Spontaneous liposome formation induced by grafted poly(ethylene oxide) layers: theoretical prediction and experimental verification.

Abstract:

:Spontaneous liposome formation is predicted in binary mixtures of fluid phase phospholipids and poly(n)ethylene oxide (PEO)-bearing lipids by using single chain mean field theory. The range of stability of the spontaneous liposomes is determined as a function of percentage of PEO-conjugated lipids and polymer molecular weight. These predictions were tested by using cast films of 1, 2-diacyl-sn-glycerophosphocholines (e.g., egg L-alpha-lecithin, 1, 2-dimyristoyl-sn-glycero-3-phosphocholine, 1, 2-dipalmitoyl-sn-glycero-3-phosphocholine, and 1, 2-distearoyl-sn-glycero-3-phosphocholine) and 1, 2-dipalmitoyl-sn-glycerophosphatidylethanolamine-PEO conjugates (i.e. , 1, 2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[methoxypoly(e thylen e glycol)2000]carboxamide and 1, 2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[methoxypoly(e thylen e oxide)5000]carboxamide) that were hydrated above their gel-liquid crystal phase transition temperatures. Particle sizes of the resulting dispersions, analyzed by quasielastic light scattering, solute retention, 31P NMR, and freeze-fracture electron microscopy measurements, confirmed the single chain mean field predictions. These data indicate that thermodynamically stable, unilamellar liposomes are formed spontaneously by simple hydration of fluid phase phospholipid bilayer films containing low molar ratios of PEO-based amphiphiles. They further suggest that the equilibrium size and colloidal properties of fluid phase, PEO-modified liposomes can be predicted by using this theoretical approach. The implication of these results on the design and processing of sterically stabilized liposomes used in drug delivery applications also is described.

authors

Szleifer I,Gerasimov OV,Thompson DH

doi

10.1073/pnas.95.3.1032

subject

Has Abstract

pub_date

1998-02-03 00:00:00

pages

1032-7

issue

3

eissn

0027-8424

issn

1091-6490

journal_volume

95

pub_type

杂志文章
  • Endothelin as an autocrine factor in the regulation of parathyroid cells.

    abstract::Endothelin, originally purified from porcine aortic endothelial cells, is widely distributed in tissues and is recognized as a product of epithelial cells, glial cells, and neurons in addition to endothelial cells. We found evidence by mRNA content and immunoreactivity that this peptide is synthesized in rat parathyro...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.88.10.4235

    authors: Fujii Y,Moreira JE,Orlando C,Maggi M,Aurbach GD,Brandi ML,Sakaguchi K

    更新日期:1991-05-15 00:00:00

  • Wild-type p53 is a cell cycle checkpoint determinant following irradiation.

    abstract::Cell cycle checkpoints appear to contribute to an increase in cell survival and a decrease in abnormal heritable genetic changes following exposure to DNA damaging agents. Though several radiation-sensitive yeast mutants have been identified, little is known about the genes that control these responses in mammalian ce...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.89.16.7491

    authors: Kuerbitz SJ,Plunkett BS,Walsh WV,Kastan MB

    更新日期:1992-08-15 00:00:00

  • Essential role of the small GTPase Rac in disease resistance of rice.

    abstract::Production of reactive oxygen intermediates (ROI) and a form of programmed cell death called hypersensitive response (HR) are often associated with disease resistance of plants. We have previously shown that the Rac homolog of rice, OsRac1, is a regulator of ROI production and cell death in rice. Here we show that the...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.021273498

    authors: Ono E,Wong HL,Kawasaki T,Hasegawa M,Kodama O,Shimamoto K

    更新日期:2001-01-16 00:00:00

  • Three-dimensional structure of the "long" neurotoxin from cobra venom.

    abstract::The three-dimensional structure of alpha-cobra-toxin, the "long" neurotoxin from the venom of Naja naja siamensis, has been determined at 2.8-A resolution. Crystals grown as hexagonal needles have space group P6522 with unit cell parameters a = b = 74.59 A, c = 42.89 A; one molecule per asymmetric unit. Phases were de...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.77.5.2400

    authors: Walkinshaw MD,Saenger W,Maelicke A

    更新日期:1980-05-01 00:00:00

  • Dependence of the rates of dissolution of the Fe4S4 clusters of Chromatium vinosum high-potential iron protein and ferredoxin on cluster oxidation state.

    abstract::The influence of oxidation state on the pH dependence of the dissolution of the Fe(4)S(4) clusters of Chromatium vinosum ferredoxin and high-potential iron protein (HIPIP) has been studied. The first-order rate constants (k(obs)) for dissolution of both the Fe(4)S(4)(S-Cys)(4) (2-) and Fe(4)S(4)(S-Cys)(4) (3-) cluster...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.74.12.5231

    authors: Maskiewicz R,Bruice TC

    更新日期:1977-12-01 00:00:00

  • Calcium control of the intestinal microvillus cytoskeleton: its implications for the regulation of microfilament organizations.

    abstract::The microvillus core-filament bundle from intestinal epithelial cells is a highly ordered structure containing actin and four major associated proteins. Two of these, villin and calmodulin, bind calcium ions (Kd approximately 10(-6) M) in the physiologically important range. Because ethylene glycol bis(beta-aminoethyl...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.77.11.6458

    authors: Glenney JR Jr,Bretscher A,Weber K

    更新日期:1980-11-01 00:00:00

  • Application of entropy measures derived from the ergodic theory of dynamical systems to rat locomotor behavior.

    abstract::Measures of complexity derived from ergodic theory of dynamical systems were developed and applied to an exemplary data set describing locomotor movements of rats in a bounded space. A symbolic dynamical system was obtained by partitioning the event space into equally probable partition elements, using a k-dimensional...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.87.2.723

    authors: Paulus MP,Geyer MA,Gold LH,Mandell AJ

    更新日期:1990-01-01 00:00:00

  • Intrasomatic injection of radioactive precursors for studying transmitter synthesis in identified neurons of Aplysia californica.

    abstract::We introduced radioactive precursors directly into identified neurons of Aplysia californica. [(3)H]-Choline and L-[(3)H]tryptophan were injected with pressure into nerve cell bodies to study synthesis of acetylcholine and serotonin. We confirmed the cholinergic nature of R2, L10, and L11, identified neurons of the ab...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.70.12.3371

    authors: Eisenstadt M,Goldman JE,Kandel ER,Koike H,Koester J,Schwartz JH

    更新日期:1973-12-01 00:00:00

  • Evaluating conformational free energies: the colony energy and its application to the problem of loop prediction.

    abstract::In this paper, we introduce a method to account for the shape of the potential energy curve in the evaluation of conformational free energies. The method is based on a procedure that generates a set of conformations, each with its own force-field energy, but adds a term to this energy that favors conformations that ar...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.102179699

    authors: Xiang Z,Soto CS,Honig B

    更新日期:2002-05-28 00:00:00

  • Decrease in telomerase activity in U-87MG human glioblastomas after treatment with an antagonist of growth hormone-releasing hormone.

    abstract::Antagonists of growth hormone-releasing hormone (GH-RH) inhibit the growth of various tumors through mechanisms that involve the suppression of the insulin-like growth factor I and/or insulin-like growth factor II levels or secretion. In the present study, we tested the hypothesis that the tumor inhibition is associat...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.96.1.226

    authors: Kiaris H,Schally AV

    更新日期:1999-01-05 00:00:00

  • Vitellogenin, juvenile hormone, insulin signaling, and queen honey bee longevity.

    abstract::In most animals, longevity is achieved at the expense of fertility, but queen honey bees do not show this tradeoff. Queens are both long-lived and fertile, whereas workers, derived from the same genome, are both relatively short-lived and normally sterile. It has been suggested, on the basis of results from workers, t...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.0701909104

    authors: Corona M,Velarde RA,Remolina S,Moran-Lauter A,Wang Y,Hughes KA,Robinson GE

    更新日期:2007-04-24 00:00:00

  • Purifying selection and birth-and-death evolution in the ubiquitin gene family.

    abstract::Ubiquitin is a highly conserved protein that is encoded by a multigene family. It is generally believed that this gene family is subject to concerted evolution, which homogenizes the member genes of the family. However, protein homogeneity can be attained also by strong purifying selection. We therefore studied the pr...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.97.20.10866

    authors: Nei M,Rogozin IB,Piontkivska H

    更新日期:2000-09-26 00:00:00

  • Temperature-sensitive tumorigenicity of cells transformed by a mutant of Moloney sarcoma virus.

    abstract::Normal rat kidney cells were nonproductively infected either with CP27, a mutant of Moloney sarcoma virus that is temperature-sensitive for maintenance of transformation, or with the parental wild-type virus. The nonproducer cells were inoculated into the tails of athymic nude mice that were subsequently incubated at ...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.77.3.1501

    authors: Klarlund JK,Forchhammer J

    更新日期:1980-03-01 00:00:00

  • Overlapping activation-induced cytidine deaminase hotspot motifs in Ig class-switch recombination.

    abstract::Ig class-switch recombination (CSR) is directed by the long and repetitive switch regions and requires activation-induced cytidine deaminase (AID). One of the conserved switch-region sequence motifs (AGCT) is a preferred site for AID-mediated DNA-cytosine deamination. By using somatic gene targeting and recombinase-me...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1018726108

    authors: Han L,Masani S,Yu K

    更新日期:2011-07-12 00:00:00

  • Figure-ground modulation in awake primate thalamus.

    abstract::Figure-ground discrimination refers to the perception of an object, the figure, against a nondescript background. Neural mechanisms of figure-ground detection have been associated with feedback interactions between higher centers and primary visual cortex and have been held to index the effect of global analysis on lo...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1405162112

    authors: Jones HE,Andolina IM,Shipp SD,Adams DL,Cudeiro J,Salt TE,Sillito AM

    更新日期:2015-06-02 00:00:00

  • Translational frameshifting generates the gamma subunit of DNA polymerase III holoenzyme.

    abstract::The dnaX gene (previously called dnaZX) of Escherichia coli has only one open reading frame for a 71-kDa polypeptide from which two distinct DNA polymerase III holoenzyme subunits, tau (71 kDa) and gamma (47 kDa), are produced. To determine how the gamma subunit is generated, we examined the influence of mutations in ...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.87.7.2516

    authors: Tsuchihashi Z,Kornberg A

    更新日期:1990-04-01 00:00:00

  • The spread of innovations in social networks.

    abstract::Which network structures favor the rapid spread of new ideas, behaviors, or technologies? This question has been studied extensively using epidemic models. Here we consider a complementary point of view and consider scenarios where the individuals' behavior is the result of a strategic choice among competing alternati...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1004098107

    authors: Montanari A,Saberi A

    更新日期:2010-11-23 00:00:00

  • Attributes of an alluvial river and their relation to water policy and management.

    abstract::Rivers around the world are being regulated by dams to accommodate the needs of a rapidly growing global population. These regulatory efforts usually oppose the natural tendency of rivers to flood, move sediment, and migrate. Although an economic benefit, river regulation has come at unforeseen and unevaluated cumulat...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.97.22.11858

    authors: Trush WJ,McBain SM,Leopold LB

    更新日期:2000-10-24 00:00:00

  • Sterigmatocystin-DNA interactions: identification of a major adduct formed after metabolic activation in vitro.

    abstract::Sterigmatocystin (ST), a potent hepatocarcinogen, was covalently bound to calf thymus DNA by incubation in the presence of phenobarbital-induced rat liver microsomes. Acid hydrolysis of ST-modified DNA liberated a major guanine-containing adduct, present in DNA at an estimated level of 1 ST residue per 100-150 nucleot...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.76.1.179

    authors: Essigmann JM,Barker LJ,Fowler KW,Francisco MA,Reinhold VN,Wogan GN

    更新日期:1979-01-01 00:00:00

  • Single-cell imaging of retinal ganglion cell apoptosis with a cell-penetrating, activatable peptide probe in an in vivo glaucoma model.

    abstract::Molecular imaging probes have potential for in vivo identification of apoptosis and other intracellular processes. TcapQ, a cell-penetrating, near-infrared fluorescent peptide probe designed to be optically silent through intramolecular fluorescence quenching and activated by effector caspases, has been previously des...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.0812884106

    authors: Barnett EM,Zhang X,Maxwell D,Chang Q,Piwnica-Worms D

    更新日期:2009-06-09 00:00:00

  • Modeling the status, trends, and impacts of wild bee abundance in the United States.

    abstract::Wild bees are highly valuable pollinators. Along with managed honey bees, they provide a critical ecosystem service by ensuring stable pollination to agriculture and wild plant communities. Increasing concern about the welfare of both wild and managed pollinators, however, has prompted recent calls for national evalua...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1517685113

    authors: Koh I,Lonsdorf EV,Williams NM,Brittain C,Isaacs R,Gibbs J,Ricketts TH

    更新日期:2016-01-05 00:00:00

  • Measuring single-cell density.

    abstract::We have used a microfluidic mass sensor to measure the density of single living cells. By weighing each cell in two fluids of different densities, our technique measures the single-cell mass, volume, and density of approximately 500 cells per hour with a density precision of 0.001 g mL(-1). We observe that the intrins...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1104651108

    authors: Grover WH,Bryan AK,Diez-Silva M,Suresh S,Higgins JM,Manalis SR

    更新日期:2011-07-05 00:00:00

  • Parent-independent genotyping for constructing an ultrahigh-density linkage map based on population sequencing.

    abstract::Bar-coded multiplexed sequencing approaches based on new-generation sequencing technologies provide capacity to sequence a mapping population in a single sequencing run. However, such approaches usually generate low-coverage and error-prone sequences for each line in a population. Thus, it is a significant challenge t...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1005931107

    authors: Xie W,Feng Q,Yu H,Huang X,Zhao Q,Xing Y,Yu S,Han B,Zhang Q

    更新日期:2010-06-08 00:00:00

  • Coupling between d-3-phosphoglycerate dehydrogenase and d-2-hydroxyglutarate dehydrogenase drives bacterial l-serine synthesis.

    abstract::l-Serine biosynthesis, a crucial metabolic process in most domains of life, is initiated by d-3-phosphoglycerate (d-3-PG) dehydrogenation, a thermodynamically unfavorable reaction catalyzed by d-3-PG dehydrogenase (SerA). d-2-Hydroxyglutarate (d-2-HG) is traditionally viewed as an abnormal metabolite associated with c...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1619034114

    authors: Zhang W,Zhang M,Gao C,Zhang Y,Ge Y,Guo S,Guo X,Zhou Z,Liu Q,Zhang Y,Ma C,Tao F,Xu P

    更新日期:2017-09-05 00:00:00

  • Linearity of the hemoglobin oxidation bohr effect.

    abstract::The hemoglobin oxidation Bohr effect below pH 7 is essentially proportional to the fraction of hemes oxidized, just as the ligation Bohr effect is proportional to fractional heme ligation. The reported nonlinear proton release during oxidation [(1965) J. Biol. Chem. 240, 3317-3324] is shown to be an artifact resulting...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.73.3.800

    authors: Hoffman BM,Bull C

    更新日期:1976-03-01 00:00:00

  • AgRP to Kiss1 neuron signaling links nutritional state and fertility.

    abstract::Mammalian reproductive function depends upon a neuroendocrine circuit that evokes the pulsatile release of gonadotropin hormones (luteinizing hormone and follicle-stimulating hormone) from the pituitary. This reproductive circuit is sensitive to metabolic perturbations. When challenged with starvation, insufficient en...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1621065114

    authors: Padilla SL,Qiu J,Nestor CC,Zhang C,Smith AW,Whiddon BB,Rønnekleiv OK,Kelly MJ,Palmiter RD

    更新日期:2017-02-28 00:00:00

  • Subcortical differentiation of stop consonants relates to reading and speech-in-noise perception.

    abstract::Children with reading impairments have deficits in phonological awareness, phonemic categorization, speech-in-noise perception, and psychophysical tasks such as frequency and temporal discrimination. Many of these children also exhibit abnormal encoding of speech stimuli in the auditory brainstem, even though response...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.0901123106

    authors: Hornickel J,Skoe E,Nicol T,Zecker S,Kraus N

    更新日期:2009-08-04 00:00:00

  • The primary signaling outputs of brassinosteroids are regulated by abscisic acid signaling.

    abstract::Phytohormones have essential roles in coordinately regulating a large array of developmental processes. Studies have revealed that brassinosteroids (BRs) and abscisic acid (ABA) interact to regulate hundreds of expression in genes, governing many biological processes. However, whether their interaction is through modi...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.0900349106

    authors: Zhang S,Cai Z,Wang X

    更新日期:2009-03-17 00:00:00

  • Dynamics and dissipation in enzyme catalysis.

    abstract::We use quantized molecular dynamics simulations to characterize the role of enzyme vibrations in facilitating dihydrofolate reductase hydride transfer. By sampling the full ensemble of reactive trajectories, we are able to quantify and distinguish between statistical and dynamical correlations in the enzyme motion. We...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.1106397108

    authors: Boekelheide N,Salomón-Ferrer R,Miller TF 3rd

    更新日期:2011-09-27 00:00:00

  • Counting human somatic cell replications: methylation mirrors endometrial stem cell divisions.

    abstract::Cell proliferation may be altered in many diseases, but it is uncertain exactly how to measure total numbers of divisions. Although it is impossible to count every division directly, potentially total numbers of stem cell divisions since birth may be inferred from numbers of somatic errors. The idea is that divisions ...

    journal_title:Proceedings of the National Academy of Sciences of the United States of America

    pub_type: 杂志文章

    doi:10.1073/pnas.0503976102

    authors: Kim JY,Tavaré S,Shibata D

    更新日期:2005-12-06 00:00:00