Characterization of Multifunctional Nanosystems Based on the Avidin-Nucleic Acid Interaction As Signal Enhancers in Immuno-Detection.

The Avidin-Nucleic-Acids-Nano-Assemb1y (ANANAS) is a kind of soft poly avidin nanopartide originating from the high affinity interaction between avidin and the nudeic acids. In this work we investigated the possibility of transforming ANANAS cores into stoichiometrirally controlled multifunctional nanopartides through a "onepot" procedure, and we measured in a quantitative way their ability to work as reagents for enhanced immunodiagnostic detection. Initially, we measured the ANANAS loading capability for biotinylated proteins of different nature. About 200 molecules of biotin-horseradish-peroxidase (4OKDa b-HRP) and 60 molecules of biotin-iminunogiobulin-G (ISOKDa b-IgG) could be accommodated Onto each nanopartide, showing that steric limitations dictate the number of loadable entities. Stoichiometrically controlled functional assemblies were generated by mixing core particles with subsaturaling amounts of b-}TRP and b-IgG. When applied as detection reagents in an Enzyme-LinkedlinmunoSorbed-Assay (ELISA), these assemblies were up to two-orders of magnitude more sensitive than comnsercial HltPbased reagents Assemblies of different composition displayed different efficacy, indicating that the system functionality can be fine-tuned. Within-assay variability (CV%), measured to assess if the assembly procedure is reproducible, was within 10%. Stability experiments demonstrated that the fimctionalyzed assemblies are stable in solution for more than one week. In principle, any biotinylated function can be loaded onto the core particle, whose high loading capacity and tunability may open the way toward further application in biomedicine. [ABSTRACT FROM AUTHOR]