Customizable design of multiple-biomolecule delivery platform for enhanced osteogenic responses via ‘tailored assembly system’

Porous titanium (Ti) scaffolds have been extensively utilized as bone substitute scaffolds due to their superior biocompatibility and excellent mechanical properties. However, naturally formed TiO₂ on the surface limits fast osseointegration. Different biomolecules have been widely utilized to overcome this issue; however, homogeneous porous Ti scaffolds could not simultaneously deliver multiple biomolecules that have different release behaviors. In this study, functionally graded porous Ti scaffolds (FGPTs) with dense inner and porous outer parts were fabricated using a two-body combination and densification procedure. FGPTs with growth factor (BMP-2) and antibiotics (TCH) exhibited suitable mechanical properties as bone substituting material and presented good structural stability. The release of BMP-2 was considerably prolonged, whereas the release of TCH was comparable to that of homogenous porous titanium scaffolds (control group). The osteogenic differentiation obtained using FGPTs was maintained due to the prolonged release of BMP-2. The antimicrobial properties of these scaffolds were verified using S. aureus in terms of prior release time. In addition, various candidates for graded porous Ti scaffolds with altered pore characteristics were presented. Graphic abstract: [Figure not available: see fulltext.]