In-situ quantitative analysis of a prostate-specific antigen (PSA) using a nanomechanical PZT cantilever

Kyo Seon Hwang, Jeong Hoon Lee, Jaebum Park, Dae Sung Yoon, Jung Ho Park, Tae Song Kim

Research output: Contribution to journalArticle

118 Citations (Scopus)

Abstract

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 SiO2/Ta/Pt/ PZT/Pt/SiO2 on a SiNx 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 μl 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.

Original languageEnglish
Pages (from-to)547-552
Number of pages6
JournalLab on a Chip
Volume4
Issue number6
DOIs
Publication statusPublished - 2004 Dec

ASJC Scopus subject areas

  • Bioengineering
  • Biochemistry
  • Chemistry(all)
  • Biomedical Engineering

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