title: Kinetic studies of microfabricated biosensors using local adsorption strategy.
abstract: Micro/nano scale biosensors integrated with the local adsorption mask have been demonstrated to have a better limit of detection (LOD) and less sample consumptions. However, the molecular diffusions and binding kinetics in such confined droplet have been less studied which limited further development and application of the local adsorption method and imposed restrictions on discovery of new signal amplification strategies. In this work, we studied the kinetic issues via experimental investigations and theoretical analysis on microfabricated biosensors. Mass sensitive film bulk acoustic resonator (FBAR) sensors with hydrophobic Teflon film covering the non-sensing area as the mask were introduced. The fabricated masking sensors were characterized with physical adsorption of bovine serum albumin (BSA) and specific binding of antibody and antigen. Over an order of magnitude improvement on LOD was experimentally monitored. An analytical model was introduced to discuss the target molecule diffusion and binding kinetics in droplet environment, especially the crucial effects of incubation time, which has been less covered in previous local adsorption related literatures. An incubation time accumulated signal amplification effect was theoretically predicted, experimentally monitored and carefully explained. In addition, device optimization was explored based on the analytical model to fully utilize the merits of local adsorption. The discussions on the kinetic issues are believed to have wide implications for other types of micro/nano fabricated biosensors with potentially improved LOD.
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China.
authors.forename: Menglun
authors.initials: M
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China.
authors.forename: Jingze
authors.initials: J
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Pang
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China. Electronic address: haozhang@tju.edu.cn.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China.
authors.forename: Daihua
authors.initials: D
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Precision Measuring Technology & Instruments, College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China. Electronic address: xduan@tju.edu.cn.
authors.forename: Xuexin
authors.initials: X
authors.lastname: Duan
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D000327:Adsorption; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation*; D002417:Cattle; D004058:Diffusion; D004867:Equipment Design; D007074:Immunoglobulin G / Q000737:chemistry; D007700:Kinetics; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000737:chemistry
chemical_list: D007074:Immunoglobulin G; D012710:Serum Albumin, Bovine
keywords: Binding kinetics; Biosensor; FBAR; Local adsorption; Signal amplification