CMAST ( Computational MAterials Science & Technology ) Virtual Lab

1. DonorAcceptor: 8HQ and GoldNanoparticle Al electrode Polystyrene ComputationalMaterials Science VLP-V3pos3 VLP-V3pos1 failed rmsd ~ 1nm SUPERATOMS Coarse-Graining ATOMS MATERIALS FOR NANOTECHNOLOGIES Reverse -Mapping VLP-V3Cter VLP-2F5Cter rmsd < 1nm rmsd < 0.8 nm CMAST (ComputationalMAterials Science & Technology) VirtualLab www.afs.enea.it/project/cmast • Project: • Progetto Grande Rilevanza, Ministero affari Esterni, bilaterale Italia-Giappone “Sfide globali per la salute. Biofarmaci derivati da pianta” Functionalization of virus-likenanoparticle C. Arcangeli(ENEA) Structuralproperties (RMSD, Rg and number of clusters) of the VLP (solid line) and single CP (dashed line) as a function of simulation time. C.- Arcangeli (ENEA) Problem: The discovery of new generation nanoparticlesisone of the mostactiveareas of nanotechnoloy. Virus-likeparticles (VLPs) are nature-made nanometer-sizedobjects and are formedby coatprotein (CP) self-assembly. Suchnanoparticles can be functionalized by gene engineering or chemical modifications of the CP subunits andexploited to produce safe vaccine vehicles and nanoparticles for drugdelivery. However, if not carefully designed, the functionalization could have negative effects on the VLPs self-assembly and stability. In silicomethod can represent a validtool for the rational design of functionalizatedVLPs. Open questions: What are the effects of the insertion of immunogenic epitopes on the packing of the subunits and on the stability of chimeric VLPs? Method: Homology Modeling (HM) and Molecular Dynamics (MD) simulations are used to model the VLPs. The simulated system is composed by ca. 4 millions of atoms. Theoreticalpredictions of the suitable positions on the CP where to insert the of immunogenicepitopes (i.e. HIV-1 V3 loop and HIV-1 2F5). • Results: • the structuralanalysis of the VLP modelsdetectedinterdomaininteractionsimportant for the stability • the in silicoprotocolrepresents an effective screening tool to design the fusion of differentepitopes on the VLP. The methodisable to predictboth positive and negative resultsasrequested by the fail-fast fail-cheap phyiosophyembraced by the pharmaceutical companies. • Projects: • FIRB Italnanonet (MIUR) in collaborationwithSTMicroelectronics • TECOP (sviluppo di nuovi materiali per automotive ed aeronautica). Ministero dello Sviluppo Economico. Polymeric electronic materials and devices G. Milano, Dipartimento di Chimica e Biologia, Università di Salerno Snapshot of stheystemhowing some polymer chains closer to the nanoparticlesurface. Polymerchainsapproach the nanoparticlesurface exposing mainly the phenyl rings (white color). The backbone carbons are in blue, hydrogen atoms are omitted for clarity. Problem: The new class of organic devices for microelectronics need a deep understanding of the interaction of nanoparticles in polimeric matrices. For this reason the effect of grafting on Gold NP/Polymer Interfaces is needed. Open questions: Which is the the structure of Gold NP/Polymer Interfaces at atomic resolution How are affected the macroscopic properties by the Interface Structure Method: Multiscale modeling based on Coarse-grained models and atomistic structures coming from reverse mapping procedure. Both models are simulated using Molecular Dynamics simulations Snapshot of the system showing some polymer chains closer to the nanoparticle surface. Similarly, to the other system polymer chains approach the nanoparticle surface exposing mainly the phenyl rings (white color) some of the phenyl rings penetrate trough the alkyl chains layer (in red). The backbone carbons are in blue, the thiols chains are depicted in red, hydrogen atoms are omitted for clarity. Organic nonvolatile memory devices made from a polystyrene (PS) film containing gold nanoparticles and 8-hydroxyquinoline (8-HQ) sandwiched between two metal electrodes shows a programmableelectricalbistability. • Results: • Atomic structures of NP/Polymer Interfaces can be generated • The molecular picture resulting from simulations can confirm some of the hypothesis made on the basis of macroscopic behavior. In particular, the effect of coating layer and the molecular orientation of the 8-HQ molecules with respect to nanoparticle surfaces CdS quantum dots E. Burresi, ENEA Faenza The lowest unoccupied molecular orbital for CdS cluster heated at 100 K Density of states for CdS cluster at T= 100 K (CdS100), T= 280 K (CdS280), T= 330 K (CdS330) Problem: The stability of the CdS phase, and particularly the stability of phase between bulk and nanostructure material, continues to be now discussed but not entirely understood . It is necessary to investigate structural modifications in order to evaluate as electronic and optical properties are subject to change. Open questions: Which is the the atomic structure of the CdS surface ? How the modification on the surface affect the electronic properties ? Method: Ab inito molecular dynamics was performed on cluster build up with 48 cadmium atoms and 48 sulfur atoms. This structure was heated from 100K to 600K . Structural and electronic properties of the cluster were accurately investigated for each temperature. Results: From Ab-initio calculation on small single wurtzite CdS nanoparticle quantum dots, a substantial modifications of surface is find out after 300 K which reduce the surface effects.; in addition this structural change cause some alterations of the intermediate electronic states around the band gap, and the atoms on the surface have a main role on the formation of the intermediate states on the band gap. CdS cluster heated at 340 K: the lowest unoccupied molecular orbital is reported. Snapshot of CdSwurtzite cluster. In yellow sulphur atoms and blue cadmium atoms. Sticks are used to enlight the first shell of coordination of each atom.