (XRD) measurements exhibited a characteristic Si diffraction peak of 2θ value at 25° and 29°, both from Si–PS hybrid nanoparticles and PET/Si–PS composites. The blending of PET with a Si–PS nanocomposite was determined by XPS (X-ray photoelectron spectroscopy) analysis, which showed three distinctive peaks representing the interatomic bonding of carbon. In XPS measurements, the decomposition of the Si 2p core peak demonstrated that the Si atom from Hwangtoh clay is composed of four chemical states such as Si0, Si+ (Si2O), Si2+ (SiO), and Si3+ (Si2O3). Our results provide evidence of the successful encapsulation of silicate from Hwangtoh clay in a PS shell, and further blending with PET by the melting extrusion method.

Wearable strain sensors based on Au–Ag core–shell nanoparticle decorated yarns were fabricated by a solution-based approach. Smart wearable systems with our strain sensors that can monitor various human motions, including finger motion, marching and squatting, and transmit the information of human motion in real time to an LED light was demonstrated.

Wan Joong Kim 1 , Han-Sung Kim 2 , Joerg Opitz 3 , Kazuya Kabayama 4 and Tack-Joong Kim 1 * Division of Biological Science and Technology, Yonsei-Fraunhofer Medical Device Lab, College of Science and Technology, Yonsei University, Wonju 220-710, Korea Department of Biomedical Engineering, Yonsei-Fraunhofer Medical Device Lab, College of Health Science, Yonsei University, Wonju 220-710, Korea Fraunhofer Institute for Ceramic Technologies and Systems-Material Diagnostics, Dresden, Germany Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan

Sensitive ELISA for C-reactive protein (CRP) was performed in a capillary tube based on simple vapor-phase surface chemistry. Amine surfaces were produced in capillary tubes in two different methods using 3-aminopropyltriethoxysilane (APTES) in liquid and vapor phases. Those amine surfaces were tethered with gold nanoparticles (AuNPs) to be characterized by field emission scanning electron microscopy (FE-SEM) resulting in more dense and dispersed AuNP populations from the vapor-phase surface. Feasibility of a miniaturized home-made optical detector for “capillary ELISA” was performed by infusing into capillary tubes the colored solutions that had just gone through ELISA on a 96-well plate. The compatibility of the two results obtained from ELISAs on a well-plate and in capillary tubes, confirmed dependability of the miniaturized detector. Finally “capillary ELISA” was performed on the home-made detector using anti-CRP immobilized capillary tubes that had been prepared via vapor-phase surface treatment, resulting in detectability of 1.0 ng/mL of CRP, which turned out to be around 10 times higher in sensitivity than that of the well-plate ELISA.

To investigate the effect of soluble silicate zeolite dressing of the rice against bakanae disease, field trial in reclaimed land and in vitro were carried out. The coated rice seeds (SCS) which were dressed with the mixture of 25% silicic acids (binder), and the zeolite (coating powder). In wet direct seeding, uniform scattering of rice seeds on the soil surface and the better seedling establishment were shown in SCS treatment plots. The incidence of bakanae disease began from the mid tillering stage toward the heading stage. Around heading stage, the ratio of infected tillers reached its highest point by 9.9% in non-SCS treatment plots. While, in SCS treatment plots, the ratio of infected tillers was no more than 0.01%. The vitality of the pathogenic fungi of bakanae disease in the SCS and non-SCS samples were assessed. Samples were incubated for one week keeping proper humidity at after inoculated with panicles of infected rice plants from experimental field plots. In non-SCS treatment, pinkish colonies were formed on the grain surface of panicle of infected plants, and mycelium, macro-conidia and micro-conidia were developed actively inside part of infected grain inoculated. While in SCS treatment, micro-conidia and mycelium were not survived and the growth of macro-conidia, mycelia were greatly inhibited and withered. Based on the results, it is concluded that the environmental friendly control of bakanae disease by use of SCS is possible and soluble silicate can be applied as agents for replacement of seed disinfection.

Cymbidiumhas known antibacterial and antiedema activity and has been used as an ingredient in cosmetics and fragrances. The effects ofCymbidiumethanol extract (CYM) on allergic response and the underlying mechanisms of action have not been reported. Therefore, the purpose of this study was to determine the effect of CYM on allergic responses. Topical application of CYM was effective against immunoglobulin E (IgE)/dinitrophenyl-conjugated bovine serum albumin- (DNP-BSA-) induced degranulation of RBL-2H3 cells and anaphylaxis in ICR mice. An allergic dermatitis-like mouse model was used to evaluate the therapeutic potential of CYMin vivo.Continuous application of 2,4-dinitrochlorobenzene (DNCB) not only induced dermatitis in ICR mice but also aggravated the skin lesioning. However, the application of CYM decreased skin lesion severity, scratching behavior, and IgE levels. In addition, CYM downregulated the expression of the proinflammatory cytokines interleukin- (IL-) 4, IL-13, and tumor necrosis factor- (TNF-)α. Studies of signal transduction pathways showed that CYM suppressed the phosphorylation of spleen tyrosine kinase (Syk), an upstream molecule. It also inhibited the phosphorylation of Akt, phospholipase C- (PLC-)γ, and mitogen-activated protein kinase kinase kinase (MEKK). These results indicate that CYM may be effective in preventing and reducing allergic response and may have therapeutic potential as an antiallergic agent in disorders such as atopic dermatitis.

We demonstrate the monolithic Si nanocrystal (NC) photonic transducer for a real-time protein detection. The monolithic photonic transducer was composed of the Si NC light-emitting diode (LED), Si NC photodetector (PD), and Si nitride (SiNx) optical waveguide that was optically self-aligned to the LED and PD. The Si NCs used as the fabrication of LED and PD were synthesized in the SiNx matrix. Antibodies were immobilized onto the surface of SiNx optical waveguide of the photonic transducer through self-assembled monolayers and surface aldehyde formation. Colloidal gold (Au) nanoparticles (NPs) were used to amplify the optical signal due to the strong surface plasmon resonance. The binding reaction of the Au NPs with the immobilized antibodies within the evanescent field at the transducer surface of the SiNx optical waveguide causes attenuated total reflection of the waveguided modes and thus reduction of the PD photocurrent. The detection limit of prostate-specific antigen (PSA) was around 1 ng/mL.

We have developed an enhanced sandwich immunogold assay for highly sensitive detection of cardiac troponin I (cTnI) in human serum. In this assay, the immunoreaction undergoes in sample solution between cTnI antigen and gold nanoparticles conjugated with detection antibodies of cTnI (immunogolds). Then, a capture antibody of cTnI immobilized on a standard 96-well plate captures the immunogold complex, followed by silver staining of the immunogold for the purpose of signal amplification. Compared to the direct assay where the immunoreaction occurs between the target and the capture antibody coated on the well, we found the enhanced assay shows greatly improved sensitivity by two orders of magnitude and a linear relation of the quantitative plot. Because the immunogold concentration affect greatly the sensitivity of the cTnI detection, we also studied the performance of direct and enhanced immunogold assay depending on the concentration of immunogold conjugates. By using the enhanced assay with the optimized procedure, we could achieve the detection of cTnI in human serum as low as 15 pg/mL. We also verified the enhanced immunogold assay by measuring the concentration of clinical samples for a healthy person and patients. This development can allow us to apply the assay not only for the analysis of other cardiac markers as well as disease-related biomarkers but also for the optimization of other chip-based silver enhanced colorimetric sensors.

A hybrid triple-layered nanocomposite structure of plasmonic gold (Au), polymethylmethacrylate (PMMA), and lead selenide (PbSe) quantum dot (QD) on quartz substrate was developed. The fabricated nanocomposite exhibited well-established triple-layered morphology (Au-PMMA-QD on quartz), but had different coupling distances between Au, on the bottom, and PbSe QD, on the top. Control of the coupling distances in terms of different thicknesses of a PMMA spacer layer was examined by etching for different durations, from 7 to 30 min. The corresponding thicknesses of the PMMA layer ranged from ~3.8 to ~88 nm at an etching rate of 2 nm/min. Atomic force microscopy measurements showed that the well-established triple-layered hybrid nanocomposite structure had the heights of ~15 nm (Au) and ~4 nm (PbSe QD). X-ray photoelectron spectroscopy results revealed the characteristic peaks assigned to each nanoparticle and polymer layer. The results illustrated the triple-layered structures with different PMMA spacer layers, with no cross interference between the layers.

Facile and efficient fabrication of polyacrylonitrile (PAN)-based conductive graphitic carbon microstructures (GCMs) and their application to the electrodes of organic field-effect transistors (OFETs) is described. The PAN thin films spin-coated on a SiO 2 -deposited Si wafer was irradiated through a pattern mask with 150 keV H + ions at various fluences, and subsequently developed to form PAN microstructures. The resulting PAN microstructures were carbonized at various temperatures to create the GCMs. The analytical results revealed that the optimized fluence and carbonization temperature for well-defined GCMs was 3 × 10 15 ions cm −2 and 100 °C, respectively, and that the resulting GCMs created at the optimized condition exhibited a greatly low surface roughness of 0.36 nm, a good electrical conductivity of about 600 S cm −1 , and a high work function of 5.11 eV. Noticeably, the GCM electrodes-based p-type OFET showed a comparable performance to that of the gold electrode-based one, demonstrating that the practical use of GCMs as cheap electrodes to replace expensive metallic ones for organic electronic devices.

We fabricate graphene oxide (GO)-coated fiber bundles via electrostatic deposition of GO sheets on polyester/cotton fiber bundles and investigate the changes in their properties by chemical reduction in a hydroiodic acid solution. The structural properties of GO sheets change rapidly upon exposure to reduction agents but remain under a high defect density regime after the reduction. The electrical resistance of the fiber bundles decreases logarithmically for the first minute of the reduction. In contrast to the structural property, a longer chemical reduction over tens of minutes deteriorates the electrical property. The effect of chemical reduction on the electrical conductance of GO-coated fiber bundles is discussed based on the competition of various factors, such as the number of conducting pathways and the carrier density, among others.

Using gold nanoparticles (AuNPs) on “capillary enzyme-linked immunosorbent assay (ELISA)”, we produced highly sensitive and rapid assays, which are the major attributes for point-of-care applications. First, in order to understand the size effect of AuNPs, AuNPs of varying diameters (5 nm, 10 nm, 15 nm, 20 nm, 30 nm, and 50 nm) conjugated with Horseradish Peroxidase (HRP)-labeled anti-C reactive protein (antiCRP) (AuNP•antiCRP-HRP) were used for well-plate ELISA. AuNP of 10 nm produced the largest optical density, enabling detection of 0.1 ng/mL of CRP with only 30 s of incubation, in contrast to 10 ng/mL for the ELISA run in the absence of AuNP. Then, AuNP of 10 nm conjugated with antiCRP-HRP (AuNP•antiCRP-HRP) was used for “capillary ELISA” to detect as low as 0.1 ng/mL of CRP. Also, kinetic study on both 96-well plates and in a capillary tube using antiCRP-HRP or AuNP•antiCRP-HRP showed a synergistic effect between AuNP and the capillary system, in which the fastest assay was observed from the “AuNP capillary ELISA”, with its maximum absorbance reaching 2.5 min, while the slowest was the typical well-plate ELISA with its maximum absorbance reaching in 13.5 min.

Sensitivity is a very important parameter for biosensor applications. We have numerically and experimentally studied the sensitivity and linewidth responses of optical resonant reflective biosensors to the thickness of high refractive index materials coating the grating layer used to create a guided mode. Zero sensitivity, which may create serious problems in biosensors, is obtained when the coating material has a relatively low refractive index and a thin coating thickness (near the cutoff condition in which a high index layer is no longer capable of acting as a waveguide). The sensitivity and linewidth are greatly influenced by the thickness of the coating material. The thickness also has an optimal state, which is a very important factor for designing highly sensitive optical resonant reflective biosensors using a guided mode resonance filter.

A novel and simple method for the colorimetric quantitative sensing of individual alkali metal ions (Li + , Na + , K + , and Rb + ) based on the reversible properties of self-assembled aggregates and individual gold nanoparticles (Au NPs) is described. This paper demonstrates reversible self-assembly processes where the degree of assembly and disassembly is dependent on the individual alkali metal ion concentration, nanoparticle size, and alkali metal ionic radii. The color changes of the colloidal Au NPs with metal ion concentrations in colloidal NP solutions occur reversibly. Below a certain concentration of alkali metal ions, the aggregates of Au NPs are redispersed. As the Au NP diameters and the alkali metal ionic radii increase, the critical concentration decreases.

The surface functionalization of bio-inert fluoropolymer films through ion beam-induced surface graft polymerization was investigated to control the cellular behavior. The surface of poly(tetrafluoroethylene-co-perfluoropropl vinyl ether) (PFA) films was selectively activated by 150 keV H + ion implantation in the presence of a pattern mask and sodium 4-styrenesulfonate (SS) was then graft polymerized onto the implanted PFA films to form hydrophilic poly(sodium 4-styrenesulfonate) (PSS)-patterned PFA films. The surface of the resulting PSS-patterned PFA films was investigated in terms of the degree of graft polymerization, chemical structure, chemical composition, wettability, and morphology. The analytical results revealed that PSS was selectively grafted onto the implanted regions of the PFA films. Furthermore, in vitro cell culture on the PSS-patterned PFA films exhibited a preferential adhesion and growth of cells onto the PSS-grafted regions, resulting in well-organized 100 μm cell patterns.

Au–Ag alloy nanoparticles (NPs) were prepared by the reduction of metal ion mixtures in aqueous sodium citrate solution using sodium borohydride (NaBH4). The resulting Au–Ag alloy NPs were analyzed by various techniques. Alloy-attached chips for the detection of microorganisms were fabricated simply by the attachment of Au–Ag alloy nanoparticles onto glass slides after silanization through self-assembled monolayers (SAMs) for the formation of activated amine (−NH2) as a terminal function group. The alloy-attached chips were investigated for their ability to bind the target Escherichia coli (E. coli) in water. E. coli was detected in water as a function of time and concentration by UV–vis spectroscopic measurements based on the interaction between the alloy-attached chip and E. coli. Field-emission scanning electron microscopy (FE-SEM) was used to directly observe the E. coli captured on the alloy chips. These studies demonstrated that E. coli in drinking water can be directly detected with Au–Ag alloy mic...

A simple and selective technique which immobilizes protein onto a solid substrate by using UV illumination has been developed. In protein immobilization, a Bovine serum albumin (BSA) performed bifunctional role as a cross-linker between substrate and proteins and as a blocker inhibiting a nonspecific protein adsorption. A new photo-induced protein immobilization process has been investigated at each step by fluorescence microscopy, ellipsometry, and Fourier transform infrared (FT-IR) spectroscopy. A UV photomask has been used to induce selective protein immobilization on target regions of the surface of the SiO2 substrates under UV illumination with negligible nonspecific binding. The UV illumination also showed improved photostability than the conventional methods which employed bifunctional photo-crosslinker molecules of photo-reactive diazirine. This new UV illumination-based photo-addressable protein immobilization provides a new approach for developing novel protein microarrays for multiplexed sensing as well as other types of bio-immobilization in biomedical devices and biotechnologies.

Plasmon-coupled CdSe/ZnS and CdTe/CdS/ZnS coreshells are investigated for their optoelectronic applications because of their high color purity, wide optical tunability, large PL enhancement, and compact and easy integration into electronic devices. The quantum confinement of carriers within quantum dots (QDs) with sizes near the exciton Bohr radius (CdSe ~ 5.8 nm, CdTe ~ 7 nm) exhibits the features of discrete energy states and blue-shift from the bulk bandgap (CdSe ~718 nm, CdTe ~ 863 nm) in the optical spectrum. While the fluorescence from the QDs is attributable to the exciton carrier recombination, large PL enhancement and fast emission time is achieved through plasmon-exciton coupling via the Coulomb interaction. Large PL enhancement of QDs in the vicinity of plasmonic particles was observed and attributed to the reduction of the non-radiative decay rate and large local field enhancement. The large PL enhancement and wide optical tunability along with high color purity from plasmon-coupled QDs enables the realization of hybrid LEDs.

Pterocarpus indicus Willd has been widely used as a traditional medicine to treat edema, cancer, and hyperlipidemia, but its antiallergic properties and underlying mechanisms have not yet been studied. The purpose of this study was to evaluate the antiallergic activity of Pterocarpus indicus Willd water extract (PIW) using activated mast cells and an atopic dermatitis (AD)-like mouse model. PIW decreased IgE/Ag-induced mast cell degranulation and the phosphorylation of Syk and downstream signaling molecules such as PLC-γ, Akt, Erk 1/2, JNK compared to stimulated mast cells. In DNCB-induced AD-like mice, PIW reduced IgE level in serum, as well as AD-associated scratching behavior and skin severity score. These results indicate that PIW inhibits the allergic response by reducing mast cell activation and may have clinical potential as an antiallergic agent for disorders such as AD.

Angiogenesis, neovascularization from pre-existing vessels, is a key step in tumor growth and metastasis, and anti-angiogenic agents that can interfere with these essential steps of cancer development are a promising strategy for human cancer treatment. In this study, we characterized the anti-angiogenic effects of Coptis japonica Makino extract (CJME) and its mechanism of action. CJME significantly inhibited the proliferation, migration, and invasion of vascular endothelial growth factor (VEGF)-stimulated HUVECs. Furthermore, CJME suppressed VEGF-induced tube formation in vitro and VEGF-induced microvessel sprouting ex vivo. According to our study, CJME blocked VEGF-induced cell cycle transition in G1. CJME decreased expression of cell cycle-regulated proteins, including Cyclin D, Cyclin E, Cdk2, and Cdk4 in response to VEGF. Taken together, the results of our study indicate that CJME suppresses VEGF-induced angiogenic events such as proliferation, migration, and tube formation via cell cycle arrest in G1.

This paper describes a new technique for the detection of uncharged or feebly charged small molecules (

Bio-functionalized gold nanoparticles (AuNPs), which bio-specifically interact with biotin-(strept)avidin, were investigated in this study. AuNPs were functionalized with a synthetically-provided biotin-linked thiol (BLT), which was synthesized by amidation of the active ester of biotin with 2-mercaptoethylamine. The BLT-attached AuNP was bio-specific for streptavidin, making it potentially useful for biosensor applications. To test the bio-specific interactions, the colors, absorption spectra and TEM images were investigated for proteins such as streptavidin, cytochrome C, myoglobin and hemoglobin. The colors and absorption spectra changed when streptavidin was added to the BLT-attached AuNP solution. However, the color and spectra did not change when the other proteins were added to the same solution. These results show that the AuNPs provided a colloidal solution with excellent stability and highly selective absorption characteristics for streptavidin as a target molecule. Proteins were also screened in order to identify a general strategy for the use of optical biosensing proteins based on AuNPs. In addition, TEM images confirmed that streptavidin led the BLT-attached AuNPs to aggregate or precipitate.

This paper presents the study of surface-enhanced Raman scattering (SERS) for Rhodamine 6G (R6G)-linked gold (Au) assemblies. The nano-assemblies fabricated with Au nanoparticles, having diameters (D) of ∼5–40 nm, possessed interparticle gaps of ∼0.03–0.2D, respectively. The R6G-linked Au assemblies displayed weak spectral shifts of localized surface plasmon resonance (LSPR) mode at shorter wavelength region and large fractional red-shifts Δλ ∼ 0.07–0.47λo at longer wavelength region. The resonant spectral coupling of the nano-assemblies LSPR mode at the longer wavelength region and the optical excitation at ∼785 nm, in addition to the highly localized hot spots, could support the large SERS enhancement of R6G-linked Au assemblies.

This study reports a portable and precision photonic biosensor reader that can measure the concentration of a particular antigen using an optical resonant reflection biosensor (ORRB). To create a compact biosensor reader, a compact tunable vertical-cavity surface-emitting laser (VCSEL) and a compact built-in wavelength meter were manufactured. The wavelength stability and accuracy of the compact built-in wavelength meter were measured to be less than 0.02 nm and 0.06 nm, respectively. The tunable VCSEL emission wavelength was measured with the compact built-in wavelength meter, it has a fast sweep time (~ 10 seconds) and a wide tuning range (> 4 nm) that are sufficient for biosensor applications based on ORRB. The reflection spectrum of a plastic based ORRB chip was measured by the fabricated portable photonic biosensor reader using the VCSEL and wavelength meter. Although the reader is the size of a palmtop device, it could make a precise measurement of the peak wavelength on equal terms with a conventional bulky optical spectrometer.

Cardiac markers in human serum with concentrations less than 0.1 ng/mL were analyzed by use of a guided-mode resonance (GMR) biosensor. Cardiac troponin I (cTnI), creatine kinase MB (CK-MB), and myoglobin (MYO) were monitored in the serum of both patients and healthy controls. Dose-response curves ranging from 0.05 to 10 ng/mL for cTnI, from 0.1 to 10 ng/mL for CK-MB, and from 0.03 to 1.7 μg/mL for MYO were obtained. The limits of detection (LOD) for cTnI, CK-MB, and MYO were less than 0.05, 0.1, and 35 ng/mL, respectively. Analysis time was 30 min, which is short enough to meet clinical requirements. Antibody immobilization and the hydrophilic properties of the guided-mode resonance filter (GMRF) surface were investigated by X-ray photoelectron spectroscopy (XPS) and by monitoring the peak wavelength shift and water contact angle (CA). Both assays used to evaluate the surface density of the immobilized antibodies, a sandwich enzyme-linked immunosorbent assay (ELISA) and a sandwich immunogold assay, showed that the antibodies were successfully immobilized and sufficiently aligned to detect the low concentration of biomarkers. Our results show that the GMR biosensor will be very useful in developing low-cost portable biosensors that can screen for cardiac diseases.

We demonstrate a commercialized injection molding method for nano patterning of polymethyl methacrylate (PMMA) for the purpose of mass production of a label-free optical biosensor chip. Scanning electron microscope (SEM) images clearly show uniform nanopattern transfer on the plastic chip fabricated by an injection molding method. A uniformly deposited silicon nitride layer having a high refractive index by a plasma enhanced chemical vapor deposition (PECVD) technique is also observed. A unique characterization method is described wherein optical resonance reflection is used accurately and quickly to characterize the geometrical sensor structure. The authors anticipate that this robust method will provide an excellent means of producing an optical resonance reflection biosensor (ORRB).

In this study, we have developed a new detection method using Si field effect transistor (FET)-type biosensors, which enables the direct monitoring of antigen-antibody binding within very high-ionic-strength solutions such as 1×PBS and human serum. In the new method, as no additional dilution or desalting processes are required, the FET-type biosensors can be more suitable for ultrasensitive and real-time analysis of raw sample solutions. The new detection scheme is based on the observation that the strength of antigen-antibody-specific binding is significantly influenced by the ionic strength of the reaction solutions. For a prostate specific antigen (PSA), in some conditions, the binding reaction between PSA and anti-PSA in a low-ionic strength reaction solution such as 10 µM phosphate buffer is weak (reversible), while that in high-ionic strength reaction solutions such as 1×PBS or human serum is strong.

Anionic sulfate (SO(4)(-))-functionalized polystyrene (PS) nanoparticles were prepared by the thermal decomposition of potassium persulfate (KPS) in the presence of sodium tetraborate via emulsion polymerization. The presence of a SO(4)(-) group at a solid/liquid interface of a particle surface was confirmed by a zeta potential value of -40.6 mV as well as the shifting of S 2p spectra toward a lower-binding-energy region around 162.7 eV (2p(3/2)) and 164.4 eV (2p(1/2)) in X-ray photoelectron spectroscopy (XPS) analysis. The electrostatic attraction between positively charged antibodies of human immunoglobulin G (hIgG) and cardiac troponin I (cTnI) and negatively charged particle surfaces was accomplished. The atomic force microscopy (AFM) measurement and bicinchoninic acid (BCA) assay results show binding structure between hIgG and antibodies of hIgG (anti-hIgG) with a gradual increase in particle diameter to 152.6 nm (bare), 170.2 nm (hIgG), and 178.9 nm (hIgG/anti-hIgG). Surface coverage densities of 331.4 ng/cm(2) (hIgG) and 320.3 ng/cm(2) (cTnI) and the binding capacity of hIgG to HyLite-750-labeled Fab-specific anti-hIgG (approximately 81.2%) indicate that the majority of hIgG was immobilized with a Y-shaped orientation. The sandwich immunoassay results provide the evidence that the immunological activity of cTnI on the PS nanoparticle surface was retained because the binding activity of the cTnI-PS nanoparticle/cTnI (antigen)/detection cTnI-antibody reaction showed a 5-fold higher activity than that of the cTnI-PS nanoparticle/human serum albumin (HSA)/detection cTnI antibody used as a negative control.

Chemical modification of titanium/titanium oxide (Ti/TiO2) substrates has recently gained a great deal of attention because of the applications of Ti/TiO2-based materials to biomedical areas. The reported modification methods generally involve passive coating of Ti/TiO2 substrates with protein-resistant materials, and poly(ethylene glycol) (PEG) has proven advantageous for bestowing a nonbiofouling property on the surface of Ti/TiO2. However, the wider applications of Ti/TiO2-based materials to biomedical areas will require the introduction of biologically active moieties onto Ti/TiO2, in addition to nonbiofouling property. In this work, we therefore utilized surface-initiated polymerization to coat the Ti/TiO2 substrates with polymers presenting the nonbiofouling PEG moiety and subsequently conjugated biologically active compounds to the PEG-presenting, polymeric films. Specifically, a Ti/TiO2 surface was chemically modified to present an initiator for atom transfer radical polymerization, and poly(ethylene glycol) methacrylate (PEGMA) was polymerized from the surface. After activation of hydroxyl groups of poly(PEGMA) (pPEGMA) withN,N′-disuccinimidyl carbonate, biotin, a model compound, was conjugated to the pPEGMA films. The reactions were confirmed by infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle goniometry, and ellipsometry. The biospecific binding of target proteins was also utilized to generate micropatterns of proteins on the Ti/TiO2 surface.

Gold nanoparticles exhibited strong surface plasmon absorption and couplings between neighboring particles within bioactivated self-assembly modified their optical properties. Colorimetric analysis on the optical modification of surface plasmon resoanance (SPR) shift and flocculation parameter functionalized bioinspired gold assembly for biophotonic application. The physical origin of bioinspired gold aggregation-induced shifting, decreasing, or broadening of the plasmon absorption spectra could be explained in terms of dynamic depolarization, collisional damping, and shadowing effects.

We have studied the current-induced dynamics of the transverse domain wall in the adiabatic limit. Above the threshold current density for the continuous domain wall motion, the transverse wall is transformed by the injection of the antivortex. In general, the wall velocity increases and the wall width decreases as the antivortex is injected. However, detailed time-dependent profiles of the wall velocity and the wall width are significantly affected by the aspect ratio of the nanostrip. The mean velocity of the TW decreases as the aspect ratio increases.

For the application of current-induced domain wall motion, the pinning position of a domain wall must be precisely defined with a low depinning current density. A conventional way of pinning a domain wall is to use a notch which is patterned on an edge of nanostrip. As an alternative scheme of domain wall pinning, we performed micromagnetic investigation of the current-induced domain wall motion in a nanostrip with alternating materials. A segment with different magnetic parameters such as saturation magnetization, exchange constant or crystalline anisotropy can effectively pin a domain wall. It is because the segment acts as an energy barrier in the domain wall motion. Threshold current densities to depin the domain wall in nanostrips with alternating materials were of the order of 10 8 A/cm 2 , and can be modulated by changing the material parameters and the length of the segment.

Novel anthracycline analogues 2-9 as potential anticancer agents were synthesized from daunomycin (1a) and doxorubicin (1b). Compounds 2, 6, and 7 were prepared by the nucleophilic displacement type esterification of a 14-bromodaunomycin (1c) with a sodium lactate, and stearic acid, respectively. Compounds 3-5 and 7-9 were prepared by the reaction of either daunomycin (1a) or doxorubicin (1b) with L-lactic and stearic acids in the presence of EDCI/PP reagents.

Aspect ratio of gold nanorods can be controlled by simply adjusting the reaction temperature in the seed-mediated synthesis of the nanorods. The gold nanorods were synthesized by the injection of gold nanoparticle seeds of around 4nm in diameter into a reaction mixture containing hydrogen tetrachloroaurate, hexadecyltrimethylammonium bromide, and ascorbic acid. Average aspect ratio of the resulting nanorod increases from 1 to about 40 with decreasing the reaction temperature from 315to276K, which can be attributed to the temperature-induced change in the shape of the micellar templates. For further understanding of the growth mechanism, silver nanoparticles were also used as seeds in the preparation of the gold nanorod.

We investigated the formation of thermoresponsive gold nanoparticle/poly(N-isopropylacrylamde) (AuNP/ PNIPAAm) core/shell hybrid structures by surface-initiated, atom transfer radical polymerization (SI-ATRP) in aqueous media and the effect of cross-linking on the thermoresponsiveness of the AuNP/PNIPAAm hybrids. The disulfide containing an ATRP initiator was attached onto AuNPs and the monomer, NIPAAm, was polymerized from the surface of AuNPs in the absence or presence of a cross-linker, ethylene diacrylate, in aqueous media at room temperature. The resulting brush-type and cross-linked AuNP/PNIPAAm hybrids were characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and variable temperature dynamic light scattering.

Monodispersive size-controlled gold nanoplates were synthesized with high purity from the reduction of hydrogen tetrachloroaurate by reduced amount of sodium citrate, which kinetically controls the reaction pathway, in the presence of poly(vinyl pyrrolidone) (PVP). With the insufficient addition of the reductant, the molar ratio of sodium citrate and PVP relative to hydrogen tetrachloroaurate played an important role in determining the geometric shape and size of the product. These nanoplates were single crystals with planar width of 80−500 nm and thickness of 10−40 nm, exhibiting strong surface plasmon absorption in the near-infrared (NIR) region of 700−2000 nm. The gold nanoplates were used as the synthetically provided nanoblocks to fabricate single-crystalline nanocomponents, such as a nanoscaled gear or a nanoscaled letter.

It has been a real challenge to form carbon nanotube (CNT)/polymer composites where CNTs are well-dispersed in the polymer matrix and the interactions between CNTs and polymers are effectively strong. In this paper, we applied surface-initiated, ring-opening polymerization (SI-ROP) of p-dioxanone (PDX) to shortened single-walled carbon naotubes (s-SWCNTs) and successfully formed s-SWCNT/PPDX composites (see Figure). Due to intimate interactions between s-SWCNTs and PPDX, we observed dramatic changes in PPDX properties upon the formation of the composites: 10%-weight-loss-temperature of PPDX increased by 20°C (measured by thermogravimetric analysis) and the patterns of T g and T m were greatly altered. We did not observed any noticeable peaks from the composite up to 120°C in differential scanning calorimetry (DSC), while DSC data of PPDX itself showed T g and T m at 13.4 and 103°C respectively.