Development of alendronate-loaded 3D-printed PCL/LDH scaffolds for controlled drug delivery in bone tissue...

Bone tissue engineering has made significant advances in recent years; however, the development of scaffolds that not only support tissue regeneration but also effectively deliver therapeutic agents remains a major challenge. The present study investigates the fabrication and evaluation of 3D-printed polycaprolactone (PCL)/layered double hydroxide (LDH) hybrid scaffolds incorporating alendronate (ALN) for bone tissue engineering applications. First, LDH particles were synthesized via a co-precipitation method and loaded with ALN. Subsequently, scaffolds with varying PCL-to-LDH ratios (2 : 1, 3 : 1, 4 : 1, and 5 : 1) were fabricated and characterized. Field emission scanning electron microscopy (FE-SEM) revealed the characteristic hexagonal morphology of the LDH particles, while X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) analyses confirmed the successful intercalation of ALN into the LDH structure. Among the different formulations, the scaffold with a PCL-to-LDH ratio of 2 : 1 exhibited the best overall performance. The incorporation of LDH into this scaffold improved hydrophilicity, reducing the water contact angle from ∼90° to 60°, increasing the ultimate tensile strength from ∼30 to 90 MPa, enhancing the elastic modulus from ∼350 to 750 MPa, and reducing the elongation at break from ∼170% to 50%. Furthermore, ALN was uniformly dispersed within the polymer matrix, resulting in a highly similar biphasic drug release profile consisting of a slight initial burst release during the first 7 days, followed by a sustained release phase extending up to 28 days. Biological evaluations, including MTT assays, cell adhesion studies, and alkaline phosphatase (ALP) activity measurements, further demonstrated that this scaffold promoted superior cell viability, attachment, and osteogenic differentiation. These findings indicate that the 3D-printed scaffold with a PCL-to-LDH ratio of 2 : 1 is a promising platform for localized ALN delivery and bone tissue engineering applications.