title: Surface-modified ZnSe waveguides for label-free infrared attenuated total reflection detection of DNA hybridization.
abstract: This communication presents a novel label-free biosensing method to monitor DNA hybridization via infrared attenuated total reflection (IR-ATR) spectroscopy using surface-modified ZnSe waveguides. Well-defined carboxyl-terminated monolayers were formed at H-terminated ZnSe by direct photochemical activation. Chemical activation of the acidic function was obtained by using succinimide/carbodiimide linkers. The sequential surface modification reactions were characterized by XPS and IR-ATR spectroscopy. Finally, a single stranded DNA probe with a C6-NH(2) 5' modifier was coupled to the ester-terminated surface via peptide bonding, and the hybridization of the immobilized DNA sequence with its complementary strand was directly evaluated by IR-ATR spectroscopy in the mid-infrared (MIR) spectral regime (3-20 μm) without requiring an additional label. A shift of the vibrational modes corresponding to the phosphodiester and deoxyribose structures of the DNA backbone was observed. Hence, this approach substantiates a novel strategy for label-free DNA detection utilizing mid-infrared spectroscopy as the optical sensing platform.
authors: School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors: Carla S
authors: CS
authors: Riccardi
authors: Dennis W
authors: DW
authors: Hess
authors: Boris
authors: B
authors: Mizaikoff
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002234:Carbodiimides / Q000737:chemistry; D004247:DNA / Q000032:analysis / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D018036:Selenium Compounds / Q000737:chemistry*; D013055:Spectrophotometry, Infrared / Q000379:methods; D013388:Succinimides / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D002234:Carbodiimides; D018036:Selenium Compounds; D013388:Succinimides; D017967:Zinc Compounds; C032620:succinimide; D004247:DNA; C044696:zinc selenide