A device for fabricating protein chips by using a surface acoustic wave atomizer and electrostatic deposition

We propose a new advanced fabrication method for protein chips using a surface acoustic wave atomizer and electrostatic deposition, named SAW-ED. A SAW atomizer is utilized in order to spray extremely small droplets, while the electrostatic force and shadow mask are used for collecting the charged particles onto the deposition substrate with the designed pattern. To estimate the quality of SAW-ED, we performed experiments concerning particle-size uniformity, the shapes of protein deposition, protein bioactivity, deposition rate, fluorescent uniformity, spot-size uniformity and collection efficiency. Protein deposition of BSA was formed in a completely dry state and particle diameter ranged from 0.05 to 0.7 mu m. By utilizing an insulator mask, protein patterns with complex shapes were formed with relatively uniform thickness distribution. The deposition of luciferase was conducted and bioluminescence showed its activity was preserved. The chips of multi anti-IgG antibodies were also formed and their specific bioactivity as an immunoglobulin was verified by luminescence immunoassay. The detecting sensitivity reached as low as 1 ng/ml mouse IgG by fluorescence immunoassay. Deposition rate is linear to atomization time. Coefficient of variation in the fluorescence and the mean diameter of SAW-ED spots are 0.0356 and 0.0361 respectively. By using a collimating electrode, the collection efficiency increased up to 33.3%. (c) 2004 Elsevier B.V. All rights reserved.