Cell adhesion experiments. Saos-2 cells seeded on undyed PLA scaffolds pretreated with adhesion protein coating: (a,b) Ingrowth of Saos-2 cells into the layers intercolumn and macroscopic pores is visible. (c,d) CFSE staining of native and CellTak pretreated PLA surfaces. (c) Native surface without preconditioning. Only a few cells were adherent. (d,e) CellTak-preconditioned surfaces showed increased cell adhesion. (f,g) CFSE/DAPI staining of Saos-2 cell coated scaffold (Design 2); cells appear green (CFSE) with blue nucleus (DAPI). (f) Stringing in a pore covered with vital cells. (g) Onsight on a pore with stringing structure. On all structural features, multiple vital cells are visible. (h) Calculated cell counts based on MTT-Test results after 1, 7, 14, and 21 days.