Photonic crystals in biology

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Poster Session, Tuesday, June 15
Theme A1 - B702
Preparation and Characterization of Bacterial Polyester Based Nanoparticlesfor Targeted Delivery of
Etoposide
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UEbru KlçayUP P, Eylem GüvenP P, Mustafa TürkP P, Baki HazerP P, Emir Baki DenkbaP
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PKaraelmas University, Chemistry Department, Physical Chemistry Division, , Zonguldak, Turkey
University, Nanotechnology and Nanomedicine Division, 06532, Beytepe, Ankara, Turkey
University, Chemistry Department, Biochemistry Division, 06532 Beytepe, Ankara, Turkey
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PKırıkkale University, Biology Department, Biochemistry Division, Kırıkkale, Turkey
Abstract-Tumour-specific nano-structured drug delivery systems have received much attention due to their unique accumulation at tumour
region. Among them polymeric nanoparticles made from natural polymers have drawn major attention due to higher stability, maneuverability
for industrial manufacture, and opportunity for further surface nanoengineering. Aim of this study was to to prepare and characterize etoposideloaded,
folic acid conjugated poly(3- hydroxybutyrate-co-3 hydroxyhexanoate) (PHBHHx) nanoparticles for using in targeted cancer therapy.
Resulting data showed that etoposide-loaded and folic acid modified PHBHHX nanoparticles show promise for targeted delivery of etoposide to
cancer cells.
Nanotechnology is an emerging multidisciplinary field for
current research and development in all technical disciplines.
Nanoparticulate drug delivery systems which are nanometric
carriers used to deliver drugs or biomolecules have received
great attention over the last decades. Polymeric nanoparticles
have been widely investigated for both diagnosis and targeted
treatment of cancer; because they (a) can show controlled
release properties, (b) can pass through the smallest capillary
vessels and avoid rapid clearance by phagocytes, (c) can
penetrate cells and tissue gap in order to arrive at target
organs, (d) can reduce side effects of drugs, (e) can increase
drug efficacy, etc [1,2].
Polyhydroxyalkanoates (PHAs) are a promising class of new
emerging biopolymers. They are the polyesthers of
hydroxyalkanoate produced by a variety of bacterial species as
an intracellular carbon and energy compound under nutrientlimiting
conditions with excess carbon. There has been
considerable interest in using them as drug carriers due to their
biodegradability and biocompatibility. A newer member of
PHA family, poly(3-hydroxybutyrate-co-3 hydroxyhexanoate)
(PHBHHx), is currently being produced in large scale [3,4].
Studies have demonstrated that PHBHHx, a microbially
synthesized polyester with good biodegradability and
biocompatibility, as well as strong mechanical properties,
consequently, is very promising for biomedical applications.
In the presented study poly(3-hydroxybutyrate-co-3-
hydroxyhexanoate) nanoparticles were prepared to use in
targeted cancer therapy. PHBHHX nanoparticles were
prepared by solvent evaporation technique using
dichloromethane as the solvent and tween-80 as the emulsifier.
Morphological evaluations of the prepared nanoparticles were
investigated by using atomic force microscopy (AFM). Effect
of stirring rate, amount of surfactant and polymer
concentration on nanoparticle size were investigated by Zeta
Size Analyser. The size of the smallest nanoparticles obtained
was in the range of 190-220 nm. Etoposide, an antineoplastic
agent was loaded into nanoparticles and drug release profiles
were obtained. 16-30 % drug loading was observed in drug
loading studies depending on the initial drug content. Release
studies of etoposide were also evaluated. For ‘active’ targeting
of cancerous cells; nanoparticles were modified with folic acid
as the model ligand for targeting nanoparticles to cancer cells.
The receptor for folic acid is upregulated in many human
cancers, including malignancies of the ovary, kidney, brain,
breast myeloid cells and lung. Therefore it can be utilized as a
useful target for tumor-specific drug delivery [5]. Different
concentrations of folic acid was used in order to investigate
the effect of ligand concentration on ligand binding efficiency.
Ligand binding efficiency was found to be between 71-93%.
Additionally physicochemical structures of nanoparticles were
analyzed by using FTIR and the system was optimized for
further in vitro and in vivo applications.
Obtained results showed that etoposide-loaded and folic acid
modified PHBHHX nanoparticles show promise for targeted
cancer therapy.
*Corresponding author: denkbas@hacettepe.edu.tr
[1] Paul, D.R., Robeson, L.M. ‘’Polymer nanotechnology:
Nanocomposites’’, Polymer 49 (2008) 3187-3204.
[2] Ferrari, M. Cancer nanotechnology: Opportunities and challenges.
Nat Rev Cancer (2005) 161–71.
[3] Bayram, C., Denkbas, E.B., Kiliçay, E., Hazer, B., Çakmak, H.B.
‘Preparation and Characterization of Triamcinolone Acetonideloaded
Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx)
Microspheres’ Journal of Bioactive and Compatible Polymers 2008;
23; 334.
[4] Zinn, M., Witholt, B., Egli, T. ‘’Occurrence, synthesis and
medical application of bacterial polyhydroxyalkanoate’’Advanced
Drug Delivery Reviews, 53 (2001) 5-21.
[5] Lu, Y., Low, P.S. ‘’Folate-mediated delivery of macromolecular
anticancer therapeutic agents’’ Advanced Drug Delivery Review,. 54
(2002) 675-693.
6th Nanoscience and Nanotechnology Conference, zmir, 2010 264