similar strategy, distearoylphosphotidylethanolamine-PEG (DSPE-PEG) was used
to substitute OA to stabilize SPION while simultaneous replacement of OA with
dimyristoylphosphatidylethanolamine-DTPA (DMPE-DTPA) enabled the radiolabeling of
111 In onto SPION [48]. Porous silica shell was also added onto SPION to
attach chelators for
64 Cu, potentially useful for PET/MR imaging [23]. Another rare
strategy for SPION functionalization is that it can be incorporated between the
layers of poly(vinyl alcohol) (PVA) microbubbles via both encapsulation and
electrostatic interactions [96], and the resulting SPION-MB was radiolabeled with
99m Tc and successfully used for SPECT/CT and MR imaging.
10.3.2 Organic Nanomaterials
Compared with inorganic nanomaterials, the structural integrity of organic nanomaterials is more susceptible to chemical/physical modifications. Surface engineering for nanomaterials of this type requires more careful consideration. Here we
discussed three categories of organic nanomaterials—protein-based (e.g. albumin)
nanomaterials, liposomes, and polymeric nanomaterials.
10.3.2.1 Protein Nanoparticles
Despite the fact that the chemical conjugation is time-consuming and requires
tedious purification and quality control, and the structure of protein nanoparticles
might be disrupted post modification, the majority surface modification strategy for
protein nanoparticle is based on chemical conjugation [97, 98], although physical
interaction techniques (encapsulation and electrostatic interaction) are sometimes
adopted as well [99]. Protein nanoparticles usually bear many residual functional
groups (e.g. carboxylic and amine), thus it facilitates the surface modification of
albumin nanoparticles via all kinds of chemical conjugation. Covalent bonds are
more robust than physical interaction, which avoids the dissociation of the
post-modification ligands from protein nanoparticles in vivo [100–102].
For example, high-density lipoprotein (HDL) nanoparticles were chemically
conjugated with deferoxamine (DFO) for
89 Zr labeling and successfully imaged
tumor-associated macrophages (Fig. 10.5a) [103]. The nano-sized capsid protein of
bacteriophage MS2 was chemically linked to
18 F-fluorobenzaldehyde via tyrosine
side chains or 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) for
64 Cu labeling [104] and eventually proven useful for tumor imaging by PET.
Another unique protein nanomaterial is called protein polymers, usually composed
from repetitive amino acid sequences, which can assemble into monodisperse
nanoparticles [105]. With site-specific conjugation of sarcophagine chelator
AmBaSar, elastin-like polypeptides (ELP)-based protein polymers were radiolabeled with
64 Cu for in vivo administration, and several hours of circulation time
was observed for these protein polymers [105].
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to substitute OA to stabilize SPION while simultaneous replacement of OA with
dimyristoylphosphatidylethanolamine-DTPA (DMPE-DTPA) enabled the radiolabeling of
111 In onto SPION [48]. Porous silica shell was also added onto SPION to
attach chelators for
64 Cu, potentially useful for PET/MR imaging [23]. Another rare
strategy for SPION functionalization is that it can be incorporated between the
layers of poly(vinyl alcohol) (PVA) microbubbles via both encapsulation and
electrostatic interactions [96], and the resulting SPION-MB was radiolabeled with
99m Tc and successfully used for SPECT/CT and MR imaging.
10.3.2 Organic Nanomaterials
Compared with inorganic nanomaterials, the structural integrity of organic nanomaterials is more susceptible to chemical/physical modifications. Surface engineering for nanomaterials of this type requires more careful consideration. Here we
discussed three categories of organic nanomaterials—protein-based (e.g. albumin)
nanomaterials, liposomes, and polymeric nanomaterials.
10.3.2.1 Protein Nanoparticles
Despite the fact that the chemical conjugation is time-consuming and requires
tedious purification and quality control, and the structure of protein nanoparticles
might be disrupted post modification, the majority surface modification strategy for
protein nanoparticle is based on chemical conjugation [97, 98], although physical
interaction techniques (encapsulation and electrostatic interaction) are sometimes
adopted as well [99]. Protein nanoparticles usually bear many residual functional
groups (e.g. carboxylic and amine), thus it facilitates the surface modification of
albumin nanoparticles via all kinds of chemical conjugation. Covalent bonds are
more robust than physical interaction, which avoids the dissociation of the
post-modification ligands from protein nanoparticles in vivo [100–102].
For example, high-density lipoprotein (HDL) nanoparticles were chemically
conjugated with deferoxamine (DFO) for
89 Zr labeling and successfully imaged
tumor-associated macrophages (Fig. 10.5a) [103]. The nano-sized capsid protein of
bacteriophage MS2 was chemically linked to
18 F-fluorobenzaldehyde via tyrosine
side chains or 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) for
64 Cu labeling [104] and eventually proven useful for tumor imaging by PET.
Another unique protein nanomaterial is called protein polymers, usually composed
from repetitive amino acid sequences, which can assemble into monodisperse
nanoparticles [105]. With site-specific conjugation of sarcophagine chelator
AmBaSar, elastin-like polypeptides (ELP)-based protein polymers were radiolabeled with
64 Cu for in vivo administration, and several hours of circulation time
was observed for these protein polymers [105].
196
D. Chen and H. Hong