“9.61x6.69” b2815 Tissue Engineering and Nanotheranostics
Multifunctional Nanomaterials for Cancer Theranostics 237
copolymers. Among them, the most representative nanomaterial is
PEG–phosphatidylethanolamine (PEG–PE) micelles, which can be
loaded with drugs through two ways, i.e. by the dispersion method
and dialysis method.147,148 Block copolymeric micelles based on PEG–
poly(amino acids) (PEG–PAA) utilize polymerized amino acids as
hydrophobic core.^149 The advantage of using amino acids as hydro
phobic core is their biocompatibility and biodegradability, easy func
tionalization of terminal amino acid groups with other versatile
functional groups.
2.5. Mesoporous Silica Nanoparticles
Mesoporous silica nanoparticles (MSNs) have been promising in the
fields of delivery vehicles for drugs with the following features: (1) An
ordered pore network, with tunable sizes of 50–300 nm, shape and
pore diameters of 2–6 nm, which is very homogeneous in size and
allows fine control of the drug load and release kinetics; (2) A high
pore volume of 0.6–1 cm^3 /g to host the required amount of pharma
ceuticals; (3) A high surface area of 700–1000 m^2 /g, which implies
high potential for drug adsorption; (4) A silanolcontaining surface
that can be functionalized to allow better control over drug loading
and release.150–159 On the other hand, MSNs can be endocytosed
through the control of their surface functionalization, size and mor
phology by a huge number of mammalian cell lines. In vitro cytotox
icity tests indicate that MSNs have no cytotoxicity for different cell
lines, even if the nanomaterials concentration was 100 μg/mL, just a
transient change in cell metabolism.^160 In vivo animal experiments
show that the MSNs have good biocompatibility, and almost no tox
icity.161,162 The maximum tolerated dosages can reach 200 mg/kg.^161
The MSNs can be intravenously administrated with good hemocom
patibility. Owing to the high specific surface area and tunable
mesoporous channel, the MSNs allow the transportation of drug
compounds of different nature, from small molecules to proteins
among others, either hydrophobic or hydrophilic drugs. Additionally,
by the modification of small molecules, polymers, and biomolecules
in both the interior (mesoporous channels) and exterior surfaces, the
