Integration of a microfluidic polymerase chain reaction device and surface plasmon resonance fiber sensor into an inline all-in-one platform for pathogenic bacteria detection

Abstract

We presented the integration of polymerase chain reaction (PCR) microdevice and surface plasmon resonance (SPR) optical fiber sensor into an inline all-in-one device for fluorophore-free detection of PCR amplification. The proposed integrated device consisted of the microfluidic PCR reactor that used channel position-dependent temperature change and the optical fiber SPR sensor with bimetallic (Ag/Al) coating. This all-in-one device performed not only the amplification of DNA of Salmonella spp. (injected volume of 20 microlitter) within 30min, but also the immediately subsequent measurement of the DNA amplicon by the SPR fiber sensor part.Results showed that the SPR sensor signal increased with the cycle number due to the amplicon refractive index smaller than the sum of its constituent dNTP molecules and its minimum resolvable DNA amplicon was that generated at the 15th cycle. The integrated device could serve as a DNA amplification-to-detection instrument. Both the label-free nature that could allow reusability of the presented device and further miniaturization of the whole system can find use in a point-of-care testing with early diagnosis genetic analysis.