ABSTRACT
A liposome system that can detect and detoxify mercury in aqueous solution is demonstrated. The system consists of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine and 20% PEG-PE (PEG MW 2000 Da) that forms liposome, which encapsulates self-quenching fluorescein for detection, and chelating agent meso-2,3-dimercaptosuccinic acid (meso-DMSA) for chelating detoxification through Hg(2+)-responsive release of fluorescein and meso-DMSA. This system can detect mercury levels as low as 10 nM with high selectivity. In particular, the release profile of meso-DMSA by the local concentration of Hg can be modulated, so that more chelators are released in regions of high concentration and less chelators are released in regions of low concentration. The design has been demonstrated both in vitro and in HeLa cells. This "budgeted" release profile is particularly useful in situations in which the local levels of Hg contamination vary, or if such contamination is time dependent.
Subject(s)
Chelating Agents/metabolism , Fluorescent Dyes/metabolism , Ions/metabolism , Liposomes/metabolism , Mercury/metabolism , Succimer/metabolism , Chelating Agents/chemistry , Fluorescent Dyes/chemistry , HeLa Cells , Humans , Ions/chemistry , Mercury/toxicity , Phosphatidylethanolamines/chemistry , Polyethylene Glycols/chemistry , Succimer/chemistryABSTRACT
Design of smart MRI contrast agent based on superparamagnetic iron oxide nanoparticles and aptamers has been described for the detection of human alpha-thrombin protein. The contrast agent is based on the assembly of the aptamer functionalized nanoparticles in the presence of thrombin. A detectable change in MRI signal is observed with 25 nM thrombin in human serum. Changes were neither observed with control analytes, streptavidin, or bovine serum albumin, nor with inactive aptamer functionalized nanoparticles.
