title: Helical rosette nanotubes: a biomimetic coating for orthopedics?
abstract: Helical rosette nanotubes (HRN) are obtained through an entropically driven self-assembly process of low-molecular-weight synthetic modules under physiological conditions. Counter-intuitively, these materials undergo extensive self-assembly under the effect of temperature, resulting in networks of very long nanotubes. We have previously shown, using an in vitro model, that titanium (Ti) coated with HRN containing a lysine side chain (HRN-K1) displayed enhanced osteoblast (OB) adhesion when compared to uncoated Ti (p < 0.01). Because it has been widely known that proteins play a critical role in OB adhesion on nanophase materials, here we examine OB adhesion on heated (+T) and unheated (-T) HRN-K1-coated Ti under serum (+S, presence of proteins) and serum-free (-S, absence of proteins) conditions. The results demonstrated that (a) while proteins enhanced OB adhesion on +T HRN-K1-coated Ti, they had no effect on -T HRN-K1-coated Ti, suggesting an active role played by the rosette nanotubes in promoting OB adhesion, and (b) under -S conditions, +T HRN-K1 induced the same level of OB adhesion as uncoated Ti under +S conditions, suggesting that +T HRN-K1 acts as a protein substitute. Finally, transmission electron microscopy and atomic force microscopy studies of +T and -T HRN-K1-coated Ti revealed a significant change in surface coverage, density and hierarchical organization of the nanotubes upon heating, which was correlated with their ability to promote cell adhesion.
authors: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907-2022, USA.
authors: Ai Lin
authors: AL
authors: Chun
authors: Jesus G
authors: JG
authors: Moralez
authors: Thomas J
authors: TJ
authors: Webster
authors: Hicham
authors: H
authors: Fenniri
mesh_terms: D000327:Adsorption; D040761:Biomimetic Materials / Q000008:administration & dosage / Q000737:chemistry*; D018786:Bone Substitutes / Q000032:analysis / Q000737:chemistry*; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D020099:Coated Materials, Biocompatible / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry; D006801:Humans; D008239:Lysine / Q000008:administration & dosage* / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D043942:Nanotubes / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D009985:Orthopedics / Q000379:methods; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D010316:Particle Size; D011485:Protein Binding
chemical_list: D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D008239:Lysine