Mercury pollution threatens the environment and human health across the globe. This neurotoxic substance is encountered in artisanal gold mining, coal combustion, oil and gas refining, waste incineration, chloralkali plant operation, metallurgy, and areas of agriculture in which mercury‐rich fungicides are used. Thousands of tonnes of mercury are emitted annually through these activities. With the Minamata Convention on Mercury entering force this year, increasing regulation of mercury pollution is imminent. It is therefore critical to provide inexpensive and scalable mercury sorbents. The research herein addresses this need by introducing low‐cost mercury sorbents made solely from sulfur and unsaturated cooking oils. A porous version of the polymer was prepared by simply synthesising the polymer in the presence of a sodium chloride porogen. The resulting material is a rubber that captures liquid mercury metal, mercury vapour, inorganic mercury bound to organic matter, and highly toxic alkylmercury compounds. Mercury removal from air, water and soil was demonstrated. Because sulfur is a by‐product of petroleum refining and spent cooking oils from the food industry are suitable starting materials, these mercury‐capturing polymers can be synthesised entirely from waste and supplied on multi‐kilogram scales. This study is therefore an advance in waste valorisation and environmental chemistry.
A polysulfide material was synthesized by the direct reaction of sulfur and d‐limonene, by‐products of the petroleum and citrus industries, respectively. The resulting material was processed into functional coatings or molded into solid devices for the removal of palladium and mercury salts from water and soil. The binding of mercury(II) to the sulfur‐limonene polysulfide resulted in a color change. These properties motivate application in next‐generation environmental remediation and mercury sensing.
Maleimides remain the reagents of choice for the preparation of therapeutic and imaging protein conjugates despite the known instability of the resulting products that undergo thiol-exchange reactions in vivo. Here we present the rational design of carbonylacrylic reagents for chemoselective cysteine bioconjugation. These reagents undergo rapid thiol Michael-addition under biocompatible conditions in stoichiometric amounts. When using carbonylacrylic reagents equipped with PEG or fluorophore moieties, this method enables access to protein and antibody conjugates precisely modified at pre-determined sites. Importantly, the conjugates formed are resistant to degradation in plasma and are biologically functional, as demonstrated by the selective imaging and detection of apoptotic and HER2+ cells, respectively. The straightforward preparation, stoichiometric use and exquisite cysteine selectivity of the carbonylacrylic reagents combined with the stability of the products and the availability of biologically relevant cysteine-tagged proteins make this method suitable for the routine preparation of chemically defined conjugates for in vivo applications.
Crude oil and hydrocarbon fuel spills are a perennial threat to aquatic environments. Inexpensive and sustainable sorbents are needed to mitigate the ecological harm of this pollution. To address this need, this study features a low‐density polysulfide polymer that is prepared by the direct reaction of sulfur and used cooking oils. Because both sulfur and cooking oils are hydrophobic, the polymer has an affinity for hydrocarbons such as crude oil and diesel fuel and can rapidly remove them from seawater. Through simple mechanical compression, the oil can be recovered and the polymer can be reused in oil spill remediation. The polysulfide is unique because it is prepared entirely from repurposed waste: sulfur is a by‐product of the petroleum industry and used cooking oil can be used as a comonomer. In this way, sulfur waste from the oil industry is used to make an effective sorbent for combatting pollution from that same sector.
The cleavage of aprotecting group from aprotein or drug under bioorthogonal conditions enables accurate spatiotemporal control over protein or drug activity.Disclosed herein is that vinyl ethers serve as protecting groups for alcoholcontaining molecules and as reagents for bioorthogonal bondcleavage reactions.Avinyl ether moiety was installed in arange of molecules,including amino acids,amonosaccharide,afluorophore,a nd an analogue of the cytotoxic drug duocarmycin. Tetrazine-mediated decaging proceeded under biocompatible conditions with good yields and reasonable kinetics.I mportantly,t he nontoxic, vinyl ether duocarmycin double prodrug was successfully decaged in live cells to reinstate cytotoxicity. This bioorthogonal reaction presents broad applicability and may be suitable for in vivo applications.Bioorthogonal chemistry for covalently conjugating synthetic molecules at ap redefined protein residue has been am ajor focus of research in the past two decades.[1] Very recently,focus has been placed on reactions which can instead cleave specific bonds under bioorthogonal conditions.[2] This strategy holds great potential for the precise spatiotemporal control of protein function in vivo. [1c,2] Fore xample,p hotodeprotection of agenetically encoded caged cysteinecould be used to reveal the active native protein in live cells.[3]Similarly,p alladium-mediated depropargylation, [4] phosphine-mediated Staudinger reduction, [5] and tetrazine-triggered inverse electron-demand Diels-Alder (IEDDA) elimination reactions [6] were successfully employed to restore the activity of proteins bearing acaged lysine residue in the active site.B ond-cleavage reactions are also attractive for drugdelivery applications.P alladium-catalyzed deprotection of a5 -fluoroacil prodrug was shown as am ethod for controlled drug release in vivo. [7] TheI EDDAr eaction between at etrazine and ac aged doxorubicin derivative efficiently releases the cytotoxic drug.[8] Strategies based on IEDDA elimination reactions with tetrazines are particularly attractive for decaging relevant molecules in cells and interrogating biology,b ecause of the favorable kinetics and the abiotic nature of tetrazines when compared to photo-and metalcatalyzed reactions.O ne limitation, however,h as been the breadth of protecting groups available for stable,y et conditionally reversible linkages.T ypically,I EDDAe limination reactions have been used with strained alkene protecting groups connected through ac arbamate,t hus resulting in ac ascade release of ap rimary amine (Figure 1a). [2,9] Furthermore,the reduced metabolic stability of strained alkenes constitutes am ajor caveat for its utility.F or instance, ciscyclooctene easily isomerizes to the non-reactive trans-cyclooctene,thus limiting the efficiencyofthe decaging process in cells. [10] Herein, we report the development of av inyl ether/ tetrazine system as IEDDAreaction partners for the traceless
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