Gold coating of micromechanical DNA biosensors by pulsed laser deposition

In this work, we describe the gold-coating of silicon microcantilever sensors by pulsed laser deposition (PLD) and their performance as DNA biosensors. To test optimum deposition conditions for coating the sensors, silicon substrates were gold coated by PLD using the fifth harmonic of a Nd:YAG laser...

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Bibliographic Details
Published in:Journal of applied physics 2012-10, Vol.112 (8)
Main Authors: Rebollar, Esther, Sanz, Mikel, Esteves, Carina, Ahumada, oscar, Castillejo, Marta
Format: Article
Language:English
Subjects:
Biomechanics
Biosensors
Deoxyribonucleic acid
Deposition
Gold
Gold coatings
Lasers
Sensors
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Summary:In this work, we describe the gold-coating of silicon microcantilever sensors by pulsed laser deposition (PLD) and their performance as DNA biosensors. To test optimum deposition conditions for coating the sensors, silicon substrates were gold coated by PLD using the fifth harmonic of a Nd:YAG laser (213 nm, pulse duration 15 ns). The gold deposits were characterized by atomic force microscopy and x-ray diffraction. The adequate conditions were selected for coating the sensors with a 20 nm thick gold layer and subsequently functionalized with a self-assembled monolayer of thiolated DNA. To verify PLD as a tool for gold coating of biomechanical sensors, they were characterized by using a scanning laser analyzer platform. Characterization consisted in the measurement of the differential stress of the cantilevers upon hydration forces before and after functionalization with a double-stranded DNA monolayer. The measurements showed that the sensor surface stress induced by the adsorption of water molecules is approximately seven times higher than that of functionalized sensors gold coated by thermal evaporation. These results indicate that gold coating by PLD could be an advantageous method to enhance the response of biomechanical sensors based on gold-thiol chemistry.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4761986