CRISPR Cas9 is a programmable single guided RNA (sgRNA) ribonucleic protein (RNP) that has demonstrated their ease and practical use as a gene editing tool for in vitro and ex vivo applications. For in vivo applications of the Cas9 RNP, physiological barriers must be overcome and gene editing to occur transiently, demonstrating the need to develop biocompatible imaging agents to protect and locate Cas9 RNP in vivo. Graphene quantum dots (GQDs) are biocompatible carbon-based nanomaterials that have served as delivery and imaging agents for drug and gene medicine due to their ease in synthesis and repertoire of complexation capabilities arising from the choice of precursor materials. In this work, we have synthesized visible and near infrared emitting GQDs with glucosamine HCl and polyethylenimine (PEI) using a bottom-up approach to use them as non-viral delivery vehicles for the Cas9 RNP. PEI increases the net positive charge of GQDs allowing their electrostatic complexation with the net negatively charged RNP. We further demonstrate their complexation with gel retardation assay and TEM. The GQDs+PEI+RNP in vitro editing capability is shown by targeting the TP53 414delC frameshift mutation locus present in PC3 cancer cell line for prostate cancer. This form of editing serves as a guide for future cancer therapy using GQDs as non-viral delivery of Cas9 RNP to mutant TP53 genes overexpressed in about 50% of cancers.

One of the large unanswered questions in astronomy is: How does the Milky Way galaxy evolve, chemically and dynamically? Of all the objects that we could use to probe this question, groups of stars which were all born from the same gas cloud, known as open clusters, are the most reliable. This makes open clusters ideal for exploring the evolution of our Galaxy because we can determine not only the distance, position, velocity, and chemistry of the cluster, but we can also pin a reliable age to the cluster as well. Historically, assembling a statistically significant dataset of open clusters has proved to be challenging without inducing large systematic uncertainties by collecting data from multiple sources. The Open Cluster Chemical Abundance and Mapping (OCCAM) survey is a uniform dataset of star clusters that uses dynamical data from the Gaia space telescope and 16 different chemical abundances from the APOGEE survey, which is a part of the Sloan Digital Sky Survey. This new update to OCCAM includes uniformly measured data for 153 open clusters and a total of 2061 member stars, which we use to investigate the chemical evolution of the Milky Way.

Through the use of large-scale surveys, astronomers are able to investigate Milky Way galaxy evolution, both dynamically and chemically; however, determining reliable stellar ages has been elusive.  Star clusters are the most reliable way to measure ages of stars, and new surveys are measuring detailed chemistry for cluster stars that may be able to be correlated with age. For our study, we are using carbon and nitrogen abundances within red giant stars as age indicators. Using the Open Cluster Chemical Abundances and Mapping (OCCAM) survey, we utilized stellar parameters and abundances, and created a uniform empirical relationship between stellar ages and carbon-to-nitrogen abundances using star clusters. This new calibration will allow us to determine reliable ages for over 100,000 stars across the Milky Way galaxy, allowing us to measure the chemical evolution of the Galaxy.

With the development of personalized cancer medicine and moving away from a conventional biopsy, there is a need in creating a multifunctional platform for cancer diagnosis and treatment monitoring. Sonography offers many advantages over standard methods of therapeutic imaging due to its non-invasiveness, deep penetration, high spatial and temporal resolution, low cost, and portability. The benefits of the ultrasound method make contrast agents an ideal platform for the efficient strategy of cancer diagnostic and therapy. In this work, we developed metal-doped graphene quantum dots that demonstrate high-contrast properties in ultrasound brightness mode. The successful imaging enhancement was observed in tissue phantom and chicken breasts tissue. The relatively small size of the metal-doped graphene quantum dots makes them easily be internalized into the cells, while functional groups on their surface allow binding a cancer-targeted marker and therefore be used as a cancer-targeted delivery. By a combination of imaging and targeting capabilities, ultrasound contrast agents based on metal-doped graphene quantum dots enable desired cancer-focused nanotherapeutic and imaging approaches.

For billions of years, our Milky Way galaxy has churned out countless stars. However, the best star-forming days of our galaxy are long gone and our galaxy is in a midlife crisis! It’s running out of gas to make new stars, and extraneous resources are scarce. Worse yet, high stellar winds might eject some gaseous material, such as the Smith Cloud. After it was ejected, the Milky Way’s gravity caused this cloud to reverse course and fall back toward our Galaxy. The Smith Cloud is now only 40,000 light-years away and carries with it the equivalent of over 1 million Suns worth of material. As it makes the journey back to our Galactic Plane, it must endure heavy winds that have temperatures in excess of 1 million degrees Celsius from the Milky Way galaxy’s coronal gas. I have already measured the amounts of various ions in adjacent cloud fragments positioned on the side of the Smith Cloud using Hubble Space Telescope observations. These ions include C+, Si+, Si2+, Si3+ , and S+. I will then determine the effects that these high winds have on the adjacent fragments and the trailing wake of the Smith Cloud to better understand the perils that gas clouds must undergo to reach massive galaxies.