BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 igure 1 TEM image showng odered chains of prismatic Baco nanopartices. The nanoparticles were prepared in AOT microemulsions at Ba? ]:[Cr04] mobr ratio a1 and w= 10 Scale bar= 50nm prsmatc mophobgyd indiidual crystalites, Scale bar= 50 nm. Inset, the electron (M. Li et al. 1999) Changing the ratio of cations to anions in the crystal alters its interaction with the organic surfactant and thus the assembly/growth properties in the microemulsion o With excess barium, cationic faces form on the crystal Strong ionic binding between headgroups and crystal prevents controlled growth and precipitation of growing crystals leads to eventual nanofilament formation o With excess chromate, anionic faces form that don t bind surfactant No longer assembled by surfactant-surfactant interactions, leading to spherical nanoparticle 5:1 Ba*: CrO4 1: 5 Ba++: crO, 2- cationic faces anionic faces 飞5 Figure 4 Characterization of BaCrO4 nanostructures formed at ditferent reactant ratios. IBa?+1: ICr02-1-5: 1 and w= 10: scale bar=500nm. b, Higher magnification dividual fibre. c, Spherical BaCr0, nanopartides prepared at (Ba2*1: ICr02-1-1: 5 and w= 10: scale bar= 50 nm Dendrimer biomineralization 0 Hydrophobic surfactant tails self-assembled on the surface of dendrimer particles Lecture 11-Inorganic biomaterials 11of12BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Lecture 11 – Inorganic Biomaterials 11 of 12 (M. Li et al. 1999) • Changing the ratio of cations to anions in the crystal alters its interaction with the organic surfactant and thus the assembly/growth properties in the microemulsion o With excess barium, cationic faces form on the crystal ƒ Strong ionic binding between headgroups and crystal prevents controlled growth and precipitation of growing crystals leads to eventual nanofilament formation o With excess chromate, anionic faces form that don’t bind surfactant ƒ No longer assembled by surfactant-surfactant interactions, leading to spherical nanoparticles 5:1 Ba++: CrO4 2- cationic faces 1:5 Ba++: CrO4 2- anionic faces • Dendrimer biomineralization10 o Approach: • Hydrophobic surfactant tails self-assembled on the surface of dendrimer particles