Realization and Characterization of Porous Gold for Increased Protein Coverage on Acoustic Sensors

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• 作者：Kristien Bonroy ; Jean-Michel Friedt ; Filip Frederix ; Wim Laureyn ; Steven Langerock ; Andrew Campitelli ; Margit Sá ; ra ; Gustaaf Borghs ; Bruno Goddeeris ; and Paul Declerck
• 刊名：Analytical Chemistry
• 出版年：2004
• 出版时间：August 1, 2004
• 年：2004
• 卷：76
• 期：15
• 页码：4299 - 4306
• 全文大小：205K
• 年卷期：v.76,no.15(August 1, 2004)
• ISSN：1520-6882

文摘

Immunosensors show great potential for the direct detection of biological molecules. The sensitivity of theseaffinity-based biosensors is dictated by the amount ofreceptor molecules immobilized on the sensor surface.An enlargement of the sensor area would allow for anincrease of the binding capacity, hence a larger amountof immobilized receptor molecules. To this end, we useelectrochemically deposited "gold black" as a poroussensor surface for the immobilization of proteins. In thispaper, we have analyzed the different parameters thatdefine the electrochemical growth of porous gold, startingfrom flat gold surfaces, using different characterizationtechniques. Applied potentials of -0.5 V versus a reference electrode were found to constitute the most adequateconditions to grow porous gold surfaces. Using cyclicvoltammetry, a 16 times increase of the surface area wasobserved under these electrochemical deposition conditions. In addition, we have assessed the immobilizationdegree of alkanethiols and of proteins on these differentporous surfaces. The optimized deposition conditions forrealizing porous gold substrates lead to a 11.4-foldincrease of thiol adsorption and a 3.3-fold increase ofprotein adsorption, using the quartz crystal microbalance(QCM-D) as a biological transducer system. Hence, itfollows that the high specific area of the porous gold canamplify the final sensitivity of the original flat surfacedevice.