Detection Of Different Analytes Research Articles

Versatile biosensor surface based on peptide nucleic acid with label free and total internal reflection fluorescence detection for quantification of endocrine disruptors

Abstract In recent years, the simultaneous detection of hundreds of substances has become increasingly important in medical diagnostics and environmental monitoring. This calls for methods that allow fast and simultaneous measurement of many analytes and require only a minimum of attendance. Biosensor-applications including easy implementation and long-term stability of the sensor element are more and more designed to meet these demands. In this paper, a surface based on covalently immobilised peptide nucleic acid (PNA) for the detection of different endocrine disruptors is used. The surface was characterised with a label free detection system, the reflectometric interference spectroscopy (RIfS). A hybridisation capacity with DNA oligonucleotides of 1.3 ng/mm 2 (180 fmol/mm 2 ) on PNA-surfaces was achieved. The PNA transducer is stable for half a year and for more than 300 regeneration steps. With this modified surface various environmentally relevant endocrine disruptors could be detected by an immunoassay. The detection is done on an optical waveguide system, based on total internal reflection fluorescence (TIRF) by using an auxiliary-system consisting of a conjugate which is formed of DNA–oligomers and analyte-derivatives. The successive detection of different analytes on the same spot by using this auxiliary-system is demonstrated as one application of multianalyte detection. Quantification of different endocrine disruptors on the same PNA-surface is demonstrated by three calibration curves.

Use of DNA hybridization for antiviral susceptibility testing : M. Forman, Johns Hopkins Hospital, Baltimore, MD. USA, J.D. Jollick, Diagnostic Hybrids, Inc., Athens, OH, USA, D. Scholl, Diagnostic Hybrids, Inc., Athens, OH, USA, P. Charache, Johns Hopkins Hospital, Baltimore, MD, USA

Microarrays/arrays/DNA chips are frequently being used to detect different analytes in biosensors. This chapter analyzes the detection of different analytes on microarrays/arrays/DNA chips and analyzes the kinetics of binding and dissociation (hybridization) in such biosensors through fractal analysis. Both single- and dual-fractal analysis are used to analyze binding (hybridization) of different targets (400 nM) in solution to a probe immobilized on a DNA chip surface, binding (hybridization) of different concentrations of free-DNA in solution to a 22-mer strand (bound DNA) immobilized via a phenylene-diisocyanate linker molecule on a glass substrate, SA-HRP (streptavidin-horseradish peroxide) in solution to a capture probe on a QCM (quartz crystal microbalance) electrode along with a detection probe, a complementary and a noncomplementary (three-base mismatch strand) DNA in solution to a 30-mer 30-thiolated DNA strand immobilized on an electrochemical enzymatic genosensor, binding (hybridization) of a perfectly matched oligonucleotide (ODN-P) and a noncomplementary ODN (ODN-N) to an electrochemical sensor with an EST2-A34 reporter. Fractal analyses are also used to discuss the binding and dissociation during PNA–DNA hybridization, PNA–DNA hybridization, and binding (hybridization) of different concentrations of ss DNA in solution preincubated with prehybridized 22-nt FQ duplex to a “broken beacon” immobilized on a sensor surface. Fractal analysis can be considered as an alternate method of analyzing the kinetics of binding and dissociation during hybridization in these types of analyte–receptor reactions occurring on biosensor surfaces.

Evaluation of anti-varicella-zoster virus activity of acyclovir by a nucleic acid hybridization assay : L.R. Stanberry, and M.G. Myers. Children's Hospital Research Foundation, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A.

Microarrays/arrays/DNA chips are frequently being used to detect different analytes in biosensors. This chapter analyzes the detection of different analytes on microarrays/arrays/DNA chips and analyzes the kinetics of binding and dissociation (hybridization) in such biosensors through fractal analysis. Both single- and dual-fractal analysis are used to analyze binding (hybridization) of different targets (400 nM) in solution to a probe immobilized on a DNA chip surface, binding (hybridization) of different concentrations of free-DNA in solution to a 22-mer strand (bound DNA) immobilized via a phenylene-diisocyanate linker molecule on a glass substrate, SA-HRP (streptavidin-horseradish peroxide) in solution to a capture probe on a QCM (quartz crystal microbalance) electrode along with a detection probe, a complementary and a noncomplementary (three-base mismatch strand) DNA in solution to a 30-mer 30-thiolated DNA strand immobilized on an electrochemical enzymatic genosensor, binding (hybridization) of a perfectly matched oligonucleotide (ODN-P) and a noncomplementary ODN (ODN-N) to an electrochemical sensor with an EST2-A34 reporter. Fractal analyses are also used to discuss the binding and dissociation during PNA–DNA hybridization, PNA–DNA hybridization, and binding (hybridization) of different concentrations of ss DNA in solution preincubated with prehybridized 22-nt FQ duplex to a “broken beacon” immobilized on a sensor surface. Fractal analysis can be considered as an alternate method of analyzing the kinetics of binding and dissociation during hybridization in these types of analyte–receptor reactions occurring on biosensor surfaces.