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Ultrasmall nanoparticles (USNPs), usually defined as NPs with core in the size range 1–3 nm, are a class of nanomaterials which show unique physicochemical properties, often different from larger NPs of the same material. Moreover, there are also indications that USNPs might have distinct properties in their biological interactions. For example, recent in vivo experiments suggest that some USNPs escape the liver, spleen, and kidney, in contrast to larger NPs that are strongly accumulated in the liver. Here, we present a simple approach to study the biomolecular interactions at the USNPs bio‐nanointerface, opening up the possibility to systematically link these observations to microscopic molecular principles.

The transport and the delivery of drugs through nanocarriers is a great challenge of pharmacology. Since the production of liposomes to reduce the toxicity of doxorubicin in patients, a plethora of nanomaterials have been produced and characterized. Although it is widely known that elementary properties of nanomaterials influence their in vivo kinetics, such interaction is often poorly investigated in many preclinical studies. The present study aims to evaluate the actual effect of size and shape on the biodistribution of a set of gold nanoparticles (GNPs) after intravenous administration in mice. To this goal, quantitative data achieved by inductively coupled plasma mass spectrometry and observational results emerging from histochemistry (autometallography and enhanced dark-field hyperspectral microscopy) were combined. Since the immune system plays a role in bionano-interaction we used healthy immune-competent mice. To keep the immune surveillance on the physiological levels we synthesized endotoxin-free GNPs to be tested in specific pathogen-free animals. Our study mainly reveals that (a) the size and the shape greatly influence the kinetics of accumulation and excretion of GNPs in filter organs; (b) spherical and star-like GNPs showed the same percentage of accumulation, but a different localization in liver; (c) only star-like GNPs are able to accumulate in lung; (d) changes in the geometry did not improve the passage of the blood brain barrier. Overall, this study can be considered as a reliable starting point to drive the synthesis and the functionalization of potential candidates for theranostic purposes in many fields of research.

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.

Everywhere in our surroundings we increasingly come in contact with nanostructures that have distinctive complex shape features on a scale comparable to the particle itself. Such shape ensembles can be made by modern nano-synthetic methods and many industrial processes. With the ever growing universe of nanoscale shapes, names such as "nanoflowers" and "nanostars" no longer precisely describe or characterise the distinct nature of the particles. Here we capture and digitise particle shape information on the relevant size scale and create a condensed representation in which the essential shape features can be captured, recognized and correlated. We find the natural emergence of intrinsic shape groups as well-defined ensemble distributions and show how these may be analyzed and interpreted to reveal novel aspects of our nanoscale shape environment. We show how these ideas may be applied to the interaction between the nanoscale-shape and the living universe and provide a conceptual framework for the study of nanoscale shape biological recognition and identity.

Three heterobimetallic gold(I)–ruthenium(II) complexes containing heteroditopic bipyridine–N-heterocyclic carbene (NHC) ligands were synthesized and fully characterized by spectroscopic methods and in one case by single-crystal X-ray diffraction. In addition, the in vitro cytotoxic, antileishmanial, and antimalarial activities of these new heterobimetallic complexes were assessed. Moreover, the photophysical properties of two compounds have been used to localize them in tumor cells by confocal microscopy.

The biological interactions of graphene have been extensively investigated over the last 10 years. However, very little is known about graphene interactions with the cell surface and how the graphene internalization process is driven and mediated by specific recognition sites at the interface with the cell. In this work, we propose a methodology to investigate direct molecular correlations between the biomolecular corona of graphene and specific cell receptors, showing that key protein recognition motifs, presented on the nanomaterial surface, can engage selectively with specific cell-receptors. We consider the case of apolipoprotein A-I, found to be very abundant in the graphene protein corona, and observe that the uptake of graphene nanoflakes is somewhat increased in cells with greatly elevated expression of scavenger receptors B1, suggesting a possible mechanism of endogenous interaction. The uptake results, obtained by flow cytometry, have been confirmed using Raman microspectroscopic mapping, exploiting the strong Raman signature of graphene.

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