Alternative Method for HDL and Exosome Isolation with Small Serum Volumes and Their Characterizations

High-density lipoprotein (HDL) and exosomes are promising sources of biomarkers. However, the limited sample volume and access to the ultracentrifuge equipment are still an issue during HDL and exosome isolation. This study aimed to isolate HDL and exosomes using an ultracentrifugation-free method with various small serum volumes. HDL was isolated from 200 mu L (HDL200) and 500 mu L (HDL500) of sera. Three different volumes: 50 mu L (Exo50), 100 mu L (Exo100), and 250 mu L (Exo250) were used for exosome isolation. HDL and exosomes were isolated using commercial kits with the modified method and characterized by multiple approaches. The HDL levels of HDL200 and HDL500 were not significantly different (p > 0.05), with percent recoveries of > 90%. HDL200 and HDL500 had the same protein pattern with a biochemical similarity of 99.60 & PLUSMN; 0.10%. The particle sizes of Exo50, Exo100, and Exo250 were in the expected range. All isolated exosomes exhibited a similar protein pattern with a biochemical similarity of > 99%. In conclusion, two different serum volumes (200 and 500 mu L) and three different serum volumes (50, 100, and 250 mu L) can be employed for HDL and exosome isolation, respectively. The possibility of HDL and exosome isolation with small volumes will accelerate biomarker discoveries with various molecular diagnostic approaches.