AVS 49th International Symposium
    Applied Surface Science Friday Sessions
       Session AS+MM+BI-FrM

Paper AS+MM+BI-FrM6
Selective Thermal Patterning of Self-Assembled DNA Monolayers on MEMS-based Microheater Devices

Friday, November 8, 2002, 10:00 am, Room C-106

Session: BioMEMS and Medical Devices
Presenter: T.H. Huang, National Institute of Standards and Technology
Authors: T.H. Huang, National Institute of Standards and Technology
N. Ku, Montgomery Blair High School
R.E. Cavicchi, National Institute of Standards and Technology
M.J. Tarlov, National Institute of Standards and Technology
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We report the selective patterning of self-assembled thiolated DNA probes on gold-coated microheater devices using temperature. The goal of our investigation is to utilize the rapid heating and cooling capabilities of MEMS-based microheaters to prepare biosensing surfaces and to monitor reactions such as DNA hybridization, melting and polymerase chain reaction (PCR). In this study, the self-assembly of thiolated-DNA probes on gold microheater array (four element array) is used as the model system. Modified DNA probes (5' end with disulfide and 3' end with fluorescein) are selectively immobilized onto the gold surface in several steps. First, a passivating layer consists of 1-mercapto-6-hexanol (MCH) is self-assembled onto the gold microheaters. The temperature for one the four heaters is elevated to ca. 200 @super o@C to drive off the MCH. Then the thiolated DNA probes are deposited onto the freshly exposed bare gold surface. Using this method, one can use temperature to selectively deposit different DNA probes on specific heaters. The presence of the DNA probes on the surface is detected using fluorescence microscopy. In order to use the DNA-microheater surface to monitor DNA melting reactions or PCR (which require cycling to high temperatures), it is important for the probe to be thermally stable at the operating temperatures (i.e. 85 @super o@C). We will also present results on the thermal stability of thiolated DNA monolayers on gold.