Folded or nonfolded fluorophores incorporating naphthalene:Their fluorescent quenching driven by charge transfer or co-aggregation in the aqueous-organic binary solvent

Folded or nonfolded fluorophores incorporating naphthalene were synthesized and characterized by steady state fluorescence technique.Paraquat as an excellent quenching reagent quenched the fluorescence of Nel6 or nDs(n = 1-4) driven by charge transfer.Under aggregation of nDs,α-CD did not quench the fluorescence of 1D.At lower concentration,the quenching tendency ofα-CD against nDs is 2D>3D>4D,while at higher concentration,the tendency is 2D<3D<4D.α-CD showed the selective recognition on its flu...

Effect of Srt A on Interspecies Adherence of Oral Bacteria

This study aimed to study whether the Sortase A(srt A)gene helps mediate coaggregation and co-adherence between Streptococcus mutans(S.mutans)and other salivary bacteria.S.mutans UA159 and srt A-deficient mutant served as"bait"in classical co-aggregation assays and membrane-based co-adherence assays were used to examine interactions of S.mutans with Fusobacterium nucleatum(F.nucleatum),Streptococcus mitis(S.mitis),Streptococcus gordonii(S.gordonii),Streptococcus sanguis(S.sanguis),Actinomyces naeslundii(A.naeslundii)and Lactobacillus.Co-adherence assays were also performed using unfractionated saliva from healthy individuals.Co-adhering partners of S.mutans were sensitively detected using polymerase chain reaction-denaturing gradient gel electrophoresis(PCR-DGGE).Both UA159 and its srt A-deficient mutant bound to F.nucleatum but not to any of the other five salivary bacteria.The srt A-deficient mutant showed lower co-adherence with F.nucleatum.The two S.mutans strains also showed similar co-adherence profiles against unfractionated salivary bacteria,except that UA159 S.mutans but not the srt A-deficient bound to a Neisseria sp.under the same conditions.Deleting srt A reduces the ability of S.mutans to bind to F.nucleatum,but it does not appear to significantly affect the binding profile of S.mutans to bulk salivary bacteria.

Ionic co-aggregates(ICAs)based oral drug delivery:Solubilization and permeability improvement

Due to the overwhelming percentage of poorly water-soluble drugs,pharmaceutical industry is in urgent need of efficient approaches for solubilization and permeability improvement.Salts consisting of lipophilic fatty acid anions and hydrophilic choline cations are found to be surface active and able to form ionic co-aggregates(ICAs)in water.Choline oleate-based ICAs significantly enhance oral absorption of paclitaxel(PTX)as compared with cremophor EL-based micelles(MCs).Aggregation-caused quenching probes enable tracking of intact ICAs in in vivo transport and cellular interaction.Prolonged intestinal retention of ICAs than MCs implies stronger solubilizing capability in vivo.Ex vivo imaging of major organs and intestinal tracts suggests transepithelial transport of intact ICAs.Cellular studies support the enhanced absorption of PTX and transmembrane transport of intact ICAs.In conclusion,ICAs,consisting of lipophilic ions and hydrophilic counter-ions,are of great potential in delivery of poorly water-soluble drugs by enhancing solubility and permeability.

The construction of aggregation-induced charge transfer emission systems in aqueous solution directed by supramolecular strategy

Novel aggregation-induced charge transfer(CT) emission systems with long luminescence lifetime directed by supramolecular strategy have been successfully developed in water. The dimethylacridine-based electron donor(Br Ac) with excellent aggregation ability can co-aggregate with a triazine-based electron acceptor(TRZ) to form nanorods in water, which exhibit CT emission with long lifetime(τ = 0.92 μs).As for a similar electron donor(Qa Ac) with poor aggregation ability, water-soluble pillar[5]arene(WP5)can be introduced to promote the aggregation process, leading to the obvious CT emission with long lifetime(τ = 0.61 μs). In addition, structural modification of the acceptor with substituent groups possessing stronger electron-accepting capabilities will cause red-shift(about 50 nm) of the emission, which allows conveniently constructing long lifetime organic luminescent materials with different emission colors.