Strand Displacement Probes Combined with Isothermal Nucleic Acid Amplification for Instrument-Free Detection from Complex Samples

Sensitive and specific detection of pathogens via nucleic acid amplification is currently constrained to laboratory settings and portable equipment with costly fluorescent detectors. Nucleic acid-detecting lateral flow immunoassay strips (LFIAs) offer a low-cost visual transduction strategy at points of need. Unfortunately, these LFIAs frequently detect amplification byproducts that can yield spurious results which can only be deciphered through statistical analysis. We integrated customizable strand displacement probes into standard loop mediated isothermal amplification (LAMP) assays to prevent byproduct capture on commercial LFIAs. We find that combining strand displacement with LAMP (SD-LAMP) yields LFIA test band intensities that can be unequivocally interpreted by human subjects without additional instrumentation, thereby alleviating the need for a portable reader’s analysis. Using SD-LAMP, we capture target amplicons on commercially available LFIAs from as few as 3.5 <i>Vibrio cholerae</i> and 2 750 <i>Escherichia coli</i> bacteria without false positive or false negative interpretation. Moreover, we demonstrate that LFIA capture of SD-LAMP products remain specific even in the presence of complex sample matrixes, providing a significant step toward reliable instrument-free pathogen detection outside of laboratories

Grundlagen und Anwendungen mehrelementiger pyroelektrischer Sensorsysteme (GAMPYS). Teilvorhaben: Sensortechnologien und Messtechnik pyroelektrischer Mehrelementsensoren Abschlussbericht

Pyroelectric single-element and multielement infrared sensors for application in pyrometry, gas analysis and thermography have been developed and tested using lithium tantalate LiTaO_3 as the pyroelectricum. LiTaO_3 wafers were prepared and their pyroelectric and dielectric properties were characterized for different chip layouts. Chip thickness of &lt;5 #mu#m was achieved by ion beam etching. INDAB (induced absorption) layers obtained by on-chip layering of LiTaO_3 wafers and chips were structurated by the lift-off technique. A high-sensitivity single-element sensor, 4-channel and 2-channel multispectral sensors and a 128-element-line sensor were constructed and the sensor characteristics of these prototypes were measured as a function of ambient temperature and chopper frequency. (WEN)SIGLEAvailable from TIB Hannover: F97B596 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman