title: Atomic force microscopy probing of receptor-nanoparticle interactions for riboflavin receptor targeted gold-dendrimer nanocomposites.
abstract: Riboflavin receptors are overexpressed in malignant cells from certain human breast and prostate cancers, and they constitute a group of potential surface markers important for cancer targeted delivery of therapeutic agents and imaging molecules. Here we report on the fabrication and atomic force microscopy (AFM) characterization of a core-shell nanocomposite consisting of a gold nanoparticle (AuNP) coated with riboflavin receptor-targeting poly(amido amine) dendrimer. We designed this nanocomposite for potential applications such as a cancer targeted imaging material based on its surface plasmon resonance properties conferred by AuNP. We employed AFM as a technique for probing the binding interaction between the nanocomposite and riboflavin binding protein (RfBP) in solution. AFM enabled precise measurement of the AuNP height distribution before (13.5 nm) and after chemisorption of riboflavin-conjugated dendrimer (AuNP-dendrimer; 20.5 nm). Binding of RfBP to the AuNP-dendrimer caused a height increase to 26.7 nm, which decreased to 22.8 nm when coincubated with riboflavin as a competitive ligand, supporting interaction of AuNP-dendrimer and its target protein. In summary, physical determination of size distribution by AFM imaging can serve as a quantitative approach to monitor and characterize the nanoscale interaction between a dendrimer-covered AuNP and target protein molecules in vitro.
authors.affiliation: Department of Chemistry & Biochemistry, Calvin College , 3201 Burton Street SE, Grand Rapids, Michigan 49546, United States.
authors.forename: Amanda B
authors.initials: AB
authors.lastname: Witte
authors.forename: Abigail N
authors.initials: AN
authors.lastname: Leistra
authors.forename: Pamela T
authors.initials: PT
authors.lastname: Wong
authors.forename: Sophia
authors.initials: S
authors.lastname: Bharathi
authors.forename: Kevin
authors.initials: K
authors.lastname: Refior
authors.forename: Phillip
authors.initials: P
authors.lastname: Smith
authors.forename: Ola
authors.initials: O
authors.lastname: Kaso
authors.forename: Kumar
authors.initials: K
authors.lastname: Sinniah
authors.forename: Seok Ki
authors.initials: SK
authors.lastname: Choi
mesh_terms: D002478:Cells, Cultured; D050091:Dendrimers / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D053761:Nanocomposites / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry / Q000378:metabolism*; D010316:Particle Size; D011956:Receptors, Cell Surface / Q000737:chemistry*; D012256:Riboflavin / Q000737:chemistry*
chemical_list: D050091:Dendrimers; D011956:Receptors, Cell Surface; D006046:Gold; D012256:Riboflavin