1. Peripheral Nerve Regeneration and Rheumatoid
Arthritis Treatment
Dr. Yu, Mr. Shah, Mr. Junka,
Melissa Conklin, and Michelle Osorio
Introduction
Over the summer, we were privileged to work on two research projects: helping to determine
the most efficient nerve guidance conduit which would help promote peripheral nerve
regeneration and on working to help develop a different delivery technique for the treatment
of Rheumatoid Arthritis.
• Peripheral Nerve Regeneration: When damage is done to the peripheral nerves
or surrounding tissues, complete loss of sensory and/or motor function can occur.
Current methods of treatments for peripheral nerve injuries greater than 4 mm
make use of an autograft. Autografts oftentimes lead to loss of function at the
secondary site of injury, and therefore, nerve guidance conduits are currently
being explored for an improved treatment method for peripheral nerve injuries.
Nerve guidance conduits are tubular channels that help promote nerve
regeneration after being sutured from the proximal stumps to the distal stumps.
There are several factors, however, that challenge the current ability to compare
the regenerating capabilities of different nerve guidance conduits: there exists an
array of gap lengths and a variety of alternate materials capable of making an
NGC.
• Improved Rheumatoid Arthritis Treatment: Current treatments for
rheumatoid arthritis involve the administration of non-steroidal anti-inflammatory
drugs (NSAIDS) delivered both orally and topically. The prolonged injection of
NSAIDS have severe effects on the gastrointestinal mucosa and topical creams
have poor drug penetration. Therefore, there is a need for the development a
subcutaneous local delivery of NSAIDS covalently bound to a hydrogel. This
system will hopefully help to promote long-term drug delivery and reduced
inflammation, while also limiting the many current harmful side effects.
Results
Project 1: After inserting the plethora of combinations into
ALINK, the prediction model yielded combinations of
good ∆L values for collagen, acceptable values for
polysulfone and polycaprolactone, and bad values for silicon.
Project 2: Below we provided the values we obtained from
the UV microplate reader for one trail. A higher number refers
to a less concentrated solution. (Less drug is released) The Ac
columns represent hydrogels bound with different
concentrations of acetaminophen and a cross linker, ID
represents hydrogels treated with Ibuprofen and a cross linker,
Ic is a hydrogel with Ibuprofen but without a cross linker, and
C is a hydrogel with just acetaminophen.
What We Did
Project 1: While working on the peripheral nerve regeneration
project, we helped to develop the majority of all possible
combinations of the materials which can be combined to
develop an NGC, including different combinations coupled
with enhancement factors. Over 365,505 combinations were
provided, which were then inserted into a prediction model,
ALINK, to estimate the regenerating capabilities of these
different combinations. ALINK was developed off of the
concept of L/Lc, a normalization standard (based off of ∆L
values) which allows for the comparisons of these
experimental conduits to the standard silicon conduits. ALINK
works by yielding a ∆L value to each combination by making
use of available data of NGCs and ensuring no duplicate
combinations.
Project 2: Our main objective for this project was to help aid
in the gathering of data for the drug release of acetaminophen
and ibuprofen bound to a hydrogel. This information provides
groundwork for future experiments necessary for the
development of an injectable hydrogel coupled to current
arthritic drugs. An injectable hydrogel will help to extend the
release of these drugs while minimizing the unwanted side
effects. A chitosan and dextran system was modified with
carboxymethyl and aldehyde, forming a cross-linking
hydrogel. Acetaminophen and Ibuprofen were then cross-
linked to these hydrogels by the uses of EDC and NHS
crosslinking agents. The primary amine groups on chitosan can
covalently bond to the carboxylate functional groups on the
NSAIDs. Different concentrations of these two drugs were
loaded onto these modified hydrogels. To help eliminate
experimental error and to gather more accurate readings, 3
trials were run for each concentration while also using control
groups treated only with PBS. After every hour, over an eight
hour time span, we pipetted out the liquid solutions present in
each vial and analyzed the solutions under a UV microplate
reader to determine the concentrations of the drugs in each of
the solutions. (Release Kinetics)
Conclusions
• Project 1: Many different possible
combinations of the materials used to develop
NGCs were tested, revealing the more
favorable ones.
• Project 2: The smaller the value that was
collected from the UV microplate reader lead
to a higher concentration of drug release from
the hydrogel. A hydrogel treated with
Ibuprofen and a cross linker seemed to have
yielded the highest drug concentrated
environments, however, the Acetaminophen
seem to have a more constant drug release.
Stevens Summer Scholar’s
Program 2013
0.0000
0.5000
1.0000
1.5000
2.0000
2.5000
3.0000
3.5000
4.0000
4.5000
5.0000
0 1 2 3 4
Absorbance(254OD)
Time (Hours)
ACETAMINOPHEN RELEASE
Acetaminophen (150/50)
Acetaminophen (160/40)
Acetaminophen (130/70)
Acetaminophen (140/60)
Acetaminophen (100/100)
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
1.2000
1.4000
1.6000
0 1 2 3 4
Absorbance(260OD)
Time (Hours)
IBUPROPHEN RELEASE
Ibuprophen (150/50)
Ibuprophen (160/40)
ibuprophen (130/70)
Ibuprophen (140/60)
Ibuprophen (100/100)
Hour 3
Ac Ac Avg. St. Dev.
150/50 0.293 0.292 0.2925 0.0007
160/40 0.345 0.232 0.2885 0.0799
130/70 0.266 0.304 0.204 0.2580 0.0412
140/60 0.129 0.128 0.1285 0.0007
100/100 0.075 0.088 0.0815 0.0092
ID Avg. St. Dev.
150/50 0.421 0.422 0.4215 0.0007
160/40 0.192 0.19 0.1910 0.0014
130/70 0.174 0.167 0.1705 0.0049
140/60 0.576 0.577 0.5765 0.0007
100/100 0.145 0.14 0.1425 0.0035
Hour 4
Ac Ac Avg. St. Dev.
150/50 0.09 0.075 0.072 0.064 0.0753 0.0109
160/40 0.087 0.071 0.083 0.085 0.0815 0.0072
130/70 0.08 0.077 0.095 0.079 0.0828 0.0083
140/60 0.184 0.184 0.075 0.074 0.1293 0.0632
100/100 0.051 0.089 0.045 0.067 0.0630 0.0197
ID Avg. St. Dev.
150/50 0.102 0.104 0.1030 0.0014
160/40 0.164 0.108 0.1360 0.0396
130/70 0.111 0.1 0.1055 0.0078
140/60 0.168 0.168 0.1680 0.0000
100/100 0.182 0.156 0.1690 0.0184
Hour 0
Ac Ac Avg. St. Dev.
150/50 3.309 3.311 3.3100 0.0014
160/40 3.305 3.293 3.296 3.21 4.3680 0.0443
130/70 3.364 3.256 3.32 3.181 4.3737 0.0797
140/60 3.379 3.305 3.303 3.184 4.3903 0.0807
100/100 0.154 0.125 0.1395 0.0205
ID Avg. St. Dev.
150/50 0.877 0.878 0.8775 0.0007
160/40 1.095 0.198 0.6465 0.6343
130/70 1.311 0.377 0.8440 0.6604
140/60 0.5 0.335 0.4175 0.1167
100/100 0.623 0.629 0.6260 0.0042
Hour 1
Ac Ac Avg. St. Dev.
150/50 1.243 2.383 2.085 1.9037 0.5912
160/40 2.512 2.884 3.075 2.82 2.8228 0.2338
130/70 2.963 3.083 3.16 3 3.0515 0.0880
140/60 3.147 3.015 3 2.996 3.0395 0.0721
100/100 0.094 0.071 0.0825 0.0163
ID Avg. St. Dev.
150/50 0.055 0.09 0.0725 0.0247
160/40 0.123 0.134 0.1285 0.0078
130/70 0.134 0.099 0.1165 0.0247
140/60 0.187 0.153 0.1700 0.0240
100/100 0.119 0.085 0.1020 0.0240