Abstract: Caveolae were spherical, elliptical or flask-shaped invaginations(50—100 nm in diameter) on the surface of cell plasma membrane. They play important roles in many biological processes, such as endocytosis, pinocytosis, cholesterol transport, signal transduction, internalization of bacteria and viruses, and so on. In this research, caveolae were separated from rat lungs by floating plasma membrane treated with ultrasonic in OptiPrep gradient(a detergent-free method), and were observed by atomic force microscopy(AFM) under different conditions. By using this method, intact caveolae were isolated from plasma membrane, and the best AFM images of caveolae were obtained by diluting them 500 times with deionized water. So, a new method for separating caveolae rapidly and completely was established, and a new way to observe the structures of caveolae was set up.

Key words: Caveolae, Detergent-free method, Atomic force microscopy(AFM)