title: Real time hybridization studies by resonant waveguide gratings using nanopattern imaging for Single Nucleotide Polymorphism detection.
abstract: 2D imaging of biochips is particularly interesting for multiplex biosensing. Resonant properties allow label-free detection using the change of refractive index at the chip surface. We demonstrate a new principle of Scanning Of Resonance on Chip by Imaging (SORCI) based on spatial profiles of nanopatterns of resonant waveguide gratings (RWGs) and its embodiment in a fluidic chip for real-time biological studies. This scheme allows multiplexing of the resonance itself by providing nanopattern sensing areas in a bioarray format. Through several chip designs we discuss resonance spatial profiles, dispersion and electric field distribution for optimal light-matter interaction with biological species of different sizes. Fluidic integration is carried out with a black anodized aluminum chamber, advantageous in term of mechanical stability, multiple uses of the chip, temperature control and low optical background. Real-time hybridization experiments are illustrated by SNP (Single Nucleotide Polymorphism) detection in gyrase A of E. coli K12, observed in evolution studies of resistance to the antibiotic ciprofloxacin. We choose a 100 base pairs (bp) DNA target (~30 kDa) including the codon of interest and demonstrate the high specificity of our technique for probes and targets with close affinity constants. This work validates the safe applicability of our unique combination of RWGs and simple instrumentation for real-time biosensing with sensitivity in buffer solution of ~10 pg/mm². Paralleling the success of RWGs sensing for cells sensing, our work opens new avenues for a large number of biological studies.
authors.affiliation: Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, kristelle_robin@yahoo.fr.
authors.forename: Kristelle
authors.initials: K
authors.lastname: Bougot-Robin
authors.forename: Rimantas
authors.initials: R
authors.lastname: Kodzius
authors.forename: Weisheng
authors.initials: W
authors.lastname: Yue
authors.forename: Longqing
authors.initials: L
authors.lastname: Chen
authors.forename: Shunbo
authors.initials: S
authors.lastname: Li
authors.forename: Xi Xiang
authors.initials: XX
authors.lastname: Zhang
authors.forename: Henri
authors.initials: H
authors.lastname: Benisty
authors.forename: Weijia
authors.initials: W
authors.lastname: Wen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D027081:DNA Gyrase / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D048168:Escherichia coli K12 / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods; D009693:Nucleic Acid Hybridization / Q000235:genetics; D062308:Optogenetics / Q000295:instrumentation / Q000379:methods; D020641:Polymorphism, Single Nucleotide
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D002939:Ciprofloxacin; D027081:DNA Gyrase