Massing, Ulrich; Cicko, Sanja; Ziroli, Vittorio, 2008. Dual asymmetric centrifugation (DAC)—A new technique for liposome preparation

 Hi, you could try via Nano Assemblr by means of microfluidics. To get the size you need, you have to play around to find the right (input) parameters

If you don't want use any specific equipment like extruder, high pressure homogenizer or ultrasound you can use ethanol injection method which allows to obtain LUV’s liposomes or reverse phase evaporation method which allows to obtain LUV’s or OLV’s liposomes. But in case of this both method you need to remember that in your’s formulation will be ethanol or diethyl ether. If you have any question just ask.

Read one of my papers. 220nm diameter. 

you can use ethanol injection method to obtain  liposome dispersion of about 220-250 nm...

Have you heard about/tried Microfluidizer? It's a very versatile technology and can be used to create many different kinds of nanomaterials.

Yangu Su I belive that Riccardo want's to obtain liposomes without using any special equipment like extruder or high pressure homogenizer, becuse in lab it is much more easier to use extruder then for example microfluidizer ( problem starts when you want to scale up your's process when you use extruder). When you want to obtain liposomes with narrow PDI and small size the best way is to use ethanol injection method but this method have some limitation.

Off topic. Yang Su I noticed that you work in Microfluidics Inc., in my company now  I'm trying to scale up process of production of liposomes and I'm wondering about using your's instrument, but in Poland it is really hard to get your's microfulidizer for some test.

Dear Dr Leinaridi

I think that it is difficult to make 220-250 size LUVs without sizing with an extruder.

Dear Ricardo, I've prepared liposome suspensions avoiding the use of the extruder by means of 1. organic solvent removal by rotary evaporation, 2. lipid film-hydration with an aqueous solution and by means of vortexing several minutes and 3. Sonication for at least 10 minutes using a water bath and maximum intensity-amplitude. Using the latter step you'll get a mixture of multilamellar vesicles (MLV) and single unilamellar vesicles (SUV) though you can optimize the sonication time and its power in order to shift the balance towards a majority of SUV.

I hope these steps will work for you!

You may use  Prolipo Neo from Lucas Meyer.  It gives liposome of 200nm size with simple process.  The INCI name of the ingredient  Propane diol and Lecithin.

Thank you all for your preciuos comments.

There are plenty of methods with which you can obtain nanometric liposomes. 

There are conventional and not-conventional methods. 

If you use a conventional method like the thin-layer-evaporation, you may first produce micrometric liposomes and then use a filter to obtain a suspension of smaller liposomes. Alternatively you can apply sonication to micrometric suspension to dirsupt the vesicles and obtain nanometric ones. But in this case the problem is that you may loose part of the active principle that you have encapsulated inside the vesicles. 

If you use supercritical methods, you can directly obtain nanometric dimension liposomes. You may dissolve phospholipids into supercritical CO2 and ethanol as a co-solvent. The expanded liquid obtained has the same solubility of pure ethanol and a lower mass transfer resistence like dense gases. Take a look to this paper to better understand one of the other methods ("Efficient encapsulation of proteins in submicro liposomes using a supercritical fluid assisted continuous process").

Using the thin film lipid hydration you can obtain liposomes of 150 nm using VERY short times of bath sonication after the hydration.

Try the reverse phase evaporation method. I used the method to prepare large unilamellar liposomes. To get reproducible resuls, you need to be very precise with every step, including the ratio of the aqueous phase and the organic phase as well as the vacuum used, though. You can use the process described in  New's Liposomes: a practical approach.

Another option is to use the new LipX liposome extruders from T&T Scientific. They are single-use and are fully-assembled and ready to use when you receive them. You can obtain 50, 100, 200, 400 nm, or even custom pore-sizes.

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