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ACS Award in the Chemistry of Materials Symposium in Honor of Prof. Yury Gogotsi: Next Generation Material for Energy Applications
10:30am - 12:30pm USA / Canada - Eastern - August 22, 2021 | Room: B203
Kelsey Hatzell, Organizer, Princeton University; Kelsey Hatzell, Presider, Princeton University
Division: [ENFL] Division of Energy and Fuels
Session Type: Oral - Hybrid
Division/Committee: [ENFL] Division of Energy and Fuels
Sunday
From LCO, NCA to NMC-811: Structure, dynamics and degradation of layered cathode materials for lithium ion batteries
10:30am - 11:00am USA / Canada - Eastern - August 22, 2021 | Room: B203
Clare Grey, Presenter
Division: [ENFL] Division of Energy and Fuels
Session Type: Oral - Hybrid
Ni-rich layered cathode materials are among the most promising candidates for high energy density Li-ion batteries for EV applications, yet improvements in their capacity retention – particularly under conditions of stress (high/low temperature, fast charging) – are still required for their more widespread use. This talk focuses recent studies aimed at understanding the initial first cycle capacity loss and capacity loss over more extended cycling in half and full cells. Operando x-ray diffraction (XRD) and nuclear magnetic resonance (NMR) spectroscopy for LixNi0.8Co0.15Al0.05O2 is used to demonstrate that the apparent first cycle capacity loss is a kinetic effect linked to limited Li mobility at x > 0.88. XRD experiments for NMC811 (LiNi0.8Mn0.1Co0.1O2) shows the emergence and growth of a “fatigued” phase with cycle number which cannot be fully delithiatied. We discuss the origins of this phenomena – which is not solely due to kinetic limitations or inter-granular cracking - and its relationship to the growth of the rock-salt surface phase. New operando methods to study LiCoO2 (LCO) are described, and an attempt to derive holistic explanations for the difference in the nature of the phase transitions between these three classes of layered materials, will be presented.
Sunday
Atomically precise chemical, physical, electronic, and spin contacts in materials
11:00am - 11:30am USA / Canada - Eastern - August 22, 2021 | Room: B203
Paul Weiss, Presenter
Division: [ENFL] Division of Energy and Fuels
Session Type: Oral - Hybrid
Two seemingly conflicting trends in nanoscience and nanotechnology are our increasing ability to reach the limits of atomically precise structures and our growing understanding of the importance of heterogeneity in the structure and function of molecules and nanoscale assemblies. By having developed the “eyes” to see, to record spectra, and to measure function at the nanoscale, we have been able to fabricate structures with precision as well as to understand the important and intrinsic heterogeneity of function found in these assemblies. The physical, electronic, mechanical, and chemical connections that materials make to one another and to the outside world are critical and are intertwined in terms of their function. Just as the properties and applications of conventional semiconductor devices depend on these contacts, so do nanomaterials, many nanoscale measurements, and devices of the future. We discuss the important roles that these contacts can play in preserving key transport and other properties. Initial nanoscale connections and measurements guide the path to future opportunities and challenges ahead. Band alignment and minimally disruptive connections are both targets and can be characterized in both experiment and theory. Chiral assemblies can control the spin properties and thus transport at interfaces. I discuss our initial forays into these areas in a number of materials systems.
Sunday
Photoinduced halide ion segregation in 2D-lead halide perovskites
11:30am - 12:00pm USA / Canada - Eastern - August 22, 2021 | Room: B203
Jeffrey DuBose, University of Notre Dame; Preethi Mathew; Junsang Cho; Prashant Kamat, Presenter
Division: [ENFL] Division of Energy and Fuels
Session Type: Oral - Hybrid
Understanding halide migration in lead halide perovskites is important for developing stable perovskites solar cells. Of particular interest is the 2D metal halide perovskite, R2An-1PbnX3n+1 (R+ = phenylethylammonium (PEA), butylammonium (BA); A+ = methylammonium (MA), cesium (Cs), and formamidium (FA); and X- = Cl, Br, and I) and its tunable layer number (n) within the 2D layered architectures. The tunability achieved through compositional variation of R+:A+ ratio, allows the control of optoelectronic properties such as bandgap, exciton binding energy, and charge carrier recombination lifetime. Although 2D perovskites have shown to suppress halide migration in bulk metal halide perovskite films, the halide ion migration in these low-dimensional perovskite film still prevails as seen from the halide ion segregation and dark recovery in mixed halide (Br:I = 50:50) perovskites films with different layer numbers (n = ∞ - 1). The fraction of halide ion segregation upon light-irradiation, as determined from the difference absorption spectra, decreased from 23.2 % (n = ∞) to < 2.5 % (n = 1) as we decrease the dimensionality of the perovskite. The dependence of excited state behavior of 2D perovskites and halide ion mobility on the layer dimensionality in 2D metal halide perovskites will be discussed.
Sunday
Essential role of electron microscopy in fundamental MXene research
12:00pm - 12:30pm USA / Canada - Eastern - August 22, 2021 | Room: B203
Division: [ENFL] Division of Energy and Fuels
Session Type: Oral - Hybrid
In less than a decade, we have witnessed significant advancement in the development of a new class of 2D materials known as MXenes, which are transition metal carbides, carbonitrides and nitrides. Due to their unique combination of physical and mechanical property attributes, a wide range of electrochemical energy storage, catalytic, electromagnetic interference shielding, nanoelectronics, optoelectronics, sensors, and biomedical applications have already been explored. From a fundamental standpoint, it is important to understand how the atomic structure and functional group chemistry govern nanoscale properties such that new insight can be gained in order to develop improved synthesis methods or to tune specific functional properties. (Scanning) transmission electron microscope (S/TEM) is ideally suited to characterize 2D MXenes using a combination of high spatial/temporal resolution imaging and analytical electron microscopy methods. In this talk, I will focus on three main topic areas of microscopy driven MXene research and detail how each microscopy technique is helping to better understand properties of MXene. In situ S/TEM is being used to determine ion intercalation mechanisms and kinetics by tracking the dynamic expansion of lattice planes during electrochemical biasing and the formation of interphase inorganic compounds. STEM, combined with electron energy loss spectroscopy (EELS), is being used to determine the bonding characteristics and electronic structure of intercalants and functional group chemistry due to its importance on ion transport and conductivity. EELS is also being used to map the plasmonic response of MXenes at high spatial resolution. Lastly, STEM based atomic fabrication methods are being explored to controllably manipulate the MXene atomic structure to realize new nanoelectronic devices.
Carbon Capture & Utilization: Conversion of CO2 to Chemicals & Fuels:
10:30am - 12:30pm USA / Canada - Eastern - August 22, 2021 | Room: B218
Juliana Carneiro, Organizer, Georgia Institute of Technology; Kandis Gilliard-AbdulAziz, Organizer, University of California Riverside; Ambarish Kulkarni, Organizer, University of California Davis; Kandis Gilliard-AbdulAziz, Presider, University of California Riverside; Juliana Carneiro, Presider, ‍ ; Ambarish Kulkarni, Presider, University of California Davis
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Division/Committee: [CATL] Division of Catalysis Science & Technology

Carbon Capture and Utilization (CCU) is seen as a means to mitigate the emissions of CO2 with the concomitant use of a catalytic component for the conversion of CO2 to fuels, chemicals and polymers. While research for CO2 capture and utilization can be broad, this symposium will focus on the thermocatalytic and electrocatalytic strategies for CO2 capture and utilization. This symposium will foster the discussion from different perspectives and provide insights to address existing challenges in advancing these technologies further.

Sunday
Nanocrystal-based catalysts for CO2 hydrogenation to fuels and chemicals
10:30am - 10:50am USA / Canada - Eastern - August 22, 2021 | Room: B218
Matteo Cargnello, Presenter, Stanford University; Aisulu Aitbekova; Chengshuang Zhou, Stanford
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
The conversion of CO2 to fuels and chemicals represents an important pathway towards a sustainable future. The reduction of CO2 using renewable hydrogen is heavily researched as one possible avenue. The main challenges associated with this process are the activation of the inert CO2 molecule as well as the control of the selectivity towards specific compounds. Designing catalysts where metal/support interfaces are controlled to exploit their synergy is a viable route to steer the selectivity of the reaction towards desired products such as long-chain hydrocarbons. Furthermore, understanding changes that occur to catalysts under the demanding reaction conditions necessary for CO2 hydrogenation is important to design more efficient materials. In this talk, I will highlight recent work from our group that uses colloidal nanocrystals to prepare well-defined catalysts with inorganic and organic/inorganic hybrid interfaces to control CO2 hydrogenation selectivity. These catalysts demonstrate in some cases specific changes under reaction conditions that lead to modified reactivity and increased production of hydrocarbons following structural rearrangements. In other cases, the specific design of hybrid interfaces allows to obtain materials with much improved selectivity towards desired products, thus highlighting how colloidal nanocrystals can be used to design efficient and selective catalysts for challenging transformations.
Sunday
Theoretical calculations of electrochemical reduction of CO2 to form hydrocarbons and alcohols
10:50am - 11:10am USA / Canada - Eastern - August 22, 2021 | Room: B218
Hannes Jonsson, Presenter, Univ of Iceland Fac SCI Vr II
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
Results of calculations of the electrochemical reduction of CO2 and the competing hydrogen evolution reaction will be presented. Activation energy of the various elementary steps has been evaluated as a function of applied voltage as well as thermodynamic properties. It has been shown experimentally that copper electrodes can give rise to a wide range of products in electrochemical CO2 reduction and a key question is why copper is so special. Many aspects of the experimental measurements can be reproduced nicely by the theoretical calculations. The fact that the onset potential of formate and CO formation is similar can be explained by the fact that the energy barrier for the two competing processes is similar. The rate limiting step for further reduction is the hydrogenation of CO and the calculations show that a Heyrovsky step to form COH is the active mechanism rather than formation of CHO. An understanding of the detailed mechanism is important in order to find ways to improve the selectivity and to reduce the overpotential in order to make electrochemical CO2 reduction viable. Recent studies have, for example, shown that incorporation of CO2 into hydrate clathrates can significantly reduce the overpotential and favor CO2 reduction over hydrogen formation. The rate of C-C bond formation is strongly dependent on the surface structure and can be affected also by addition of small alloying component in the copper electrode. The extension of the simulation methodology to electrochemical reactions is challenging and represents an active front in the development of theoretical tools. Describing the effect of the electrostatic potential on the reaction rate is a challenge, but also the proper inclusion of a liquid dielectric at the surface of the electrode as it makes the DFT calculations too computationally demanding. Various levels of approximations have been developed and compared in the calculations of the electroreduction of CO2.
Sunday
Withdrawn
11:10am - 11:30am USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person

Sunday
Intensified catalytic conversion of CO2 into C1 and C2 chemicals
11:30am - 11:50am USA / Canada - Eastern - August 22, 2021 | Room: B218
Dr. Jesse Thompson, Presenter, University of Kentucky Center for Applied Energy Research; Daniel Moreno; Muthu Kumaran Gnanamani; Pom Kharel; Keemia Abad; Ayokunle Omosebi
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
The use of CO2 produced from power generation plants as a feedstock for creating valuable products offers a commercially viable strategy to reduce greenhouse gas (GHG) emissions and offset the cost of carbon capture. Despite years of CO2 conversion research, the development of efficient, robust, and selective heterogeneous CO2 reduction (CO2R) catalysts to convert CO2 into value-added compounds has yet to fully mature. In recent years, CO2R catalysts have become more sophisticated but still struggle with limited long-term activity. Producing value-added CO2 products via an electrochemical pathway can greatly depend on current density, Faradaic efficiency, electrode material and loading, and performance and material degradation.

To overcome the aforementioned limitations, development of a novel copper-based catalytic electrochemical system that can be used to convert carbon dioxide (CO2) to formic acid has been conducted. Formic acid (FA) is a high-value C1 chemical feedstock, but its current production process can require other high-valued chemicals as inputs, including methanol and/or hydrogen. In order to selectively convert CO2 to FA, Cu-based catalysts are commonly used. The metal-to-oxide interface of these catalysts can be tuned to offer higher peripheral metal-to-oxide interfacial area by alkylamine directed synthesis of morphology controlled metal layers formation on oxides.

The developed process leverages highly conductive mesoporous carbon xerogels electrodes, that have already been demonstrated as excellent supports in fuel cells, with Cu-based catalysts for the electrocatalytic conversion of CO2. Current results indicate that modifying CX cathodes with CuCo:CeO2 produces over 2X increase in FA compared only using Cu or CuCo at an operating voltage of -0.75 V vs. Ag/AgCl. Further FA selectivity customization is available in the -0.75 V to -1.0 V vs. Ag/AgCl range. Additionally, increasing the cell pressure from 1 to 3 bar to take advantage of the greater equilibrium concentration of CO2 increased FA production by over 5X, without compromising the structural integrity of the electrochemical cell.

Sunday
Combined electro-thermochemical system for conversion of waste carbon to C4+ synthetic fuels using 3D-printed reactors
11:50am - 12:10pm USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
With the realization of the global impact of waste carbon on the atmosphere, coupled with a clear and growing demand for abundant electricity, there are both environmental and economic driving forces for capturing and converting carbon dioxide (CO2) into high value hydrocarbon products. Two conversion approaches that have been studied extensively are the electrochemical CO2 reduction reaction (eCO2R) and the thermochemical Fischer-Tropsch reaction (F-T); however, leveraging the two reactions together for direct CO2 conversion to synthetic fuels has been challenging due to mismatched reactor size and scales of production, incompatible operating conditions, and poor stability of F-T catalysis in the presence of CO2-rich reactant streams.

This work employs advanced manufacturing to bridge the gap between these two technologies by creating custom 3D-printed reactors. These reactors were designed to align the scale of production for each reaction and consequently allow for a combined electrochemical-thermochemical approach for converting CO2 to C4+ synthetic fuels. A range of operating conditions for each process were investigated: for eCO2R, electrochemical potential and reactor geometry were tailored for maximum conversion of CO2 to CO and optimal ratio of H2:CO; for F-T, catalyst synthesis and operating temperature were studied for conversion of CO2-rich reactant streams to multi-carbon products at ambient pressure. As a result, we report a joint electro-thermochemical system that reaches a maximum of 20% single-pass conversion of CO2 that is stable for over 8 hours; furthermore, we achieve > 60% selectivity to C4+ products. This work represents a method to achieve high selectivity to desired products from CO2, as well as a viable path for scaling these technologies together for sustainable production of synthetic fuels and valuable products from waste carbon.

Sunday
Life cycle assessment of an integrated direct air capture system with advanced algal biofuel production
12:10pm - 12:30pm USA / Canada - Eastern - August 22, 2021 | Room: B218
Division: [CATL] Division of Catalysis Science & Technology
Session Type: Oral - In-person
This study investigates the life cycle environmental impacts of options for integrating a solid amine-based DAC system with advanced algal biofuel production in photobioreactors (PBRs). DAC utilization allows the removal of atmospheric CO2 while also decoupling algae production facilities from anthropogenic point CO2 sources and avoiding the challenges of transporting CO2 long distances to remote facilities. Life cycle assessment is used to assess the environmental benefits of heat and mass integration between the DAC and the PBR for biofuel production. The analysis includes life cycle greenhouse gas emissions, water consumption, land use, criteria air pollutant emissions, and wastewater emissions. This presentation will discuss a range of options and will evaluate the potential for low carbon, sustainable biofuel through air capture of carbon dioxide.
Advances in Separations:
10:30am - 12:30pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Amaris Borges-Munoz, Organizer, Bristol Myers Squibb; Facundo Fernandez, Presider, Georgia Tech
Division: [ANYL] Division of Analytical Chemistry
Session Type: Oral - Virtual
Division/Committee: [ANYL] Division of Analytical Chemistry

This symposium is open to oral and poster presentations that feature new advances in the use and/or development of analytical separation methods not covered in other ANYL symposia.

Sunday
Introductory Remarks
10:30am - 10:35am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Division: [ANYL] Division of Analytical Chemistry
Session Type: Oral - Virtual

Sunday
Evaluation of a polysaccharide-based chiral reversed-phase lquid chromatography screen strategy in pharmaceutical analysis
10:35am - 10:50am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Division: [ANYL] Division of Analytical Chemistry
Session Type: Oral - Virtual
Chirality control plays a critical role in developing stereoisomeric drugs. Due to the complexity and lack of predictability in chiral separations, column screening remains the gold standard to initiate chiral method development for active pharmaceutical ingredients (APIs) and synthetic intermediates. Chiral reversed-phase (RP) liquid chromatography (LC) has gained favor over other modes due to its versatility and compatibility in analyzing a wide range of chiral compounds in various matrices. Herein, we established a tier-based chiral RPLC screen strategy by constructing and analyzing a database of 101 chiral screens with a total of 3,401 entries (unique LC runs) for proprietary APIs or intermediates at Bristol Myers Squibb. Up to 17 polysaccharide-based chiral stationary phases (CSPs) and four mobile phases (MPs) have been screened with gradient elution. A selection of ten CSPs with two MPs was found sufficient to achieve successful separation for 82% of the total screens. Two RPLC screen tiers (Tier 1: AZ, OD, ID, and IG) and (Tier 2: AY, OJ, OZ, IA, IC, and IH) were proposed along with two MPs (acidic and neutral) to target ~70% hit rate for Tier 1, and ~80% for the combined set. We also implemented a user-friendly workflow to enable walk-up chiral RPLC screening with automated reports and system suitability tests.
Sunday
Withdrawn
10:50am - 11:05am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Session Type: Oral - Virtual

Sunday
Analytical control of potential mutagenic impurity 3-bromo-2-chloropyridine in pharmaceutical process development
11:05am - 11:20am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Cong Bi, Presenter, Bristol Myers Squibb; Li Li; Yueer Shi
Division: [ANYL] Division of Analytical Chemistry
Session Type: Oral - Virtual
3-Bromo-2-chloropyridine is a halogenated heterocyclic building block used in many pyridine-based synthetic applications such as catalysis, drug design, and natural product synthesis. It is used as an early starting material in the synthetic route of an immunology drug candidate at BMS. It is also a possible mutagenic impurity that has the potential to directly cause DNA damage when present at low levels, leading to mutations and therefore possibly causing cancer. Based on the threshold of toxicological concern and the estimated maximum tolerated dose, a strategy was established to conservatively control 3-bromo-2-chloropyridine to ≤ 7.5 ppm in the penultimate of the active pharmaceutical ingredient. The low ppm control limit restricted the use of LC-UV for a sensitive determination. Limited solubility of the penultimate in common organic solvents posed additional challenges for sample preparation and analysis.

In this presentation, we will discuss the development and optimization of a sensitive and reliable LC-MS method with simple, nominal mass detection for use in testing for 3-bromo-2-chloropyridine in the penultimate with a control limit of 7.5 ppm. Systematic method development was performed, including column screening, sample preparation evaluation, and LC and MS condition optimization, to ensure method specificity, sensitivity, accuracy, precision, and stability. The established LC-MS method was successfully implemented for scale-up penultimate batches, demonstrating excellent control of 3-bromo-2-chloropyridine prior to the final drug substance step.

Sunday
In silico predictive toolset for straightforward method development in centrifugal partition chromatography
11:20am - 11:35am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Division: [ANYL] Division of Analytical Chemistry
Session Type: Oral - Virtual
Although the mechanism of retention and separation is considered as simpler in liquid-liquid chromatographic (LLC) separations compared to conventional solid support-based chromatography (e.g., RP-HPLC), the lack of specific in silico tools slows down the multistep process of LLC method development. To tackle this issue, we have developed the following sequence: (i) a searchable structure-based database (N>2000) of experimental partition coefficient (Kd) data has been compiled: this database can provide solvent system (SS) candidates which are applicable for the purification of new target compounds; (ii) partition behavior and selectivity of these SS candidates can be further finetuned and validated in thermodynamic (e.g., Conductor-like Screening Model for Realistic Solvation, COSMO-RS) or in computational (e.g., Abraham-type general solvation) models; (iii) finally, using these Kd values along with solvent system and instrument parameters (e.g., settling time, overloading capacity), ultimate LLC chromatograms can be predicted and visualized in a simple application. Workflow of this approach will be exemplified by the centrifugal partition chromatography-based separation of major and minor phytocannabinoids.
Sunday
Intermission
11:35am - 11:40am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Division: [ANYL] Division of Analytical Chemistry
Session Type: Oral - Virtual

Sunday
Aptamers for binding against DNA-methyltransferase1 and SARS-COV-2 RdRp complex by AF4-SELEX
11:40am - 11:55am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Division: [ANYL] Division of Analytical Chemistry
Session Type: Oral - Virtual
Asymmetric flow field-flow fractionation (AF4) is a gentle and non-destructive separation tool that allows a laminar flow of the liquid and a perpendicular crossflow for analyte separation by their different diffusion coefficient. Coupling AF4 with SELEX enables efficient separation of bound DNA-protein complex while maintaining a high integrity of target protein and even protein complex owing to gentle flows and lack of the stationary phase. In our project, we discovered aptamers against DNMT1 and SARS-COV-2 RdRp complex by coupling AF4 with SELEX. Aptamers selected by this newly developed method showed excellent binding properties such as strong affinity and specificity. Furthermore, we kept engineering Apt. #9 against DNMT1 for further development of new cancer therapeutic approaches and study of the functions of DNMTs and the related epigenetic mechanisms.

Sunday
Withdrawn
11:55am - 12:10pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Division: [ANYL] Division of Analytical Chemistry
Session Type: Oral - Virtual

Sunday
Titanium dioxide-coated magnetic nano-stir bar for rapid and simple miRNA extraction
12:10pm - 12:25pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Sir Zongbo Li, Presenter, University of California Riverside
Division: [ANYL] Division of Analytical Chemistry
Session Type: Oral - Virtual
MicroRNAs (miRNAs) are a class of short, endogenous, non-coding RNAs with a length of 18-24 nucleotides, which can act as a gene regulator via binding the 3’ untranslated region of target mRNAs, causing mRNA degradation and regulating protein expression. However, to functional study of miRNAs and exploration of their utility as disease markers, miRNA should be isolated from the complicated sample matrix. The traditional extraction methods are liquid-liquid extraction (LLE) or solid-phase extraction (SPE), which still suffer some disadvantages, including time-consuming, labor-intensity, and low recovery. Besides, most of the current methods couldn’t do small volume which will increase the sample consumption or dilute the miRNA in the final elution, making detection more difficult. Herein, we design a titanium dioxide-coated magnetic nano-stir bar to extract miRNA from complex samples. The strong interaction between the phosphate group and titanium dioxide endow the high binding efficiency. The nano-features of the materials will provide more binding sites for extraction, increasing the loading capacity. What’s more, the nano-stir bar could spin under the magnetic field which will facilitate molecule transportation and increase the extraction efficiency. And the small size of the nano-stir bar allows us to extract miRNA in a very small volume (10ul) even in droplets. Finally, we could extract the miRNA in a very small volume (10ul) with recovery over 50% in the water matrix and over 10% in the serum matrix.
Sunday
Concluding Remarks
12:25pm - 12:30pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 23
Division: [ANYL] Division of Analytical Chemistry
Session Type: Oral - Virtual

Colloidal nano- and materials intended for biological applications:
10:30am - 12:10pm USA / Canada - Eastern - August 22, 2021 | Room: B206
Neus Feliu Torres, Organizer, Hamburg University; Wolfgang Parak, Organizer, Universitaet Hamburg; Sebastian Schwaminger, Presider, Massachusetts Institute of Technology
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Hybrid
Division/Committee: [COLL] Division of Colloid & Surface Chemistry

There are many reports of (potential) applications of colloids in biology/medicine. Classically emphasis is given on one property, originating from homogeneous particles. However, colloids in the context of biology are hybrid materials, for example by modification of the particle by adsorbed proteins, which forms together a new hybrid particle. Colloids also can be intentionally made by different compounds, allowing for multi-functionality. Such assemblies however do not need to be stable, as (intracellular) degradation processes may change the composition of the hybrid particle over time. In this symposium emphasis will be given on the hybrid nature of colloids. Appropriate topics include, but are not limited to: • Synthesis of hybrid particles • Self assembly of particle particle complexes • Analysis methods to characterize hybrid particles • Protein corona formation • Particle degradation • Multi-functionality of particles for imaging, treatment, diagnosis, etc.

Sunday
Anti-biofilm activity of chiral graphene quantum dots and their effects on functional bacterial amyloid proteins
10:30am - 10:50am USA / Canada - Eastern - August 22, 2021 | Room: B206
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Hybrid
The ability of bacteria to form complex structures called biofilms create numerous human health and industrial problems. These 3D architectures are defined by the extracellular polymer substance (EPS) that consists of a protective assembly of biomolecules for the encased bacterial cells. The current strategies for targeting biofilms weaken the EPS layer but are typically organic in nature and are subject to enzymatic degradation. Nanoparticles are a promising new class of anti-biofilm agents for their highly tunable physical and chemical properties, stability, and ability to interact with biological molecules, namely proteins. Here, we report the anti-biofilm activity of l-cysteine or d-cysteine derived chiral graphene quantum dots (GQDs) against amyloid rich staphylococcus aureus (S. aureus) biofilms. Both chiral nanoparticles disseminate S. aureus biofilms and inhibit fibrillation of phenol soluble modulin alpha 1 (PSMα1), a primary constituent of S. aureus biofilms. In particular, d-cysteine derived GQDs (D-GQDs) display higher anti-biofilm activity and increased the formation rate of supramolecular structures with PSMα1.
Sunday
Targeted bioorthoganal prodrug activation enabled by pH responsive classical polymer photocatalysts
10:50am - 11:10am USA / Canada - Eastern - August 22, 2021 | Room: B206
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Hybrid
The use of photocatalytic in situ prodrug activation and against cancer has received increasing attention over recent years. However, the application of the currently approved photocatalysts is limited by their poor aqueous solubility, aggregation, photobleaching, off target effects and poor tumour uptake. One approach to overcome these limitations is through the use of a delivery vector for the photoactive species. Recently we have reported a new class of polymer photocatalysts formed by combining small molecular photocatalysts/ with classical polymer chemistry. 1-3 Creating photocatalytic polymer constructs that contain the beneficial properties from both components.
We have designed pH responsive classical polymer catalysts that respond to the well reported pH changes between healthy and cancerous tissue. Here, we have used RAFT polymerisation to produce diblock copolymers consisting of PEG114-b-(PAEMA40-s-PPH2BT2). At pH >7 crosslinking of primary amines in the PAEMA block with terephthalaldehyde occurs, resulting in the formation of nanoparticles (NPs). In this particulate form the polymer is photocatalytically inactive as the active centres are imbedded within the core of the particle. These non-active NPs can freely circulate around the body and will accumulate in tumour tissue through the EPR effect. Within the tumour cell environment a pH drop is observed to pH 6.4. This change stimulates the disassembly of the NP, where the polymer once again becomes photocatalytically active. We have used this photocatalytic material for the in situ activation of a cancer prodrug based on fluorouracil (5-FU). Where the prodrug version of 5-FU shows limited toxicity but can be easily activated in the presence of light and the photoactive polymer into the toxic form. We have demonstrated by both In vitro and cellular studies that this approach has the potential to enable targeted prodrug activation for cancer treatment.

Sunday
optogenetics uses a visible light source to modulate neural activities and allows us to understand the neural mechanism, to improve and fix when malfunctioning. However, this technique is invasive in nature and limited by light penetration depth. Therefore, we are investigating tools that can use for non-invasive, in vivo optogenetic neuron stimulation. We synthesize and functionalize nanophosphors that emit bright visible-light when irradiated with x-ray. Also, we study x-ray stimulated behavior of Caenorhabditis elegans that we might bypass the need of visible-light source in the future of optogenetics. We synthesize Eu- and Tb-doped NaGdF4 nanoparticles using co-precipitate and hydrothermal processes and annealed at high temperature to increase the emission intensity. To prevent sintering during annealing and to facilitate biotin functionalization, nanoparticles are encapsulated in a silica shell. We study generating and collecting light through tissue by exciting nanophosphors using a focused X-ray source and the ability to use it as an MRI contrast agent. The nanoparticle size is ~100 nm. x-ray excited optical luminescence (XEOL) has low emission intensity at low- and high-dopant levels. Hydrothermal treatment and annealing without a silica-shell increase the emission intensity. However, the formation of silica-shell decreases the emission intensity. After annealing silica-coated NaGdF4: Eu, there is no significant increase in intensity, the structure changed to Eu-doped sodium-gadolinium-silicate. We confirmed biotin-functionalization by attaching nanoparticles to streptavidin in vitro. Light-generating and collecting through tissue are confirmed using XEOL and x-ray excited luminescence chemical imaging (XELCI). The particles are also served as MRI contrast agents. To study x-ray stimulated behavior, Caenorhabditis elegans are used. C. elegans are exposed to x-ray and observed their behavior (avoiding x-ray and ejecting eggs) before and after expose to x-ray. Our experiments proved that C. elegans x-ray avoidance behavior is proportional to x-ray dose, Lite-1 photoreceptor is responsible for this behavior, and 50% of C. elegans (type: pmyo-3::Lite-1) ejected eggs after x-ray on. In the future, we will optimize synthesis and annealing protocols to obtain bright nanophosphors, insert nanophoshors into C. elegans to study change in behavior and explore the potential of Lite-1 to control mammalian-cell neurons.
Sunday
Further advancements in controlling nanoscale diamond chemistry with a brominated surface intermediate
11:30am - 11:50am USA / Canada - Eastern - August 22, 2021 | Room: B206
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Hybrid
High-pressure high-temperature nanoscale diamond is the most common host of the nitrogen vacancy center (NVC) for magnetometry and electric field sensing applications. Limiting advancements in NVC charge state control and atomic/molecular control of the diamond surface are the limited routes to chemically removing C-O bonds after aerobic oxidation protocols. Previous discoveries about the highly labile C-Br bond on the diamond surface revealed that catalysis-free C-N bond formation was possible at 25oC and was largely understood as a consequence of the high energy state of the alkyl-bromide and the long-lived carbocation intermediate after debromination. Here we detail further information on retaining the labile C-Br moieties and the subsequent nucleophilic addition of nitrogen containing small molecules. Atomic and molecular details of the diamond surface is confirmed with vibrational spectroscopy and synchrotron-based X-ray spectroscopies and confirms our assignments. The removal of the highly stable C-O bond should now allow tunablility of the surface dipole moment with carbon-carbon and carbon-heteroatom bonding environments. This work is applicable to researchers investigating the modulation of NVC (or other colour center) photophysics, their use as a biolabeling nanoprobe and quantum sensing applications.
Sunday
Synthesis of novel hybrid inorganic/organic nanoscintillators for biomedical application
11:50am - 12:10pm USA / Canada - Eastern - August 22, 2021 | Room: B206
Division: [COLL] Division of Colloid & Surface Chemistry
Session Type: Oral - Hybrid
The uses of x-rays coupled with nanoscintillators have recently attracted researchers in biomedical theranostic for its deep tissue penetration and optical energy generation. Scintillators are a class of materials that can convert high excitation energies into light. The ideal scintillators for biomedical applications have high density, high light output, and discrete emission characteristics. This makes silicate based materials (e.g. Lu2SiO5:Ce, Y2Si2O7:Ce) an ideal candidate however, these materials can only be synthesized at temperatures when sub-100 nm particulates begin to sinter (>1000oC).
Two types of monodisperse scintillating colloids were synthesized at >1000oC using a high temperature multi-composite reactor (HTMcR). A particle with a core-bishell architecture was designed with a SiO2 core and a Re2O3 (Re = Y3+ or Lu3+) shell by sol-gel and precipitation techniques, followed by polymerization of poly(divinylbenzene) encapsulating the inorganic nanoparticulate. At >1000oC the inorganic species recrystallized to Re2Si2O7 while the organic specie carbonized to amorphous carbon and prevented particle aggregation.
The HTMcR has the potential to open new opportunities in nanotechnology that will be demonstrated in this presentation. First, the structure-luminescent properties of the sub-100 nm particulates were explored. A series of mono-, co-, and tri- doped systems (Ce3+, Tb3+, and Eu3+) were then incorporated into the sub-100 nm particulate to enhance its x-ray luminescence using Forester resonance energy transfers. Lastly, these nanoscintillators were surface functionalized with bovine serum albumin and rose bengal using click chemistry. The scintillators explored here have the potential to be applied in novel theranostic techniques such as x-ray optogenetics and x-ray induced photodynamic therapy.

Chemistry Teachers Day:
10:30am - 12:25pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 26
Sherri Rukes, Organizer, Libertyville High School; Sherri Rukes, Presider, Libertyville High School
Division: [CHED] Division of Chemical Education
Session Type: Oral - Virtual
Division/Committee: [CHED] Division of Chemical Education
Sunday
Introductory Remarks
10:30am - 10:35am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 26
Division: [CHED] Division of Chemical Education
Session Type: Oral - Virtual

Sunday
Withdrawn
10:35am - 11:05am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 26
Division: [CHED] Division of Chemical Education
Session Type: Oral - Virtual

Sunday
Withdrawn
11:05am - 11:35am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 26
Division: [CHED] Division of Chemical Education
Session Type: Oral - Virtual

Sunday
Intermission
11:35am - 11:45am USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 26
Division: [CHED] Division of Chemical Education
Session Type: Oral - Virtual

Sunday
Withdrawn
11:45am - 12:20pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 26
Division: [CHED] Division of Chemical Education
Session Type: Oral - Virtual

Sunday
Concluding Remarks
12:20pm - 12:25pm USA / Canada - Eastern - August 22, 2021 | Room: Zoom Room 26
Division: [CHED] Division of Chemical Education
Session Type: Oral - Virtual