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Abstract: Colorimetric uranium sensors based on uranyl (UO[sub2][sup2+]) specific DNAzyme and gold nanoparticles (AuNP) have been developed and demonstrated using both labeled and label-free methods. In the labeled method, a uranyl-specific DNAzyme was attached to AuNP, forming purple aggregates. The presence of uranyl induced disassembly of the DNAzyme functionalized AuNP aggregates, resulting in red individual AuNPs. Once assembled, such a "turn-on" sensor is highly stable, works in a single step at room temperature, and has a detection limit of 50 nM after 30 mm of reaction time. The label-free method, on the other hand, utilizes the different adsorption properties of single-stranded and double-stranded DNA on AuNPs, which affects the stability of AuNPs in the presence of NaCI. The presence of uranyl resulted in cleavage of substrate by DNAzyme, releasing a single stranded DNA that can be adsorbed on AuNPs and protect them from aggregation. Taking advantage of this phenomenon, a "turn-off" sensor was developed, which is easy to control through reaction quenching and has 1 nM detection limit after 6 mm of reaction at room temperature. Both sensors have excellent selectivity over other metal ions and have detection limits below the maximum contamination level of 130 nM for UO[sub2][sup2+] in drinking water defined by the U.S. Environmental Protection Agency (EPA). This study represents the first direct systematic comparison of these two types of sensor methods using the same DNAzyme and AuNPs, making it possible to reveal advantages, disadvantages, versatility, limitations, and potential applications of each method. The results obtained not only allow practical sensing application for uranyl but also serve as a guide for choosing different methods for designing colorimetric sensors for other targets. [ABSTRACT FROM AUTHOR]

One major challenge in analytical chemistry is multiplex sensing of a number of analytes with each analyte displaying a different signal. To meet such a challenge, quantum dots that emit at 525 and 585 nm are used to encode aptamer-linked nanostructures sensitive to adenosine and cocaine, respectively. In addition to quantum dots, the nanostructures also contain gold nanoparticles that serve as quenchers. Addition of target analytes disassembles the nanostructures and results in increased emission from quantum dots. Simultaneous colorimetric and fluorescent detection and quantification of both molecules in one pot is demonstrated. [ABSTRACT FROM AUTHOR]

The article features results of the study that probes the efficacy of backbone-modified phosphorothioate DNA and bifunctional linkers to control the alignment of multiple proteins and nanoparticles in the U.S. Researchers found the technique to be efficient because it allows precise alignment of proteins using phosphorothioate DNA and short bifunctional linkers. Moreover, the method enables researchers to produce high yield conjugation of multiple proteins to DNA with nanometer resolution.

A simple design of “turn-on” fluorescent sensor for mercury was demonstrated based on structure-switching DNA with a low detection limit of 3.2 nM and high selectivity. [ABSTRACT FROM AUTHOR]

Mesoporous silica has received considerableattention as a drugdelivery vehicle because of its large surface area and large porevolume for loading drugs and large biomolecules. Recently, mesoporoussilica microparticles have shown potential as a three-dimensionalvaccine platform for modulating dendritic cells via spontaneous assemblyof microparticles in a specific region after subcutaneous injection.For further in vivoapplications, the biodegradationbehavior of mesoporous silica microparticles must be studied and known.Until now, most biodegradation studies have focused on mesoporoussilica nanoparticles (MSNs); here, we report the biodegradation ofhexagonally ordered mesoporous silica, SBA-15, with micrometer-sizedlengths (∼32 μm with a high aspect ratio). The degradationof SBA-15 microparticles was investigated in simulated body fluid(SBF) and in mice by analyzing the structural change over time. SBA-15microparticles were found to degrade in SBF and in vivo. The erosion of SBA-15 under biological conditions led to a lossof the hysteresis loop in the nitrogen adsorption/desorption isothermand fingerprint peaks in small-angle X-ray scattering, specificallyindicating a degradation of ordered mesoporous structure. Via comparisonto previous results of degradation of MSNs in SBF, SBA-15 microparticlesdegraded faster than MCM-41 nanoparticles presumably because SBA-15microparticles have a pore size (∼8 nm) and a pore volume largerthan those of MCM-41 mesoporous silica. The surface functional groups,the residual amounts of organic templates, and the hydrothermal treatmentduring the synthesis could affect the rate of degradation of SBA-15.In in vivotesting, previous studies focused on theevaluation of toxicity of mesoporous silica particles in various organs.In contrast, we studied the change in the physical properties of SBA-15microparticles depending on the duration after subcutaneous injection.The pristine SBA-15 microparticles injected into mice subcutaneouslyslowly degraded over time and lost ordered structure after 3 days.These findings represent the possible in vivouseof microsized mesoporous silica for drug delivery or vaccine platformafter local injection. [ABSTRACT FROM AUTHOR]

We report the development of surfactant free-gold nanoparticle (AuNP)-DNA complexes that remained stable in solutions with extremely high ionic strength, using seawater as a model solution. Although the stability of AuNPs can be increased to a certain degree by functionalizing negatively charged DNA strands on their surfaces, they still have limited stability in highly concentrated salt solutions. However, we found that AuNPs functionalized with poly-T bases have exceptional stability in high ionic strength solutions. For example, AuNPs functionalized with a 5T spacer remained highly stable in seawater, with no color change and no red-shift in absorbance spectra for up to 9 days. Using this surprising property of poly-T spacers, we prepared highly stable AuNP-DNA complexes containing random sequences by introducing 5T spacers on the random sequenced DNA strand. The random sequenced AuNP-DNA complexes remained stable in seawater, several molar concentrations of monovalent metal ion solutions (6.1 M Na+ or 4.8 M K+), and millimolar concentrations of diverse divalent metal ions. In addition, the highly stable AuNP-DNA complex maintained biological activity in seawater, which was demonstrated by complementary reaction and aptamer based biosensing. These results provide important insight into NP use for various applications under harsh biological and environmental conditions. [ABSTRACT FROM AUTHOR]

Abstract  A fed-batch fermentation process for the production of organophosphorus hydrolase (OPH) (EC 3.1.8.1) by E. coli pET812 was developed in this research. With batch fermentation, the maximum OPH concentrations attained by batch fermentation were as low as 4 × 105 U/l because cell growth and OPH production were inhibited by a high initial concentration of glucose. To develop a fed-batch fermentation process for obtaining higher concentrations of OPH, highly concentrated glucose solution (500 g/l) was added intermittently or continuously to increase the carbon source concentration. Eventually, 3.2 × 106 U/l of OPH was produced with fed-batch fermentation in 24 h. This was eight times higher than the yield with conventional batch fermentation. A total concentration of 399–441 mg of OPH was produced/l, which was four times higher than that reported when using E. coli. Nearly half (44%) of the produced OPH was secreted into the culture solution. [ABSTRACT FROM AUTHOR]

Background and Objectives: Hizikia fusiformis is widely used in oriental health food in Japan, China, and Korea, and is known for its anti-oxidation properties. Materials and Method: In this study, we investigated the anti-inflammatory and immune-modulatory effects and mechanisms of Hizikia fusiformis (H. fusiformis) extracts in lipopolysaccharide (LPS)-treated RAW 264.7 cells. RAW 264.7 cells were incubated in the presence of different concentrations of the viscozyme component of H. fusiformis (1, 2, 5, and 10 μg/mL), and changes in expression of pro-inflammatory cytokines (GM-CSF, iNOS, VEGF, and COX-2) were evaluated by real-time PCR and immunoblotting. In addition, the associated signaling pathway including phospho (p)-pNF-κB 65, p-pIkBa, p-p38, and p-p44/42 was also evaluated. Results: The viscozyme component of H. fusiformis downregulated the expression of GM-CSF, iNOS, VEGF, and COX-2 mRNA. The augmented NO and ROS production was decreased by administration of H. fusiformis. The signal intensity of p-pNF- κB 65, p-pIkBa, p-p38, and p-p44/42 protein activated by LPS was ameliorated by administration of the viscozyme fraction in RAW 264.7 cells. Conclusion: These results suggest that H. fusiformis has potential as a therapeutic agent for inflammatory diseases. [ABSTRACT FROM AUTHOR]

The article discusses the fabrications of soft, smart contact lenses with integrations of glucose sensors, wireless power ttransper circuits and display circuits for real-time visualization of sensing signals using stretchable and transparent nanostructures. It suggests that the fabricated soft and smart contact lens offers real-time, wireless operations and with in vivo tests for the monitoring of glucose concentration in tears.

The recent bio-applications (i.e. bio-sensing, tissue engineering and cell proliferation etc.) are driving the fundamental research in carbon based materials with functional perspectives. High stability in carbon based coatings usually demands the high density deposition. However, the standard techniques, used for the large area and high throughput deposition of crystalline carbon films, often require very high temperature processing (typically >800 °C in inert atmosphere). Here, we present a low temperature (<150 °C) pulsed-DC plasma sputtering process, which enables sufficient ion flux to deposit dense unhydrogenated carbon thin films without any need of substrate-bias or post-deposition thermal treatments. It is found that the control over plasma power density and pulsed frequency governs the density and kinetic energy of carbon ions participating during the film growth. Subsequently, it controls the contents of sp³ and sp² hybridizations via conversion of sp² to sp³ hybridization by ion's energy relaxation. The role of plasma parameters on the chemical and surface properties are presented and correlated to the bio-activity. Bioactivity tests, carried out in mouse fibroblast L-929 and Sarcoma osteogenic (Saos-2) bone cell lines, demonstrate promising cell-proliferation in these films. [ABSTRACT FROM AUTHOR]

Strontium-substituted hydroxyapatite (SrHAP) microspheres with three-dimensional (3D) structures were successfully prepared via hydrothermal method using self-assembled poly(aspartic acid) (PASP) as a template. By controlling various parameters, including hydrothermal reaction time, amount of l-aspartic acid (l-Asp), and ratio of Sr ions, we were able to investigate the influences of the additive l-Asp on morphology and properties of final products as well as the role of self-assembled PASP template on the formation of HAP microspheres. The change in the amount of Sr substitution significantly affected the particle size, morphology, and concurrent surface area. This difference caused variation in the drug-release properties. In addition, substitution of Sr ions into Ca ion sites affected luminescence of HAP powders. Particularly, multifunctional SrHAP with molar ratios (Sr/[Ca+Sr]) of 0.25 possessed the strongest luminescence as well as superior drug-loading and sustained-releasing properties. These properties were associated with large surface area and large pore size of the SrHAP. This study suggests that the optical and structural properties of the HAP particles can be carefully tuned by controlling the amount of Sr ions doped into HAP particles during synthesis. This work provides new opportunities to synthesize HAP particles suitable for diverse applications including bone regeneration and drug delivery. [ABSTRACT FROM AUTHOR]

Carbon thin films, having a combination of unique physical and chemical properties, exhibit an interesting biocompatibility and biological response to living entities. Here, the carbon films are developed in the morphology form of nano-domains with nanoscale inter-domain separations, tuned by plasma conditions in the facing target magnetron sputtering process. The wettability and surface energy are found to have a close relation to the inter-domain separations. The chemical structure of carbon films exhibited the relative enhancement of sp3 in comparison to sp2 with the increase of domain separations. The cell-viability of these films shows promising results for L929 mouse fibroblast and Saos-2 bone cells, when inter-domain separation is increased. Electrical conductivity and surface energy are identified to play the key role in different time-scales during the cell-proliferation process. The contribution from electrical conductivity is dominant in the beginning of the cultivation, whereas with the passage of time (~3–5 d) the surface energy takes control over conductivity to enhance the cell proliferation. [ABSTRACT FROM AUTHOR]