Electrochemical Biosensing Using Amplification-by-Polymerization
2009; American Chemical Society; Volume: 81; Issue: 16 Linguagem: Inglês
10.1021/ac9011254
ISSN1520-6882
AutoresYafeng Wu, Songqin Liu, Lin He,
Tópico(s)Analytical Chemistry and Sensors
ResumoA novel signal amplification strategy for electrochemical detection of DNA and proteins based on the amplification-by-polymerization concept is described. Specifically, a controlled radical polymerization reaction is triggered after the capture of target molecules on the electrode surface. Growth of long chain polymeric materials provides numerous sites for subsequent aminoferrocene coupling, which in turn significantly enhances electrochemical signal output. Activators generated electron transfer for atom transfer radical polymerization (AGET ATRP) is used in this study for its high efficiency in polymer grafting and better tolerance toward oxygen in air. 2-Hydroxyethyl methacrylate (HEMA) and glycidyl methacrylate (GMA) are examined to provide excess hydroxyl or epoxy groups for aminoferrocene coupling. A limit of detection of 15 pM and 0.07 ng/mL is demonstrated for DNA and ovalbumin, respectively. More than 7-fold signal enhancement in ovalbumin detection has been achieved comparing to the unamplified method. In addition, a more than 5 orders of magnitude of dynamic range is achieved with a linear correlation coefficient (R(2)) of 0.997 for DNA, and a more than 3 orders of magnitude with R(2) of 0.999 for ovalbumin. Together, the results show that the coupling of amplification-by-polymerization concept with electrochemical detection offers great promises in providing a sensitive and cost-effective solution for biosensing applications.
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