Justin Priddy

As a middle school science teacher in the Everett Public Schools, two common questions that my students regularly ask me are: “What do scientists do?” and “Are we doing things in our class that scientists also do?” Rather than rely on my distant memories of undergraduate science courses and past experiences working in a lab, I decided to look for an opportunity to spend time with career scientists to answer these questions and hopefully create a more authentic science learning experience for my students along the way. (As a side note, I regularly remind my students that they are, in fact, scientists, and have been since they were very young.)

This summer marks the second year in the Adair Lab as part of my Hutch Teacher Fellowship. Dr. Jennifer Adair and her team are focused on developing gene therapy technologies that can be delivered safely and efficiently to individuals throughout the world, and specifically to areas where access to cutting edge medical treatments are not readily available. Using CRISPR gene editing tools and gold nanoparticles (AuNP) the Adair lab is making progress toward their goal.

Over the course of my time spent in Dr. Adair’s lab this summer my research was focused on helping to answer the question of how to successfully preserve gold nanoparticle/CRISPR formulations (AuNP/CRISPR) for long-term storage after they have been manufactured. These AuNP/CRISPR formulations have shown promise in the process of gene editing for both the CCR5 and the γ-globin genes. Editing of the CCR5 gene is known to be an effective approach to preventing HIV from binding to and infecting T cells while modification of the γ-globin gene helps to inhibit the disruption of hereditary persistence of fetal hemoglobin (HPFH). When fetal hemoglobin is allowed to persist, individuals who suffer from sickle-cell anemia or β-thalassemia experience relief from these debilitating diseases.

As the Adair lab continues to refine their AuNP/CRISPR formulations the question of how to maintain the gene editing efficiency after manufacture and during long-term storage is now being investigated. Working alongside Adair lab member Karthik Gottimukkala, I was able to assist in a series of experiments that measured the characteristics of different AuNP/CRISPR formulations before and after they were preserved for long-term storage.

Our study began by looking at the effects of protecting the AuNP/CRISPR formulations during lyophilization (freeze drying) using three different cryopreservants: mannitol, trehalose, and sucrose. The characteristics (size, zeta potential, and monodispersity) of each AuNP/CRISPR formulation were measured both before and after they were added to the different cryopreservant solutions and then frozen for storage.

Based on the results of this initial study we determined that we would focus our future experiments on sucrose as a possible cryopreservant and test the effects of different concentrations (5%, 10%, 20%) of sucrose on the characteristics of the AuNP/CRISPR formulations during freezing and storage. Using both -20°C and -80°C environments, we again measured the characteristics of each AuNP/CRISPR formulation and determined that samples treated with lower concentrations of sucrose solution exhibited more favorable characteristics.

This led us to next ask the question of what the optimal concentration of sucrose is for maintaining the characteristics of the AuNP/CRISPR formulations during freezing and storage. Using much lower concentrations of sucrose (0.5% - 5%), a new study was designed to find out the answer. Through measurement and analysis, a cryopreservant formulation was selected and a manufacturing process for preparing and storing the AuNP/CRISPR formulations was developed.

Toward the end of my time in the Adair Lab we began designing a year-long experiment to study the effects of long-term cryopreservation and storage of the AuNP/CRISPR formulations. The results of this investigation will hopefully provide additional evidence that can be used to design an effective solution for how to successfully produce and store large quantities of this gene editing technology for transport to destinations throughout the world.

Spending time again in a research setting like the Adair lab provided me with a wealth of experiences to help inform my teaching practice. Taking on the role of a learner each day allowed me to think about my students’ experiences in our classroom and their feelings of excitement, stress, wonder, and uncertainty. The idea of productive uncertainty that was a theme during my first year at the Hutch and something that I made a part of my instructional model last year resurfaced during my time in the lab.

As I attempted to make sense of our experimental data each day, I thought about my 7^thgraders as they used simulations to model the process of natural selection and my 8^thgraders as they analyzed data to construct explanations for chemical reactions. While the answers to each of our questions may have initially seemed well beyond our reach, persistence and a growth mindset eventually led us to a deeper level of understanding. Through an iterative process of using each fresh set of results to drive new questions and more refined models and explanations, we all grew as learners and scientists. I hope to continue to use this idea of productive uncertainty as the catalyst for new learning as I embark with my students on another year of scientific exploration. With the help of the Science Education Partnership, the Adair Lab, and Fred Hutch, I am better prepared to offer students learning opportunities that will challenge their own productive uncertainty and help them answer the question, “What do scientists, like myself, do?”.