A biomaterial is any matter, surface, or construct that interacts with biological systems. The development of biomaterials, as a science, is about fifty years old. The study of biomaterials is called biomaterials science. It has experienced steady and strong growth over its history, with many companies investing large amounts of money into the development of new products. Biomaterials science encompasses elements of medicine, biology, chemistry, tissue engineering and materials science.
SEGREGATION AND PHASE TRANSITION IN MIXED LIPID FILMS.
Giulio Caracciolo, Stefano Piotto, Cecilia Bombelli, Ruggero Caminiti, Giovanna Mancini
ABSTRACT:Energy dispersion X-ray diffraction (EDXD) was applied to investigate the structure of partly dehydrated mixed films formed by the phospholipid dimyristoyl phosphatidylcoline (DMPC) and any of the three diastereomers of the dicationic gemini surfactant (2S,3S)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium) butane dibromide. As the surfactant to lipid molar ratio (R(S/L)) increases, the gemini monotonically solubilizes the lipid bilayer promoting the formation of a cubic phase of space group Pmn segregating from the residual lamellar phase of the lipid. Finally, at R(S/)(L) = 1, the phase transition is complete. The mixed film at the highest surfactant to lipid molar ratio (R(S/L) = 2.3) was hydrated by a vapor saturated atmosphere. At full hydration, a cubic to lamellar phase transition occurs. Coarse grain dynamic investigations, carried out as a function of both the surfactant to lipid molar ratio and the number of water molecules for amphiphile unit, allowed us to elucidate the structure of the emerging cubic phase and the hydration-induced structural pathway of the cubic to lamellar phase transition observed by EDXD.
Langmuir : the ACS journal of surfaces and colloids. 10/2005; 21(20):9137-42
ANTIOXIDANT ACTIVITY OF DIPHENYLPROPIONAMIDE DERIVATIVES: SYNTHESIS, BIOLOGICAL EVALUATION AND COMPUTATIONAL ANALYSIS.
Paolo Urbani, Anna Ramunno, Rosanna Filosa, Aldo Pinto, Ada Popolo, Erminia Bianchino, Stefano Piotto, Carmela Saturnino, Rocco De Prisco, Barbara Nicolaus, Giuseppina Tommonaro
ABSTRACT:We report the synthesis, antioxidant and antiproliferative activity and a QSAR analysis of synthetic diphenylpropionamide derivatives. Synthesis of these compounds was achieved by direct condensation of 2,2- and 3,3-diphenylpropionic acid and appropriate amines using 1-propylphoshonic acid cyclic anhydride (PPAA) as catalyst. Compound structures were elucidated by NMR analysis and their melting points were measured. The in vitro antioxidant activity of these compounds was tested by evaluating the amount of scavenged ABTS radical and estimating ROS and NO production in LPS stimulated J774.A1 macrophages. All compounds were tested for their effect on viability of cells and results demonstrated that they are not toxic towards the cell lines used. The cytotoxic activity of all compounds was evaluated by a Brine Shrimp Test.
Molecules 13.4 (2008): 749-761.
LIPID AGGREGATES INDUCING SYMMETRY BREAKING IN PREBIOTIC POLYMERISATIONS.
ABSTRACT:It is a long-standing and still open problem to determine the origin of biomolecular homochirality, and many scenarios have been suggested. Amphiphilic molecules are renowned for their capability to reorganize themselves in a variety of different morphologies and topologies, and for their capability to partition chemicals in well defined domains. Here a possible role for amphiphilic molecules inducing symmetry breaking is suggested in the framework of the research on origin of life.
Origins of life and evolution of the biosphere : 03/2004; 34(1-2):123-32
MONTE CARLO SIMULATIONS OF VESICLES AND FLUID MEMBRANES TRANSFORMATIONS.
Stefano Piotto, Fabio Mavelli
ABSTRACT:The appearance of compartmentalization is recognized as a key step in biogenesis. The study of the dynamical behaviour of amphiphilic close membranes at equilibrium or under some external stress (osmotic pressure or dehydration process) can be useful in order to better elucidate the role of vesicles in the origin of life and to get insight into the molecular and membrane properties that bring to a spontaneous vesicle division. A Monte Carlo approach to simulate the evolution of close membranes under an external stress will be presented. This approach is mainly based on the accepted surface energy model introduced by Helfrich (1973) and Seifert (1997a). Some preliminary results will be also illustrated and possible developments and limits of this method discussed.
Origins of life and evolution of the biosphere 03/2004; 34(1-2):225-35.
SEGREGATION INTO DOMAINS OBSERVED IN LIQUID CRYSTAL PHASES: COMPARISON OF EXPERIMENTAL AND THEORETICAL DATA
Heinz Amenitsch, Cecilia Bombelli, Stefano Borocci, Ruggero Caminiti,Francesca Ceccacci, Simona Concilio, Camillo La Mesa, Giovanna Mancini,Stefano Piotto, Michael Rappolt
ABSTRACT: The phase diagram of an amidic surfactant, sodium N-dodecanoylprolinate, was investigated by experimental means such as optical microscopy, multinuclear NMR, and SAXS experiments, and by dissipative particle dynamics and all-atoms molecular dynamics simulations. The organization in domains based on the stereochemical information of the surfactant (E and Z), as well as being observed previously under micellar aggregating conditions, was also observed in the liquid crystal phases. The combination of the different experimental techniques and of the theoretical investigation allowed us to clarify the nature of the domains and some of the involved interactions in their segregation and organization.
Soft Matter 7.7 (2011): 3392-3403.
CURVIS: A PROGRAM TO STUDY AND ANALYZE CRYSTALLOGRAPHIC STRUCTURES AND PHASE TRANSITIONS
S.P. Piotto, R. Nesper
ABSTRACT: The visualization of scientific data is, nowadays, of extreme importance. Phase transitions, the topology of a crystallographic system, the electron density distribution inside a lattice or the changes in crystal structure during phase transitions cannot be fully investigated without the help of proper visualization. The program CURVIS (downloadable free of charge upon request) was developed as a tool for investigating crystal structures and occurring transitions. In this tool, some features are implemented to analyse, display and manage the three-dimensional structure of crystals and single molecules. More importantly, CURVIS can generate and handle hyperbolic surfaces in three dimensions, and provide specific routines to perform calculations of curvature and energy of such surfaces. The most important features are (i) file format conversion (with assignment of the atom types and atomic charges), (ii) surface calculation and (iii) curvature and surface-energy analysis.
J. Appl. Cryst. 38:223-227.