Bulletin of the American Physical Society
Prairie Section Fall 2022 Meeting
Volume 67, Number 12
Thursday–Saturday, October 13–15, 2022; University of South Dakota, Sioux Falls, SD
Session K01: Parallel Session III |
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Chair: Pablo Palafox, The College of St. Scholastica Room: University of South Dakota FADM 152 |
Saturday, October 15, 2022 10:45AM - 10:57AM |
K01.00001: Using silver nanoclusters to detect cancer-associated micro-RNA sequences. Dylan R Fredrick, Alexey V Krasnoslobodtsev DNA-templated silver nanoclusters (AgNC@DNA) are a novel type of nanomaterials with advantageous optical properties. Only a few atoms in size – the fluorescent of nanoclusters can be tuned using loose DNA overhangs. In this study, we explore the properties of AgNC manufactured on a short single-stranded 12 cytosines long DNA fragment. We observe differences between designs containing the same AgNC templating sequence – twelve consecutive cytosines, (dC)12, when adjacent G-rich sequences (dGN, with N=3-15) are added. The single "basic" element, C12, emits in "red" with lambda max = 635 nm (red). Addition of G-rich overhang with NG=15 dramatically changes the pattern of the Emission-Excitation Matrix (EEM) with two new emission peaks appearing λ1 = 575 nm (green) and λ2 = 700 nm (far-red). The appearance of these peaks provides a novel way for the design of biosensors capable of detecting specific nucleic acid sequences. We have used this property to construct an NA switch that brings AgNC and G-overhang near one another turning "ON" the new fluorescence peaks only when a specific miRNA sequence is present. Next, we have tested this detecting switch on miR-371a-3p, which is typically overexpressed in testicular cancer, thus providing evidence that such a novel fluorescent switch is both sensitive and specific. |
Saturday, October 15, 2022 10:57AM - 11:09AM |
K01.00002: Gd-doped Superparamagnetic Iron Oxide Nanoparticles (SPION) for Potential Cancer Theranostics Maheshika S Palihawadana Arachchige, Ratna Naik, Vaman M Naik Integration of diagnostic imaging and therapeutic function into a single platform, so-called “Theranostics”, is of great research interest as a new direction in nanomedicine research. Superparamagnetic Fe3O4 (SPION) is considered as an ideal vehicle in the development of theranostic nanomedicines as they can be multi-purposely used for magnetic resonance imaging (MRI) and targeted delivery of therapeutic agents such as anticancer drugs, siRNA and magnetic hyperthermia (MHT). Even though the multi-functionality of SPION based nano systems for drug delivery and imaging modalities has been investigated widely, the possibility of incorporating MHT and MRI is not explored much. According to other studies, Gd-doped SPION can be used as a T1 –T2 dual-modal contrast agent for MR imaging. They have the potential to act as an effective MHT agent but to the best of our knowledge, there are very few studies done in that light. Our recent research interest focuses on Gd-doped SPION as a potential theranostic agent for combined MHT/MRI and the results of our recent MHT study on Gd-doped SPION as a possible theranostic agent are discussed in this talk. |
Saturday, October 15, 2022 11:09AM - 11:21AM |
K01.00003: Tuning near-infrared fluorescence in DNA-templated silver nanoclusters. Julio E Navas Hernandez, Alexey V Krasnoslobodtsev Silver nanoclusters templated on DNA (AgNCs@DNA) comprise only a few silver atoms. AgNCs@DNA develop a structure of discrete electronic levels leading to molecule-like properties such as strong luminescence with high quantum yield. Unlike molecular fluorescence, the luminescence of AgNC features a more complex nature with plenty of possibilities for tuning. We demonstrate that a rational optical tuning can allow for specific generation of emission in the near infrared region. A unique hairpin loop structure with N cytosines in the loop, 7 base pair double-stranded stem, and a random R-tail (R-hpCN) produces NIR peak with high yield at λMAX=830 nm. In this study, we explore the effect of loop size (N) on the yield of the NIR emission showing that R-hpC13 has the largest yield. AgNC@R-hpC13. Single cytosine-to-thymine replacements in the hpC12T1 allowed us to identify critical involvement of cytosines for the NIR emission demonstrating the possibility for fine-tuning of NIR emission. Noteworthy, weakening C8-AgNC connection significantly increases the quantum yield of the λMAX=830 nm peak. Our studies point to the complexity of the electronic structure of the AgNCs, suggesting plenty of possibilities for fine-tuning of AgNC’s NIR emission with practical applications for bioimaging. |
Saturday, October 15, 2022 11:21AM - 11:33AM |
K01.00004: Smart Electrochemical Glucose Biosensor via Assemblies of DNA– Silver Nanoclusters as Sensitive probes AKHILESH K GUPTA, Alexey V Krasnoslobodtsev The incidence of diabetes and prediabetes remains a major risk factor for long-term complications, deaths, and costs increasing yearly [1]. This metabolic condition due to insulin deficiency causes hyperglycemia characterized by blood glucose readings that are either higher or lower than normal. Monitoring blood glucose levels is crucial in diabetes diagnosis and management [2]. Consequently, improving existing methodologies and creating a better glucose detection method that is straightforward, precise, and sensitive is an essential step. Herein, we propose the construction of glucose biosensors utilizing an electrochemical approach in combination with DNA-templated silver nanoclusters (AgNCs@DNA). Due to the small size of AgNC@DNA, they also exhibit advantageous characteristics as optical probes providing a second readout strategy. We investigated the efficacy of the AgNCs@DNA/Glucose Oxidase/Glucose system for sensing small glucose amounts. H2O2 is produced during the oxidation process of glucose catalyzed by GOx etches AgNCs producing the extensive amount of charges detected electrochemically. We achieved a sensitive and reliable method for the accurate detection of glucose. The biosensor design involving AgNCs@DNA opens new prospects for developing smart biosensor devices, which are expected to help solve the key challenges and opportunities in their further development and use. |
Saturday, October 15, 2022 11:33AM - 11:45AM |
K01.00005: Comprehensive site-specific probabilities for bond rearrangement in ethanol photofragmentation Eleanor Weckwerth, Eric Wells, Travis Severt, Balram Kaderiya, Peyman Feizollah, Bethany C Jochim, Farzaneh Ziaee, Kurtis D Borne, KANAKA PANDIRI, Kevin D Carnes, Daniel Rolles, Artem Rudenko, Itzik Ben-Itzhak Ethanol (CH3CH2OH) has three non-equivalent sites for hydrogen atoms: the hydrogen that is part of the hydroxyl group, the three β-hydrogens attached to the carbon atom opposite the hydroxyl group, and the two α-hydrogens attached to the central carbon atom. Bond rearrangement initiated by an ultrafast laser pulse, leading to hydrogen-rich photofragments such as H3+, can involve hydrogen atoms from all three sites. Using COLTRIMS experiments examining different deuterium-tagged isotopologues of ethanol under the same laser pulse conditions (800 nm central wavelength, 3.0×1014 W/cm2 peak intensity, 23 fs FWHM), we measure the relative probabilities of producing H3+, CH4+, H2O+, and H3O+ as a function of the initial sites of the hydrogen atoms that compose the final products. These site-specific measurements provide a new benchmark for molecular dynamics calculations. |
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