Long term viable cell encapsulation into microparticles (500µm) is achieved by mixing cells with a mixture of Na-alginate and gelatin. By dripping this mixture in a CaCl2 bath initiating instant gelification. By adding a coating through layer-by-layer the particles are stabilized. The encapsulated cells are sustained in culture medium. Proteins secreted by the encapsulated cells are retained in the coating. The surface of the microparticles mimics the matrix produced by the encapsulated cells and allows /stimulates adhesion of other cells to the surface. Both cell types are physically separated.
We make use of 3D printed gelatin-coated PLA scaffolds (d 6mm, h 4mm) to co-culture cells in a 3D manner. The cells are suspended in a collagen gel and transferred to the scaffolds by applying vacuumed pressure. During in vitro culture, the cells self-organize themselves and form 3D structures. These scaffolds can also be implanted in an animal model. Within 4 weeks the scaffold is infiltrated by host- tissue and supplied by newly formed blood vessels, visible on contrast-enhanced µCT.
Left: Confocal image of a scaffold seeded with 2 × 106 SK-OV-3 Luc eGFP (green) and 8 × 106 CAF tdTomato (red) after 5 weeks of in vitro culture. Inset shows a phase-contrast image at a similar position of the confocal image. The dotted line indicates spheroid in both confocal and DIC images.
Right: H&E staining of a tumour scaffold 4 weeks post-implantation. Black rectangular boxes on the overview slide indicate the areas used for magnification represented in 1–4. PLA = PLA scaffold that is dissolved during histological processing S = Spheroid of cancer cells and CAF B = Blood vessel Me = Mesothelium Mu = Muscle St = Stroma Ic = Immune cells At = Adipose tissue
