Electrojetted Biodegradeable Polymer Nanoparticles for drug delivery and cell targeting applications.
Preparation of protein-releasing micro and nanoscale particles by two-phase electrojetting of protein in the biodegradeable polymer PLGA using surfactants as emulsifying agents.
Sejal Tailor, Sarah Richardson-Burns, Kyung-Ho Roh, Joerg Lahann, and David C. Martin
Abstract
Current drug treatments for many ailments are invasive, unspecific, and
uncomfortable, so studies involve developing implantable drug delivery methods.
A new method for drug delivery involves electrojetted proteins emulsified
in nanospheres made of a polymer. We employed a two-phase electrojetting/electrospinning
technique in order to generate micro and nanoscale spheres and fibers comprised
of 50:50 poly(lactic-co-glycolic acid) (PLGA, dissolved in chloroform) into
which the protein bovine serum albumin (BSA, diluted in phosphate buffered
saline; PBS) was mixed using the surfactant Triton X-100. The surfactant
acted as an emulsifying agent to maintain the protein in suspension within
the polymer. We first conducted solubility tests on a variety of surfactants
including Triton X-100, Tween-20, Tween-80, Pluronic, Span-80, polyethylene
glycol to determine which surfactant allowed PBS to remain in suspension
in the PLGA the longest. Triton X-100, Span-80, and Tween-80 showed the
best results with Triton X-100 showing the most complete, longest lasting
emulsion. Therefore for future experiments the electrojetting solution used
was comprised of .323 % (w/v) BSA (fluorescently labeled with AlexaFluor
594), .323% (v/v) Triton X, 9.68% (w/v) PLGA, 2.90 % PBS, 86.774% (v/v)
Chloroform. After electrojetting/electrospinning of the PLGA-protein-surfactant
emulsion, we assessed the morphology of the resulting micro/nanospheres
using optical microscopy and used fluorescence microscopy to detect the
presence of the protein within the PLGA nanospheres. Distinct globules of
protein were detectable within both the micro/nanospheres and the nanofibers.
PLGA is a biodegradable protein therefore, we next measured the amount of
protein released from the micro/nanospheres incubated in PBS at 37oC over
a two month timecourse. Data points were taken at 0h, 24h, 5 days, 12 days,
28 days, and 56 days and the BCA protein assay (Pierce Biochemicals) was
used to quantify protein release. For the first four days an average of
8 µg of protein was released, and eight days later an average of 6
µg of protein released, and after 28 days of incubation an average
of 13 µg of protein was released. A second experiment performed over
a two week timecourse revealed that for the first two days an average of
18 µg of protein was released, and five days later an average of 18
µg of protein was released and at the end of the two-week period an
average of 6 µg of protein had been released. We are currently performing
cytotoxicity tests on PLGA-protein-surfactant spheres prepared using the
surfactant Triton X-100 exposed to SH-SY5Y human neuroblastoma cells. We
are also assessing whether two biologically-derived phospholipids, Dimodan
(distilled monoglyceride) and Phosphotidylcholine (plasma membrane phospholipid)
can act as emulsifying agents to replace the Triton X-100 in the PLGA-protein-surfactant
mixture. We will also be using the biologically-active protein Nerve Growth
Factor (NGF) to replace the BSA in the electrojetting mixture to generate
NGF-containing PLGA micro/nanoparticles to deliver NGF to PC-12 neural cells.
When exposed to NGF, PC-12 cells undergo differentiation characterized by
specific morphological changes such as neurite extension. The utility of
the PLGA micro/nanospheres as possible protein/drug-delivery vehicles will
be assessed by detecting whether the PC-12 cells undergo differentiation
following exposure to the NGF-containing particles.
Current Researchers
Sarah Richardson-Burns
Jeffrey Hendricks
Kyle Roebuck
Kyung-Ho Roh
Sejal Tailor
Mohammad Abidian
