This chapter explores the fundamental principles and applications of self-assembly processes and nanovesicles in nanotechnology. Beginning with the theoretical foundations of selfassembly, it examines the thermodynamic and kinetic factors that drive spontaneous organization at the nanoscale. It then delves into nanovesicles, discussing their formation mechanisms, structural characteristics, and dynamic behaviors. A distinction is made between nanospheres and nanocapsules, highlighting their unique properties and fabrication methods. Advanced characterization techniques essential for analyzing these nanostructures are thoroughly explained, including microscopy, spectroscopy, and scattering methods. The chapter concludes with an extensive examination of nanovesicle applications in biotechnology, covering drug delivery systems, biosensors, tissue engineering, and bioimaging technologies. Throughout, the interplay between fundamental science and practical implementation in various biomedical contexts is emphasized.