Immunoassays make use of highly specific antigen-antibody binding and provide sensitive ways to detect a wide range of biomacromolecules, bacteria, viruses, and small molecules. There are a range of types of immunoassay systems including single analyte sensors, 96well plate formats, arrays, microfluidic sensors, microfluidic arrays, etc. A big target is encompassed by medical diagnostic biomarkers, which are "molecules that can be measured objectively as indicators of normal or disease processes and responses to therapeutic intervention". 1 Accurate, low-cost measurements of multiple proteins are major applications of immunoarrays that are critical for future early detection and monitoring of cancer and other diseases. Multiplexing is very important, since panels of biomarker proteins, as opposed to single biomarkers, are required to provide sufficient information content for reliable disease diagnostics.

Nitrosamine metabolites resulting from cigarette smoking and E-cigarette (E-cig) vaping cause DNA damage that can lead to genotoxicity. While DNA adducts of metabolites of nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosonornicotine (NNN) are well-known tobacco-related cancer biomarkers, only a few studies implicate NNN and NNK in DNA oxidation in humans. NNK and NNN were found in the urine of E-cigarette users who never smoked cigarettes. This paper proposes the first chemical pathways of DNA oxidation driven by NNK and NNN metabolites in redox reactions with Cu 2+ and NADPH leading to reactive oxygen species (ROS). A microfluidic array with thin films of DNA and metabolic enzymes that make metabolites of NNN and NNK in the presence of Cu 2+ and NADPH was used to estimate relative rates of DNA oxidation. Detection by electrochemiluminescence (ECL) employed a new ECL dye [Os(tpy-benz-COOH) 2 ] 2+ that is selective for and sensitive to the primary DNA oxidation product 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) in DNA. Enzyme−DNA films on magnetic beads were used to produce nitrosamine metabolites that enter ROS-forming redox cycles with Cu 2+ and NADPH, and liquid chromatography−mass spectrometry (LC−MS) was used to quantify 8-oxodG and identify metabolites. ROS were detected by optical sensors. Metabolites of NNK and NNN + Cu 2+ + NADPH generated relatively high rates of DNA oxidation. Lung is the exposure route in smoking and vaping, human lung tissue contains Cu 2+ and NADPH, and lung microsomal enzymes gave the highest rates of DNA oxidation in this study. Also, E-cigarette vapor contains 6-fold more copper than that in cigarette smoke, which could exacerbate DNA oxidation.

We report the synthesis of ordered mesoporous ceria (mCeO2) with highly crystallinity and thermal stability using hybrid polymer templates consisting of organosilanes. Those organosilane-containing polymers can convert into silica-like nanostructures that further serve as thermally stable and mechanically strong templates to prevent the collapse of mesoporous frameworks during thermal-induced crystallization. Using a simple evaporation-induced self-assembly process, control of the interaction between templates and metal precursors allows the co-self-assembly of polymer micelles and Ce3+ ions to form uniform porous structures. The porosity is well-retained after calcination up to 900 oC. After the thermal engineering at 700 oC for 12 h (mCeO2-700-12 h), mCeO2 still has a specific surface area of 96 m2/g with a pore size of 14 nm. mCeO2 is demonstrated to be active for electrochemical oxidation of sulfite. mCeO2-700-12 h with a perfect balance of crystallinity and porosity shows the fastest intrinsic activity that is about 84 times more active than bulk CeO2 and 5 times more active than mCeO2 that has a lower crystallinity.

“The TOXI Chemical Exposures and Impact on Health” session at the 2020 Fall ACS meeting presented analytical and biological approaches, advancing our understanding of legacy and emerging chemical pollutants and their impact on human health.

Enzymes as catalysts in organic syntheses can provide high regio‐ and stereo‐selectivity, which is often not possible with chemical catalysts. Biocatalysis with iron heme enzymes has proven efficient when the enzyme is sequestered in thin films. An added feature is improved stability. For example, peroxidases chemically crosslinked in poly‐lysine in films on silica nanoparticles were stable for 9 hrs or more at 90 °C, and were used for biocatalysis up to 90 °C. We show here for a series of para‐substituted phenols, single nitro‐phenol products can be selectively synthesized using biocatalytic magnetic beads coated with horseradish peroxidase (HRP) crosslinked in polylysine films. Nitrophenols moieties are important as synthetic intermediates and in drugs. For a series of para‐substituted phenols, biocatalytic nitration gave average turnover numbers 1.8‐fold larger at 75 °C than at 25 °C. For phenols giving <50 % conversion after 1 hr at 25 °C, twice the nitration yield was achieved in 1 hr at 75 °C. Results indicate that this approach should be valuable as a general tool for biocatalytic chemical synthesis.