Talk:Liposome

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Organisation[edit]

Needs to be sorted into sections

Specificity of Liposomes[edit]

Article needs more details on how liposomes can be targeted for specific cells using receptors etc. The diagram shows "homing peptides" but they are not mentioned anywhere in the actual article.

History[edit]

Any article on liposomes should mention the history of their discovery (in 1961 by Alec D. Bangham). --Hjesp03 10:21, 17 January 2007 (UTC) ///////////////////////////////////////////////////////// — Preceding unsigned comment added by 111.68.105.214 (talk) 11:12, 6 March 2012 (UTC)

Didn't Unilever have a patent on liposomes from the 1940s or early 1950s? 121.216.108.66 (talk) 12:37, 15 March 2013 (UTC)

Sonication[edit]

The person who is writing this page obviosly does not know much about liposomes. Sonication is only a method for sizing down the liposomes and not making the liposomes. Liposome are made by the natural orientation of the lipid molecules in the presence of the water. Liposomes are not made by sonication or extrusion.

The above comment was unsigned at the time I insted this section heading. EatYerGreens (talk) 23:22, 12 June 2008 (UTC)

Understandable introduction[edit]

Wikipedia is written for the layman, non-specialist, according to WP:MEDMOS

A layman could understand this introduction:

A liposome is a tiny bubble, smaller than a human cell, that is filled with drugs to treat cancer and other diseases. It is made out of cell membranes.

A layman could not understand this introduction:

A liposome is a spherical vesicle composed of a bilayer membrane. In biology, this specifically refers to a membrane composed of a phospholipid and cholesterol bilayer (see on the right).

You cannot understand this defintion unless you already understand the meaning of the words "vesicle," "membrane," "phospholipid," "cholesterol" and "bilayer." These are not terms that a layman would understand.

As proof, you can pick up any standard high school biology textbook and look up these terms in the index. You'll see that they define the terms, because their readers won't understand them. Or you can look in any publication written for laymen, like the New York Times, Science News.) You'll see that they define these terms every time they use them.

As a compromise, I left in the more technical definition as the second paragraph to the introduction. But a Wikipedia article must be understandable to the layman, particularly in the introduction. Nbauman (talk) 15:00, 14 June 2008 (UTC)

I agree about simpler terminology. Below is my first attempt at a re-write.
Original wording (including markup) for archival purposes

A liposome is a spherical vesicle composed of a bilayer membrane. In biology, this specifically refers to a membrane composed of a phospholipid and cholesterol bilayer (see on the right). Liposomes can be composed of naturally-derived phospholipids with mixed lipid chains (like egg phosphatidylethanolamine), or of pure surfactant components like DOPE (dioleoylphosphatidylethanolamine). Liposomes, usually but not by definition, contain a core of aqueous solution[1]; lipid spheres that contain no aqueous material are called micelles, however, reverse micelles [1] can be made to encompass an aqueous environment.

COMMENT: By the way, liposomes CANNOT be made of dioleoylphosphatidylethanolamine!!!
Draft rewording (requires markup to be applied later, in places)

In biology, a liposome is a spherical structure consisting of a biological membrane enclosing a pocket of water (see on the right). The word liposome is frequently used in reference to the man-made equivalent of a naturally-occurring structure, found inside the cell, called a vesicle and shares many of the natural vesicle's properties. Both are much smaller than the cell, with a typical liposome being only 50 nanometres in diameter and cells ranging between 20 and 200 times that size. The membrane confers two valuable properties. Firstly, it does not allow certain types of molecule pass through it which means that these can be trapped in the pocket of water on the inside, during manufacture. Secondly, when the liposome comes into contact with the outside of a cell, they fuse together in such a way that the pocket of water is released into the interior of the cell while the liposome membrane blends into the cell's membrane, because of their similar composition. This has applications in medical treatments, where drug molecules can be delivered to the inside of a cell in a targeted manner (described in further detail below).
In detail, the outer layer is a membrane composed of a phospholipid and cholesterol bilayer. Liposomes can be composed of naturally-derived phospholipids with mixed lipid chains (like egg phosphatidylethanolamine), or of pure surfactant components like DOPE (dioleoylphosphatidylethanolamine). Liposomes, usually but not by definition, contain a core of aqueous solution[2]; lipid spheres that contain no aqueous material are called micelles, however, reverse micelles [2] can be made to encompass an aqueous environment. (end introduction)
Of necessity, this is much longer than the original. I would have no qualms with the "In detail,...." para being moved down into the main body of the article, allowing us to concentrate on knocking the opening into shape. Let me know what you think (I will insert fact tags to my own copy, where applicable, if it goes into the article). EatYerGreens (talk) 07:51, 15 June 2008 (UTC)
I make my living as a medical writer. Most of the time I write for doctors, but sometimes I write for patients and other laymen.
I spend a lot of time talking to the people who will read my articles, to get a sense of what they understand and what they don't. I was surprised to find out that even well-informed cancer patients and social workers didn't understand basic terms like "neuropathy" and "apoptosis." I was surprised that they couldn't understand the tutorial reviews in the New England Journal of Medicine. They didn't understand most of the terms that high school students have to learn in biology. If you see a term defined in a high school biology textbook, or if it appears on a biology test, you can be sure that most laymen won't understand it. And according to WP:MEDMOS, Wikipedia is written for laymen.
I know from talking to my readers, and from discussing readability with other medical editors and writers, and from reading the readability literature, that a layman wouldn't be able to understand your introduction. They won't get past "In biology, a liposome is a spherical structure consisting of a biological membrane...."
Readers have two simultaneous tasks. First, they have to understand the language. Second, they have to understand the concepts. The language has to be as simple as possible. (One editor called it "extreme clarity.) If the language is too complicated, then the combined cognitive burden of figuring out the language and figuring out the concepts becomes impossibly great -- and they give up.
Your language is too complicated. When I see the phrase "spherical structure", I have to slow down to figure it out (and I already know what you're trying to say). Why not just call it a "bubble"?
There's extensive literature on comprehensibility, which I've read in the BMJ, JAMA and elsewhere. Even medical doctors and PhDs have trouble getting through a paragraph of polysyllables (compared to a paragraph of simple words). They give up and stop reading. Researchers have videos to prove it.
The problem, as science editors know, is that scientists are encouraged to write in a pedantic language with as many technical terms as possible. Editors at these journals are constantly rewriting polysyllables and complicated sentences into simple English. They know that otherwise, their audience won't read it.
But don't take my word for it. As the Royal Society says, nullius in verba. Find out for yourself. Show that introductory paragraph to someone who has not recently taken a biology course, and ask them what a liposome is. They won't understand it. Run a Fleisch index on it. It will be unreadable for normal people.
That paragraph is incomprehensible. Why do you think a lay reader could get through it? Nbauman (talk) 14:37, 15 June 2008 (UTC)
You've lost me now. You're saying lay people are curious enough about something technical (liposomes) to look it up in wikepedia but that they won't understand words like spherical? Perhaps I should back away from here, for now, go to the talk page discussing what wikipedia means by 'layman' and see what the concensus is there? EatYerGreens (talk) 06:21, 16 June 2008 (UTC)
I'm saying that (1) Many people are interested in science, but if they read an article with a word they don't understand, they won't look up the word. They'll skip the article. When people have to click on links, they don't come back to the original article. That's what science magazine editors told me. They hired psychologists to research the reading activities of actual readers in their target audience, and that's what the researchers saw and videotaped. Every editor and writer for a sucessful science magazine knows this.
(2) Forget about laymen. Talk about doctors. The editors of the BMJ (formerly British Medical Journal) are writers and editors themselves, so they're very interested in how doctors read, how to make their writing easier for busy doctors, and what makes writing difficult for doctors. They say that it's easiest for doctors to read simple words. Polysyllabic, technical words are harder for doctors to read. I can't find the example offhand, but I remember a doctor writing in BMJ about how a patient used a polysyllabic specialist medical term on him, and he had to stop for a moment to figure out what it meant. The New Scientist, which often has contributions from scientists that they must rewrite extensively, has had many essays which also say the same thing: use simple everyday language, not technical language. If you read the New Scientist, you'll see that they don't use fancy words like "spherical," they use simple words like "bubble."
For a specific reference, see The Elements of Style, which most American magazines use. That's general magazines, science magazines, magazines for laymen, for high school students, for MDs, for PhDs, for everybody.
I'll ask you again: Why do you say "spherical structure" (or "spherical vesicle") instead of just "bubble"? Nbauman (talk) 12:55, 16 June 2008 (UTC)
I think I only took objection to bubble on account of it conjuring up an image of something containing air but, on reflection, it will do just fine. I see you've also toned-down the categorical "is used to" to the more flexible "can be used for" with regard to drug content. The article is shaping up already. In the meantime, I'm trying to find ways of rustling up more lay-person editors. As far as I can make out it is only you and me who are interested in this one at the moment. EatYerGreens (talk) 03:40, 18 June 2008 (UTC)
I agree with the earlier sentiment that bubble is an inaccurate way of describing a liposome for two reasons. First, a bubble is, by definition, something that contains air (according to OED definition). Of course, the dictionary definition often does not tell the whole story, but I think that in this case common usage and formal definition are the same. If you ask anyone on the street what a bubble is, they will probably talk about an enclosed volume of air. Since liposomes contain water and not air, I think this is a major problem. Secondly, I would argue that the liposome itself is the shell of lipid bilayer, not the solution contained inside. The solution on the inside is simply the _content_ of the liposome. One piece of evidence for this definition is the fact that people often speak of "leaky" or even "ruptured" liposomes. If it is still a liposome once the contents have exchanged with the external environment, then the term must refer to the lipid and not the aqueous portion. I agree that comprehensibility should be a high priority, but not at the expense of accuracy. I'll think this over and see if I can come up with an alternate few sentences to start the article, then post here for feedback. Any other thoughts on this matter? --MDougM (talk) 19:01, 18 November 2008 (UTC)

so liposome is very important part in such case. —Preceding unsigned comment added by 203.124.20.15 (talk) 07:15, 28 November 2008 (UTC)

It looks like no one had an idea that liposomes are artificially created vesicles, usually by sonication of biological membranes or by dispersing phospholipids in water... [3]. Biophys (talk) 22:57, 13 August 2010 (UTC)

Use of Liposomes in cosmetics[edit]

This aspect is currently missing from the article but I will have to hunt around and be careful about what to cite, since the majority of online sources are likely to be company websites and could be justifiably construed as linking from wiki directly to an advert. This site is an example of how they go about explaining "the science bit" to their customers. EatYerGreens (talk) 05:43, 16 June 2008 (UTC)

Dietary and nutritional supplements[edit]

This section is not written in a neutral tone. In particular, phrases such as: "cleverly implemented", "A very small number of ... companies are currently pioneering the benefits of this unique science" seem to be trying to sell the use of liposomes in supplements. Deltacrux (talk) 01:11, 4 February 2014 (UTC)

  1. ^ Stryer S. (1981) Biochemistry, 213
  2. ^ Stryer S. (1981) Biochemistry, 213