The geometry of targeting molecules on nanomaterials is also important for the
binding affinity of nanomaterials to target proteins. There are few reports on this
issue. Park et al. prepared two types of tumor-targeting nanoparticles for varying
PEG lengths. For a given number of peptides bound to nanoparticles, the presence
of a PEG linker facilitated peptide targeting by reducing conformational restriction
as well as increasing the residence time of the nanostructures in the blood stream
[54]. The short length of sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane1-carboxylate (SMCC) linker restricted the targeting peptide conformation.
Recently, Jeong et al. reported that antibody orientation on nanoparticles could
significantly affect the maintenance of full bio-functionality [55]. They prepared the
site-specific and orientation-controlled antibody conjugation on nanoparticles and
showed the 8-times higher target-binding ability than those prepared by the conventional non-site-specific and random amine-acid coupling using 1-ethyl-3(3-dimethylaminopropyl)carbodiimide (EDC) (Fig. 12.3).
Finally, all these results suggest that there should be the optimal number or
geometry on nanomaterials for each disease targeting strategy, and we should
carefully consider and investigate to find the optimal structure for the development
of targeted multifunctional nanoparticle systems for imaging and therapy.
Fig. 12.3 Quantitative evaluation of the antigen-binding capability of anti-bodies conjugated to
SiNPs. a Schematic of the quantitative bio-assay using a fluorescent HER2 antigen.
b Fluorescence images of the fluorescent HER2 antigen bound BSA treated SiNPs and
anti-HER2 antibody conjugated SiNPs prepared using the EDC/NHS coupling or click coupling
method, respectively. c Quantitative analysis of the number of antigens bound to a single SiNP
us-ing the fluorescence signal. The fluorescence images were obtained by IVIS with 2 s acquisition
time. SiNP: silica nanoparticle (copyright permission from [55])
240
Y.-S. Lee et al.
binding affinity of nanomaterials to target proteins. There are few reports on this
issue. Park et al. prepared two types of tumor-targeting nanoparticles for varying
PEG lengths. For a given number of peptides bound to nanoparticles, the presence
of a PEG linker facilitated peptide targeting by reducing conformational restriction
as well as increasing the residence time of the nanostructures in the blood stream
[54]. The short length of sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane1-carboxylate (SMCC) linker restricted the targeting peptide conformation.
Recently, Jeong et al. reported that antibody orientation on nanoparticles could
significantly affect the maintenance of full bio-functionality [55]. They prepared the
site-specific and orientation-controlled antibody conjugation on nanoparticles and
showed the 8-times higher target-binding ability than those prepared by the conventional non-site-specific and random amine-acid coupling using 1-ethyl-3(3-dimethylaminopropyl)carbodiimide (EDC) (Fig. 12.3).
Finally, all these results suggest that there should be the optimal number or
geometry on nanomaterials for each disease targeting strategy, and we should
carefully consider and investigate to find the optimal structure for the development
of targeted multifunctional nanoparticle systems for imaging and therapy.
Fig. 12.3 Quantitative evaluation of the antigen-binding capability of anti-bodies conjugated to
SiNPs. a Schematic of the quantitative bio-assay using a fluorescent HER2 antigen.
b Fluorescence images of the fluorescent HER2 antigen bound BSA treated SiNPs and
anti-HER2 antibody conjugated SiNPs prepared using the EDC/NHS coupling or click coupling
method, respectively. c Quantitative analysis of the number of antigens bound to a single SiNP
us-ing the fluorescence signal. The fluorescence images were obtained by IVIS with 2 s acquisition
time. SiNP: silica nanoparticle (copyright permission from [55])
240
Y.-S. Lee et al.