We report on the first application of silica-gold nanoshells to a solid-phase dot immunoassay. The assay principle is based on staining of a drop (1μL ) analyte on a nitrocellulose membrane strip by using silica/gold nanoshells conjugated with biospecific probing molecules. Experimental example is human IgG (hIgG, target molecules) and protein A (probing molecules). For usual 15-nm colloidal gold conjugates, the minimal detectable amount of hIgG is about 4ng. By contrast, for nanoshell conjugates (silica core diameter of 70 nm and gold outer diameter of 100 nm) we have found significant increase in detection sensitivity and the minimal detectable amount of hIgG is about 0.5 ng.

Date Published: 1 May 2007
PDF: 6 pages
Proc. SPIE 6534, Fifth International Conference on Photonics and Imaging in Biology and Medicine, 65343L (1 May 2007);

Published in SPIE Proceedings Vol. 6534:
Fifth International Conference on Photonics and Imaging in Biology and Medicine
Qingming Luo; Lihong V. Wang; Valery V. Tuchin; Min Gu, Editor(s)