Lipoprotein analysis by differential charged-particle mobility

Abstract

The invention provides methods of preparation of lipoproteins from a biological sample, including HDL, LDL, Lp(a), IDL, and VLDL, for diagnostic purposes utilizing differential charged particle mobility analysis methods. Further provided are methods for analyzing the size distribution of lipoproteins by differential charged particle mobility, which lipoproteins are prepared by methods of the invention. Further provided are methods for assessing lipid-related health risk, cardiovascular condition, risk of cardiovascular disease, and responsiveness to a therapeutic intervention, which methods utilize lipoprotein size distributions determined by methods of the invention.

What is claimed is: 
     
         1 . An apparatus for differential charged-particle mobility analysis, the apparatus comprising:
 one or more pumps adapted to transport sample through a capillary;   an ionizer adapted to charge particles of the sample as the sample flows within the capillary; and   an ion mobility analyzer adapted to perform a differential charged-particle mobility analysis on the sample of charged particles.   
     
     
         2 . The apparatus according to  claim 1  further comprising an autosampler adapted to provide a sample for differential charged-particle mobility analysis to the one or more pumps. 
     
     
         3 . The apparatus according to  claim 1 , wherein the sample comprises lipoproteins. 
     
     
         4 . The apparatus according to  claim 1 , wherein the one or more pumps comprise a high-flow pump adapted to provide the sample to a nanoflow pump, the nanoflow pump adapted to provide the sample to the capillary. 
     
     
         5 . The apparatus according to  claim 4 , wherein the high-flow pump pumps the sample at a rate of approximately 15-25 microliters per minute, and wherein the nanoflow pump pumps the sample at a rate of approximately 100-200 nanoliters per minute. 
     
     
         6 . The apparatus according to  claim 5 , wherein the ionizer comprises a conductive union around a part of the capillary. 
     
     
         7 . The apparatus according to  claim 6 , wherein the conductive union applies a charge to the sample flowing therethrough, thereby charging particles of the sample. 
     
     
         8 . The apparatus according to  claim 7 , wherein the conductive union forms a microtite region in a part of the capillary and applies a charge to the sample flowing therethrough, thereby charging particles of the sample. 
     
     
         9 . The apparatus according to  claim 8 , wherein the microtite region has a dead volume of approximately, 5-50 nanoliters. 
     
     
         10 . The apparatus according to  claim 9 , wherein the microtite region has a dead volume of approximately, 10-15 nanoliters. 
     
     
         11 . A computer-readable medium comprising a computer code stored thereon, the computer code for analyzing the size distribution of lipoproteins, comprising:
 determining a differential mobility particle size distribution in one or more regions of particle sizes for one or more lipoproteins subjected to differential charged-particle mobility analysis;   subtracting contribution to the particle size distribution of a non-lipoprotein reagent or a non-lipoprotein sample material to obtain a lipoprotein particle size distribution; and   outputting the lipoprotein size distribution to a display, a printer or a memory.   
     
     
         12 . The computer-readable medium according to  claim 11 , wherein the computer code further comprises determining a particle size distribution by determining a best fit for the one or more regions. 
     
     
         13 . The computer-readable medium according to  claim 12 , wherein the best fit is of the form:
     y   1   =k   1   *e   (−0.7*d) ;   
       where y 1  is a contribution to the measured differential mobility size distribution, k 1  is an empirical constant of the fit, and d is particle diameter;
 wherein the determining a best fit includes calculating a value for k 1.    
 
     
     
         14 . The computer-readable medium according to  claim 11 , wherein the subtracting comprises applying a theoretical curve representing particle size distribution of the non-lipoprotein reagent or the non-lipoprotein sample material. 
     
     
         15 . The computer-readable medium according to  claim 11 , wherein the non-lipoprotein reagent is Reactive Green 19 conjugated with dextran (RGD). 
     
     
         16 . The computer-readable medium according to  claim 11 , wherein the non-lipoprotein sample material is albumin.