This paper demonstrates the direct sensing of glucose at physiologically relevant concentrations with surface-enhanced Raman spectroscopy (SERS) on gold film-over-nanosphere (AuFON) substrates functionalized with bisboronic acid receptors. The combination of selectivity in the bisboronic acid receptor and spectral resolution in the SERS data allow the sensors to resolve glucose in high backgrounds of fructose and, in combination with multivariate statistical analysis, detect glucose accurately in the 1-10 mM range. Computational modeling supports assignments of the normal modes and vibrational frequencies for the monoboronic acid base of our bisboronic acids, glucose and fructose. These results are promising for the use of bisboronic acids as receptors in SERS-based in vivo glucose monitoring sensors.
The fully regioselective reactivity of four new highly substituted silyl aryl triflate aryne precursors in aryne acyl-alkylation, acyl-alkylation/ condensation, and heteroannulation reactions is reported. The application of these more complex arynes provides access to diverse natural product scaffolds and obviates late-stage functionalization of aromatic rings.It has been well established that substituted arynes undergo nucleophilic attack with levels of regioselectivity dependent on the identity of substituents and their locations relative to the reactive aryne triple bond. 1 In our own investigations, we have observed fully regioselective acyl-alkylation 2 and aryne heteroannulation 3 reactions with the aryne (2) generated in situ from a 3-methoxy-substituted silyl aryl triflate (1) (Scheme 1). Each of these products (3-6) stems presumably from initial attack at C(1) of the aryne (2), which suggests that the o-methoxy substituent electronically polarizes the triple bond and sterically shields the adjacent atom to favor this reactivity. More recently, we have been able to exploit this selectivity in aryne acyl-alkylation/condensation sequences to produce either substituted hydroxynaphthoquinones (6) or hydroxyisoquinolines (5). 4 These observations led us to investigate whether more highly functionalized silyl aryl triflates would also exhibit the predictable regioselectivity seen for precursor 1.Specifically, we chose to examine whether unsymmetrically substituted polyalkyoxy silyl aryl triflates would react
The competition of two drugs for the same metabolizing enzyme is a common mechanism for drug-drug interactions that can lead to altered kinetics in drug metabolism and altered elimination rates in vivo. With the prevalence of multidrug therapy, there is great potential for serious drug-drug interactions and adverse drug reactions. In an effort to prevent adverse drug reactions, the FDA mandates the evaluation of the potential for metabolic inhibition by every new chemical entity. Conventional methods for assaying drug metabolism (e.g., those based on HPLC) have been established for measuring drug-drug interactions; however, they are low-throughput. Here we describe an approach to measure the catalytic activity of CYP2C9 using the high-throughput technique self-assembled monolayers for matrix-assisted laser desorption-ionization (SAMDI) mass spectrometry. We measured the kinetics of CYP450 metabolism of the substrate, screened a set of drugs for inhibition of CYP2C9 and determined the Ki values for inhibitors. The throughput of this platform may enable drug metabolism and drug-drug interactions to be interrogated at a scale that cannot be achieved with current methods.
The tetracyclic core of the integrastatin natural products has been prepared in a convergent and rapid manner. Our strategy relies upon a palladium(II)-catalyzed oxidative cyclization to form the central [3.3.1]-dioxabicycle of the natural product core. Overall, the core has been completed in only 4 linear steps from known compounds.
The interactions of adherent cells with their insoluble extracellular matrices are complex and challenging to study in the laboratory. Approaches from interface science have been important to preparing models of the biological matrix wherein discreet ligands are immobilized and interact with cellular receptors. A recent theme has been to develop dynamic substrates, where the activities of immobilized ligands can be modulated in real-time during cell culture. This short opinion reviews the strategies to manipulate ligand activity, highlights recent work that has advanced the field and discusses the applications that have been enabled. This work suggests that dynamic substrates will continue to find important uses in basic and applied biointerfaces.
This article describes a photochemical approach for independently patterning multiple proteins to an inert substrate, particularly for studies of cell adhesion. A photoactivatable chloropyrimidine ligand was employed for covalent immobilization of SnapTag fusion proteins on self-assembled monolayers of alkanethiolates on gold. A two-step procedure was used: first, patterned UV illumination of the surface activated protein capture ligands, and second, incubation with a SnapTag fusion protein bound to the surface in illuminated regions. Two different fluorescent proteins were patterned in registry with features of 400 nm in size over a 1 mm2 area. An example is given wherein an anti-carcinoembryonic antigen (anti-CEA) scFv antibody was patterned to direct the selective attachment of a human cancer cell line that express the CEA antigen. This method enables the preparation of surfaces with control over the density and activity of independently patterned proteins.
Dynamic substrates for cell culture control the spatial and temporal presentation of extracellular matrix ligands that interact with adherent cells. This paper reports a photoactive surface chemistry that can repeatedly activate regions of the substrate for cell adhesion, spreading, and migration. The approach uses self-assembled monolayers presenting the integrin ligand RGD that is caged with a nitrophenyl-based photoprotecting group. The group is also modified with a maltoheptaose oligosaccharide to prevent nonspecific protein adsorption and cell attachment. The peptide is uncaged when irradiated with a laser source at 405 nm on a microscope to reveal micron-size regions for single cell attachment. This method is applied to studies of gap junction-mediated communication between two neighboring cells and requires the patterning of an initial receiver cell population and then the patterning of a second sender population to give a culture wherein each pair of cells are separated by 30 μm. Finally, activation of the region between the cells permits cell–cell contact and gap junction assembly between the sender and receiver cells. This example demonstrates the broad relevance of this method to studying complex phenotypes in cell culture.
In the ongoing COVID-19 pandemic, detecting the appearance and spread of variants of concern (VOC) is a critical capability in the fight to quell the virus and return to normalcy. Genomic surveillance of the emergence, propagation, and geographical spread of VOCs is thus an important tool for public health officials and government leaders to make policy decisions and advise the public. As part of our role as a major SARS-CoV-2 diagnostic testing facility in New York City, the Pandemic Response Lab (PRL) has been performing genomic surveillance on the large number of positive samples processed by the facility on a daily basis from throughout the New York metropolitan area. Here we describe the development and optimization of a high-throughput SARS-CoV-2 genome sequencing facility at PRL serving New York City.
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