In-situ quantitative analysis of a prostate-specific antigen (PSA) using a nanomechanical PZT cantilever.
We report on a novel technique of resonant frequency shift measurement based on a nanomechanical cantilever with a PZT actuating layer for label-free detection of a prostate-specific antigen (PSA) in a liquid environment. The nanomechanical PZT thin film cantilever is composed of SiO(2)/Ta/Pt/PZT/Pt/SiO(2) on a SiN(x) supporting layer for simultaneous self-exciting and sensing; it was fabricated using a standard MEMS (micro electromechanical system) process. The specific binding characteristics of the PSA antigen to its antibody, which is immobilized with Calixcrown self-assembled monolayers (SAMs) on a gold surface deposited on a cantilever, are determined to a high sensitivity. For the bioassay in a liquid environment, a liquid test cell with a 20 microl volume reaction chamber has been fabricated, using a bonding technique between poly(dimethyl siloxane) (PDMS) bilayers. An observed trend of resonant frequency change with respect to time could be explained by the binding kinetics due to the Langmuir isotherm and diffusion and by the effects of a small volume reaction chamber. In the saturated regimes, the resonant frequency of the cantilever increased with increase of the PSA concentration in the reaction chamber, showing that the trend of the resonance frequency change was similar to that of the fluorescence results. The saturated resonance frequency shift of the cantilever was proportional to the PSA antigen concentration of analyte solution.
Hwang
Kyo Seon
KS
Microsystem Research Center, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136-761, Republic of Korea.
Lee
Jeong Hoon
JH
Park
Jaebum
J
Yoon
Dae Sung
DS
Park
Jung Ho
JH
Kim
Tae Song
TS
D000906:Antibodies / Q000032:analysis / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000032:analysis / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D019563:Mechanics; D008832:Microchemistry / Q000295:instrumentation* / Q000379:methods; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012996:Solutions; D014159:Transducers; D014732:Vibration
D000906:Antibodies; D000936:Antigen-Antibody Complex; D012996:Solutions; D017430:Prostate-Specific Antigen