Date and Location

Date: April 8, 2019 at 5 p.m. in the La Plata Multipurpose Room

Speaker: Hannah Horng

Background

Retinal oximetry is a non-invasive technique that uses imaging methods to calculate the oxygen saturation of retinal blood vessels in the eye. Knowledge of these oxygen levels can allow the diagnosis of several different retinal diseases, like macular degeneration and tears in the retina. Imaging, however, requires the knowledge of the intricate network of veins and arteries that run through it, or its “vasculature.” In order to get an accurate representation of retinal vasculature, researchers in this experiment currently use a Photonic professional 3D printer to create models that can be used and analyzed.

Observations

The replica of the vasculature in the retina is called a “phantom,” as it represents a model of what is actually present in the eye. Via a 3D printing process, a laser is used to “write a solid” into a curable photoresist resin. The resolution is extremely high and is able to capture all the twists and turns of the branching vasculature, creating an empty “phantom” of the network. Once made and set, sample blood is injected into the phantom and the oxygen saturation levels are measured using the model.

One challenge the speaker emphasized that she and her research group faced was that during the creation of the phantom, some leftover resin would remain in the mold, as it remained undissolved with the appropriate solvent. This caused some of the hollow spaces within the vasculature to be filled with resin, which then caused issues later when blood was to be injected into the phantom. However, this challenge was overcome when they found that adding clear titanium dioxide would cause little to no excess resin to be leftover, allowing for better oxygen level analysis.

Again, it was evident that the speaker was fully interested in her subject of research, and went on to state that the use of 3D printing in the world of scientific research is something of great interest to her, and she believes it is the future of research itself.

Reflection and Questions

Overall, this was another great seminar. The speaker was invested in her topic and helped her audience learn more about her own field of research. While the presentation itself was engaging and interesting, the use of several unfamiliar terms and concepts (ex: multispectral imaging, planar retina model) made it a little difficult to keep and follow along during the seminar. Because of this, I would assume that her seminar was aimed more towards an audience already familiar with retinal oximetry and ophthalmology in general.

Questions:

1. Do you think that 3D printing of phantoms can be used to model vasculature of other more complex systems within the human body?
2. How exactly are oxygen saturation levels in the blood measured after injection into the phantom?
3. How much time goes into the making of each phantom model? Is the process very tedious?

Date and Location

Date: April 8, 2019 at 5 p.m. in the La Plata Multipurpose Room

Speaker: Justin Buck

Background

In this experiment, researchers looked at the dopamine circuitry in a mouse brain, as its connections can cause development of projections (in the prefrontal cortex), sex differences, and are an important part of neural development. They also found that in females, the presence of dopamine regulates maternal and pair bonding behavior. In terms of psychiatry, researchers wanted to look at the dopamine pathways in the mouse brain, and how deficiencies in different regions and sections of the brain can affect the body as a whole. Therefore, through experimentation they were able to construct a “brain mapping pipeline” for dopamine circuitry in mice using serial thin tissue sectioning methods (thin slices allow light to shine through the sections of the brain).

Observations

Slicing the brain into thin sections for imaging can distort each slice and cause the loss of information with each piece, so researchers made the tissue sections clear by removing lipids and replacing them with a protein-like solution that allows light to travel through it more easily, allowing for deeper imaging. Through taking hundreds of thousands of images of each section and using light microscopy methods, the researchers were able to stitch together a three-dimensional model of the brain. One of the most interesting things they found was that this model could be used to observe cell counts (which directly corresponds to increased or decreased activity) in different regions of the brain in response to different stimuli.

The speaker chose to research this mainly due to his own broad research interests in human disease models. He was most interested in specific diseases like schizophrenia, which can be studied further by creating other clinically relevant maps, like serotonin circuitry, in the same manner.

Reflection and Questions

Overall, I really enjoyed this seminar. I thought the speaker was well versed in his area of research, and I could tell that he held a lot of passion for the subject and for the future of his own research experience. The content was relatively easy to understand in terms of terminology that was used, and the imaging techniques and concepts were kept simple for ease of comprehension. In all, it was a great seminar experience, especially for someone who doesn’t know much about the mapping of signaling pathways in model organisms, and how they can affect human disease models.

Questions:

1. How long did it take for the separate images of each brain slice to be stitched together into one comprehensive map?
2. How exactly can the model organism be used to learn more about human diseases associated with dopamine levels, like schizophrenia?
3. How do you feel about the future of using 3D modeling techniques to further understand the inner workings of the brain?

Seminar Reflection: Who is the Audience?

For this reflection, I’m posting a blog writeup on a website, meaning my audience is the general public and anyone who happens to come across this site. More specifically, I expect my audience to be students of all ages who are interested in finding more information regarding these seminars. I chose this format due to its ability to make information more widely accesible, as well as provide an engaging and simple format to disseminate this information so that it reaches as many people as possible.