A multicomponent sensing ensemble in solution: differentiation between structurally similar analytes.
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Biomedical subjects
Publications and source records attributed to John T McDevitt.
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The development of miniaturized chromatographic systems localized within individual polymer microspheres and their incorporation into a bead-based cross-reactive sensor array platform is reported. The integrated chromatographic and detection concept is based on the creation of distinct functional layers within the microspheres. In this first example of the new methodology, complexing ligands have been selectively immobilized to create "separation" layers harboring an affinity for various metal cations. Additionally, a broadly responsive compleximetric dye is used to yield the "detection" layers that exhibit optical responses in the presence of a wide range of metal cations. Information concerning the identities and concentrations of solution-dissolved metal cations can be drawn from the temporal properties of the beads' optical responses. Varying the nature of the ligand in the separation shell yields a collection of cross-reactive sensing elements well-suited for use in array-based micrototal analysis systems. Accordingly, such beads have been incorporated into the "Electronic Taste Chip" platform and used for discriminating among aqueous metal cation solutions.
Herein we report the combination of a library of resin-bound sensors along with a multicomponent sensor array. This novel combinatorial array sensor system shows selectivity for nucleotide phosphates in solution. The design of the anchored receptor includes a 1,3,5-trisubstituted-2,4,6-triethylbenzene scaffold coupled with peptide libraries. Each chemosensor is placed into a micromachined cavity within a silicon wafer, and the optical changes observed by a charged-coupled device result in near-real-time digital analysis of solutions. A colorimetric displacement assay was performed, and time-dependent imaging studies of the selected sensing ensembles result in a differential responses upon addition of adenosine 5'-triphosphate (ATP), adenosine 5'-monophosphate (AMP), or guanosine 5'-triphosphate (GTP). An advantage to this approach is that it creates an array of sensors that gives a fingerprint response for each analyte. Principal component analysis indicates that the library of chemosensors can differentiate between ATP, GTP, and AMP. On the basis of factor loading values, individual sensors from the library were sequenced to elucidate their chemical composition.
The development of a novel chip-based multianalyte detection system with a cardiac theme is reported. This work follows the initial reports of "electronic taste chips" whereby multiple solution-phase analytes such as acids, bases, metal cations, and biological cofactors were detected and quantitated. The newly fashioned "cardiac chip" exploits a geometry that allows for isolation and entrapment of single polymeric spheres in micromachined pits while providing to each bead the rapid introduction of a series of reagents/washes through microfluidic structures. The combination of these miniaturized components fosters the completion of complex assays with short analysis times using small sample volumes. Optical signals derived from single beads are used to complete immunological tests that yield outstanding assay characteristics. The power and utility of this new methodology is demonstrated here for the simultaneous detection of the cardiac risk factors, C-reactive protein and interleukin-6, in human serum samples. This demonstration represents the first important step toward the development of a useful cardiac chip that targets numerous risk factors concurrently and one that can be customized readily for specific clinical settings.