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TRACK 5 TRACK 5 Technical Program

Gianluca Ciardelli, Clara Mattu, Monica Boffito, Susanna Sartori, 10:40am Design and Characterization of Biomimetic Vesicles
Politecnico di Torino, Torino, Select State/Province, Italy Deriving from Leukocyte Plasma Membrane

In virtue of their high chemical versatility, Polyurethane (PUR)-based bioma- Technical Presentation. NEMB2016-6055
terials represent a very promising alternative to traditional polymers as both,
drug delivery nanovectors and tissue engineering supports. PUR synthesis Roberto Molinaro, Claudia Corbo, Francesca Taraballi, Houston
is quite straightforward: it requires a first reaction between a diol and a diiso-
cyanate to form a prepolymer, which is then reacted with a chain extender to Methodist Research Inst., Houston, TX, United States, Silvia Mi-
obtain the polymer. A wide variety of starting reagents can be used to obtain nardi, Department of NanoMedicine, Houston Methodist Research
PURs with the desired physical, mechanical and biological properties [1]. Institute, Houston, TX, USA, Houston, TX, United States, Michael
In my group a two-step synthesis procedure has been optimized and a wide Evangelopoulos, Houston Methodist Research Institute, Hous-
library of PURs based on polyether (polyethyleneglycol, PEG or Pluronics) ton, TX, United States, Michael Sherman, Univ. of Texas Medical
and polyester (poly(ε-caprolactone), PCL) blocks or a combination thereof (at Branch, Galveston, TX, United States, Kelly A Hartman, Alessan-
varying PCL/PEG ratio) has been obtained. These polymers have been used dro Parodi, Houston Methodist Research Institute, Houston, TX,
to prepare nanoparticles, nano-micells, and injectable hydrogels-based drug
delivery vectors for several active principles [2]. United States, Ennio Tasciotti, The Methodist Hospital Research
Institute, Houston, TX, United States
For instance, Pluronic-based polyurethane hydrogels with sol-gel thermal
transition at desired temperature and concentration have been obtained. To date, a multitude of micro- and nanocarriers have been developed to
These polymers are readily soluble in water at low temperature and rapidly improve the systemic delivery of pharmaceuticals. All these carriers are
undergo a phase transition from sol to gel at body temperature through subjected to a number of biological barriers that limit their optimal biodis-
micellar aggregation. Moreover, their ability to sustain the release of both, tribution, providing one of the main obstacles to an effective drug delivery.
hydrophilic and hydrophobic, drugs has been demonstrated. Bio-inspired approaches have been utilized as alternative treatments to
evade the mononuclear phagocytic system and facilitate the transport
The hydrophobic core of the micelles has been exploited to host hard-to-ad- across the endothelial vessel wall. In the past decades, bottom-up and top-
minister hydrophobic drugs, obtaining a drug reservoir for the treatment of down approaches have been developed to formulate these biomimetic ves-
localized pathologies. For instance, Curcumin, Resveratrol and Dexametha- icles. However, both approaches are not without their own set of limitations.
sone, 3 model hydrophobic drugs, as well as Ampicillin and Bovine Serum In fact, although bottom-up approaches have the great advantage of pro-
Albumin (BSA) as model hydrophilic drugs have been entrapped inside viding superior physicochemical control over the final formulation, current
the hydrogel and their release kinetics have been studied. In all cases, the chemical conjugation methods remain inadequate to synthetically reproduce
polymer formed a stable hydrogel in less than 5 min at 37 °C (body tem- the complexity of the cellular membrane on the surface of nanocarriers. On
perature) and was able to sustain the release of the hydrophobic drugs for the other hand, top-down strategies lacked the control of the physical pa-
up to 25 days, whereas the release of hydrophilic molecules was faster and rameters (i.e. size, homogeneity), and a poor encapsulation and retention of
completed in about 2 weeks. Moreover, BSA integrity was demonstrate by payload molecules (i.e. hydrophilic, amphiphilic, and lipophilic small drugs).
SDS-page analysis of the released protein, indicating no adverse interaction
between the protein and the hydrogel. In addition, the PUR hydrogel could Here, we describe the formulation of a biological material (the plasma mem-
be extruded into continuous filaments able to host cells, opening the possi- brane) into nano-sized vesicles. Our method combines both bottom-up and
bility of using PURs in bioprinting applications [3,4]. top-down approaches, to produce a biomimetic nanovesicle with original
drug delivery properties. At the same time, we transferred some functional
PURs with modulated hydrophilic/hydrophobic balance have also been properties of the plasma membrane onto the synthetic nanoparticles. This
proposed for the preparation nanoparticles for the controlled release of the new class of biomimetic nanoparticles were extensively characterized for
anticancer drug Paclitaxel. The effect of the polyurethane composition on both their physical (dynamic light scattering, cryoTEM, atomic force micros-
cellular internalization, drug release and nanoparticles properties has been copy, Fourier-transform infrared spectroscopy, and differential scanning cal-
studied. orimetry), as well biological (protein composition and protein orientation and
activity) properties. We leveraged on the high versatility of liposomal assem-
For active cancer recognition, surface coating and surface functionalization bly methods, to formulate a highly standardized and stable product. Theo-
strategies with the monoclonal antibody Trastuzumab have been imple- retical calculations were used to quantify the number of copies of selected
2
mented. In the first case, hydrophilic/hydrophobic interactions have been proteins per particles and per surface area unit (µm ). From the physical
exploited to obtain antibody-coated PUR nanoparticles, whereas for surface standpoint, the biomimetic formulation of the membrane proteins produced
coupling we took advantage of the presence of BOC-protected amino func- particles with homogeneous size (around 120 nm, with >>90% unilamellarity),
tionalities, previously inserted in the polyurethane backbone, to covalently as demonstrated by low magnification cryo-TEM and the polydispersity in-
couple the antibody to PUR nanoparticles. In both cases, high drug loading, dex (PDI) from DLS, and negative surface charge (-13.8 mV). High magnifica-
sustained release and good selectivity towards the selected cell type has tion cryo-TEM revealed that the incorporation of the membrane proteins pro-
been achieved [5,6]. duced a 1.3 fold-increase in bilayer thickness compared to bare liposomes.
Additionally, the proteomic analysis showed that this method permitted the
Our group has demonstrated that PURs hold a number of advantages transfer of over 180 membrane-associated proteins to the particle’s surface,
over traditional polymers and that they are optimal candidates to build tai- conserving their orientation, post-transcriptional modifications, functions,
lor-made nano-scale drug delivery systems. and their cooperation with other proteins. To the best of our knowledge, this
approach represents the first time such a complex material as the plasma
[1] S.Sartori,..., G. Ciardelli. J. Mater. Chem.. B, 2014, 2:. 5128-5144. membrane is formulated into a lipid vesicle, using a reproducible method, to
[2] S. Sartori,..., G. Ciardelli REACTIVE & FUNCTIONAL POLYMERS, 2013; 73 exploit the incorporation of membrane proteins into a lipid bilayer.
(10): 1366-1376
[3] E.Gioffredi et. Al. Submitted to Procedia CIRP
[4] M. Boffito,..., G. Ciardelli Submitted to Polymer International
[5] C. Mattu,..., G. Ciardelli. J. Nanop. Res. 2012; 14:1306.
[6] C. Mattu,..., G. Ciardelli, Z. Ramtoola. Eur. J. Pharm. Biopharm. 2013, 85(3);
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