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Bojesen Christensen posted an update 6 months, 2 weeks ago
Deep eutectic solvents (DESs) with excellent physicochemical properties similar to ionic liquids and biocompatibility are potential solvent candidates for designing novel lanthanide luminescent soft materials. In this paper, the fabrication and characterization of such luminescent gels in three choline chloride (ChCl)-based DESs through self-assembly of the sodium cholate and europium nitrate are presented. The microstructure and gel-like nature of the obtained eutectogels were explored and confirmed by scanning electron microscopy and rheology measurements. While Fourier transform infrared spectroscopy and small-angle X-ray scattering were used to analyze the gel formation mechanism, which was considered to be synergistically driven by metal coordination, hydrogen bonding and solvophobic interactions. All three eutectogels exhibited good photophysical properties. Among these, the one formed in ChCl/urea DES was found to possess the strongest mechanical strength. While the one formed in ChCl/glycerol DES exhibited the longest luminescence lifetime and quantum efficiency. The obtained results demonstrate the possibility of using DESs to construct lanthanide luminescent soft materials or control their properties through the choice of hydrogen-bond donor molecules.The formation of catalytically active alkyl-Ni(i) complexes by comproportionation of diorgano-Ni(ii) precursors and Ni(0) species proceeds easily through triplet states by alkyl ligand exchange. The process involves inversion of the configuration at the carbon that is transferred.Cyclodextrins (CDs) are commercially produced via enzymatic breakdown of starch or amylose. In contrast, we show that cyclodextrins can be synthesised directly from the disaccharide maltose in good yields by exploiting the use of templates to favour the enzymatic build-up of cyclodextrins. learn more Using cyclodextrin glucanotransferase to catalyse reversible transglycosylation, and 1-adamantane carboxylic acid as the template, we can synthesise β-CD from maltose in approximately 70% yield. This work represents a step towards supramolecular control over enzymatic production of complex oligosaccharides from simple building blocks.Although dense colloidal gels with interparticle bonds of order several kT are typically described as resulting from an arrest of phase separation, they continue to coarsen with age, owing to the dynamics of their temporary bonds. Here, k is Boltzmann’s constant and T is the absolute temperature. Computational studies of gel aging reveal particle-scale dynamics reminiscent of condensation that suggests very slow but ongoing phase separation. Subsequent studies of delayed yield reveal structural changes consistent with re-initiation of phase separation. In the present study we interrogate the idea that mechanical yield is connected to a release from phase arrest. We study aging and yield of moderately concentrated to dense reversible colloidal gels and focus on two macroscopic hallmarks of phase separation increases in surface-area to volume ratio that accompanies condensation, and minimization of free energy. The interplay between externally imposed fields, Brownian motion, and interparticle forces during aging or yield, changes the distribution of bond lengths throughout the gel, altering macroscopic potential energy. The gradient of the microscopic potential (the interparticle force) gives a natural connection of potential energy to stress. We find that the free energy decreases with age, but this slows down as bonds get held stretched by glassy frustration. External perturbations break just enough bonds to liberate negative osmotic pressure, which we show drives a cascade of bond relaxation and rapid reduction of the potential energy, consistent with renewed phase separation. Overall, we show that mechanical yield of reversible colloidal gels releases kinetic arrest and can be viewed as non-equilibrium phase separation.Based on the linkage of genotype and phenotype, display technology has been widely used to generate specific ligands for profiling, imaging, diagnosis and therapy applications. However, due to the lack of effective monoclonal manipulation and affinity evaluation methods, traditional display technology has to undergo tedious steps of selection, clone isolation, amplification, sequencing, synthesis and characterization to obtain the binding sequences. To directly acquire high-affinity clones, we propose a double monoclonal display approach (dm-Display) for peptide screening based on highly paralleled monoclonal manipulation in emulsion droplets. dm-Display can monoclonally link the genotype, phenotype and affinity to realize integrated monoclonal separation, amplification, recognition and staining in one droplet so that discrete high-affinity clones can be quickly extracted. Monoclonal manipulations highly-parallelly occur in millions of droplets so that molecular screening of a highly diverse phage library is achieved. We have screened specific peptide ligands against CD71 and GPC1, proving the feasibility and generality of dm-Display. As a highly efficient ligand screening platform, dm-Display will promote the further development of molecular screening.The present study investigated ultraviolet-induced in situ gold nanoparticles (AuNPs) coupled with loop-mediated isothermal amplification (LAMP) for the point-of-care testing (POCT) of two major infectious pathogens, namely, Coronavirus (COVID-19) and Enterococcus faecium (E. faecium spp.). In the process, gold ions in a gold chloride (HAuCl4) solution were reduced using trisodium citrate (Na3Ct), a reducing agent, and upon UV illumination, red-colored AuNPs were produced in the presence of LAMP amplicons. The nitrogenous bases of the target deoxyribonucleic acid (DNA) acted as a physical support for capturing gold ions dissolved in the sample. The high affinity of gold with the nitrogenous bases enabled facile detection within 10 min, and the detection limit of COVID-19 plasmid DNA was as low as 42 fg μL-1. To ensure POCT, we designed a portable device that contained arrays of reagent chambers and detection chambers. In the portable device, colorimetric reagents such as HAuCl4 and Na3Ct were contained in the reagent chambers; these reagents were subsequently transferred to the detection chambers where LAMP amplicons were present and thus allowed convenient sample delivery and multiplex detection.
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