Additive-Manufactured S53P4@PCL Composite Scaffolds Functionalized with Aptamers and Antibacterial Exosomes for Rapid Bacterial Capture and Killing

Bone defects remain a significant challenge in bone tissue engineering, driving an urgent need for advanced materials with enhanced therapeutic properties. Additive manufacturing highlights a unique capacity for customization, which enables the precise realization of complex and personalized composite scaffolds. This study innovatively integrates the superior mechanical properties of polycaprolactone (PCL) with the antibacterial characteristics of S53P4 bioactive glass. Utilizing thermal melt extrusion processing and fused deposition modeling (FDM) technology, we fabricated gradient-structured S53P4@PCL composite three-dimensional porous scaffolds with varying doping ratios (5 wt%, 10 wt%, 20 wt%). To further improve the antibacterial efficacy of the scaffold, exosomes (EXO) derived from grouper eggs were functionalized with bacteria-targeting aptamers (APTs), a type of functional DNA capable of binding to bacterial peptidoglycan, and EXO-APT-20%S53P4@PCL was fabricated. The resulting EXO-APT-20%S53P4@PCL scaffold was able to facilitate the targeted capture and subsequent eradication of bacteria. This study pioneers the synergistic integration of aptamer-modified exosomes into 3D composite scaffolds. Our analysis confirmed that the incorporation of APTs enabled targeted bacterial capture, and antibacterial EXO further enhanced the overall bacterial killing capability of the S53P4@PCL scaffolds. The fabrication of porous S53P4@PCL scaffolds through an innovative composite-molding strategy, combined with EXO-APT functionalization, establishes a new paradigm for customized bone repair.