Virtual Seminar Series organized by the Department of Chemistry, Materials and Chemical Engineering "Giulio Natta" waiting to be able to resume the live activity.
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From medieval alchemy to modern chemistry, symmetry has always been a key element both aesthetically and scientifically in shaping human perceptions across different length scales. Over the last decades, increasing scientific attention has been devoted to systems with five-fold symmetry, e.g. aperiodic quasicrystals, metal-organic assemblies resembling Platonic and Archimedean solids, as well as many biomolecules such as icosahedral virus capsids.
In 2008, a class of new macrocycle, pillar[5]arenes (P[5]s),[1] was introduced by T. Ogoshi and co-workers, and soon became popular molecular scaffolds in supramolecular and macrocyclic chemistry communities. In view of taking advantage of this unique five-fold molecular scaffold, our research group developed a “pre-oriented” protocol, leading to convenient and selective syntheses of C5-symmetric P[5]s, which feature two types of different chemical functionalities on their two rims.[2] Furthermore, a variety of chemical modifications can be effectively executed on the macrocyclic scaffolds, including routine alkylation, esterification, C-C coupling and SuFEx reactions.[3] These synthetic efforts also made it possible for us to construct a new five-fold symmetric oligophenolic macrocycle, the tiara[5]arenes (T[5]s),[4] that are not accessible from the addition of formaldehyde to phenol, for the first time.
In this webinar, the design and synthesis strategies of these novel macrocycles will be introduced. Attention will also be paid to their applications in supramolecular chemistry, both in solution and in the solid state. In addition, examples of employing these five-fold symmetric building blocks for constructing complex architectures will be shown.
[1] Pillar-shaped macrocyclic hosts pillar[n]arenes: new key players for supramolecular chemistry, Rev. 2016, 116, 7937–8002
[2] Rim-differentiated C5-symmetric tiara-pillar[5]arenes, Am. Chem. Soc. 2018, 140, 74–77
[3] Functionalization at will of rim-differentiated pillar[5]arenes, Lett. 2019, 21, 3976−3980
[4] Tiara[5]arenes: synthesis, solid-state conformational studies, host-guest properties, and application as nonporous adaptive crystals, Chem. Int. Ed. 2020, 59, 3994–3999
One of the main functions of nanoparticles is to deliver therapeutic agents to targeted diseased site. The therapeutic nanoparticle can kill or chemically alter sick cells. However, nanoparticles interact with a number of organs, tissues, and cells when they administered into the body. These biological entities sequester them and prevents the nanoparticles from being delivered at a high enough concentration to the diseased site to function effectively. In this presentation, I will discuss current and re-analysis of the mechanisms of nanoparticle transport in the body. These mechanism impact the design of nanomaterials for cancer targeting. Finally, I will discuss the future state in engineering of nanotechnology for cancer imaging and therapy.
Materials are at the core of our technological advances, and are needed to address many of our societal challenges: from energy to information, from food to medicine. I’ll highlight the great strides made in the last few years in the design and discovery of novel materials, where computational simulations can now precede, streamline, or accelerate experiments. This acceleration is driven by the central paradigm of computational science (doubling performance every 14-16 months), combined with powerful and predictive quantum simulation techniques, and by the convergence of data mining and machine learning towards materials simulations. I'll also underscore the IT requirements needed to perform calculations in a reproducible, shareable, high-throughput mode, highlighting applications to novel two-dimensional materials and solid-state Li-ion conductors.
Cells are signaled to proliferate, migrate, differentiate, and die through the action of receptors, membrane-spanning proteins that translate extracellular ligand binding events into cellular decisions by initiating networks of intracellular biochemical reactions. The complexity of these problems is ideal for, and often requires, application of computational modeling approaches to interpret data, predict system performance, and generate new hypotheses. However, the specific modeling approach must be tailored to the type and scope of problem at hand. While some problems are sufficiently circumscribed for use of familiar mechanistic governing equations, others are more easily tackled by first seeking statistical inferences from large data sets for which mechanistic governing equations are unknown. This seminar will primarily cover examples of the second type, where data-driven modeling approaches are used to dissect the complexity of large signaling networks in order to design combination therapy approaches for cancer. The talk will also cover the development of new reagents and tools for measuring or targeting specific signaling processes in vivo.
Mononuclear phagocytes such as monocytes, tissue-specific macrophages, and dendritic cells are primary actors in both innate and adaptive immunity. These professional phagocytes can be parasitized by intracellular bacteria, turning them from housekeepers to hiding places and favoring chronic and/or disseminated infection. One of the most infamous is the bacteria that cause tuberculosis (TB), which is the most pandemic and one of the deadliest diseases, with one-third of the world’s population infected and an average of 1.8 million deaths/year worldwide. Here we demonstrate the effective targeting and intracellular delivery of antibiotics to infected macrophages both in vitro and in vivo, using pH-sensitive nanoscopic polymersomes made of PMPC–PDPA block copolymer. Polymersomes showed the ability to significantly enhance the efficacy of the antibiotics killing Mycobacterium bovis, Mycobacterium tuberculosis, and another established intracellular pathogen, Staphylococcus aureus. Moreover, they demonstrated to easily access TB-like granuloma tissues — one of the harshest environments to penetrate — in zebrafish models. We thus successfully exploited this targeting for the effective eradication of several intracellular bacteria, including M. tuberculosis, the etiological agent of human TB. Because of their ability to selectively target human macrophages, PMPC-PDPA polymersomes have been also loaded with Glucocorticoid (GC) drugs to enhance their anti-inflammatory effect in the treatment of Rheumatoid Arthritis. Polymersomes were proved to efficiently promote the inflammation shutdown, while reducing the well-known therapeutic limitations in GC-based therapy.
With the advent of computer controlled additive manufacturing (AM) techniques applied to medicine, gradually researchers have adopted and transform these techniques to manufactured three-dimensional (3D) scaffolds for tissue engineering and regenerative medicine. Gradually these techniques have also started to be largely used to manufacture in vitro models for tissue and organ-like constructs. The techniques covered during this seminar will span from the traditional electrospinning technique to the more advance direct-writing modalities where nano and micron size fiber can be deposited in a controlled fashion. AM techniques such as fused deposition modeling, selective laser sintering, 3D printing, stereolithography and AM wet-spinning will be explained cover the working principles, the materials commonly used and the applications. Bioprinting techniques will also be showcased, highlighting the main differences to the traditional AM counterparts. The currently applications of bioprinting will be covered largely highlighting the creation of in vitro models. Finally the ultimate ambition of using these techniques to build tissues and organs for patients will be covered highlighting the challenges and the future roadmap.
Today, we are witnessing important developments that go beyond “traditional” chemical engineering. Chemists and engineers are working together on techniques that could transform our concept of “chemical plant”. This will lead to modular, miniaturized, safe, energy-efficient, and ecological processes. These advancements have opened the doors to synthetic transformations that were once considered “impossible” under “traditional” conditions, and are particularly relevant for the pharmaceutical and fine chemical industries, the two sectors that have historically produced the highest amount of pollution and waste.
With examples from our research, this seminar will highlight the impact of process intensification on several layers, from the utilization of catalytic materials with unprecedented structural control to the experimental design of continuous processes and flow conditions for the chemical industry of tomorrow.
Carbon allotropes from sp3-hybridized carbon (diamond) and sp2-hybridized carbon (graphite,
graphene, fullerenes, nanotubes) have well-established properties, many of which are technologically relevant. In particular, the discovery of fullerenes and graphene has captured the imagination of many chemists since these allotropes and their derivatives might serve as platforms for the next generation of electronic and energy capture devices. One needs to look no further than Nobel Prizes awarded in 1996 (C60) and 2010 (graphene) to appreciate the impact of these discoveries. A carbon allotrope derived from sp-hybridized carbon atoms (carbyne) has been discussed since the 1960s,[1] although an authentic sample of “natural” carbyne has not yet been identified. Recent computational studies suggest that carbyne might be the strongest known material or the ideal molecular wire, although experimental confirmation of these predictions remains elusive and the search for carbyne continues.
Organic chemists have tackled the challenge of carbyne through the synthesis and study of model compounds. With this goal in mind, we have developed a new methods toward the synthesis of polyynes[2–3] and cumulenes[4] as compounds to model the properties of carbyne. These efforts provide us with a unique opportunity to explore the physical characteristics of these compounds as a function of length. This presentation will describe the evolution of properties in the progression of oligoynes, to polyynes, to carbyne. The contrast of various properties through correlations drawn from spectroscopic analyses and X-ray crystallography are key to these studies and will be discussed. Finally, some predictions for the properties of carbyne will be offered.
[1] A. El Goresy, G. Donnay, Science 1969, 161, 363–364
[2] W. A. Chalifoux, R. R. Tykwinski, Nat. Chem. 2010, 2, 967–971
[3] Y. Gao, Y. Hou, F. Gordillo-Gámez, M. J. Ferguson, J. Casado, R. R. Tykwinski, Nat. Chem. 2020, accepted
[4] J. A. Januszewski, R. R. Tykwinski, Chem. Soc. Rev. 2014, 43, 3184–3203
June 19, 2020, 11:30 am
Signal and Data Processing Workflows for Untargeted Chemical Analysis: Sensor Array and Mass Spectrometry Analysis of Complex Gas Samples
Santiago Marco
Department of Electronics and Biomedical Engineering, University of Barcelona & Institute for Bioengineering of Catalonia, Barcelona Institute of Science and Technology
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In diverse sectors such as health, food, environment, complex natural gas samples are analysed. Those samples can contain hundreds or thousands of compounds. In many cases, the question to be answered does not require full separation, quantification, and identification of all compounds. Instead detection of abnormal samples (normal/ faulty), assignation of classes to samples (e.g.healthy/disease), or evaluation of global quantitative indexes (e.g odour intensity) is required.
The analysis of gas phase samples can be carried out with high-end lab equipment based on Chromatography-Mass Spectrometry or lower cost systems based on chemical sensors. In all cases, the resulting raw signals/data need substantial efforts to extract the hidden information. In health applications the problem of biomarker discovery becomes like finding a needle in a haystack. Intimate knowledge of the instrumental problems and the sampling conditions is key for the correct interpretation of the results.
These problems are often addressed by building mega-variate predictive models using tools from machine learning. However, in small sample conditions the possibilities to obtain overoptimistic results abound due to the curse of dimensionality. Careful model validation and statement of model validity domains is needed.
Integrated structural biology approaches provide us with an opportunity to understand the inner workings of proteins and protein complexes that controls basic cellular functions. Recent technical advances in electron. Microscopy (EM) have allowed us to overcome previous limitations restricting the size and heterogeneity of complexes under study. The resulting movies show, at near atomic resolution, large macromolecular machines at work. Looking forwards, the future holds the promise of routinely carrying out high-resolution imaging of these machines operating within normal and diseased cells.
Viral infections are among the main causes of death in the world. When prevention is not an option, antiviral drugs are the last resort to prevent the spread and the mortality of these infections. There are only a few effective drugs on the market, for the most part they prevent intracellular viral replication. Unfortunately, they are too few when compared to the many viruses that threaten humans.
In this talk, I will show a new design rule to achieve drugs that fight viruses extracellularly by irreversibly inhibiting their infectivity, i.e. I will show how to create virucidal compounds. The design of these macromolecular virucidal agents starts by a bio-mimic approach and is characterized by the limited toxicity towards host cells that one would expect from such compounds. Yet, I will demonstrate that the multivalent binding to the viruses, coupled with a large hydrophobic contact between the compounds and the virus leads to a loss of integrity of the virion that obviously leads to an irreversible loss of infectivity. Results in and ex-vivo will be illustrated especially for the cases of influenza, herpes, and respiratory syncytial virus.
In bioinspired materials there is a search for ever more complex functionalities and responses. Classic functionalities in materials science are stimuli-responses and shape-memory effects, relevant for numerous applications. Beyond those, could materials showing a response to a particular stimulus become responsive to another stimulus to which they are originally indifferent? Such a behavior would mimic the classical conditioning in behavioral psychology, one of the elementary forms of associative learning, originally shown by Pavlov in his experiments with dogs. Here we demonstrate two soft matter systems (a hydrogel and a liquid crystalline network) programmed to mimic classical conditioning. We foresee a wealth of possibilities for different materials systems, combinations of stimuli and different "memory" concepts for classically conditioned functional materials.
Edificio 6
P.zza Leonardo da Vinci, 32
I-20133 Milano
Edificio 28
Via Luigi Mancinelli, 7
I-20131 Milano
