Now showing 1 - 4 of 4
  • Publication
    Mapping of Molecular Structure of the Nanoscale Surface in Bionanoparticles
    Characterizing the orientation of covalently conjugated proteins on nanoparticles, produced for in vitro and in vivo targeting, though an important feature of such a system, has proved challenging. Although extensive physicochemical characterization of targeting nanoparticles can be addressed in detail, relevant biological characterization of the nanointerface is crucial in order to select suitable nanomaterials for further in vitro or in vivo experiments. In this work, we adopt a methodology using antibody fragments (Fab) conjugated to gold nanoparticles (immunogold) to map the available epitopes on a transferrin grafted silica particle (SiO2−PEG8−Tf) as a proxy methodology to predict nanoparticle biological function, and therefore cellular receptor engagement. Data from the adopted method suggest that, on average, only∼3.5% of proteins grafted on the SiO2−PEG8−Tf nanoparticle surface have a favorable orientation for recognition by the cellular receptor.
  • Publication
    Biological recognition of graphene nanoflakes
    The systematic study of nanoparticle-biological interactions requires particles to be reproducibly dispersed in relevant fluids along with further development in the identification of biologically relevant structural details at the materials-biology interface. Here, we develop a biocompatible long-term colloidally stable water dispersion of few-layered graphene nanoflakes in the biological exposure medium in which it will be studied. We also report the study of the orientation and functionality of key proteins of interest in the biolayer (corona) that are believed to mediate most of the early biological interactions. The evidence accumulated shows that graphene nanoflakes are rich in effective apolipoprotein A-I presentation, and we are able to map specific functional epitopes located in the C-terminal portion that are known to mediate the binding of high-density lipoprotein to binding sites in receptors that are abundant in the liver. This could suggest a way of connecting the materials' properties to the biological outcomes.
      365Scopus© Citations 72
  • Publication
    In situ characterization of nanoparticle biomolecular interactions in complex biological media by flow cytometry
    Nanoparticles interacting with, or derived from, living organisms are almost invariably coated in a variety of biomolecules presented in complex biological milieu, which produce a bio-interface or ‘biomolecular corona’ conferring a biological identity to the particle. Biomolecules at the surface of the nanoparticle–biomolecule complex present molecular fragments that may be recognized by receptors of cells or biological barriers, potentially engaging with different biological pathways. Here we demonstrate that using intense fluorescent reporter binders, in this case antibodies bound to quantum dots, we can map out the availability of such recognition fragments, allowing for a rapid and meaningful biological characterization. The application in microfluidic flow, in small detection volumes, with appropriate thresholding of the detection allows the study of even complex nanoparticles in realistic biological milieu, with the emerging prospect of making direct connection to conditions of cell level and in vivo experiments.
      460Scopus© Citations 130
  • Publication
    Identification of Receptor Binding to the Biomolecular Corona of Nanoparticles
    Biomolecules adsorbed on nanoparticles are known to confer a biological identity to nanoparticles, mediating the interactions with cells and biological barriers. However, how these molecules are presented on the particle surface in biological milieu remains unclear. The central aim of this study is to identify key protein recognition motifs and link them to specific cell-receptor interactions. Here, we employed an immuno-mapping technique to quantify epitope presentations of two major proteins in the serum corona, low-density lipoprotein and immunoglobulin G. Combining with a purpose-built receptor expression system, we show that both proteins present functional motifs to allow simultaneous recognition by low-density lipoprotein receptor and Fc-gamma receptor I of the corona. Our results suggest that the “labeling” of nanoparticles by biomolecular adsorption processes allows for multiple pathways in biological processes in which they may be “mistaken” for endogenous objects, such as lipoproteins, and exogenous ones, such as viral infections.
      543Scopus© Citations 183