title: Ultrathin-film oscillator biosensors excited by ultrafast light pulses.
abstract: Novel thin-film oscillator biosensors are developed using picosecond ultrasound method. 100-nm silicon-nitride thin films and 16-nm Pt thin films are used, and ultrashort light pulses are focused on their surfaces to excite the through-thickness resonance vibrations, which are detected by the delayed probe-light pulses using the optoelastic effect. Their fundamental resonance frequencies are 45 and 132 GHz, corresponding to theoretical mass sensitivities of 5.0×10(-5) and 2.2×10(-5) pg/cm(2)/Hz, respectively. These thin-film biosensors are used for detecting human immunoglobulin G (hIgG) with Staphylococcus aureus protein A nonspecifically immobilized on the film surfaces. Injection of a 5 nM analyte caused 2% decrease in the resonance frequency.
authors.affiliation: Graduate School of Engine Science, Osaka University Machikaneyama 1-3, Toyonaka, Osaka 560-8531, Japan. ogi@me.es.osaka-u.ac.jp
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ogi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kawamoto
authors.forename: Nobutomo
authors.initials: N
authors.lastname: Nakamura
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hirao
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Nishiyama
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D008027:Light; D055096:Optical Devices; D055620:Optical Phenomena; D010984:Platinum; D058525:Quartz Crystal Microbalance Techniques; D017655:Silicon Compounds; D013205:Staphylococcal Protein A / Q000032:analysis; D014732:Vibration
chemical_list: D007074:Immunoglobulin G; D017655:Silicon Compounds; D013205:Staphylococcal Protein A; D010984:Platinum; C032734:silicon nitride