Page 21 - ASME_NEMB_2016_Program

TRACK 2 Technical Program

TRACK 2 NANOPARTICLE-BASED DELIVERY synovial fluid (SF) interactions using ex vivo models. We hypothesize that
cationic NPs will exhibit greater retention within the cartilage due to electro-
static interactions with the anionic extracellular matrix components. Howev-
MONDAY, FEBRUARY, 22 er, the affect of SF on NPs is unknown, and may impact those interactions.
Materials and Methods: NPs were formulated using FDA approved poly (lac-
2-1 tic-co-glycolic acid) (PLGA) for its demonstrated biocompatibility in joints and
EMERGING NANOTHERAPEUTICS controllable physicohemical properties. The zeta potential of the NPs was
controlled by emulsification of the organic PLGA solution in 1% polyvinyl al-
cohol (PVA NPs) or 1% PVA plus 0.2% didodecyldimethylammonium bromide
Bexar/Travis 11:30 AM - 1:00 PM (DMAB NPs) to yield negatve and positive zeta potentials respectively. The
NPs were loaded with nile red dye for ex vivo imaging and quantification.
Hydrodynamic diameter, zeta potential, and polydispersity, before and after
Session Organizer: Nicole Levi-Polyachenko, Wake Forest School incubation with SF were analyzed with ZetaPALS Dynamic Light Scattering.
of Medicine, Winston-Salem, NC, United States Analysis of NP retention within cartilage was conducted on viable bovine
Session Co-Organizer: Jacob Berlin, City of Hope, Beckman Re- cartilage explants with intact superfical zone. NPs were constituted in either
search Inst., Duarte, CA, United States phosphate buffered saline (PBS) or bovine SF, incubated on the cartilage
surface for 30 min, washed, and imaged with a Zeiss Axio fluorescence
11:30am Delivery of siRNA with Nanoparticles Based on PEG- microscope. To quantify NP retention, explants were homogenized and dye
PLA Block Polymer was extracted using methanol which was measured using a fluorescent
plate reader (BioTek Syngery HT) against known standards prepared in a
similar manner.
Keynote. NEMB2016-6154
Results and Discussion: Mean NP characteristics (n = 3) varied with emulsifi-
Jun Wang, University of Science and Technology of China, Hefei, er composition - PVA NPs were 218 nm in diameter with a zeta potential of
Anhui, China -19.7mV, and DMAB NPs were 202 nm with a zeta potential of 17.1 mV. In PBS,
dye loading efficiency was 27.3% ± 4.3% and 26.4% ± 4.1% (n=3) for PVA and
Clinical application of RNA interference is limited by the delivery of siRNA DMAB particles respectively. Size and zeta potential changed upon incuba-
in vivo. We have developed nanoparticle system with stealthy property for tion with SF, indicating adsorption of macromolecules from the SF onto the
efficient siRNA encapsulation and delivery, which is fabricated with poly(eth- NP surface. Specifically, the size of the PVA and DMAB NPs increased to
ylene glycol)-b-poly(d,l-lactide) (PEG-PLA), siRNA and a cationic lipid, using 300nm and 250nm, respectively; the DMAB NPs also experienced a rever-
a double emulsion-solvent evaporation technique. Such formulation exhib- sal in zeta potential at -20mV. Overall, the cationic DMAB NPs demonstrated
ited high encapsulation efficiency of siRNA, significant down-regulation of greater surface interaction and penetration with cartilage compared to the
gene expression in vivo, and was used for anti-tumor treatments. To more anionic PVA NPs, however, both NPs experienced a significance drop in
efficiently down-regulate gene expression in solid tumor, such nanoparticles retention when incubated with SF. This was more pronounced with DMAB
should be more effectively internalized by tumor cells, escaped from the en- NPs, where the decreased retention may be attributed to adsorption of neg-
dosome/lysosome and released the cargo in cells, and we further improved atively charged hyaluronic acid or serum albumins onto the cationic NP sur-
its efficacy via integrating different strategies using block copolymer of PEG face, thereby diminshing the electrostatic interactions between the cationic
and PLA. We synthesized block copolymer of PEG and PLA bridged with a NPs and the negatively charged gycosaminoglycans in the cartilage.
linkage responsive to the tumor acidity, and fabricated nanoparticles, which
deshielded the PEG layer at the slightly acidic tumor extracellular microen- Conclusions: Results indicate that surface properties, particularly zeta po-
vironment and facilitated the delivery of siRNA to tumor cells after accumu- tential, play an important role in NP interactions with articular cartilage, and
lation at the tumor site. In addition, by incorporating highly membrane-active SF can significantly influence NP-cartilage interactions. The use of cationic
cationic helical polypeptides to the internal aqueous phase during the surfactants, such as DMAB, can facilitate cartilage interactions important for
nanoparticle preparation process, we significant improved the endosomal localizing NP delivery systems to the tissue. This study represents a step to-
escape of nanoparticles. Moreover, we observed that replacing PLA block wards understanding how physicochemical properties of NPs impact tissue
with poly(lactide-co-glycolide) (PLGA) block promoted intracellular siRNA re- interactions wthin the joint. Ongoing studies investigate the impact of NP
lease. Our results demonstrated that integrating these strategies significantly size, presence of OA, off-target tissue binding, and conjugation of targeting
improved the down-regulation of oncogene expression with specific siRNA peptides.
in tumor, and substantially reduced the dose of injected siRNA to achieve
similar efficacy in tumor growth inhibition when compared with our previous 12:20pm Ultrarapid Rewarming of Vitrified Biomaterials at
nanoparticle system. 1000 °C/min

12:00pm Nanoparticle Targeting to Cartilage: Effects of Surface Technical Presentation. NEMB2016-6142
Charge on Nanoparticle Interactions with Joint Tissues
Navid Manuchehrabadi, University of Minnesota, Minneapolis, MN,
Technical Presentation. NEMB2016-6064 United States, Meng Shi, University of Xi’an Jiaotong, China, China,
China, Aiden Carley Clopton, University of Minnesota, Minneapolis,
Shannon Brown, Blanka Sharma, University of Florida, Gaines- MN, United States, Feng Xu, Jinbin Qiu, Tian Jian Lu, University
ville, FL, United States of Xi’an Jiaotong, China, China, John Bischof, Univ Of Minnesota,
Minneapolis, MN, United States
Introduction: Osteoarthritis (OA) is a debilitating disease characterized by
the degeneration of cartilage in articulating joints, and is presently without a Vitrification is an attractive technology to bank and store tissues in a glassy
cure. Chondrogenic growth factors and small molecule drugs are currently vs. crystalline state for eventual warming and use in regenerative medicine.
under investigation as OA therapeutics, but lack targeting modalities and For example, tissues have been successfully vitrified by loading high mo-
localization to the cartilage, resulting in poor joint retention and low efficacy larity (6 – 8.4 M) cryoprotective agents (CPA) such as VS55, DP6 and even
after direct injection into the joint. The overall goal of this research is to ad- glycerol at critical cooling rates of 2.5, 40 and 85 °C/min respectively. How-
vance our understanding of how nanoparticle (NP)-based delivery systems ever, successful warming from the vitrified state often cannot be achieved by 21
can be engineered for localizing therapeutics to OA cartilage. Towards this standard methods as it requires critical warming rates of 55, 185 and 32000
goal, this study investigates the impact of NP zeta potential on cartilage and