This week is the ninth week of my trip to China, and the beginning of my third month in HeFei. Since I have about a month left in my trip, I decided to write out some attainable goals for my remaining time here. To begin, I had a long conversation with Yuan Shuai about my short term and long term goals, and how I can achieve them.
A long term release profile study cannot be completed with
the short time I have left, so instead, I will be doing a release study lasting
slightly less than a month. Completing this will allow me to understand the
experiment so I can complete a longer term release study when I am back in
America. Yuan Shuai and I outlined the specific goals for each day this week so
that the release study will be underway by the end of the week.
On Monday, I was able to practice my first coaxial
electrospray experiment using curcurmin. Below is a photo of the Taylor cone I
formed. It was very stable and produced a lot of microcapsules that Yuan Shuai
collected for his experiment. The inner and outer solutions both contain acetone
that must evaporate to create stable microcapsules. While collecting them, Yuan
Shuai was saying “they’re all trash” as he placed them in a small container. I
was confused by this because he was keeping all the microcapsules that he
described as trash. I later realized that he was trying to describe the
microbubbles as “ash” because they were all dry and would easily blow away.
Microbubbles that behave as ash are ideal, and are not to be confused with trash.
Below are two photos of me in the lab. For one experiment I had to wear a heavy
mask that can be seen below.
On Tuesday morning I had another practice for the dragon
boat rowing team. This was another exhausting practice, but it was nice to have
a better understanding of the distances we would travel. Last practice I would see
every check point and hope that we might take a break there. Now I understand
that we generally row for about 2000 meters at a time. Knowing this has made
the practice seem less difficult, even if we row farther distances. It was
difficult for me to get a good photo because it was pouring rain all morning,
but I did take a photo of the lake as we were leaving.
It is difficult to get back into the lab after a tough
practice, but now I have a schedule for myself that I am trying to stick to. In
the afternoon I tried to encapsulate rhodamine in a PLGA shell, but rhodamine
is only slightly soluble in acetone. Acetone is the ideal solvent because it evaporates
quickly and is good for forming stable microcapsules. We tried to encapsulate 2
different concentrations of rhodamine, but in both solutions, there was rhodamine
sediment that would not completely dissolve and therefore caused the Taylor
cone to be unstable.
Wednesday and Thursday:
Wednesday I began reading 2 papers that Dr. Si sent to the
whole lab about modeling the interaction of microbubbles and the affect a shear
boundary layer has on the stability of a capillary jet. Later in the afternoon
I shadowed Yuan Shuai for his triaxial electrospray experiment. He had a lot of
success collecting the microcapsules. The photo below shows how the dry
microbubbles collect on the electrode and have the consistency of ash.
Thursday morning we had our usual meeting that lasted up
until lunch. In the afternoon I worked with Yuan Shuai to create the rhodamine
encapsulated microbubbles. Our first experiment did not go well because we were
unable to form a stable Taylor cone for a long period of time. When we did finally
form a stable cone, it would not collect any microcapsules. To determine the
problem with the experiment Yuan Shaui did his experiment encapsulating curcurmin.
He was able to form the Taylor cone easily, so we determined that something may
be wrong with the solutions used. We recreated the experiment and were able to
form a more stable Taylor cone as a result.
After I collected these microcapsules, Yuan Shuai and I prepared
the solutions for the HPLC experiment. The calibration solution was created by
dissolving rhodamine in a solution comprised of acetone and hexane. We also
created the mobile phase solution that has a ratio of 75 parts methanol to 25
parts water.
Thursday night we were able to go to eat “toast” with some
of the other members of the lab again! Though I really enjoyed this night, I
stayed up later than I should have the day before another Dragon Boat practice.
Friday, Saturday, and Sunday:
Friday morning was another rainy practice for the team. We
traveled another 10,000m before we got our lunch and went back to campus. I had
to run straight from the practice to the lab to give my presentation about
writing biomedical engineering papers. This week I presented about references
and the abstract of a paper. The presentation went well overall, but it was
difficult to get participation from the group because most of the examples for
these sections were long and dense with scientific terms. Next week will be my
last presentation on this book.
After my presentation, Yuan Shuai and I started the release
experiment. It was convenient because as I am doing my experiment, Yuan Shuai
will also be doing his own experiment. To
begin, I placed 45mg of the microbubbles in one dialysis bag, and 10 grams of
pure rhodamine B in another. These bags were filled with phosphate buffered
saline and placed in a solution of acetone and hexane. The containers with the
dialysis bags were placed in a device that consistently shakes the containers at
a temperature of 37° C. I took samples from the surrounding solution at 1, 2,
4, 6, 9, 12, and 24 hours. I will also be taking samples every 24 hours for the
next few weeks. Since I started the experiment at about 4:00 p.m., this meant
that I would have to take a measurement at 1:00 a.m. and 4:00 a.m. I brought
snacks and movies to watch for a long night in the lab.
I was very lucky there were two World Cup games on Friday
night because some of the other students stayed in the lab all night watching
the games. It was nice to have the company. I went back to my room to sleep at
about 6:00 in the morning.
Saturday I spent most of my morning catching up on sleep. When
I got back into the lab Yuan Shuai informed me of some bad news. It turned out
that at some point, the clips holding the bag of the pure rhodamine came off
and the rhodamine emptied from the bag. After we discussed the problem, we
decided to continue taking samples for the experiment, but I will also begin
developing microbubbles using ethanol instead of acetone. If I am successful,
this will allow me to encapsulate more rhodamine B in each microbubble and
therefore result in a more effective release study.
After I took my sample for the day, I went out to dinner with
He Yutong, Lei Fan, and Dr. Tong. We went out to dinner because Dr. Tong will
be working at OSU for a year starting this September, and he wanted to practice
his English as well as ask some questions about the school. We went to a hot pot
restaurant and talked a lot about OSU and what he should expect when he
arrives. It was a delicious dinner and nice to meet Dr. Tong. We made plans to
have dinner again this coming week!
Right after dinner I went to a swimming practice that the
dragon boat team coach asked us to attend. It was nice to be able to swim some
laps because the pool is much less crowded at this time. I also attended this
practice on Sunday night.
The highlight of my Sunday was meeting 4 other American
students that moved in to the guest house. They are from Lehigh and will be in
HeFei for about 6 weeks. I am so excited to get to know these people better!
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