In principle, incorporating nanoparticles into growing crystals offers an attractive and highly convenient route for the production of a wide range of novel nanocomposites. Herein we describe an efficient aqueous route that enables the spatially controlled occlusion of gold nanoparticles (AuNPs) within ZnO crystals at up to 20 % by mass. Depending on the precise synthesis protocol, these AuNPs can be (i) solely located within a central region, (ii) uniformly distributed throughout the ZnO host crystal or (iii) confined to a surface layer. Remarkably, such efficient occlusion is mediated by a non‐ionic water‐soluble polymer, poly(glycerol monomethacrylate)70 (G70), which is chemically grafted to the AuNPs; pendent cis‐diol side groups on this steric stabilizer bind Zn2+ cations, which promotes nanoparticle interaction with the growing ZnO crystals. Finally, uniform occlusion of G70‐AuNPs within this inorganic host leads to faster UV‐induced photodegradation of a model dye.

The mineralized collagen fibril is the basic building block of bone, commonly pictured as a parallel array of ultrathin carbonated hydroxyapatite (HAp) platelets distributed throughout the collagen. This orientation is often attributed to an epitaxial relationship between the HAp and collagen molecules inside 2D voids within the fibril. Although recent studies have questioned this model, the structural relationship between the collagen matrix and HAp, and the mechanisms by which collagen directs mineralization remain unclear. Here, we use XRD to reveal that the voids in the collagen are in fact cylindrical pores with diameters of ~2 nm, while electron microscopy shows that the HAp crystals in bone are only uniaxially oriented with respect to the collagen. From in vitro mineralization studies with HAp, CaCO3 and γ-FeOOH we conclude that confinement within these pores, together with the anisotropic growth of HAp, dictates the orientation of HAp crystals within the collagen fibril.

Einkristalline Calcit‐Nanodrähte werden durch Kristallisation von morphologisch äquivalenten amorphen Calciumcarbonat(ACC)‐Partikeln in den Poren von „Track‐Etch“‐Membranen gebildet. Das durch Polyasparaginsäure stabilisierte ACC wird durch Kapillarwirkung in die Poren gezogen, und die einkristalline Natur der Nanodrähte wird auf den beschränkten Kontakt des intramembranären ACC‐Partikels mit der umgebenden Lösung zurückgeführt. Die Reaktionsumgebung unterstützt dann die Umwandlung in ein einkristallines Produkt.

Polymerization‐induced self‐assembly (PISA) mediated by reversible addition–fragmentation chain transfer (RAFT) polymerization offers a platform technology for the efficient and versatile synthesis of well‐defined sterically stabilized block copolymer nanoparticles. Herein we synthesize a series of such nanoparticles with tunable anionic charge density within the stabilizer chains, which are prepared via statistical copolymerization of anionic 2‐(phosphonooxy)ethyl methacrylate (P) with non‐ionic glycerol monomethacrylate (G). Systematic variation of the P/G molar ratio enables elucidation of the minimum number of phosphate groups per copolymer chain required to promote nanoparticle occlusion within a model inorganic crystal (calcite). Moreover, the extent of nanoparticle occlusion correlates strongly with the phosphate content of the steric stabilizer chains. This study is the first to examine the effect of systemically varying the anionic charge density of nanoparticles on their occlusion efficiency and sheds new light on maximizing the loading of guest nanoparticles within calcite host crystals.

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