Ex-vivo fluorescence imaging for the identification of rhodamine-labeled bovine serum albumin and chitosan-coated gold and silver nanoparticles.

Therapeutic potential and toxic effects of in vivo administered gold nanoparticles (GNP) and silver nanoparticles (SNP) depend on distribution in tissues. Rhodamine (Rho) labeled bovine serum albumin (BSA) and chitosan (Chi) were prepared by covalent conjugation and were characterized by fluorescence spectral analysis. GNP and SNP were coated with the labeled conjugates of BSA and chitosan by adsorption. The soluble Rho-BSA or Chi conjugates, uncoated, and conjugate-coated GNP, and SNP were orally administered in to 8-week-old rats. After 24 hours, rats were euthanized and the liver, kidney, spleen, and thymus were dissected. The tissues were examined ex vivo using a small animal in vivo imaging system. Liver, kidney and thymus displayed higher fluorescence due to increased accumulation of Rho-BSA or Chi conjugate coated NP in the tissues as compared to spleen where lower fluorescence noticed. Tissues obtained from rats that were administered Rho-BSA or Chi conjugated coated GNP and SNP showed tenfold higher fluorescence intensity as compared to tissues from rats that were given soluble conjugates or NP alone. The results strongly suggest significant tissue distribution of NP following oral administration. This article is protected by copyright. All rights reserved.