Nanomaterials represent a rapidly expanding area of research with huge potential for future medical applications. Nanotechnology indeed promises to revolutionize diagnostics, drug delivery, gene therapy and many other areas of research. For any biological investigation involving nanomaterials, it is crucial to study the behavior of such nano-objects within tissues to evaluate both their efficacy and their toxicity. Here, we provide the first account of 3D label-free nanoparticle imaging at the entire-organ scale. The technology used is known as laser-induced breakdown spectroscopy (LIBS) and possesses several advantages such as speed of operation, ease of use and full compatibility with optical microscopy. We then used two different but complementary approaches to achieve 3D elemental imaging with LIBS: a volume reconstruction of a sliced organ and in-depth analysis. This proof-of-concept study demonstrates the quantitative imaging of both endogenous and exogenous elements within entire organs and paves the way for innumerable applications.

We report a simple synthesis of silver:glutathione (Ag:SG) clusters using a cyclic reduction under oxidative conditions. Two syntheses are described which lead to solutions containing well-defined Ag₃₁(SG)₁₉ and Ag₁₅(SG)₁₁ clusters that have been characterized by mass spectrometry. The optical properties of silver:glutathione (Ag:SG) cluster solutions have been investigated experimentally. In particular, the solution containing Ag₁₅(SG)₁₁ clusters shows a bright and photostable emission. For Ag₃₁(SG)₁₉ and Ag₁₅(SG)₁₁ clusters, the comparison of experimental findings with DFT and TDDFT calculations allowed us to reveal the structural and electronic properties of such low nuclearity liganded silver clusters.

The term “ In Silico Trial” indicates the use of computer modelling and simulation to evaluate the safety and efficacy of a medical product, whether a drug, a medical device, a diagnostic product or an advanced therapy medicinal product. Predictive models are positioned as new methodologies for the development and the regulatory evaluation of medical products. New methodologies are qualified by regulators such as FDA and EMA through formal processes, where a first step is the definition of the Context of Use (CoU), which is a concise description of how the new methodology is intended to be used in the development and regulatory assessment process. As In Silico Trials are a disruptively innovative class of new methodologies, it is important to have a list of possible CoUs highlighting potential applications for the development of the relative regulatory science. This review paper presents the result of a consensus process that took place in the InSilicoWorld Community of Practice, an online forum for experts in in silico medicine. The experts involved identified 46 descriptions of possible CoUs which were organised into a candidate taxonomy of nine CoU categories. Examples of 31 CoUs were identified in the available literature; the remaining 15 should, for now, be considered speculative.

We focus on the functional role of small silver clusters in model hybrid systems involving peptides in the context of a new generation of nanostructured materials for biosensing. The optical properties of hybrids in the gas phase and at support will be addressed with the aim to bridge fundamental and application aspects. We show that extension and enhancement of absorption of peptides can be achieved by small silver clusters due to the interaction of intense intracluster excitations with the π–π* excitations of chromophoric aminoacids. Moreover, we demonstrate that the binding of a peptide to a supported silver cluster can be detected by the optical fingerprint. This illustrates that supported silver clusters can serve as building blocks for biosensing materials. Moreover, the clusters can be used simultaneously to immobilize biomolecules and to increase the sensitivity of detection, thus replacing the standard use of organic dyes and providing label-free detection. Complementary to that, we show that protected silver clusters containing a cluster core and a shell liganded by thiolates exhibit absorption properties with intense transitions in the visible regime which are also suitable for biosensing applications.

We explored experimentally and theoretically the optical properties of isolated silver trimer-dipeptide bioconjugates. The metallic moiety induces a strong enhancement of the optical absorption of the peptide. We also show that its binding to a peptide can reduce the conformational flexibility and induce transitions between secondary structures.

The 2$p$ core-level electron binding energies of size-selected silicon cluster ions have been determined from soft x-ray photoionization efficiency curves. Local chemical shifts and global charging energy contributions to the 2$p$ binding energy can be separated, because core-level and valence-band electron binding energies exhibit the same inverse radius dependence. The experimental 2$p$ binding energy distributions show characteristic size-specific patterns that are well reproduced by the corresponding electronic density of states obtained from density functional theory modeling. These results demonstrate that 2$p$ binding energies in silicon clusters are dominated by initial state effects, i.e., by the interaction with the local valence electron density, and can thus be used to corroborate structural assignments. DOI: http://dx.doi.org/10.1103/PhysRevB.85.195454 ©2012 American Physical Society