Cholesterol-based anchors and tethers for phospholipid bilayers and for model biological membranes

Achalkumar, Ammathnadu S.; Bushby, Richard J.; Evans, Stephen D.

doi:10.1039/c0sm00030b

Cited by 42 publications

(39 citation statements)

References 102 publications

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“…There are three methods to link DNA to a liposome. 46 First, lipid-functionalized DNAs (e.g. with cholesterol) are incorporated during liposome preparation, resulting in DNA being present at both the inner and outer-leaflets of the bilayer membrane.…”

Section: Resultsmentioning

confidence: 99%

Programmable Assembly of DNA-Functionalized Liposomes by DNA

Dave

Liu

2011

ACS Nano

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Bionanotechnology involves the use of biomolecules to control both the structure and property of nanomaterials. One of the most studied examples is DNA-directed assembly of inorganic nanoparticles such as gold nanoparticles (AuNPs). However, systematic studies on DNAlinked soft nanoparticles, such as liposomes, are still lacking. We herein report the programmable assembly and systematic characterization of DNA-linked liposomes as a function of liposome size, charge, fluidity, composition, DNA spacer, linker DNA sequence, and salt concentration for direct comparison to DNA-directed assembly of AuNPs. Similar to the assemblies of AuNPs, sharp melting transitions were observed for liposomes where the first derivative of the melting curve full width at half-maximum (fwhm) is equal to or less than 1 °C for all of the tested liposomes, allowing sequence specific DNA detection. We found that parameters such as liposome size, charge, and fluidity have little effect on the DNA melting temperature. Cryo-TEM studies showed that programmable assemblies can be obtained and that the majority of the liposomes maintained a spherical shape in the assembled state. While liposome and AuNP systems are similar in many aspects, there are also important differences that can be explained by their respective physical properties. KEYWORDS: liposomes

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Section: Resultsmentioning

confidence: 99%

Programmable Assembly of DNA-Functionalized Liposomes by DNA

Dave

Liu

2011

ACS Nano

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“…17−21, 66 We therefore expect that the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 groups. In aqueous solutions, free PpIX molecules were poorly dispersed and easily formed large aggregates (~1 µm) due to the strong π-π stacking between themselves.…”

Section: Hemolysis Rate Testmentioning

confidence: 97%

Cholesterol-Assisted Bacterial Cell Surface Engineering for Photodynamic Inactivation of Gram-Positive and Gram-Negative Bacteria

Hao

Zhu

Chen

et al. 2017

ACS Appl. Mater. Interfaces

162

134

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Antibacterial photodynamic therapy (PDT), which enables effective killing of regular and multidrug-resistant (MDR) bacteria, is a promising treatment modality for bacterial infection. However, because most photosensitizer (PS) molecules fail to strongly interact with the surface of Gram-negative bacteria, this technique is suitable for treating only Gram-positive bacterial infection, which largely hampers its practical applications. Herein, we reveal for the first time that cholesterol could significantly facilitate the hydrophobic binding of PSs to the bacterial surface, achieving the hydrophobic interaction-based bacterial cell surface engineering that could effectively photoinactivate both Gram-negative and Gram-positive bacteria. An amphiphilic polymer composed of a polyethylene glycol (PEG) segment terminated with protoporphyrin IX (PpIX, an anionic PS) and cholesterol was constructed (abbreviated Chol-PEG-PpIX), which could self-assemble into micelle-like nanoparticles (NPs) in aqueous solution. When encountering the Gram-negative Escherichia coli cells, the Chol-PEG-PpIX NPs would disassemble and the PpIX moieties could effectively bind to the bacterial surface with the help of the cholesterol moieties, resulting in the significantly enhanced fluorescence emission of the bacterial surface. Under white light irradiation, the light-triggered singlet oxygen (O) generation of the membrane-bound PpIX could not only severely damage the outer membrane but also facilitate the entry of external Chol-PEG-PpIX into the bacteria, achieving >99.99% bactericidal efficiency. Besides, as expected, the Chol-PEG-PpIX NPs also exhibited excellent antibacterial performance against the Gram-positive Staphylococcus aureus. We also verified that this nanoagent possesses negligible dark cytotoxicity toward mammalian cells and good hemocompatibility. To the best of our knowledge, this study demonstrates for the first time the feasibility of constructing a fully hydrophobic interaction-based and outer membrane-anchored antibacterial PDT nanoagent.

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“…14 The development of these proteinspecific binding tethers has been driven by the need to attach different types of complex protein to lipid vesicles and to sBLMs and from the potential use of such systems in drug delivery, medical imaging systems, biosensors, and drug screening arrays. 15 The main goal of the present work is to demonstrate a general strategy for constructing NTA terminated tethers, which can anchor His-tagged proteins to sBLMs on silica. As part of the same work we have developed an NTA terminated tether, which can anchor Histagged proteins to a gold surface; a variant on existing gold binding tethers.…”

Section: Introductionmentioning

confidence: 99%

“…The solvent was removed in vacuo and the residue was dissolved in chloroform and washed with water (3Â30 ml), brine (20 ml) and dried over anhydrous Na 2 SO 4 . Evaporation under reduced pressure yielded a viscous liquid, which was purified by flash column chromatography on silica gel with 5% methanolechloroform eluent mixture to obtain a yellowish viscous liquid (0 15. g, 95%).…”

mentioning

confidence: 99%