1.Polybutylcyanoacrylate nanoparticles as novel vectors in cancer gene therapy.
Zhang Y1, Zhang Y, Chen J, Zhang B, Pan Y, Ren L, Zhao J, Luo Y, Zhai D, Wang S, Wang J. Nanomedicine. 2007 Jun;3(2):144-53. Epub 2007 Apr 30.
To make progress toward an efficient gene vector for cancer gene therapy, a novel nonviral vector of polybutylcyanoacrylate nanoparticles (PBCA NPs) was developed. Cetyltrimethyl ammonium bromide (CTAB) was used to modify the surface of PBCA NPs, and then the plasmid DNA (pDNA) of pAFP-TK was wrapped into PBCA-CTAB NPs. Atomic force microscopy and zeta potential demonstrated that PBCA-CTAB NPs were 80-200 nm in diameter and had +15.6 mV positive surface charges. Assay using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide showed that PBCA-CTAB NPs had less cytotoxicity to 3T3 cells than HepG2 cells. The analysis of PBCA-CTAB-DNA complexes could not only protect DNA from degradation by DNase I, it could also transfer pDNA into targeted cells with high transfection efficiency. Furthermore, when PBCA-CTAB NPs combined with suicide gene pAFP-TK, alpha-fetoprotein-positive cells transfected by it were highly sensitive to ganciclovir treatment, and cell survival declined precipitously.
2.Investigation of the interaction of a putative allosteric modulator, N-(2,3-diphenyl-1,2,4-thiadiazole-5-(2H)-ylidene) methanamine hydrobromide (SCH-202676), with M1 muscarinic acetylcholine receptors.
Lanzafame A1, Christopoulos A. J Pharmacol Exp Ther. 2004 Mar;308(3):830-7. Epub 2003 Nov 14.
The interaction between a novel G protein-coupled receptor modulator, N-(2,3-diphenyl-1,2,4-thiadiazole-5-(2H)-ylidene) methanamine hydrobromide (SCH-202676), and the M(1) muscarinic acetylcholine receptor (mAChR) was investigated. In contrast to the prototypical mAChR allosteric modulator, heptane 1,7-bis-(dimethyl-3'-phthalimidopropyl)-ammonium bromide (C(7)/3-phth), SCH-202676 had no effect on the dissociation kinetics of [(3)H]N-methylscopolamine ([(3)H]NMS) at M(1) mAChRs stably expressed in Chinese hamster ovary (CHO) cell membranes. However, SCH-202676 completely inhibited the binding of [(3)H]NMS in membrane preparations, with a Hill slope significantly greater than unity, indicative of positive cooperativity in the binding of the inhibitor. Moreover, SCH-202676 caused dextral shifts of the [(3)H]NMS saturation binding curve that were greater than expected for a competitive interaction. The addition of C(7)/3-phth (100 microM) had no significant effect on the inhibitory potency of SCH-202676.
3.Spontaneous transition of micelle-vesicle-micelle in a mixture of cationic surfactant and anionic surfactant-like ionic liquid: a pure nonlipid small unilamellar vesicular template used for solvent and rotational relaxation study.
Ghosh S1, Ghatak C, Banerjee C, Mandal S, Kuchlyan J, Sarkar N. Langmuir. 2013 Aug 13;29(32):10066-76. doi: 10.1021/la402053a. Epub 2013 Aug 1.
The micelle-vesicle-micelle transition in aqueous mixtures of the cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and the anionic surfactant-like ionic liquid 1-butyl-3-methylimidazolium octyl sulfate, [C4mim][C8SO4] has been investigated by using dynamic light scattering (DLS), transmission electron microscopy (TEM), surface tension, conductivity, and fluorescence anisotropy at different volume fractions of surfactant. The surface tension value decreases sharply with increasing CTAB concentration up to ∼0.38 volume fraction and again increases up to ∼0.75 volume fraction of CTAB. Depending upon their relative amount, these surfactants either mixed together to form vesicles and/or micelles, or both of these structures were in equilibrium. Fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH), incorporated in this system at different composition of surfactant indicates the formation of micelle and vesicle structures. The apparent hydrodynamic diameter of these large multilamellar vesicles is about ∼200 nm-300 nm obtained by DLS measurement and finally confirmed by TEM micrographs.