ABSTRACT
Two metallo-triangles, SA and SB, with cis-TPE motifs were constructed, and their fluorescence properties were explored. Compared with the dilute solution, both triangles SA and SB exhibited significant AIE behavior in the aggregated states. Moreover, the shorter version SA showed higher quantum yields than SB in the aggregated states.
Subject(s)
Fluorescence , Spectrometry, FluorescenceABSTRACT
Studies of amyloid proteins have gradually become a hot topic. Nevertheless, very few effective drugs and treatments is available to cope with amyloid diseases. New molecules that can inhibit the protein fibrillation are highly anticipated. Insulin is one of the popular amyloid protein research models. On the other hand, resazurin and resorufin are widely known as a redox pair. We describes here an unexpected finding that resazurin plays a role in modulating insulin fibrillation, whereas resorufin doesn't. We hypothesize that the positively charged insulin at low pH can combine with the negatively charged resazurin due to electrostatic interaction, through which resazurin inhibited the process of insulin fibrillation. This effect was characterized and verified by using various biochemical, spectroscopic and imaging tools. This inhibition of this biocompatible dye can be achieved at various stages of fibrillation, suggesting the toxicity of the protein fibrils can be eliminated by using resazurin.
Subject(s)
Insulin/chemistry , Insulin/metabolism , Protein Aggregates , Escherichia coli/drug effects , Models, Molecular , Oxazines/chemistry , Oxazines/metabolism , Oxazines/toxicity , Oxidation-Reduction , Protein Conformation , Xanthenes/chemistry , Xanthenes/metabolism , Xanthenes/toxicityABSTRACT
Antifouling polymeric films can prevent undesirable adhesion of bacteria but are prone to accidental scratches, leading to a loss of their antifouling functions. To solve this problem, we report the fabrication of healable antifouling polymeric films by layer-by-layer assembly of partially hydrolyzed poly(2-ethyl-2-oxazoline) (PEtOx-EI-7%) and poly(acrylic acid) (PAA) based on hydrogen-bonding interaction as the driving force. The thermally cross-linked (PAA/PEtOx-EI-7%)*100 films show strong resistance to adhesion of both Gram-negative Escherichia coli and Gram-positive Bacillus subtilis bacteria due to the high surface and bulk concentration of the antifouling polymer PEtOx-EI-7%. Meanwhile, the dynamic nature of the hydrogen-bonding interactions and the high mobility of the polymers in the presence of water enable repeated healing of cuts of several tens of micrometers wide in cross-linked (PAA/PEtOx-EI-7%)*100 films to fully restore their antifouling function.
ABSTRACT
The first case of selective Fe(3+) ions and 1,4-dioxane luminescent sensor based on a porous organic polymer, POP-HT, was synthesized by reaction of tetra(p-aminophenyl)methane and chromophoric 2,5,8-trichloro-s-heptazine. POP-HT displayed prominent fluorescence quenching or enhancement in the presence of Fe(3+) ion or 1,4-dioxane. Moreover, an excellent linear relationship was established between luminescent intensity and the corresponding Fe(3+) ion or 1,4-dioxane concentration. The mechanisms of luminescence quenching and enhancement were also studied by both experiment and theoretical calculation. The results of this study suggest that POP-HT can work as an effective luminescent indicator for qualitative and quantitative detection of Fe(3+) ions and 1,4-dioxane in aqueous solution over other metal ions and organic solvents.
ABSTRACT
It remains a challenge to fabricate sacrificial films that are stable in most of solvents and can be readily decomposed on demand. Here we report the fabrication of a near-infrared (NIR) light decomposable sacrificial film by layer-by-layer (LbL) assembly of UV-light-decomposable poly((4-(2-bromoethoxy)-5-methoxy-2-nitrobenzyl acrylate) triethylammonium bromide) (PNBA-TEA), poly(sodium 4-styrene-sulfonate) (PSS), branched polyethyleimine (bPEI), and lanthanide-doped upconversion nanoparticles (UCNPs). The [(PNBA-TEA/PSS)*2/(bPEI/UCNPs)*3]*2 films are stable in deposition solutions of various materials and decompose upon NIR light irradiation. In the [(PNBA-TEA/PSS)*2/(bPEI/UCNPs)*3]*2 films, UCNPs can convert NIR light into UV light, which can decompose PNBA-TEA. After immersing the NIR light-irradiated [(PNBA-TEA/PSS)*2/(bPEI/UCNPs)*3]*2 films in 0.1 M aqueous NaHCO3 solution, the disintegration of the entire films occurs because of the repulsive force between the negatively charged photoproduct of PNBA-TEA and PSS. LbL-assembled (PAH/PAA)*50 films deposited on top of the NIR-light-decomposable [(PNBA-TEA/PSS)*2/(bPEI/UCNPs)*3]*2 films can be conveniently released to produce large-area and defect-free (PAH/PAA)*50 free-standing films after NIR light irradiation and subsequent immersion in 0.1 M aqueous NaHCO3 solution. Because of the satisfactory stability and on-demand decomposable property, the [(PNBA-TEA/PSS)*2/(bPEI/UCNPs)*3]*2 films are promising as sacrificial layers for the fabrication of various free-standing films.
