The phase and miscibility behavior of a triple-chain phosphatidylcholine (TPHPC) and a single-chain surfactant (CTAB) were investigated in aqueous dispersions and in monolayers at the air/water interface. CTAB can be incorporated in the TPHPC monolayer because of its complementary molecule shape and reduces the tilt angle of TPHPC. The type of phases and the phase sequence (L2 - LS) are the same in the pure TPHPC monolayer and in the TPHPC/CTAB (80:20 mol:mol) mixture. No indication of any ordering of adsorbed DNA was observed. In the aqueous dispersions, TPHPC exhibits an inverted hexagonal phase above the chain melting. The addition of 30 mol% CTAB leads to the appearance of a lamellar Lalpha phase. The binding of DNA to the mixture is obvious but this is accompanied by a separation of the two lipids what is supported by monolayer experiments. The system has no long-term stability. The main reason seems to be not only the stronger interaction of DNA with CTAB, but also especially the unexpected weak interaction between CTAB and TPHPC. The transfection efficiency is lower compared with lipofectamine. The main disadvantage of this system is the cytotoxicity of CTAB, which could not be lowered by incorporation of CTAB in the TPHPC bilayer.
"Despite difference in particle shape, one primary concerns about GNRs in biological research is cetyltrimethylammonium bromide (CTAB), the surfactant which is essential for nanorods growth in popularly used seed-growth GNRs synthesis method, but toxic to cell lines [26, 31–33]. CTAB is important in controlling the particle size and shape to achieve designed localized surface plasmon resonance bands for spectroscopic and microscopic applications in biological research   . As removal of CTAB will cause instability of GNRs, polymers, such as poly(acrylic acid) (PAA), poly(diallyldimethylammonium chloride)-poly(4-styrenesulfonic acid) (PDADMAC-PSS), and poly(ethylene glycol) (PEG), have been introduced to functionalize the GNRs surface    . "
[Show abstract][Hide abstract] ABSTRACT: There have been increasing interests in applying gold nanoparticles in biological research, drug delivery, and therapy. As the interaction of gold nanoparticles with cells relies on properties of nanoparticles, the cytotoxicity is complex and still under debating. In this work, we investigate the cytotoxicity of gold nanoparticles of different encapsulations, surface charge states, sizes and shapes to both human HEp-2 and canine MDCK cells. We found that cetyltrimethylammonium-bromide- (CTAB-) encapsulated gold nanorods (GNRs) were relatively higher cytotoxic than GNRs undergone further polymer coating and citrate stabilized gold nanospheres (GNSs). The toxicity of CTAB-encapsulated GNRs was mainly caused by CTAB on GNRs' surface but not free CTAB in the solution. No obvious difference was found among GNRs of different aspect ratios. Time-lapse study revealed that cell death caused by GNRs occurred predominately within one hour through apoptosis, whereas cell death by free CTAB was in a time- and dose-dependent manner. Both positively and negatively surface-charged polymer-coated GNRs (PSS-GNRs and PAH-PSS-GNRs) showed similar levels of cytotoxic, suggesting the significance of surface functionality rather than surface charge in this case.
Journal of Nanomaterials 01/2012; DOI:10.1155/2012/375496 · 1.64 Impact Factor
"However, biological applications have not been widely pursued with gold nanorods in part because nanorod solutions are stabilized by the presence of concentrated CTAB surfactant . Although conjugates have been formed in the presence of CTAB , surfactant solutions are cytotoxic  and may interfere with established protein-linking protocols. A recent report explored the cytotoxicity of CTAB stabilized spherical gold nanoparticles . "
[Show abstract][Hide abstract] ABSTRACT: For possible future use in Photodynamic Therapy (PDT) and/or Photothermal Therapy (PTT) of cancer and screening of cancer cells a new type of ionic liquid photosensitizer -Cholinium-Purpurin-18 (Chol-Pu-18) - was synthesized and small gold (Au) nanoparticles, stabilized by this photosensitizer were prepared without adding any particular reducing agents and CTAB. UV-Vis spectroscopy and Transmission Electron Microscopy (TEM) were used for characterization of the nanoparticles and FAB-MS and NMR of the ionic liquid choline hydroxide, purpurin carboxylate and their ionic liquid type of photosensitizer were obtained.
International Journal of Molecular Sciences 06/2008; 9(5):864-71. DOI:10.3390/ijms9050864 · 2.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A robust functionalized procedure for gold nanorods (Au NR) with mercaptoundecanoic acid (MUA), which are assembled with nanoparticles, has been reported in the present work. The self-assembled nanostructures were characterized by UV–Vis-NIR spectrophotometer and transmission electron microscopy (TEM). Self-assembly procedures, governed by surface chemistry, indicated that chemical reactivity of nanomaterial may contribute in construction of potential nanoscale assemblies. These nanostructures have striking applications as single-molecule detection, plasmonics, and sensing.
Journal of Nanoparticle Research 01/2013; 15(1). DOI:10.1007/s11051-012-1404-5 · 2.18 Impact Factor
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