Lipid microtubules with contolled bilayer numbers

Abstract

The wall thickness of lipid microtubules are controlled by selecting a methanol/water system and determining the required amount of a lipid to form the desired wall thickness. The lipid is dissolved in a small portion of the heated methanol and that clear solution is added to the remaining amount of the heated methanol/water system. By slowly cooling the solution, microtubules are formed which have the desired wall thickness. Preferred microtubules have a wall thickness of just 2 bilayers and they are robust so they can be further coated. They can be made with a large aspect ratio and with lengths of greater than 250 microns. The process permits production of microtubules in very high yields.

1 - 31 . (canceled)  
   
   
       32 . A population of lipid microtubules having a controlled wall thickness, wherein the median length of at least 50 microns as made by the method comprising: 
 (a) selecting a methanol-water system to be used which is characterized by a volume ratio of methanol and water that totals  100  volume percent, wherein the methanol and water are first filtered to remove any particulates and wherein the filter is at least as fine as a 0.22 micron filter,    (b) determining the amount of lipid to be used for the solvent system selected in step (a) so as to produce the desired wall thickness of the microtubule;    (c) dissolving the determined amount of lipid from step (b) into a portion of the methanol which has been heated to a temperature above the transition temperature for the lipid to form a clear solution;    (d) adding the heated methanol lipid solution of step (c) into a mixture of the remaining methanol and water as selected in step (a) which has been heated to a comparable temperature above the transition temperature for the lipid as in step (c) so that the total amount of methanol and water is in the desired amount selected in step (a); and    (e) cooling the heated mixture in step (d) slowly to permit the formation of microtubules with a controlled, uniform number of bilayers.    
   
   
       33 . A population of lipid microtubules according to  claim 32 , wherein the median length is at least 100 microns.  
   
   
       34 . (canceled)  
   
   
       35 . The lipid microtubule of  claim 32  having a controlled wall thickness of just 2 bilayers.  
   
   
       36 . A population of lipid microtubules according to  claim 35 , wherein the median length is at least 250 microns.  
   
   
       37 - 38 . (canceled)