Biomedical Engineering Reference
In-Depth Information
Table 8.2
Methods for Creating Nanofeatures on Ti Implants Using Inorganic Materials
[24,35-40]
Methods
Characteristics
Physical approaches
Surface chemistry of the implants will not be altered
Compaction of micro-/nanoparticles
Localized only to certain parts of the implant surface
Possible weak bonds between particles and the
implant surfaces
Ion beam deposition
Create nanofeatures on the surface depending on
materials used
Chemical approaches
Surface chemistry of the implants might also be
altered
Acid etching
Often used with other methods
Imparts nanofeatures randomly
Peroxidation
Produces a TiO
2
gel layer
Imparts both chemical and topographical properties
NaOH treatment
Produces a sodium titanate gel layer
Varies both chemical and topographical properties
Can be used to deposit HA
Others
Surface chemistry of the implants might or might not
be altered
Sol-gel (colloidal particle adsorption)
Deposits nanoparticles
Creates a nanoscale thick film consisting of chemical
properties
Crystalline deposition
Deposits crystals to obtain a unique complex
topography
Self-assembly of monolayers
Exposes functional end groups (e.g., RGD) that have
specific functions
Lithography
Impart several microtopographic features on the
surface
Expensive, time consuming
coating method
[37]
. Other nanostructures made of metals such as alumina, titania, and zirconia have
also been deposited onto implant surfaces to provide nanoscale ridges that aid cellular adhesion and
differentiation
[44,45]
. Since the contacts are on the quantum scale, physical interaction between the
nanoparticles and the implant surface has been shown to be very strong
[46-48]
. In addition, nanode-
position of calcium phosphate on acid-treated titanium has been shown to significantly increase
mechanical interlocking with bone and accelerate healing of bone tissue
[49]
. Major concerns with
this method include the agglomeration of nanoparticles during the coating process and the uneven
distribution of nanoparticles onto the Ti implant surfaces, especially when nanoparticles are used at
high concentrations.
A modern approach to creating topography on titanium implants is the use of photolithography.
However, this method is expensive, time consuming, and requires considerable development prior to
actual use. Additionally, photolithography is rarely used to create nanoscale structures and mostly
