b2815 Tissue Engineering and Nanotheranostics “9.61x6.69”
106 Tissue Engineering and Nanotheranostics
and amphiphilic polymers to enhance the biocompatibility.14,15
Extensively used superparamagnetic iron oxide nanoparticles with
various surface functionalities are favorable to carry targeting ligands
such as peptides, proteins, DNA, RNA, carbohydrates and enzyme to
improve particular tumor targeting.1,7,16,17 These features and the
multifunctionality of magnetic nanohybrids are potentially applicable
as contrast agents, smart drug delivery vehicles and in theranostic
applications. The delivery via magnetic nanohybrid material to tar-
geted cells is a significant and challenging task in medicinal diagnosis
and therapy.
2.1. Preparation of Magnetic Nanohybrids
2.1.1. Seed-mediated Growth Towards Magnetic Nanohybrids
Seed-mediated growth presents an efficient technique for the fabrica-
tion of the magnetic hybrid nanostructures with heterogeneous
growth. The hybrid part is attached onto the surface of a magnetic
core and then sequentially cultivated. In the heterogeneous process,
growth via atomic collision and heterogeneous nucleation play a very
important role. Excellent progress has been made in the preparation
of the core–shell and dumbbell nanostructures by making two differ-
ent hybrid species. Reverse microemulsion contributes an important
character in the synthesis of core–shell magnetic nanohybrids. The
individual components which have large lattice space difference pro-
duce core–shell structure by growing a uniform layer in the form of
shell material around core particles, whereas the individual compo-
nents which have similar lattice parameters and crystal structures
produce dumbbell-shaped structures.18–20
Some general synthesis models for the growth of core–shell
and dumbbell magnetic hybrid structures are shown in Fig. 2 and
can be categorized into synthetic direction. Figures 2(a)–2(c)
show an example of direct heterogeneous growth of hybrid species
on primary seed. A chemical activation agent is used on the
surface of primary core–seed to grow the secondary precursor
