Design of pectin-based bioink containing bioactive agent-loaded microspheres for bioprinting

Bioprinting offers an alternative approach for tissue engineering and exhibits the great potential to play a key role in personalized medicine. One of the major advantages of bioprinting is its capability of achieving the homogeneous distribution of cells within large tissue scaffolds. Microspheres have been used for controlled release of bioactive molecules in tissue engineering. Recently studies show that microspheres, especially positively charged, could promote the vascularized tissue formation. This study aims to develop a bioprinted scaffold containing microspheres. The double emulsion system, water in oil in water (W/O/W), was used to produce the microspheres considering its advantage for controlled release of small molecules. Design Expert Software was used to optimize the microsphere production process and chitosan coating was performed to provide the positively charged surface of the microspheres. Fourier-transform infrared spectroscopy (FTIR) and confocal microscopic analysis confirmed the successful formation of the microspheres as well as the loading of bioactive molecules, e.g., estradiol (E2), into the microspheres. Bioprintability of the microsphere incorporated bioink was tested. The results indicated that microspheres did not adversely affect the bioprinting process. This novel tissue scaffold shows great promise for tissue engineering applications.