Plastic versus glass support for an immunoassay on metal-coated surfaces in optically dense samples utilizing directional surface plasmon-coupled emission.

We compared plastic (polycarbonate) and high-quality glass support materials for gold-coated slides, when performing a model immunoassay against rabbit IgG using fluorescently labeled (AlexaFluor-647) anti-rabbit IgG, and detecting surface plasmon-coupled emission (SPCE) signals. Both, glass and plastic slides were simultaneously coated with a 48-nm layer of gold and protected with a 10-nm layer of silica. The maximum SPCE signal of AlexaFluor-647 was only two- to three-fold smaller on plastic slides than on glass slides.

Directional surface plasmon-coupled emission: application for an immunoassay in whole blood.

We present a new approach for performing fluorescence immunoassay in whole blood using fluorescently labeled anti-rabbit immunoglobulin G (IgG) on a silver surface. This approach, which is based on surface plasmon-coupled emission (SPCE), provides increased sensitivity and substantial background reduction due to exclusive selection of the signal from the fluorophores located near a bioaffinity surface. This article describes the effect of an optically dense sample matrix, namely human whole blood and serum, on the intensity of the SPCE.

Phase-modulation fluorometry using a frequency-doubled pulsed laser diode light source.

We used the Hamamatsu model PLP-01 picosecond light pulser as a 413-nm excitation light source for frequency-domain fluorescence measurements. In comparison with sync-pumped/cavity dumped/frequency-doubled dye lasers, the 413-nm PLP-01 shows a longer FWHM (40 ps), a similar pulse repetition rate (up to 10 MHz), much less output power at a fixed wavelength (0.44 mW peak, 220 nW maximum average power), but is less expensive, small-sized, and easy to handle.