Biomedical Engineering Reference
In-Depth Information
Table 11.1
Comparison of different wet synthetic techniques
with respect to favorable qualities for biomedical functional
magnetic nanoparticles.
Precipitation
Precipitation + micelles
Improved thermal
decomposition
Bacterial
biomineralization
Reproducibility
Low. Very diffi cult to
control all parameters
High
High
High
Monodispersed
(size and shape)
Low. Various products
at low temperatures.
Defi ned shape at high
temperatures, various
sizes
High. Micelles
restricted to a defi ned
size
High
High. Genetic
control gives
highly defi ned
sizes and shapes
Range of particle
variety
Many different
particle morphologies.
Can be diffi cult to
specify
2 - 500 nm - diameter
spherical particles can
be formed using
various surfactants
Low. Method can
only produce small
particles < 20 nm
Many different
shapes and sizes
of
magnetosomes
known, but very
few able to be
utilized at
present
Organic/
biological coating
Multiple steps needed
Diffi cult. Inorganic
coating only, unless
use multiple steps
Multiple steps
needed
Integral lipid
coating already
present
Ambient
conditions
(biomolecule
friendly)
Can be compatible
Can be compatible
Multiple steps
needed due to
harsh synthetic
conditions
Very compatible
with lipids and
proteins present
Cost
Lowest cost
Quite low cost
(demands specialist
surfactants)
Higher cost. High
temperature, costly
starting materials
Higher cost.
Fermenter
running and
media costs
Yield
High
High
High
Low
reproducible product with regards to size and shape distribution. Furthermore,
the presence of ferric oxide impurities is commonplace.
The precipitation method can be refi ned with a greater degree of control over
particle size by the addition of a surfactant to the reaction, so as to form micelles.
In this improved synthesis, the reaction is carried out in an organic solvent so that
the surfactant forms reverse micelles with a central core of a well-defi ned volume
of inorganic reaction solution. The particles are then synthesized and controlled
