Silica microcarriers produced from a microfluidics-generated emulsion

Fabrication of micrometric and submicrometric capsules capable of carrying bioactive substances is important for many biological applications. Here we show the results of our work on creating water-in-oil emulsion and encasing the water droplets in silica shell with microfluidic techniques. The emulsion was generated in a polydimethylsiloxane (PDMS) flow-focusing microfluidic chip. TWEEN 80 and lecithin were used as surfactants to stabilize the emulsion. Tetraethylorthosilicate (TEOS) and 3-aminopropyl trimethoxysilane (APTMOS) were then added to the emulsion to form silica shell around water droplets via hydrolysis. We obtained silica microcapsules of about 2 μm in diameter and studied them using confocal fluorescent microscopy. This method allows encapsulating a wide range of sensitive substances including genetic material, enzymes, proteins for intracellular delivery and other biomedical applications.