Tubular Microcapsules with Polysaccharide Membranes Based on a Co-axial Microfluidic Chip

The tubularlike three-dimensional tissue scaffold is an important architecture in biomedical engineering, but its construction remains a big challenge for existing techniques. This work reports the polysaccharide-biomaterial-based tubular microcapsule, which was fabricated by integrating a co-axial flow microfluidic chip and a polyelectrolyte complex technique. First, we fabricate the densely packed coiled calcium alginate hydrogel microfibers as the building block by a co-axial microfluid chip. Then, the densely packed coiled microfibers were coated with a multilayer membrane through layer-by-layer adsorption of alginate and chitosan. After that, the microfibers with an alginate-chitosan-alginate membrane were expanded and transformed into a tubular microcapsule structure by liquefaction. The tubular microcapsule exhibits a selectively permeable property of different-molecular-weight FITC-dextran/bovine serum albumin compared with original calcium alginate microfibers. Moreover, the tubular microcapsule with a liquefied lumen and a thin membrane allows the sustainable release of encapsulants under the alkaline environment. Our research paves an alternative way of manufacturing artificial biological tube architectures having potential applications for transporting and delivering drugs.