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Biomimetic helical rosette nanotubes and nanocrystalline hydroxyapatite coatings on titanium for improving orthopedic implants.

Zhang L, Chen Y, Rodriguez J, Fenniri H, Webster TJ - Int J Nanomedicine (2008)

Bottom Line: Some of the nanocrystalline HA formed dense coatings with HRNs on titanium.More importantly, results demonstrated enhanced osteoblast adhesion on the HRN/nanocrystalline HA-coated titanium compared with conventional uncoated titanium.Among all the HRN/nanocrystalline HA coatings tested, osteoblast adhesion was the greatest when HA nanometer particle size was the smallest.

View Article: PubMed Central - PubMed

Affiliation: Division of Engineering, Brown University, Providence, RI 02912, USA.

ABSTRACT
Natural bone consists of hard nanostructured hydroxyapatite (HA) in a nanostructured protein-based soft hydrogel template (ie, mostly collagen). For this reason, nanostructured HA has been an intriguing coating material on traditionally used titanium for improving orthopedic applications. In addition, helical rosette nanotubes (HRNs), newly developed materials which form through the self-assembly process of DNA base pair building blocks in body solutions, are soft nanotubes with a helical architecture that mimics natural collagen. Thus, the objective of this in vitro study was for the first time to combine the promising attributes of HRNs and nanocrystalline HA on titanium and assess osteoblast (bone-forming cell) functions. Different sizes of nanocrystalline HA were synthesized in this study through a wet chemical precipitation process following either hydrothermal treatment or sintering. Transmission electron microscopy images showed that HRNs aligned with nanocrystalline HA, which indicates a high affinity between both components. Some of the nanocrystalline HA formed dense coatings with HRNs on titanium. More importantly, results demonstrated enhanced osteoblast adhesion on the HRN/nanocrystalline HA-coated titanium compared with conventional uncoated titanium. Among all the HRN/nanocrystalline HA coatings tested, osteoblast adhesion was the greatest when HA nanometer particle size was the smallest. In this manner, this study demonstrated for the first time that biomimetic HRN/nanocrystalline HA coatings on titanium were cytocompatible for osteoblasts and, thus, should be further studied for improving orthopedic implants.

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Schematic illustration of the hierarchical assembly of HRNs with a lysine side chain (HRN-K1). (A) The DNA base pair building blocks (Guanine-cytosine, G^C motif) and lysine side chain, (B) Six G^C motifs assemble into a rosette supermacrocycle by the formation of 18 H-bonds, and (C) The rosettes stack up to form a stable 3.5 nm diameter HRN with a 11 Å inner tube channel.
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f1-ijn-3-323: Schematic illustration of the hierarchical assembly of HRNs with a lysine side chain (HRN-K1). (A) The DNA base pair building blocks (Guanine-cytosine, G^C motif) and lysine side chain, (B) Six G^C motifs assemble into a rosette supermacrocycle by the formation of 18 H-bonds, and (C) The rosettes stack up to form a stable 3.5 nm diameter HRN with a 11 Å inner tube channel.

Mentions: One type of novel nanomaterial, helical rosette nanotubes (HRNs), are novel organic nanotubes that mimic the natural nanostructure of collagen and other components in bone. The DNA base pair building blocks of HRNs (the guanine-cytosine motif) undergo self-assembly in body solutions to form a stable nanotube with a 3.5 nm outer diameter tube based on hydrogen bond formation, base-stacking interactions and hydrophobic effects (Figure 1) (Fenniri et al 2001). Not only are HRNs biologically-inspired nanometric and helical architectures similar to collagen in bone, but they also can be functionalized with a diverse range of peptides (such as arginine-glycine-aspartic acid [RGD] and lysine) which have been known to enhance osteoblast functions. Previous studies have demonstrated the ability of HRNs to increase osteoblast adhesion as a coating material on titanium (Chun et al 2004, 2005).


Biomimetic helical rosette nanotubes and nanocrystalline hydroxyapatite coatings on titanium for improving orthopedic implants.

Zhang L, Chen Y, Rodriguez J, Fenniri H, Webster TJ - Int J Nanomedicine (2008)

Schematic illustration of the hierarchical assembly of HRNs with a lysine side chain (HRN-K1). (A) The DNA base pair building blocks (Guanine-cytosine, G^C motif) and lysine side chain, (B) Six G^C motifs assemble into a rosette supermacrocycle by the formation of 18 H-bonds, and (C) The rosettes stack up to form a stable 3.5 nm diameter HRN with a 11 Å inner tube channel.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2626930&req=5

f1-ijn-3-323: Schematic illustration of the hierarchical assembly of HRNs with a lysine side chain (HRN-K1). (A) The DNA base pair building blocks (Guanine-cytosine, G^C motif) and lysine side chain, (B) Six G^C motifs assemble into a rosette supermacrocycle by the formation of 18 H-bonds, and (C) The rosettes stack up to form a stable 3.5 nm diameter HRN with a 11 Å inner tube channel.
Mentions: One type of novel nanomaterial, helical rosette nanotubes (HRNs), are novel organic nanotubes that mimic the natural nanostructure of collagen and other components in bone. The DNA base pair building blocks of HRNs (the guanine-cytosine motif) undergo self-assembly in body solutions to form a stable nanotube with a 3.5 nm outer diameter tube based on hydrogen bond formation, base-stacking interactions and hydrophobic effects (Figure 1) (Fenniri et al 2001). Not only are HRNs biologically-inspired nanometric and helical architectures similar to collagen in bone, but they also can be functionalized with a diverse range of peptides (such as arginine-glycine-aspartic acid [RGD] and lysine) which have been known to enhance osteoblast functions. Previous studies have demonstrated the ability of HRNs to increase osteoblast adhesion as a coating material on titanium (Chun et al 2004, 2005).

Bottom Line: Some of the nanocrystalline HA formed dense coatings with HRNs on titanium.More importantly, results demonstrated enhanced osteoblast adhesion on the HRN/nanocrystalline HA-coated titanium compared with conventional uncoated titanium.Among all the HRN/nanocrystalline HA coatings tested, osteoblast adhesion was the greatest when HA nanometer particle size was the smallest.

View Article: PubMed Central - PubMed

Affiliation: Division of Engineering, Brown University, Providence, RI 02912, USA.

ABSTRACT
Natural bone consists of hard nanostructured hydroxyapatite (HA) in a nanostructured protein-based soft hydrogel template (ie, mostly collagen). For this reason, nanostructured HA has been an intriguing coating material on traditionally used titanium for improving orthopedic applications. In addition, helical rosette nanotubes (HRNs), newly developed materials which form through the self-assembly process of DNA base pair building blocks in body solutions, are soft nanotubes with a helical architecture that mimics natural collagen. Thus, the objective of this in vitro study was for the first time to combine the promising attributes of HRNs and nanocrystalline HA on titanium and assess osteoblast (bone-forming cell) functions. Different sizes of nanocrystalline HA were synthesized in this study through a wet chemical precipitation process following either hydrothermal treatment or sintering. Transmission electron microscopy images showed that HRNs aligned with nanocrystalline HA, which indicates a high affinity between both components. Some of the nanocrystalline HA formed dense coatings with HRNs on titanium. More importantly, results demonstrated enhanced osteoblast adhesion on the HRN/nanocrystalline HA-coated titanium compared with conventional uncoated titanium. Among all the HRN/nanocrystalline HA coatings tested, osteoblast adhesion was the greatest when HA nanometer particle size was the smallest. In this manner, this study demonstrated for the first time that biomimetic HRN/nanocrystalline HA coatings on titanium were cytocompatible for osteoblasts and, thus, should be further studied for improving orthopedic implants.

Show MeSH
Related in: MedlinePlus