Fabrication of biconcave discoidal silica capsules and their uptake behavior by smooth muscle cells

Biconcave discoidal silica microcapsules were fabricated by reaction of tetraethoxysilane (TEOS) on biconcave discoidal Ca(OH)2 templates, followed by core removal. The biconcave discoidal morphology of microcapsules was characterized by confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). The thickness of silica capsule shell can be tuned by two methods, "Gradient concentration" method and "Multi-step growth" method. Through the latter one, the shell thickness can be controlled more effectively. Compared with spherical microcapsules, the biconcave discoidal ones were internalized into smooth muscle cells (SMCs) with a slower rate.