“9.61x6.69” b2815 Tissue Engineering and Nanotheranostics
Multifunctional Nanomaterials for Cancer Theranostics 239
is also achievable by utilization of CNTs’ unique optical properties.^186
When conjugated with a targeting ligand, CNTs can be adopted as
tumorselective delivery vectors. Functionalized MWCNTs modified
with a ligand of LRP receptor of angiopep2 (ANG) were used for the
targeted delivery of DOX to glioma. Improved therapeutic efficacy
was obtained for DOX–MWCNTs–PEG–ANG when compared with
free DOX.^185 Covalent binding of drugs onto CNTs can also be
employed for hydrophilic drugs. For example, the anticancer drug of
cisplatin and targeting ligand of epidermal growth factor (EGF) were
covalently attached to SWCNTs and had enhanced killing efficacy of
cancer cells.187,188 According to the literatures reported, CNTs can
also be good gene delivery vector of plasmid DNA and small interfer
ing RNA (siRNA).189–192 Other categories of carbon nanomaterials are
nanosized graphene including graphene oxide (GO), reduced gra
phene oxide (RGO), and hybrid graphene nanostructures. With
unique physical and chemical characteristics of ultrahigh surface area,
optical absorption, and versatile surface modification, graphene also
attracts enormous research interests.63,193–198 Like CNTs, the presence
of reactive functional groups and localized πelectrons, which support
the π–π bond with aromatic compounds such as DOX, render gra
phene a suitable candidate as a drug delivery system.195,199 Moreover,
the multifunctional graphene theranostics has also been developed.
For example, DOX was loaded onto magnetic GO to be used for
MRI detectable and magnetically targeted drug delivery.^2 00–202
Following a similar approach, a GObased T 1 MRI detectable nano
platform was developed via a GOgadolinium complex.203,204 Graphene
derivatives have also been used for directing a gene of DNA or RNA,
with PEI or chitosan being two primary mediators to improve the
DNA/RNA binding and condensation, to the cancerous sites.205–211
3. Nanotherapeutic Agents
3.1. Anti-cancer Drugs
Up to now, DOX and paclitaxel (PTX) have been two of the most
extensively studied cancer therapeutics that have been encapsulated
into nanoparticles for theranostic applications.^73 PEGylated liposomal
