Bulletin of the American Physical Society
Joint Fall 2021 Meeting of the Texas Sections of APS, AAPT, and SPS
Volume 66, Number 10
Thursday–Saturday, October 21–23, 2021; Houston; Central Time
Session J03: Biological Physics and Medical Physics I |
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Chair: Paul Withey, UHCL Room: STEM 1200 |
Friday, October 22, 2021 10:00AM - 10:36AM |
J03.00001: Biomedical Imaging with Biocompatible Graphene Quantum Dots Invited Speaker: ANTON NAUMOV Due to a variety of their remarkable properties, nanomaterials serve a plethora of applications in biomedicine including molecular sensing, drug and gene delivery as well as photothermal and photodynamic therapy. Most of these applications can benefit from additional modality of biomedical imaging that is often performed by a dye attached to the nanomaterial. Nanomaterial imaging agents are more rare due to the need of high quantum yields and low toxicity at high concentrations which are complex to achieve for nanostructures. In this work we utilize simple scalable one-step hydrothermal synthesis to develop graphene quantum dots (GQDs) with high biocompatibility (up to 2 mg/mL) and substantial (over 60{\%}) fluorescence quantum yield in the visible. These GQDs show efficient cellular internalization maximized at 12 h as well as remarkable biodegradability in cell medium. Furthermore, their backbone can be doped with a variety of heteroatoms during the synthetic process with minimum effect to their biocompatibility. Such doping can serve to develop a number of beneficial biomedical imaging applications. For instance, Gd or Mn doping can generate magnetic resonance imaging capabilities allowing to perform joint fluorescence and MR imaging for in vitro and in vivo detection respectively. Nitrogen doping renders GQD fluorescence linearly sensitive to temperature in the biological range allowing those to serve in nanothermometry imaging applications. Rare earth metal doping makes these GQDs emissive in the near-infrared (NIR), which is beneficial for therapeutic imaging in the NIR water window, where biological tissue is more transparent. Several NIR-emissive GQD structures are tested in our work for imaging in vitro as well as in live sedated animals. Due to high NIR penetration depth, GQD fluorescence was observed through the bodies of live mice injected intravenously with GQD suspensions and imaged with diffuse 808 nm laser excitation. Excised organs show NIR GQD emission from kidneys, liver, spleen and intestine with GQDs also detected in single organ slices indicating their location within the particular organ. Based on the variety of observed imaging modalities, we suggest these biocompatible GQDs as a novel modifiable imaging platform that can be further doped and tailored for specific bioapplications. [Preview Abstract] |
Friday, October 22, 2021 10:36AM - 10:48AM |
J03.00002: Tracking the effect of a chemotherapeutic drug on pancreatic cancer cells using $^{13}$C NMR spectroscopy Wirya Feizi, Lloyd Lumata Pancreatic Ductal Adenocarcinoma (PDAC) is a deadly type of cancer that has a dismal 5-year survival rate of just 6{\%} for patients. One of these metabolic features of PDAC is the abundance of the NAD(P)H Quinone Dehydrogenase 1 (NQO1) enzyme. The abundance of NQ01 is in some way beneficial to chemotherapeutic intervention as catalyzes the conversion of $\beta $-lapachone into semiquinone which is detrimental to cancer cells. In this study, we have investigated the utility of ethyl acetoacetate and other $^{13}$C-tracers as NMR probes in monitoring the peripheral metabolic effects of $\beta $-lapachone as it disrupts the cancel cell proliferation. Protein expression and cellular proliferation assay studies will also be presented here. This study is supported by the Welch Foundation grant AT-1877, DOD grants W81XWH-21-1-0176 and W81XWH-19-1-0741, CPRIT grant RP180716, and the UTD CoBRA and SPIRE grants. [Preview Abstract] |
Friday, October 22, 2021 10:48AM - 11:00AM |
J03.00003: Monitoring the Effects of $\beta $-Lapachone on $^{13}$C-Ethyl Acetoacetate Metabolism in Cultured Colo-205 Colorectal Cancer Cells Wirya Feizi, Lloyd Lumata Colorectal cancer (CRC) is the third most common malignancy diagnosed globally and the fourth leading cause of cancer-related death worldwide. In this study, we have investigated the metabolic effects of chemotherapeutic drug $\beta $-lapachone on cultured Colo-205 CRC cells. $\beta $-lapachone works through the critical enzyme NQO1, which is abundant in CRC, through its conversion to semiquinone which eventually leads to destroy the cancer cells. In particular, we have studied the effects of $\beta $-lapachone on the metabolism of $^{13}$C-ethyl acetoacetate (EAA) using $^{13}$C nuclear magnetic resonance (NMR) spectroscopy. Our results indicate that EAA metabolism is sensitive to the chemotherapeutic effect of $\beta $-lapachone. In addition to NMR results detailing the influence of $\beta $-lapachone on EAA metabolism, additional data on MTT cell viability assays, Western blots of NQ01 protein expression, and microscopic images of cells will also be presented here. This study is supported by the Welch Foundation grant AT-1877, DOD grants W81XWH-21-1-0176 and W81XWH-19-1-0741, CPRIT grant RP180716, and the UTD CoBRA and SPIRE grants. [Preview Abstract] |
Friday, October 22, 2021 11:00AM - 11:12AM |
J03.00004: Enhancement of liquid-state $^{1}$H NMR signals at room temperature using a homebuilt X-band Overhauser DNP setup Wirya Feizi, Cody Larsen, Daniel Anable, Lloyd Lumata Overhauser effect (OE) dynamic nuclear polarization (DNP) involves the transfer of the high spin alignment of the electron spins to the nuclear spin by microwave radiation at the electron paramagnetic resonance (EPR) frequency of the free electron source. Herein we report the preliminary results of an instrumental setup of an X-band Overhauser DNP polarizer in pursuit of enhancing the 1H nuclear magnetic resonance (NMR) signals of water doped with free radicals by tens if not hundreds of times relative to the thermal NMR signal of the sample. Different free radicals of varying EPR linewidths were used in this research. The NMR signal-enhancing capability of this technology has a potential practical application in improving the sensitivity of magnetic resonance imaging (MRI) signals for improved diagnostics. The preliminary $^{1}$H NMR results, EPR characterization studies, and the technical engineering challenge will be presented in this talk. This study is supported by the Welch Foundation grant AT-1877, DOD grants W81XWH-21-1-0176 and W81XWH-19-1-0741, CPRIT grant RP180716, and the UTD CoBRA and SPIRE grants. [Preview Abstract] |
Friday, October 22, 2021 11:12AM - 11:24AM |
J03.00005: NMR tracking of the effects of deuterated water in glucose metabolism of yeast Khoa Nguyen, Lloyd Lumata, James Mulhern Nuclear magnetic resonance (NMR) spectroscopy is a non-invasive technique used to analyze the chemical composition and structural elucidation of samples. This experiment tracks real-time changes in glucose uptake and subsequent ethanol production to determine metabolism and growth of Saccharomyces Cerevisiae (Baker's yeast). Deuterium oxide (D$_{\mathrm{2}}$O), which is a heavy form of water, is used as the substitute of regular water H$_{\mathrm{2}}$O in yeast cell suspension in this study. The main finding of this research is that glucose metabolism is being suppressed especially in fully deuterated nutrient media in these experiments. We will discuss the detailed results of this study and the potential effects of D$_{\mathrm{2}}$O on other biological processes. This study is supported by the Welch Foundation grant AT-1877, DOD grants W81XWH-21-1-0176 and W81XWH-19-1-0741, CPRIT grant RP180716, and the UTD CoBRA and SPIRE grants. [Preview Abstract] |
Friday, October 22, 2021 11:24AM - 11:36AM |
J03.00006: Isotopic effects of metabolism of $^{\mathrm{13}}$C-fructose in yeast James Mulhern, Khoa Nguyen, Lloyd Lumata Saccharomyces cerevisiae (SC) is a useful organism for studying metabolic pathways because of its hardiness and simplicity in culturing. Using proton ($^{\mathrm{1}}$H) and carbon-13 ($^{\mathrm{13}}$C) nuclear magnetic resonance (NMR), we can study SC metabolism in vivo using $^{\mathrm{13}}$C-enriched sugar such as fructose. The fruit sugar fructose, structurally similar with glucose, has slightly different metabolic route to ethanol production compared to glucose and therefore is an interesting subject of study. A reduction of fructose metabolism was seen when the $^{\mathrm{1}}$H spins in the media were replaced with $^{\mathrm{2}}$H spins. These results will be discussed in light of the isotopic effects in fructose metabolism in yeast. This study is supported by the Welch Foundation grant AT-1877, DOD grants W81XWH-21-1-0176 and W81XWH-19-1-0741, CPRIT grant RP180716, and the UTD CoBRA and SPIRE grants. [Preview Abstract] |
Friday, October 22, 2021 11:36AM - 11:48AM |
J03.00007: Development of the Web-based Simulation Platform for gMicroMC Parvat Sapkota, Thomas Shipman, Edward Gonzales, Yujie Chi Purpose: Our lab developed an open-source graphical processing unit (GPU)-based microscopic Monte Carlo simulation tool (gMicroMC) for ionizing radiation-induced DNA damage computation. Although the package has gained an increasing interest, the current version requires relatively high coding experience from the user thus hindering its broad application. In this work, we initiated an effort to build a web-based interface to enable a user-friendly simulation environment. Method: We proposed to establish two servers: a web server for storing static files and an application server for performing GPU-based gMicroMC simulation. We will employ the Django web framework for various tasks such as job submission and implement the Three.js framework to render the 3D graphics at the platform. Result: We were able to establish a first version of the simulation platform, where the user can setup the simulation parameters and visualize the setup geometry in 3D. We also configured our web server and were able to transfer our codes to it from our local machine. Conclusion: We laid the foundation for the web-based simulation platform of gMicroMC. Our next steps are to fully accomplish the proposed function of the platform, test it and make it available to the public. [Preview Abstract] |
Friday, October 22, 2021 11:48AM - 12:00PM |
J03.00008: Creating Metaphase DNA Model with~Loop Extrusion Bryan Dinh, Youfang Lai, Yujie Chi The structure of DNA at different phases is critical in determining radiobiological responses to ionizing radiation. Yet, due to its complexity, metaphase DNA has never been studied in radiobiological simulations. In this work, we report our recent progress in applying the loop-extrusion method to construct a metaphase DNA model for this purpose. We modeled a section of chromosome of a human cell containing 12 million DNA base pairs (bp) with polymer physics, with each monomer representing a nucleotide (\textasciitilde 200 bp). A series of loop extrusion factors (LEFs) arranged in a helical structure were applied to divide polymer chain into distinct loops. Four forces in harmonic, repulsive, stiffness, and cylindrical confinement formats among monomers and a harmonic force among LEFs were applied to obtain the desired structure until reaching equilibrium amongst monomers. The contact frequency of monomers were computed after each set of parameters tuning. The contact frequency map is consistent with the empirical measurements in the regions of DNA separations between 0.1 and 1 Mbp. This model is promising to represent metaphase DNA for radiobiological study. [Preview Abstract] |
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