Combinatorial-designed Hyaluronic Acid Nanoparticles for Tumour Targeted Drug and Small Interfering Ribonucleic Acid Delivery - Hyaluronic Acid for Biomedical and Pharmaceutical Applications - page 70

nanosystems to possibly block all the receptors expressed on the cell
surface ( Figure 3.4c ). A highly diminished cellular localisation/uptake
(>90% inhibition) of the Cy3-labelled siRNA complex indicates that
the cell entry was receptor-mediated and that it is independent of the
charge on the surface [19].

a b

Cell line Indication CD44

expression
levels

HA-PEI/cy3 siRNA

H69 SCLC ~60%

H69AR SCLC ~90%

A549 NSCLC >99%

c

A549 DDP NSCLC >99%

MDA-
MB468

Breast >99%

Hep3B Liver ~4%

B16F10 Murine

melanoma

~65%

Figure 3.4 CD44 receptor levels in different types of cells, and
the corresponding cell uptake. (a) Non-small cell lung cancer
(NSCLC), small cell lung cancer (SCLC), breast, liver and murine
melanoma cells were treated with monoclonal antibody against
CD44 receptors to determine the receptor levels on the surface of
the cells by flow cytometry. (b) To demonstrate that the particles
enter the cells via the receptors, MDA-MB468 cells were treated
with HA-PEI/siRNA nanosystems at 50 nm for 12 h and observed
under confocal microscope to capture images. The internalised
Cy3-labelled-siRNA appears as red. (c) For competitive inhibition
study, the cells were incubated with HA-PEI/Cy3-loaded-siRNA in
the presence and absence of excess free soluble HA and observed
under confocal microscope as shown. Reproduced with permission
from S. Ganesh, A.K. Iyer, D.V. Morrissey and M.M. Amiji,
Biomaterials , 2013, 34 , 3489. ©2013, Elsevier [19]

It was also realised that not all the particles that enter the cells
mediated gene down-regulation. Only particles that have the