Selective cell affinity of biomimetic micro-nano-hybrid structured TiO2 overcomes the biological dilemma of osteoblasts
Received 19 July 2009; received in revised form 13 November 2009; accepted 18 November 2009.
Abstract
Objective
There is a great demand for dental implant surfaces to accelerate the process of peri-implant bone generation to reduce its healing time and enable early loading. To this end, an inverse correlation between the proliferation and functional maturation (differentiation) in osteoblasts presents a challenge for the rapid generation of greater amounts of bone. For instance, osteoblasts exhibit faster differentiation but slower proliferation on micro-roughened titanium surfaces. Using a unique micro-nano-hierarchical topography of TiO2 that mimics biomineralized matrices, this study demonstrates that this challenge can be overcome without the use of biological agents.
Methods
Titanium disks of grade 2 commercially pure titanium were prepared by machining (smooth surface). To create a microtexture with peaks and valleys (micropit surface), titanium disks were acid-etched. To create 200-nm TiO2 nanonodules within the micropits (nanonodule-in-micropit surface), TiO2 was sputter-deposited onto the acid-etched surface. Rat bone marrow-derived osteoblasts and NIH3T3 fibroblasts were cultured on machined smooth, micropit, and nanonodule-in-micropit surfaces.
Results
Despite the substantially increased surface roughness, the addition of 200-nm nanonodules to micropits increased osteoblast proliferation while enhancing their functional differentiation. In contrast, this nanonodule-in-micropit surface decreased proliferation and function in fibroblasts.
Significance
The data suggest the establishment of cell-selectively functionalized nano-in-micro smart titanium surfaces that involve a regulatory effect on osteoblast proliferation, abrogating the inhibitory mechanism on the micropitted surface, while enhancing their functional differentiation. Biomimetic and controllable nature of this nanonodules-in-micropits surface may offer a novel micro-to-nanoscale hierarchical platform to biologically optimize nanofeatures of biomaterials. Particularly, this micro-nano-hybrid surface may be an effective approach to improve current dental implant surfaces for accelerated bone integration.
aThe Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, CA, USA
bDepartment of Prosthodontics, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
cBiomaterials Center, National Institute for Materials Science, Tsukuba, 305-0044, Japan
Corresponding author at: Laboratory for Bone and Implant Sciences (LBIS), The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, 10833 Le Conte Avenue (B3-081 CHS), Box 951668, Los Angeles, CA 90095-1668, USA. Tel.: +1 310 825 0727; fax: +1 310 825 6345.
ABSTRACT