Aggregation-induced-enhancement

Keywords Aggregation-induced enhanced emission (AIEE) Fluorescent organic nanoparticles Ion-association method Organic dye nanoparticles Reprecipitation method Restriction of intramolecular rotation Size-dependent optical properties... 

Fig. 5.16 Selected fluorophores 44 with aggregation-induced enhanced emission. soi, fluorescence quantum yield in dioxane < agg, fluorescence quantum yield in dioxane-water (20 80).

Aggregation-induced enhanced emission polymeric nanoparticles... 

A self-assembled chitosan polymeric nanoparticle conjugated with fluorescent stilbene derivatives that exhibit aggregation-induced enhanced emission (AIEE) in vivo was reported by Lim et al. The AIEE phenomenon occnrs in a special class of dyes that have lower flnorescence in solution, but in a concentrated environment (snch as when encapsnlated in a nanoparticle or vesicle), the dyes show a marked enhancement in emission intensity, in contrast to common organic dyes. Dipolar tricyanostilbene derivatives... 

Fig. 16 Sensors used in enantioselective aggregation induced enhancement (a) Phenylglycinol-derived Schiff base 52 (b) proposed mechanism of oligomeric interaction of 52 with mandelic acid enantiomers (c) chiral derivatives of 2-phenyl-3-(p-ammophenyl)acrylonitrile 53,54 showing an AIEE effect in the presence of bases and acids respectively (d) fluorescence response as a function of enantiomeric excess of dibenzoyl tartrate observed using the amine 54 (adapted from [113]. Copyright (2010) with permission from Elsevier) (e) AIEE sensor 55, based on BINOL...

A similar aggregation-induced enhanced emission is reported by the same group of Park and co-workers (Fig. 17). Trifluoromethyl-based cyanostilbene 32 acts as a gelator for 1,2-dichlormethane. The formed gel is strongly fluor-... 

Qian Y, Li S, Zhang G, Wang Q, Wang S, Xu H, Li C, Li Y, Yang G (2007) Aggregation-induced emission enhancement of 2-(2 -hydroxyphenyl)benzothiazole-based excited-state intramolecular proton-transfer compounds. J Phys Chem B 111 5861-5868... 

Fig. 13 Aggregation-induced hydrogen bonding enhancement of HFIP...

It is also possible that vitamin E can nullify some of the main adverse effects of oestrogen on blood platelets. Administration of ethynyloestradiol to female rats increased lipid synthesis, mainly lanosterol, and thrombin-induced platelet aggregation. Treatment of the rats with a-tocopheryl acetate depressed the enhanced lipid synthesis and aggregation induced by the oestrogen. In vitro, too, platelet aggregation was enhanced by the addition of lanosterol, and this response was almost completely antagonised by preincubation with a-tocopheryl acetate [145]. 

It is known that metals such as zinc and copper become more concentrated in the brain with increasing age and that these metals can induce Ab aggregation, thereby enhancing the deposition of senile plaques. In addition, the presence of these metals with Ab initiates the formation of hydrogen peroxide which causes oxidative damage to neurons. By using... 

Berkessel A, Adrio JA, Ffiittenhain D, Neudorfl JM (2006) Unveiling the booster effect of fluorinated alcohol solvents aggregation-induced conformational changes and cooperatively enhanced Fl-bonding. J Am Chem Soc 128 8421-8426... 

Fig. 3.5 Model of cell activation initiated by LBP. Dual role of the LPS-binding protein LBP On the one hand, LBP mediates and enhances the activation of immune cells induced by LPS. This process seems to be influenced by LBP which is intercalated in or associated with the immune cell membrane (upper cartoon). An interaction of membrane-bound LBP (mLBP) with LPS can led to an intercalation of LPS into the phospholipid matrix. On the other hand, the interaction between soluble LBP (sLBP) and LPS aggregates induces a multilamellarization of the aggregates and finally to a neutralization of the endotoxin because of the inhibition of the binding to signaling proteins of the immune cell (lower cartoon)...

Berkessel A, Adrio JA (2004) Kinetic studies of olefin epoxidation with hydrogen peroxide in l,l,l,3,3,3-hexafluoro-2-propanol reveal a crucial catalytic role for solvent clusters. Adv Synth Catal 346 275-280 Berkessel A, Adrio JA (2006) Dramatic acceleration of olefin epoxidation in fluorinated alcohols activation of hydrogen peroxide by multiple H-bond networks. J Am Chem Soc 128 13412-13420 Berkessel A, Adrio JA, Huttenhain D, Neudorfl JM (2006a) Unveiling the booster effect of fluorinated alcohol solvents aggregation-induced conformational changes, and cooperatively enhanced H-bonding. J Am Chem Soc 128 8421-8426... 

Sugar-lectin specific interaction is an important cellular phenomenon. Li et al. [64] linked L-fucose to chitosan, which can act as a somatic agglutinin to induce bacteria aggregation. The enhanced antimicrobial activity of chitosan-L-fucose is attributed to the specific recognition and binding of the L-fucose moiety with PA-Il lectin on Pseudomonas aeruginosa surface. 

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