Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session Y05: Biomaterials and Nanotechnology IIFocus Recordings Available
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Sponsoring Units: DBIO DPOLY Chair: Lydia Kisley, Case Western Reserve University Room: McCormick Place W-178A |
Friday, March 18, 2022 8:00AM - 8:12AM |
Y05.00001: 3D Porous Liquid Crystal Elastomer Scaffolds as Cell Supports for Long-term Tissue Cultures Senay Ustunel, Marianne E Prévôt, Grace Rohaley, Robert J Clements, Elda Hegmann Three-dimensional (3D) biological scaffolds that mimic endogenous tissues must have multiple functional, structural, and mechanical components and properties. Their main purpose is to provide suitable environments for cells to grow and proliferate for longer periods of time and act as suitable models for the study of cell interactions and tissue engineering. |
Friday, March 18, 2022 8:12AM - 8:24AM |
Y05.00002: Enhanced Strength and Shape Memory in Microgel Filled Biopolymer Networks Vignesh Subramaniam, Thomas E Angelini Biopolymer networks comprise an essential and substantial proportion of 3D bioprinting materials because of their abundance and role in living tissues. While biopolymers serve to strengthen tissues in vivo, biopolymer networks in vitro are notoriously soft and weak; bioprinted structures made from biopolymer networks exhibit the same limitations. To stiffen and strengthen printable in vitro biopolymer networks, we developed a biomaterial made from collagen-1 in which the polymer mesh-space is filled with micron-scale microgel particles made from polyethylene glycol (PEG). We find that this combination of material components synergistically enhances the system material properties. For example, by filling in the mesh space of the polymer networks with low volume fraction microgels, the elastic modulus can increase by more than an order of magnitude. By packing the microgels into the polymer network at volume fractions approaching jamming, the material takes on a shape-memory property, where the material will spontaneously lock-in deformations at intermediate strain levels; reversal of these strains requires a stress-reversal and results in the material resulting to its original deformation state. This new class of materials opens up wide possibilities in its capacity as a 3D bioprinting material and has potential applications in the fabrication of model tissues. |
Friday, March 18, 2022 8:24AM - 8:36AM |
Y05.00003: E-cadherin Substrates Alter the Biophysics of Collective Cell Migration and Proliferation Youn Kyoung Cho, Kevin Suh, Daniel J Cohen While conventional biomaterials focus on cell-matrix interaction, cell-cell adhesion is a promising, complementary process to target given its significance in tissue integrity, mechanical signaling, and stem cell fate. We investigate this by patterning zones of E-cadherin – a key cell-cell adhesion protein – and collagen on culture surfaces and explore how this 'cell-mimetic' biomaterial influences collective cell behaviors in macro-scale epithelial monolayers. First, we observe nearly 5X slower mean collective cell migration speeds on E-cadherin substrates compared to those on collagen control substrates. Such slower migration can be explained by our data showing that focal adhesions cannot form on cadherin surfaces, in turn altering cytoskeletal architecture. However, pronounced cellular recruitment of E-cadherin is observed at the cell-material interface, which not only stabilizes cell geometry, but extends the cell cycle, specifically resulting in a large increase in G1 transit times, with no effect on the S-G2-M phases. This effect seems to be driven by biomechanical reprogramming of cell size control effectors such as YAP, beta-catenin, and Wnt. |
Friday, March 18, 2022 8:36AM - 9:12AM |
Y05.00004: Effect of extracellular matrix age on disease progression Invited Speaker: Pinar Zorlutuna The fact that the most significant life-threatening diseases of our times such as Cardiovascular Diseases or Cancer remains the number one killer for over a century suggests that, despite the advancements in science and medicine over the years, there is a huge gap in translating these scientific findings to clinical setting. One of the major reasons for this gap is pre-clinical research's heavy dependence on young animal models despite the fact that aging is the biggest risk factor for these diseases. For example, the average age for first heart attack is 65.3 years for males and 71.8 years for females, and most breast cancers develop in a postmenopausal, aged mammary gland tissue microenvironment at age of 62. Yet, due to the logistical limitations, current pre-clinical research predominately relies on experimental animals with a human-equivalent age of less than 35 years, which does not faithfully replicate the clinically prevailing aged tissue microenvironment. With increasing appreciation of the role of the tissue microenvironment in regulating disease progression and the response to therapeutics, there is an urgent need to develop, optimize and validate novel 3D culture systems that fully recapitulate the aged tissue microenvironment to reproducibly model natural disease progression. In this talk I will present our research in understanding biophysical and biochemical changes in the native tissue matrix with age and our efforts to create engineered tissue models that possess these variables to study myocardial infarction and breast cancer progression. |
Friday, March 18, 2022 9:12AM - 9:24AM |
Y05.00005: Cas nucleases binding selectivity Pete B Rigas Cas enzymes have generated significant attention over the past several years, mostly for their ability to serve as DNA or RNA targeting platforms, either for manipulation of expression of single or multiple genes that have been investigated within commercial and academic sectors. To further build upon previously established knowledge of CRISPR binding activity, selectivity and efficiency, we study analytical solutions to first passage times which can be successfully exploited to model binding affinity, and precision, across several Cas nucleases. To achieve more precise computational approximations of first passage times for a range of nucleases given varying landscape potentials, ambient binding temperature, and base pair of inspection against the guide DNA or RNA sequence, we draw upon experimental data gathered for spCas9, saCas9, stCas9, asCas12a, and FnCas12a to model CRISPR binding efficiency given selection conditions. To appropriately model the time scales during which DNA or RNA bonds are targeted in successful binding events that minimze off-target impacts, we simulate trajectories of different Cas nucleases throughout genome interrogation and comment upon physical characteristics of the Cas nuclease trajectory, which ultimately determine if binding occurs. |
Friday, March 18, 2022 9:24AM - 9:36AM |
Y05.00006: Topology-dependent hole transfer in G-quadruplex by molecular dynamics and density functional theory Samprita Nandi, Angel-Emilio Villegas Sanchez, Colin Coane, Angana Ray, Rosa Di Felice Molecular electronics is one of the explored possibilities to fabricate computational devices beyond the limits of Moore's law. DNA-based molecular wires are particularly appealing in this context because of DNA’s nanoscale self-organization and high yield synthesis. G-quadruplex, a helical form of nucleic acids, is a fascinating alternative to duplex DNA with higher stiffness and electronic coupling. For the development of molecular wires, it is important to optimize electron transport along the wire axis. One powerful basis to do so is by manipulating the structure, based on known effects that electron transport strongly depends on the structural changes. Here, we investigate such effects, by a combination of classical simulations of the structure and dynamics and quantum calculations of electronic couplings. We find that this structure-function relationship is complex. A single helix shape parameter alone does not embody such complexity. Nay, it is a linear combination of different inter-base helix shape parameters that influences the charge transfer. The coefficients of this linear combination can be tuned to optimize charge transport. We provide an optimized combination of the shape parameters to maximize the structure-function correlation in G-quadruplex. |
Friday, March 18, 2022 9:36AM - 9:48AM |
Y05.00007: The Mesoscale Order of Nacreous Pearls Robert Hovden, Jiseok Gim, Alden Koch, Laura M Otter, Benjamin H Savitzky, Sveinung Erland, Lara A Estroff, Dorrit E Jacob A pearl’s distinguished beauty and toughness are attributable to the periodic stacking of aragonite tablets known as nacre. Nacre has naturally occurring mesoscale periodicity that remarkably arises in the absence of discrete translational symmetry. Gleaning the inspiring biomineral design of a pearl requires quantifying its structural coherence and understanding the stochastic processes that influence formation. By characterizing the entire structure of pearls (~3 mm) in cross-section at high resolution, we show nacre has medium-range mesoscale periodicity. Self-correcting growth mechanisms actively remedy disorder and topological defects of the tablets and act as a countervailing process to long-range disorder. Nacre has a correlation length of roughly 16 tablets (~5.5 µm) despite persistent fluctuations and topological defects. For longer distances (> 25 tablets ~8.5 µm), the frequency spectrum of nacre tablets follows f-1.5 behavior suggesting growth is coupled to external stochastic processes—a universality found across disparate natural phenomena which now includes pearls. |
Friday, March 18, 2022 9:48AM - 10:00AM |
Y05.00008: Enhancing Sustainability of Palm-Leaf Foodware by Secretion of Surface Wax Layer Debapriya Pinaki Mohanty, Anirudh Udupa, Mysore Dayananda, Srinivasan Chandrasekar Areca catechu palm leaf sheath has shown promise as a sustainable natural material for eco-friendly foodware. One of the principal factors controlling the life of palm-leaf foodware is diffusion of water through the sheath, which results in lowering of structural integrity of the plant material. We study diffusion of water through the sheath using mass gain measurements and in situ observations of water transport. We find that subjecting the sheath to a short-time thermal treatment at 1200C reduces the diffusion coefficient of water by 1/4 compared to that in the untreated sheath, along with a 4-fold increase in sheath-product life. This reduction of diffusion is shown to be a consequence of secretion of a thin natural hydrophobic wax layer onto the sheath surface from the bulk. By controlling the thermal treatment, a uniform wax surface layer can also be achieved. The results suggest opportunities for improving foodware product life and sustainability of these plant-based products |
Friday, March 18, 2022 10:00AM - 10:12AM |
Y05.00009: Electrospray deposition as an efficient alternative to coat medical devices Sarah H Park, Lin Lei, Catherine J Nachtigal, Emran Lallow, Maria Atzampou, Alex Liu, Jeffrey Zahn, Hao Lin, Jonathan P Singer Electrospray deposition (ESD) is a common thin film coating technique that can produced charged droplets at the micro- and nano-scale capable of being used in medicine, such as for drug delivery purposes and medical implants. In ESD, an electrostatic force is applied to a solution, which then disperses charged droplets loaded with the materials to be deposited. Our lab has categorized various modes of ESD, including self-limiting electrospray deposition (SLED). In SLED, the material arrives onto a target as a dried spray, carrying a charge that eventually begins to repel itself over time. The charged spray is redirected to regions that are uncoated such that manipulation of the electrostatic repulsion, hydrodynamic forces, and evaporation kinetics can be employed to conformally cover 3D architectures with micro-coatings. The generated coatings are hierarchical, possessing either nano-shell, nanoparticle, or nanowire microstructure, which can be smoothed through further post processing. We envision SLED as being a replacement for dip or conventional-spray coating, where its greatest advantage would be the potential for much higher materials utilization. While many studies have presumed high efficiency in ESD, this is rarely quantified. Here, I will show how architecting the local charge landscape can lead to SLED coatings approaching 100% deposition efficiency on microneedle arrays and other complex substrates of relevant therapeutics and model materials, including biocompatible polymers, DNA vaccines, and bioactive small molecules. |
Friday, March 18, 2022 10:12AM - 10:24AM |
Y05.00010: Antibacterial Activity of Pulsed Laser Synthesized Silver Nanoparticles Combined with Methylene Blue for Prosthetic Joint Infection Somon Hakimov, Salizhan Kylychbekov, Shreya Neupane, Simran Banga, Ali Oguz Er Photosensitizing agents play an essential role in deactivation process of multidrug resistant pathogens and tumor treatments. In this work, methylene blue (MB) functionalized silver nanoparticles (Ag NPs) are used as an effective photodynamic therapy (PDT) agent for prosthetic joint infection (PJI). Ag NPs were synthesized by pulsed laser ablation technique in different aqueous solutions such as polyvinylpyrrolidone (PVP), citrate and polyvinyl alcohol (PVA) at different wavelength and power. With 1064nm wavelength, Ag NPs average size distribution in citrate, PVP, and PVA were found to be 6nm, 10nm, and 12nm respectively. Further, with 532nm wavelength it was found to be 4nm, 7nm, and 10nm respectively. The synthesized Ag NPs were characterized in depth using a transmission electron microscopy (TEM), UV–vis, and photoluminescence (PL) spectra. These Ag NPs were combined with MB and used to deactivate Escherichia coli, a Gram-negative bacterium, and Staphylococcus aureus, a Gram-positive bacterium. MB and Ag NPs combination was found to possess higher antimicrobial activity and thus were more effective in killing both Gram –positive and Gram-negative bacteria in comparison to MB and Ag NPs alone. Within 6 min of irradiation time with 660 nm LED, the MB/Ag NPs deactivated entire bacterial population containing ~108 CFU/mL of E.coli. Thus, MB/Ag NPs used in PDT could be effective in killing bacterial pathogens in open wounds, prosthetic joint infections, in vivo cancer and tumor treatments. We are further exploring the effect of magnetic field during the silver nanoparticle synthesis on particle size and distribution. |
Friday, March 18, 2022 10:24AM - 10:36AM |
Y05.00011: Heat transfer through functionalized carbon nanotubes for photothermal therapy of cancer Delaram Nematollahi, Kieran Mullen, Dimitrios V Papavassiliou Carbon nanotubes (CNTs) functionalized with the protein annexin V (AV) bind specifically to anionic phospholipids expressed externally on the surface of tumor cells. Such CNTs can be used to kill metastatic cancer cells by subsequently heating them with near-infrared radiation or a radiofrequency field. We use Dissipative Particle Dynamics with energy conservation (DPDe) package from Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) in order to study heat transfer from CNTs to the cell and surrounding medium. The CNT is simulated as a cylinder consisting of “beads” representing a coarse-grained CNT. We develop the model parameters needed to represent the CNT, and its interaction with the protein and cell wall. To prepare the cell environment in our simulation we are using water or water/oil molecules as our medium. We study heat transfer from the CNT’s to the protein, medium and membrane using DPDe in the same. We examine how the CNT might be optimized for this application. |
Friday, March 18, 2022 10:36AM - 10:48AM |
Y05.00012: Polyethylene Oxide doped with Nano Cobalt Cerium Dioxide Nanocomposite as an antimicrobial surface Ahmad M Alsaad, A A Ahmad, Q M Al-Bataineh In this work, we propose an innovative idea by using doping method in doping a polymeric surface with nano cobalt cerium dioxide (CeO2:Co) forming a multifunctional polymeric nanocomposite complex. This new nanocomposites will serve as an antimicrobial surface because CeO2:Co nanoparticles behave as antimicrobial and antifungal agents. The successfully prepared doped polymeric nanocomposite can be used as a standalone antimicrobial surface to coat surfaces in hospitals and other institutions free of disinfection chemicals such as chlorine. The polymeric nanocomposite surface will be modeled, simulated, prepared, and characterized based on advanced experimental investigation techniques such as FTIR, SEM, and EDX. Moreover, the controlled doping of the polymeric surface with nano cobalt cerium dioxide (CeO2:Co) ensures a higher density of the antimicrobial and antifungal particles on the membrane surface. Moreover, the doping leads to a proper and efficient chemical interaction between nanoparticles and polyamide matrix. Therefore, the nanoparticles cannot easily leach out during the cleaning process. |
Friday, March 18, 2022 10:48AM - 11:00AM |
Y05.00013: Polymorphism, Structure, and Nucleation of Cholesterol.H2O at Aqueous Interfaces and in Pathological Media: Revisited from a Computational Perspective Margarita Shepelenko, Anna Hirsch, Neta Varsano, Fabio Beghi, Lia Addadi, Leeor Kronik, Leslie Leiserowitz We revisit the important issues of polymorphism, structure, and nucleation of cholesterol.H2O using first principles calculations based on dispersion-augmented density functional theory. For the monoclinic polymorph, we obtain a fully extended H-bonded network in a structure akin to that of hexagonal ice. We show that the energy of the monoclinic and triclinic polymorphs is similar, strongly suggesting that kinetic and environmental effects play a significant role in determining polymorph nucleation. Furthermore, we find evidence in support of various OH…O bonding motifs that may result in hydroxyl disorder. We have been able to explain why a single cholesterol bilayer in hydrated membranes always crystallizes in the monoclinic polymorph. We rationalize what we believe is a single-crystal to single-crystal transformation of the monoclinic form on increased interlayer growth, interleaved by a water bilayer, and show that the ice-like structure is also relevant to the related cholestanol.2H2O crystal. Finally, we posit a possible role for one of the sterol esters in the crystallization of cholesterol.H2O in pathological environments, based on a composite of a crystalline bilayer of cholesteryl palmitate bound epitaxially as a nucleating agent to the monoclinic cholesterol.H2O form. |
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