title: Ultraspecific and highly sensitive nucleic acid detection by integrating a DNA catalytic network with a label-free microcavity.
abstract: Nucleic acid detection with label-free biosensors circumvents costly fluorophore functionalization steps associated with conventional assays by utilizing transducers of impressive ultimate detection limits. Despite this technological prowess, molecular recognition at a surface limits the biosensors' sensitivity, specificity, and reusability. It is therefore imperative to integrate novel molecular approaches with existing label-free transducers to overcome those limitations. Here, we demonstrate this concept by integrating a DNA strand displacement circuit with a micron-scale whispering gallery mode (WGM) microsphere biosensor. The integrated biosensor exhibits at least 25-fold improved nucleic acid sensitivity, and sets a new record for label-free microcavity biosensors by detecting 80 pM (32 fmol) of a 22nt oligomer; this improvement results from the catalytic behavior of the circuit. Furthermore, the integrated sensor exhibits extremely high specificity; single nucleotide variants yield 40- to 100-fold lower signal. Finally, the same physical sensor was demonstrated to alternatingly detect 2 different nucleic acid sequences through 5 cycles of detection, showcasing both its reusability and its versatility.
authors.affiliation: Laboratory of Nanophotonics and Biosensing, Max Planck Insitute for the Science of Light, Erlangen, 91058, Germany.
authors.forename: Yuqiang
authors.initials: Y
authors.lastname: Wu
authors.forename: David Yu
authors.initials: DY
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Yin
authors.forename: Frank
authors.initials: F
authors.lastname: Vollmer
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000295:instrumentation*; D002384:Catalysis; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000235:genetics*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000295:instrumentation*; D013194:Staining and Labeling; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D018511:Systems Integration
chemical_list: D004247:DNA
keywords: DNA catalytic circuit; biosensor; oligonucleotides; optical microcavity; single-nucleotide polymorphism detection