Biomedical Engineering Reference
In-Depth Information
67 % decrease in KB cell viability was observed compared to large number of live
cells treated with complexes lacking FA ligand suggesting anticancer therapeutic
efficacy of these complexes against FAR expressing cells.
Majoros and group reported targeted MTX delivery via FA/FITC conjugated
G5 PAMAM dendrimer to epithelial cancer cells (KB) overexpressing FAR
(Majoros et al. 2009). Reports exist wherein dendrimer modified imaging nano-
probes have been used for targeted cancer imaging. Aptamer-conjugated PAMAM
dendrimer-modified quantum dots have been used specifically for imaging of
U251 glioblastoma cells in vitro (Li et al. 2010). By virtue of unique structural
characteristics of dendrimers, they have been utilized for design of dendrimer-
entrapped metal NPs or dendrimer-stabilized metal NPs for computed tomography
(CT)/magnetic resonance (MR) imaging applications. Incorporation of anticancer
drug to such modalities can provide the platform for development of multifunc-
tional theranostic agents. Alpha-tocopheryl succinate (apoptosis inducing vitamin
E derivative) conjugated multifunctional dendrimer-entrapped gold nanoparticles
with FA and FI as targeting entity and imaging probe could act as multifunctional
theranostic platform to achieve targeted CT imaging of tumors and therapy (Zhu
et al. 2014). All the above stated examples clearly implicate prospective candida-
ture of dendrimers as delivery systems for cancer nanotheranostics. The structural
architecture of these nanosized polymeric systems can be fine-tuned according
to the therapeutic needs for the clinical benefit. Researchers are trying to deeply
understand the pharmacodynamics and pharmacokinetic aspects of drugs associ-
ated with dendrimers before entering the clinical trials. Moreover, the biodegra-
dability of dendrimers is still controversial. Upon entering the body and release of
therapeutic cargo what is the ultimate fate of dendrimers is still under investiga-
tion. Henceforth, still plenty of work needs to be done to develop dendrimers as
promising nanotools for cancer theranostics.
3 Porphyrins as Cancer Theranostic Agents
Although various techniques are prevalent in clinical trials for cancer therapy
such as surgery, chemotherapy and radiation therapy, etc. Nevertheless cancer
therapeutics and diagnostic techniques also benefiting from components that
efficiently absorb light (Photonics) includes photothermal and photodynamic
therapy (Dolmans et al. 2003; Haung et al. 2006), optical frequency domain
imaging (Vakoc et al. 2009), fluorescent and colorimetric detection (Chan and
Nie 1998; Storhoff et al. 2004), photoacoustic tomography (also known as optoa-
coustic tomography) (Wang 2009; Xu et al. 2006), and multimodal techniques
(Weissleder and Pittet 2008), etc. Optically active inorganic nanoparticles often
interacts strongly with photons thus can be used as agents for above mentioned
techniques.
Among the fluorescent probes, quantum dots are valuable and have extinc-
tion coefficients in the range of 105-106 M
−
1
cm
−
1
(Klostranec and Chan
