Aggregation-induced emission (AIE) nanoparticles based on γ-cyclodextrin and their applications in biomedicine.

Amphiphilic AIE nanoparticles (CD-TPE) were obtained by linking γ-cyclodextrin (γ-CD) and 1, 2-diphenyl-1, 2-(p-hydroxyphenyl)-ethylene (OH-TPE-OH) by an esterification reaction using hexamethylene diisocyanate (HMDI) in a one-step process. The CD-TPE was characterized by FTIR, 13C NMR, DSC, XRD, particle size analysis, TEM, and FL. The obtained CD-TPE had good water dispersibility and could self-assemble into AIE nanoparticles. The large cavity of CD-TPE provided convenient conditions for the loading of doxorubicin (DOX) and slow-release DOX with the loading and release rates of 67.4 % and 71.3 % (pH = 5.4), respectively. The DOX release kinetic model was suitable for the Bhaskar model. Cytotoxicity analysis and cell imaging of CD-TPE were performed, showing that CD-TPE has good biocompatibility and excellent cell imaging performance. Moreover, both in vitro and in vivo antitumor experiments showed that CD-TPE has promising applications in drug delivery.

Photorhabdus luminescens toxin-induced permeability change in Manduca sexta and Tenebrio molitor midgut brush border membrane and in unilamellar phospholipid vesicle.

Photorhabdus luminescens, a Gram-negative bacterium, secretes a protein toxin (PL toxin) that is toxic to insects. In this study, the effects of the PL toxin on large receptor-free unilamellar phospholipid vesicles (LUVs) of Manduca sexta and on brush border membrane vesicles (BBMVs) of M. sexta and Tenebrio molitor were examined. Cry1Ac served as a positive control in our experiments due to its known channel-forming activity on M. sexta. Voltage clamping assays with dissected midguts of M. sexta and T. molitor clearly showed that both Cry1Ac and PL toxin caused channel formation in the midguts, although channel formation was not detected for T. molitor midguts under Cry1Ac and it was less sensitive to PL toxin than to Cry1Ac for M. sexta midguts. Calcein release experiments showed that both toxins made LUVs (unilamellar lipid vesicles) permeable, and at some concentrations of the toxins such permeabilizing effects were pH-dependent. The lowest concentrations of PL toxin were more than 600-fold and 24-fold lower to induce BBMV permeability of T. molitor and M. sexta than those to induce calcein release from LUVs of M. sexta. These further support that PL toxin is responsible for channel formation in the larvae midguts. The lower concentration to induce permeability in BBMV than in LUV is, probably, attributable to that BBMV has PL toxin receptors that facilitate the toxin to induce permeabilization. Furthermore, our results indicate that the effects of PL toxin on BBMV permeability of M. sexta were not significantly influenced by Gal Nac, but those of Cry1Ac were. This implies that PL toxin and Cry1Ac might use different molecular binding sites in BBMV to cause channel formation.