Immobilization Techniques and Integrated Signal Enhancement for POC Nanocolor Microfluidic Devices

Figure 5

Thiosulfate-stabilized silver enhancement. (a) PEI-coated REA chips grafted with PdNP-conjugated probe (low, medium, and high surface coverage) before Ag enhancement (−) (left). The chips were cut in two and one half of each chip was subjected to Ag enhancement (+) (right). (b) The enhancement factor (EF) strongly depended on the signal intensity before silver enhancement (i.e., the PdNP coverage density) (EF = [signal after Ag enhancement in % black]/[signal before Ag enhancement in % black]). (c) AFM scans of REA chips before PdNP grafting (left) and after PdNP grafting and Ag enhancement (middle and right) (the grafted PdNP conjugate could not be imaged due to the inherent roughness of the chip surface and the polymer layer and the small size of the PdNPs of ≤20 nm.).

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(b)

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