Oxidative stress modulating nanomaterials and their biochemical roles in nanomedicine.

Many pathological conditions are predominantly associated with oxidative stress, arising from reactive oxygen species (ROS); therefore, the modulation of redox activities has been a key strategy to restore normal tissue functions. Current approaches involve establishing a favorable cellular redox environment through the administration of therapeutic drugs and redox-active nanomaterials (RANs). In particular, RANs not only provide a stable and reliable means of therapeutic delivery but also possess the capacity to finely tune various interconnected components, including radicals, enzymes, proteins, transcription factors, and metabolites.

A 3D In-vitro model of the human dentine interface shows long-range osteoinduction from the dentine surface.

Emerging regenerative cell therapies for alveolar bone loss have begun to explore the use of cell laden hydrogels for minimally invasive surgery to treat small and spatially complex maxilla-oral defects. However, the oral cavity presents a unique and challenging environment for in vivo bone tissue engineering, exhibiting both hard and soft periodontal tissue as well as acting as key biocenosis for many distinct microbial communities that interact with both the external environment and internal body systems, which will impact on cell fate and subsequent treatment efficacy. Herein, we design and bioprint a facile 3D in vitro model of a human dentine interface to probe the effect of the dentine surface on human mesenchymal stem cells (hMSCs) encapsulated in a microporous hydrogel bioink.

Genomic Analysis and Surveillance of Respiratory Syncytial Virus Using Wastewater-Based Epidemiology.

Respiratory syncytial virus (RSV) causes severe infections in infants, immunocompromised or elderly individuals resulting in annual epidemics of respiratory disease. Currently, limited clinical surveillance and the lack of predictable seasonal dynamics limit the public health response. Wastewater-based epidemiology (WBE) has recently been used globally as a key metric in determining prevalence of severe acute respiratory syndrome coronavirus 2 in the community, but its application to other respiratory viruses is limited.

Tubular nanomaterials for bone tissue engineering.

Nanomaterial composition, morphology, and mechanical performance are critical parameters for tissue engineering. Within this rapidly expanding space, tubular nanomaterials (TNs), including carbon nanotubes (CNTs), titanium oxide nanotubes (TNTs), halloysite nanotubes (HNTs), silica nanotubes (SiNTs), and hydroxyapatite nanotubes (HANTs) have shown significant potential across a broad range of applications due to their high surface area, versatile surface chemistry, well-defined mechanical properties, excellent biocompatibility, and monodispersity. These include drug delivery vectors, imaging contrast agents, and scaffolds for bone tissue engineering.

Stereospecific Iron-Catalyzed Carbon(sp)-Carbon(sp) Cross-Coupling with Alkyllithium and Alkenyl Iodides.

An efficient synthetic protocol involving iron-catalyzed cross-coupling reactions between organolithium compounds and alkenyl iodides as key coupling partners was achieved. More than 30 examples were obtained with moderate to good yields and high stereospecificity. Gram-scale and synthetic applications of this procedure are recorded herein to demonstrate its feasibility and potential utilization.

Advancing Community-Based Participatory Research to Address Health Disparities in Hawai'i: Perspectives from Academic Researchers.

Community-based participatory research (CBPR) continues to be recognized as an effective research approach in which academic researchers work in partnership with communities to address health disparities. Although the literature suggests benefits associated with CBPR, more needs to be done to advance CBPR to ultimately reduce health disparities. Hawai'i presents a research-rich opportunity for CBPR because of its ethnic diversity and geographic location, resulting in close-knit communities with unique experiences and concerns.

Identification of inhibitors regulating cell proliferation and FUS-DDIT3 expression in myxoid liposarcoma using combined DNA, mRNA, and protein analyses.

FUS-DDIT3 belongs to the FET (FUS, EWSR1, and TAF15) family of fusion oncogenes, which collectively are considered to be key players in tumor development. Even though over 90% of all myxoid liposarcomas (MLS) have a FUS-DDIT3 gene fusion, there is limited understanding of the signaling pathways that regulate its expression. In order to study cell proliferation and FUS-DDIT3 regulation at mRNA and protein levels, we first developed a direct cell lysis approach that allows DNA, mRNA, and protein to be analyzed in the same sample using quantitative PCR, reverse transcription quantitative qPCR and proximity ligation assay, respectively.

Homogeneous and digital proximity ligation assays for the detection of toxins A and B.

Background: The proximity ligation assay (PLA) detects proteins via their interaction with pairs of proximity probes, which are antibodies coupled to noncomplementary DNA oligonucleotides. The binding of both proximity probes to their epitopes on the target protein brings the oligonucleotides together, allowing them to be bridged by a third oligonucleotide with complementarity to the other two. This enables their ligation and the detection of the resulting amplicon by real-time quantitative PCR (qPCR), which acts as a surrogate marker for the protein of interest.

Is cell culture a risky business? Risk analysis based on scientist survey data.

Cell culture is a technique that requires vigilance from the researcher. Common cell culture problems, including contamination with microorganisms or cells from other cultures, can place the reliability and reproducibility of cell culture work at risk. Here we use survey data, contributed by research scientists based in Australia and New Zealand, to assess common cell culture risks and how these risks are managed in practice.

Enhanced sub-micron colloidal particle separation with interdigitated microelectrode arrays using mixed AC/DC dielectrophoretic scheme.

Dielectrophoretic separation of particles finds a variety of applications in the capture of species such as cells, viruses, proteins, DNA from biological systems, as well as other organic and inorganic contaminants from water. The ability to capture particles is constrained by poor volumetric scaling of separation force with respect to particle diameter, as well as the weak penetration of electric fields in the media. In order to improve the separation of sub-micron colloids, we present a scheme based on multiple interdigitated electrode arrays under mixed AC/DC bias.

A regenerable oxide-based H2S adsorbent with nanofibrous morphology.

Hydrogen sulphide is found in raw fuels such as natural gas and coal/biomass-derived syngas. It is poisonous to catalysts and corrosive to metals and therefore needs to be removed. This is often achieved using metal oxides as reactive adsorbents, but metal oxides perform poorly when subjected to repeated cycles of sulphidation and re-oxidation as a result of complex structural and chemical changes.

Nano-fabrication with a flexible array of nano-apertures.

We report fabrication and use of a flexible array of nano-apertures for photolithography on curved surfaces. The batch-fabricated apertures are formed of metal-coated silicone tips. The apertures are formed at the end of the silicone tips by either electrochemical etching of the metal or plasma etching of a protective mask followed by wet chemical etching.

Synthesis, characterization, and photoactivity of Ta2O5-grafted SiO2 nanoparticles.

Herein, we discuss the synthesis as well as material and photochemical characterization of nanometer-sized Ta(2)O(5) decorated, in a controlled fashion, on top of 20 nm diameter SiO(2) particles to yield a composite oxide with a tunable band-gap width. Particular emphasis is paid to control of particle size, and control of the distribution of the overlying oxide. The nanoscale dimension imparts a high surface area and introduces quantum confinement effects that displace the conduction band more negatively and the valence band more positively on the electrochemical scale of potentials.

Applications of quantitative polymerase chain reaction protein assays during reprogramming.

The capability to reprogram human somatic cells to induced pluripotent stem cells (iPSCs) has opened a new area of biology and provides unprecedented access to patient-specific iPSCs for drug screening, disease models, and transplantation therapies. Although the process of obtaining iPSC lines is technically simple, reprogramming is a slow and inefficient process consisting of a largely uncharacterized chain of molecular events. To date, researchers have reported a wide range of reprogramming efficiencies, from <0.

Dynamic response of AFM cantilevers to dissimilar functionalized silica surfaces in aqueous electrolyte solutions.

The dynamic response of an oscillating microcantilever with a gold-coated tip interacting with dissimilar functionalized silica surfaces was studied in electrolyte solutions with pH ranging from 4 to 9. Silica surfaces were chemically modified, yielding dissimilar surfaces with -Br, -NH(2), and -CH(3) functional group terminations. The relative hydrophobicity of the surfaces was characterized by contact angle measurements.

Expanding applications of protein analysis using proximity ligation and qPCR.

The correlation of gene and protein expression changes in biological systems has been hampered by the need for separate sample handling and analysis platforms for nucleic acids and proteins. In contrast to the simple, rapid, and flexible workflow of quantitative PCR (qPCR) methods, which enable characterization of several classes of nucleic acid biomarkers (i.e.

An inorganic-organic proton exchange membrane for fuel cells with a controlled nanoscale pore structure.

Proton exchange membrane fuel cells have the potential for applications in energy conversion and energy storage, but their development has been impeded by problems with the membrane electrode assembly. Here, we demonstrate that a silicon-based inorganic-organic membrane offers a number of advantages over Nafion--the membrane widely used as a proton exchange membrane in hydrogen fuel cells--including higher proton conductivity, a lack of volumetric size change, and membrane electrode assembly construction capabilities. Key to achieving these advantages is fabricating a silicon membrane with pores with diameters of approximately 5-7 nm, adding a self-assembled molecular monolayer on the pore surface, and then capping the pores with a layer of porous silica.

Nanoporous silica-water interfaces studied by sum-frequency vibrational spectroscopy.

Using sum-frequency vibrational spectroscopy, we found that water structure at nanoporous silica/water interfaces depended on the nanoporous film structure. For a periodic, self-assembled nanoporous film with monosized 2 nm pores occupying 20% of the top surface area, the surface vibrational spectrum was dominated by water in contact with silica, bare or covered by silane, at the top surface. It resembled the spectral characteristic of the hydrophilic water/silica or the hydrophobic water/silane interface.

Partially buried microcolumns for micro gas analyzers.

This article demonstrates the feasibility of making a partially buried micro gas chromatography (micro-GC) column with a rounded channel wall profile, which enables coating the stationary phase more uniformly and shows better separation characteristics than a square deep reactive ion etched (DRIE) wall profile. A buried structure fabrication method was adapted to fabricate 34 cm long, 165 microm wide, and 65 microm deep partially buried microcolumns, which had a unique rounded microcolumn wall profile similar to that of a flattened circular tube. The separation characteristics were compared to that of a 34 cm long, 100 microm x 100 microm square DRIE microcolumn, which had a similar hydraulic diameter.

Multidimensional separation of chiral amino acid mixtures in a multilayered three-dimensional hybrid microfluidic/nanofluidic device.

Microscale total analysis systems (microTAS) allow high-throughput analyses by integrating multiple processes, parallelization, and automation. Here we combine unit operations of microTAS to create a device that can perform multidimensional separations using a three-dimensional hybrid microfluidic/nanofluidic device composed of alternating layers of patterned poly(methyl methacrylate) and nanocapillary array membranes constructed from nuclear track-etched polycarbonate. Two consecutive electrophoretic separations are performed, the first being an achiral separation followed by a chiral separation of a selected analyte band.

Effect of solution concentration, surface bias and protonation on the dynamic response of amplitude-modulated atomic force microscopy in water.

The dynamic response of amplitude-modulated atomic force microscopy (AM-AFM) is studied at the solid/water interface with respect to changes in ionic concentration, applied surface potential, and surface protonation. Each affects the electric double layer in the solution, charge on the tip and the sample surface, and thus the forces affecting the dynamic response. A theoretical model is developed to relate the effective stiffness and hydrodynamic damping of the AFM cantilever that is due to the tip/surface interaction with the phase and amplitude signals measured in the AM-AFM experiments.

Micromachined GC columns for fast separation of organophosphonate and organosulfur compounds.

This article demonstrates how to prepare microfabricated columns (microcolumns) for organophosphonate and organosulfur compound separation that rival the performance of commercial capillary columns. Approximately 16,500 theoretical plates were generated with a 3 m long OV-5-coated microcolumn with a 0.25 microm phase thickness using helium as the carrier gas at 20 cm/s.

Immobilization of DNAzyme catalytic beacons on PMMA for Pb2+ detection.

Due to the numerous toxicological effects of lead, its presence in the environment needs to be effectively monitored. Incorporating a biosensing element within a microfluidic platform enables rapid and reliable determinations of lead at trace levels. A microchip-based lead sensor is described here that employs a lead-specific DNAzyme (also called catalytic DNA or deoxyribozyme) as a recognition element that cleaves its complementary substrate DNA strand only in the presence of cationic lead (Pb(2+)).

Mechanical response of a living human epidermal keratinocyte sheet as measured in a composite diaphragm inflation experiment.

Sheets of normal human epidermal keratinocytes (NHEKs) were reconstituted in vitro on tensed but highly compliant, freestanding polydimethylsiloxane (PDMS) membranes, 5.0 mm in diameter and 10 mum thick. NHEK-PDMS composite diaphragm (CD) specimens were then subjected to cyclical axisymmetric inflation tests to investigate epithelial sheet rheology under conditions of physiologically severe deformations (~50% nominal polar biaxial strains).