Gold-Silver and Gold-Palladium Alloy Nanoparticles as Mass-Probes for Immunosensing

Abstract

Silver or palladium shelled gold nanoparticles were fused into alloy nanoparticles by pulsed-laser irradiation. The alloy nanoparticles could carry antibodies on their surfaces without affecting their immune functionalities and interact selectively with antigens on a blotting membrane. Silver or palladium ions desorbed from the alloy nanoparticles as reporter ions upon the UV laser irradiation in a mass spectrometer.

Anionic gold ions desorbed from gold nanorods and nanospheres

“…Gold nanoparticles have been developed as a mass probe for imaging mass spectrometry of tissue sections using a conventional mass spectrometer designed for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). 1,[3][4][5][6][7][8][9][10] The irradiation of 355-nm pulsed-laser light in a MALDI-MS instrument causes preferential desorption of gold cations (Au + , Au2 + , Au3 + ) in the absence of matrix molecules. The gold cations act as reporter ions to represent the distribution of target molecules.…”

“…We have found that gold ion signals showed good linearity and remarkable limits of detection even when an insulating porous membrane was used as a substrate for gold nanoparticles. 1,5,6 The ionization efficiency was dependent on the sizes and shapes of the gold nanoparticles. 6,11 Previous works have shown that gold nanoparticles could be a highly sensitive mass probe for investigating distribution using a conventional MALDI-MS instrument.…”