title: Resonance acoustic microbalance with naked-embedded quartz (RAMNE-Q) biosensor fabricated by microelectromechanical-system process.
abstract: A resonance acoustic microbalance with a naked-embedded quartz (RAMNE-Q) is realized by a microfabrication method, aiming at broader applications of quartz-crystal microbalance (QCM) biosensors. The RAMNE-Q biosensor consists of three layers; a silicon layer with an engraved microchannel and sandwiching glass layers. The naked AT-cut quartz resonator of 9.3 or 28.5 μm thick is located in the microchannel and supported by the silicon micropillars and semicircular walls without fixing, and it is encapsulated by the rigid body. Cupper antennas are used for generating and receiving electromagnetic fields to excite and detect the shear vibration of the quartz oscillator during the solution flow, thereby achieving the noncontact measurement of the resonance frequency. Because of the isolated resonator, the Q factor is high enough (about 1500 at 170-180 MHz) even in the flowing solution. We succeeded in detecting 1 ng/ml human immunoglobulin G in phosphate-buffered-saline solution via Staphylococcus aureus protein A immobilized nonspecifically on the quartz surfaces, demonstrating the high sensitivity and high signal-to-noise ratio of the RAMNE-Q biosensor. It does not require electrodes and is a replacement-free biosensor, and its reusability is confirmed.
authors.affiliation: Graduate School of Engineering Science, Osaka University, Machikaneyama 1-3, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Fumihito
authors.initials: F
authors.lastname: Kato
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ogi
authors.forename: Taiji
authors.initials: T
authors.lastname: Yanagida
authors.forename: Shintaro
authors.initials: S
authors.lastname: Nishikawa
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hirao
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Nishiyama
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D055664:Electrochemical Techniques / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D055616:Microtechnology; D058525:Quartz Crystal Microbalance Techniques; D012680:Sensitivity and Specificity
chemical_list: D007074:Immunoglobulin G