Differentiation of bone marrow stem cells on inkjet printed silk lines

Water based silk solutions were successfully inkjet printed for the first time into patterns of parallel lines onto vinyl plastic substrates. Human bone marrow stromal cells (hMSCs) were seeded on the silk printed patterns and cultured in the presence of 100 ng/ml of bone morphogenic protein (BMP-2). After one week of culture cell growth and attachment showed site specificity on the silk printed lines. Both alkaline phosphatase activity and cell morphology indicated hBMSCs differentiation into osteogenic cells along the silk printed lines. After 4 week of culture, the cellular bridging of adjacent silk printed lines took place for all interline distances lower than 1.25 mm. Therefore, commercial inkjet printing technology can produce complex viable cellular patterns with 111 ± 24 μm lateral resolution, through the deposition of bioactive materials. The results provide a first step toward cell specific control using 3D inkjet printing techniques using biocompatible gel systems to regulate cell functions.