In addition, unlike other hydrogels, PNIPAM produces a thin wall which provides a unique hollow inner structure. Because of this unique structural advantage, microorganisms could be encapsulated inside the resulting microcapsule and it could provide enough space for their Rapamycin mw growth [7,11].The fabrication method used to generate 3D microstructures of uniform size and shape is another important factor. In order to achieve these goals, microdroplet-based microfluidic systems have been developed and widely used [12,13]. With the advanced technologies for the transport and manipulation of droplets, many possibilities exist nowadays to carry out synthesis and functionalize microdroplets for biomedical applications, including therapeutic delivery and biomedical imaging, biotransformation, diagnostics, and drug discovery [3,14�C16].
For this reason, microdroplets have been widely employed as a container to encapsulate various types of biological substances (i.e., cells, DNAs, and proteins) in discrete microdroplets [7,12,16].Unlike conventional systems, the selection of materials for the production of microfluidic devices is important for the generation of microdroplets of uniform shape. Among several materials, polydimethylsiloxane (PDMS) has been widely used as a material of choice to produce microfluidic devices due to the low-cost fabrication of the microfluidic channels, high transparency, and biocompatibility. The polymerization method of a monomer mixture in microdroplets is also important to produce the hydrogels [7,9].
Previous studies show the great potential fabrication method using UV irradiation in many fabrication methods, especially in the fabrication of polymer particles. However, the polymer residues are normally stacked in the orifice or microchannels and they disrupt the flow inside of PDMS channels rendering difficult the stable production of particles of uniform size. In addition, the PDMS itself adsorbs UV light, preventing proper curing of polymers [17]. In order to overcome this issue, chemical polymerization has been developed and applied to fabricate Entinostat hydrogels [8,18].In this study, we have developed a new method to produce bioactive monodisperse PNIPAM-based microcapsules by using a combination of a microfluidic device and a chemical polymerization method. Monodisperse microdroplets were formed by two immiscible fluids in a flow-focusing microfluidic device. The polymerization process of continuously producing microdroplets was initiated by the addition of N,N,N��,N��-tetramethylethylenediamine (TEMED) http://www.selleckchem.com/products/Belinostat.html which acts as a catalyst. In addition, the produced microcapsules were highly monodispersed and suitable for the mass production of microcapsules at room temperature with easy size control.