b2815 Tissue Engineering and Nanotheranostics “9.61x6.69”116 Tissue Engineering and Nanotheranostics
2.2.2. Janus or heterodimer structures
Another important category of the hybrid structure is the Janus or
heterodimer structure. Nowadays, a most interesting and fascinating
design of the hybrid structure called “Janus” is attracting much atten-
tion owing to its multicompartmental nature. Janus particles,55–57
named by Casagrande and de Gennes for resembling the two-faced
Roman god, are presently composed of a type of soft-matter with dif-
ferent polarity, chemistry, or special physicochemical properties on
opposite sides.55,58,59 Various synthetic approaches have been reported
to generate purely inorganic–inorganic, polymer–inorganic heterodi-
mer, droplets, microgels, Janus polymersomes, or fibers and polymer–
polymer in different shapes and geometries ranging from nanometers
to micrometers. Some beautiful examples of heterostructures other
then magnetic hybrids are shown in Fig. 10.60–62
All Janus particle synthesis mechanisms are based on a three-step
order: masking, phase separation and self-assembly. Self-assembly
Fig. 9. (a) Physical appearance of prepared GdOF:Ln@mSiO 2 ZnPC–CDs hybrids.
(b) and (c) TEM and STEM images with EDS compositional analysis, and (d) the
elemental mapping images of GdOF:Ln@mSiO 2 ZnPC-CDs. Reprinted with permis-
sion from Ref. 54.