In most of the cases, the diagnostic and therapy stages are carried out independently and this lead to
delays in the application of the treatments and, therefore, an important risk to the patients´ health. To
overcome these incoveniences, in the few last years theranostic has reached an important role to join
in a unique nanoplatform therapeutic treatment, action and monitoring of the response to simultaneous
therapy. Thus, we designed an hybrid nanosystems based on gold nanoparticles capable of
simultaneously combining their potential as a photodynamic therapeutic agent (PDT), plasmonic
photothermal therapy (PPTT) and/or chemotherapy to kill malignant cells. In order to do that,
gold nanorods (GNR) were functionalized by the layer-by-layer (LbL) assembly technique using
alternate layers of polyelectrolytes (PE): poly (styrene sulfonate) (PSS) and poly-L-lysine (PLL) as
anionically and cationically charged polymeric layers, and an outer layer of hyaluronic acid (HA) to
provide the hybrid particles with sufficient colloidal stability and steering ability. Doxorrubicin
(DOXO) and SiRNA were added by electrostatic interactions to the PSS and PLL layers for providing
chemo- and genetic therapy, respectively, controlling the % weight and encapsulated efficiency of
doxorubicin and SiRNA with their calibration curve. To provide the PDT capabilities to the
nanoplatform, the green indocyanine photosensitizer (ICG) was previously conjugated to the PLL
polymer and assembled into the nanoplatform by electrostatic interactions, checking its efficiency
with the fluorometer. In this way, hybrid particles formed by GNR coated with PSS/DOXO/PLL @
ICG@SiRNA / HA layers were obtained, in which the therapeutic PDT activity of the dye ICG,
chemo- activity of DOXO and the photothermal properties of the plasmonic metal nanoparticles can
be simultaneously be applied for efficient cancer therapeutics. Nanoplatforms were characterizated by
UV-Vis, FTIR and RAMAN spectroscopy, -potential and TEM. In addition, PPTT therapy of the
nanoplatforms was evaluated at different irradiation powers. Finally, single oxygen ( 1 O 2 ) production
under NIR light excitation by the hybrid nanosystem was evaluated in vitro at several power
intensities by means of fluorescence and absorbance spectroscopies and fluorescent microscopy.