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1. Structural and biochemical characterization of iminodiacetate oxidase from Chelativorans sp. BNC1

   https://doi.org/10.1111/mmi.14399  

   Kang, ChulHee; Jun, Se‐Young; Bravo, Abigail G.; Vargas, Erick M.; Liu, Honglei; Lewis, Kevin M.; Xun, Luying (November 2019, Molecular Microbiology)

   Summary Ethylenediaminetetraacetate (EDTA) is the most abundant organic pollutant in surface water because of its extensive usage and the recalcitrance of stable metal‐EDTA complexes. A few bacteria includingChelativorans sp.BNC1 can degrade EDTA with a monooxygenase to ethylenediaminediacetate (EDDA) and then use iminodiacetate oxidase (IdaA) to further degrade EDDA into ethylenediamine in a two‐step oxidation. To alleviate EDTA pollution into the environment, deciphering the mechanisms of the metabolizing enzymes is an imperative prerequisite for informed EDTA bioremediation. Although IdaA cannot oxidize glycine, the crystal structure of IdaA shows its tertiary and quaternary structures similar to those of glycine oxidases. All confirmed substrates, EDDA, ethylenediaminemonoacetate, iminodiacetate and sarcosine are secondary amines with at least one N‐acetyl group. Each substrate was bound at there‐side face of the isoalloxazine ring in a solvent‐connected cavity. The carboxyl group of the substrate was bound by Arg²⁶⁵and Arg³⁰⁷. The catalytic residue, Tyr²⁵⁰, is under the hydrogen bond network to facilitate its deprotonation acting as a general base, removing an acetate group of secondary amines as glyoxylate. Thus, IdaA is a secondary amine oxidase, and our findings improve understanding of molecular mechanism involved in the bioremediation of EDTA and the metabolism of secondary amines. 

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2. Dynamic Coordination of Eu–Iminodiacetate to Control Fluorochromic Response of Polymer Hydrogels to Multistimuli

   https://doi.org/10.1002/adma.201706526  

   Weng, Gengsheng; Thanneeru, Srinivas; He, Jie (January 2018, Advanced Materials)

   Abstract New fluorochromic materials that reversibly change their emission properties in response to their environment are of interest for the development of sensors and light‐emitting materials. A new design of Eu‐containing polymer hydrogels showing fast self‐healing and tunable fluorochromic properties in response to five different stimuli, including pH, temperature, metal ions, sonication, and force, is reported. The polymer hydrogels are fabricated using Eu–iminodiacetate (IDA) coordination in a hydrophilic poly(N,N‐dimethylacrylamide) matrix. Dynamic metal–ligand coordination allows reversible formation and disruption of hydrogel networks under various stimuli which makes hydrogels self‐healable and injectable. Such hydrogels show interesting switchable ON/OFF luminescence along with the sol–gel transition through the reversible formation and dissociation of Eu–IDA complexes upon various stimuli. It is demonstrated that Eu‐containing hydrogels display fast and reversible mechanochromic response as well in hydrogels having interpenetrating polymer network. Those multistimuli responsive fluorochromic hydrogels illustrate a new pathway to make smart optical materials, particularly for biological sensors where multistimuli response is required. 

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3. An Adaptable Tough Elastomer with Moisture‐Triggered Switchable Mechanical and Fluorescent Properties

   https://doi.org/10.1002/adfm.201903543  

   Zhou, Xing; Wang, Libing; Wei, Zichao; Weng, Gengsheng; He, Jie (July 2019, Advanced Functional Materials)

   Abstract Smart materials with coupled optical and mechanical responsiveness to external stimuli, as inspired by nature, are of interest for the biomimetic design of the next generation of soft machines and wearable electronics. A tough polymer that shows adaptable and switchable mechanical and fluorescent properties is designed using a fluorescent lanthanide, europium (Eu). The dynamic Eu‐iminodiacetate (IDA) coordination is incorporated to build up the physical cross‐linking network in the polymer film consisting of two interpenetrated networks. Reversible disruption and reformation of Eu‐IDA complexation endow high stiffness, toughness, and stretchability to the polymer elastomer through energy dissipation of dynamic coordination. Water that binds to Eu³⁺ions shows an interesting impact simultaneously on the mechanical strength and fluorescent emission of the Eu‐containing polymer elastomer. The mechanical states of the polymer, along with the visually optical response through the emission color change of the polymer film, are reversibly switchable with moisture as a stimulus. The coupled response in the mechanical strength and emissive color in one single material is potentially applicable for smart materials requiring an optical readout of their mechanical properties. 

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4. A Sensor Array for the Ultrasensitive Discrimination of Heavy Metal Pollutants in Seawater

   https://doi.org/10.1002/adfm.202112634  

   Ihde, Michael_H; Tropp, Joshua; Diaz, Miguel; Shiller, Alan_M; Azoulay, Jason_D; Bonizzoni, Marco (June 2022, Advanced Functional Materials)

   Abstract Metal cations are potent environmental pollutants that negatively impact human health and the environment. Despite advancements in sensor design, the simultaneous detection and discrimination of multiple heavy metals at sub‐nanomolar concentrations in complex analytical matrices remain a major technological challenge. Here, the design, synthesis, and analytical performance of three highly emissive conjugated polyelectrolytes (CPEs) functionalized with strong iminodiacetate and iminodipropionate metal chelates that operate in challenging environmental samples such as seawater are demonstrated. When coupled with array‐based sensing methods, these polymeric sensors discriminate among nine divalent metal cations (Cu^II, Co^II, Ni^II, Mn^II, Fe^II, Zn^II, Cd^II, Hg^II, and Pb^II). The unusually high and robust luminescence of these CPEs enables unprecedented sensitivity at picomolar concentrations in water. Unlike previous array‐based sensors for heavy metals using CPEs, the incorporation of distinct π‐spacer units within the polymer backbone affords more pronounced differences in each polymer's spectroscopic behavior upon interaction with each metal, ultimately producing better analytical information and improved differentiation. To demonstrate the environmental and biological utility, a simple two‐component sensing array is showcased that can differentiate nine metal cation species down to 500 × 10⁻¹² min aqueous media and to 100 × 10⁻⁹ min seawater samples collected from the Gulf of Mexico. 

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5. Perspective: Wearable Internet of Medical Things for Remote Tracking of Symptoms, Prediction of Health Anomalies, Implementation of Preventative Measures, and Control of Virus Spread During the Era of COVID-19

   https://doi.org/10.3389/frobt.2021.610653  

   Mehrdad, Sarmad; Wang, Yao; Atashzar, S. Farokh (April 2021, Frontiers in Robotics and AI)

   null (Ed.)

   The COVID-19 pandemic has highly impacted the communities globally by reprioritizing the means through which various societal sectors operate. Among these sectors, healthcare providers and medical workers have been impacted prominently due to the massive increase in demand for medical services under unprecedented circumstances. Hence, any tool that can help the compliance with social guidelines for COVID-19 spread prevention will have a positive impact on managing and controlling the virus outbreak and reducing the excessive burden on the healthcare system. This perspective article disseminates the perspectives of the authors regarding the use of novel biosensors and intelligent algorithms embodied in wearable IoMT frameworks for tackling this issue. We discuss how with the use of smart IoMT wearables certain biomarkers can be tracked for detection of COVID-19 in exposed individuals. We enumerate several machine learning algorithms which can be used to process a wide range of collected biomarkers for detecting (a) multiple symptoms of SARS-CoV-2 infection and (b) the dynamical likelihood of contracting the virus through interpersonal interaction. Eventually, we enunciate how a systematic use of smart wearable IoMT devices in various social sectors can intelligently help controlling the spread of COVID-19 in communities as they enter the reopening phase. We explain how this framework can benefit individuals and their medical correspondents by introducing Systems for Symptom Decoding (SSD), and how the use of this technology can be generalized on a societal level for the control of spread by introducing Systems for Spread Tracing (SST). 

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