In here, we present the microfluidic approach to produce monodispersed microbeads that will contain viable cells. The utilization of microfludics is helpful to synthesize monodispersed alginate hydrogels and <i>in situ</i> encapsulate cell into the generating hydrogels in microfludic device. First, the condition of formation of hydrogels in multiphase flows including oil, CaCl<sub>2</sub>, and alginate was optimized. Based on the preliminary survey, microfludic device could easily manipulate the size of alginate beads having narrow size distribution. The microfluidic method manipulates the size of hydrogel microbeads from 30 to 200um with a variation less than 2%. For the proof of concept of cell entrapment, the live yeast expressing green fluorescence protein is successfully encapsulated in microfluidic device.
The patterning of biomolecules in well-defined microstructures is critical issue for the development of biosensors and biochips. However, the fabrication of microstructures with well-ordered and spatially discrete forms to provide the patterned surface for the immobilization of biomolecules is difficult because of the lack of distinct physical and chemical barriers separating patterns.
This study present rapid biomolecule patterning using micromolding in capillaries (MIMIC), soft-lithographic fabrication of PEG microstructures for prevention of nonspecific binding as a biological barrier, and self assembled polymeric thin film for efficient immobilization of proteins or cells. For the proof of concept, protein (FITC-BSA), bacteria (<i>E.coli</i> BL21-pET23b-GFP) were used for biomolecules patterning on polyelectrolyte coated surface within PEG microstructures.
The novel approach of MIMIC combined with LbL coating provides a general platform for patterning a broad range of materials because it can be easily applied to various substrates such as glass, silicon, silicon dioxide, and polymers.