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Abstract: Surface plasmon resonance (SPR) can detect molecules bound to a surface by subtle changes in the SPR angle. By immobilizing probes onto the surface and passing analyte solution through the surface, changes in SPR angle indicate the binding between analyte and probes. Detection of analyte from solution can be achieved easily. By using rolling circle amplification (RCA) and nanogold-modified tags, the signals of analyte binding are greatly amplified, and the sensitivity of this technique is significantly improved. Furthermore, this technique has potentials for ultra-sensitive detection and microarray analysis. In this paper, this detection technique is introduced and shown to have great amplification capability. Using 5nm nanogold with 30min of RCA development time, this proposed protein detection technique shows over 60 times amplification of the original signal. [Copyright &y& Elsevier]

Developing a readily available biosensor with excellent performances is the main focus of many research groups. Recently, major breakthroughs in miniaturization of molecular analysis have produced DNA and protein microarrays. The aim of our group is to develop a sensitive technique for analyzing signals on protein microarray by applying the surface plasmon resonance (SPR) method. This new detection technique for specific molecular binding utilizes rolling circles amplification (RCA) post-signal processing method [Nat. Genet. 19 (1998) 225–232] and optical visualization by nanogold particle-labeled molecules on a micro-structured chip surface. By covalent bonding of the RCA primer to the detection antibody guarantees that the linkage between the analyte and the amplified RCA product is maintained during the assay. Experimental results show that RCA has significantly enhanced sensitivity compared to conventional methods. This combination of an easily detectable signal with chip technology should have the potential to become a successful commercial application. [Copyright &y& Elsevier]