2018 Volume 46 Issue 9 Pages 495-
A novel spectroscopic measurement method has been established that enables to detect biomolecules in a simple measurement configuration with a small absolute amount of sensing targets. A spectroscopic cell with a sensing volume of sub-picoliter has been fabricated inside a glass optical fiber by use of near ultraviolet (NUV) femtosecond laser pulses. By use of the cell with a combination of a halogen white light source and a compact CCD spectrometer, spectroscopic measurements using localized surface plasmon resonance (LSPR) were demonstrated. Absorption spectra using LSPR, which had the absorption peak centered at 518 nm, were obtained when a solution of gold nanoparticles (GNPs) with a diameter of 5‒10 nm was injected into the cell with a volume of 0.4 pL. An aggregation of GNPs caused by biomolecules of L-cysteine was monitored by the change in the absorption spectra. The absorption peak of LSPR decreased due to an injection of 7.5 mM of L-cysteine with the detection sensitivity of 3.0 × 10‒15 mol (3.6 × 10‒13 g).
