Lablog4-3:Liposome immunoblotting assay using a substrate-forming precipitate inside immunoliposomes

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Yoichi Kumada, Masumi Maehara, Kanji Tomioka, Shigeo Katoh

First author

Yoichi Kumada

Corresponding author

Shigeo Katoh

Publication Style

Journal name Biotechnology and bioengineering


Volume, issue, pages

 80, 4, 414-418


A new immunoblotting assay which uses antibody-coupled liposomes containing horseradish peroxidase is proposed. A substrate 4-chloro-1-naphthol permeated through the phospholipid membrane of the antibody-coupled liposomes and formed a colored product precipitating inside the liposomes. The precipitates accumulated in the liposomes and could be detected at the positions where the liposomes coupled with a target in blotted samples. Combination of liposomes with average diameter of 350 nm and a PVDF membrane with a pore size of 450 nm, 0.02 ng of IgM was detected, while the conventional immunoblotting using antibody-HRP conjugates detected 2 ng of IgM. The sensitivity increased about two orders of magnitude by the liposome immunoblotting assay. This liposome immunoblotting assay gives a simple detection method of proteins with a high sensitivity, as well as a high sensitivity Western blotting assay.