98990 - BIOMIMETIC MATERIALS

Learning outcomes

At the end of the course the student has acquired knowledge to design, develop and characterize inorganic and organic-inorganic materials with tailored technological properties, according to the biomimetic principles, such as synthesis in confined reaction spaces, templated synthesis, morphosynthesis, crystal tectonics.

Course contents

1. Introduction. Introduction to biomimetic chemistry. Program outline.

2. Introduction to biomineralization processes. Functions of biomineralized tissues, inorganic and organic components, organic matrix control on inorganic phase deposition.

3. Characterization techniques. General principles of techniques useful to characterize biomimetic materials: wide and small angle X-ray diffraction techniques; Transmission Electron Microscopy (TEM); Scanning Electron Microscopy (SEM); Contact angle (wettability).

4. Main inorganic components. Carbonates: chemical and structural properties of calcium carbonate polymorphs, biogenic carbonates. Phosphates: chemical and structural properties of calcium phosphates, biogenic phosphates. Silicates: amorphous and biogenic silicates. Iron oxides: synthetic and biogenic magnetite.

5. Biomineralization processes. Biologically induced mineralization. Biologically controlled mineralization: intercellular, extracellular and intracellular mineralization. Control mechanisms.

6. Chemical control. Classical nucleation theory: homogeneous nucleation, free energy of nucleation and critical nucleus, nucleation rate, heterogeneous nucleation; crystal growth; polymorphism: Ostwald’s law; role of additives on nucleation and growth. Non-classical crystallization: oriented attachment, mesocrystals.

7. Spatial control. Supersaturation control: direct and indirect mechanisms. Phospholipidic vescicles: magnetotactic bacteria. Proteic vesicicles: ferritin. Cellular assembly. Macromolecular frameworks.

8. Structural control. Structural and acidic macromolecules. Organic matrix mediated nucleation. Composition and structure of nacre as a result of structural control.

9. Morphological control. Symmetry breaking. Vectorial regulation. Pattern formation through: organic scaffolds, vescicles grouping, cellular grouping. Silica deposition in diatomee as exemplum of morphological control.

10. Constructional control. Hierarchical organization of bone: bone composition, mineralized collagen fibril, organization levels of bone, osteons.

11. Synthesis in confined reaction spaces. Synthesis into phospholipidic vescicles. Synthesis of metals and metal oxides into apoferritin. Synthesis into polymer sponges.

12. Template-directed material synthesis. Biological matrices. Lipid tubules. Oriented nucleation on Langmuir monolayers. Oriented nucleation on self-assembled monolayers.

13. Morphosynthesis. Physical patterning with supramolecular templates. Physical patterning from reaction field replication. Chemical patterning in unstable reaction fields.

14. Crystal tectonics. Supramolecular assemblies. Complex shapes formation in presence of additives. Nacre inspired layered structural composites.

15. Biomaterials. Synthesis, properties and structure of biocompatible and bioactive materials with potential applications in the field of biomaterials for hard tissues substitution and repair: functionalized calcium phosphates and their uses for the preparation of bone cements, prostheses coatings, scaffolds for regenerative medicine.

Readings/Bibliography

The use of lecture notes and teaching material (PowerPoint presentations and indications on scientific articles useful for exam preparation) will be fundamental during the course. The course covers advanced topics of great scientific relevance and therefore in continuous evolution. There is no textbook covering the whole program.

Many of the topics covered can be found in the book: S. Mann "Biomineralization" Oxford Chemistry Masters, Oxford University Press

Teaching methods

The course consists of class lectures on the main properties of biomineralized tissues as model systems for the design and development of synthetic materials with tailored functionalities through the strategies of biomimetic chemistry.

For each specific topic, the introductory concepts as well as some singificant examples taken from the scientific literature are presented.

Assessment methods

The acquired knowledge and skills will be verified through an oral exam. The theme of the first question is selected by the student. The oral test is aimed to estabilsh the student’s comprehension of the biomimetic chemistry strategies and of their applications to the synthesis of materials with tailored properties.

Teaching tools

PC, video projector, powerpoint presentations, videos.

Office hours

See the website of Elisa Boanini