title: Fiber optofluidic biosensor for the label-free detection of DNA hybridization and methylation based on an in-line tunable mode coupler.
abstract: An optical fiber optofluidic biosensor for the detection of DNA hybridization and methylation has been proposed and experimentally demonstrated. An in-line fiber Michelson interferometer was formed in the photonic crystal fiber. A micrhole in the collapsed region, which combined the tunable mode coupler and optofluidic channel, was fabricated by using femtosecond laser micromachining. The mode field diameter of the guided light is changed with the refractive index in the optofluidic channel, which results in the tunable coupling ratio. Label-free detections of the DNA hybridization and methylation have been experimentally demonstrated. The probe single stranded DNA (ssDNA) was bound with the surface of the optofluidic channel through the Poly-l-lysine layer, and the hybridization between a short 22-mer probe ssDNA and a complementary target ssDNA was carried out and detected by interrogating the fringe visibility of the reflection spectrum. Then, the DNA methylation was also detected through the binding between the methylated DNA and the 5-methylcytosine (5-mC) monoclonal antibody. The experiments results demonstrate that the limit of detection of 5nM is achieved, establishing the tunable mode coupler as a sensitive and versatile biosensor. The sensitive optical fiber optofluidic biosensor possesses high specificity and low temperature cross-sensitivity.
authors.affiliation: State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Dan-Feng
authors.initials: DF
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Cheng
authors.affiliation: School of Opto-Electronics, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Laser Micro/Nano Fabrication Laboratory, Beijing Institute of Technology, 100081, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Jian-Dong
authors.initials: JD
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China. Electronic address: zhimei-qi@mail.ie.ac.cn.
authors.forename: Zhi-Mei
authors.initials: ZM
authors.lastname: Qi
mesh_terms: D004247:DNA / Q000032:analysis / Q000235:genetics*; D019175:DNA Methylation / Q000235:genetics; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D017403:In Situ Hybridization / Q000295:instrumentation*; D007368:Interferometry / Q000295:instrumentation*; D056656:Lab-On-A-Chip Devices; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling
chemical_list: D004247:DNA
keywords: DNA hybridization detection; DNA methylation detection; Optofluidic biosensor; Photonic crystal fiber; Tunable mode coupler