Enhancing Biodegradable Bone Plate Performance: Stereocomplex Polylactic Acid for Improved Mechanical Properties and Near-Infrared Transparency

The use of biodegradable materials in bone plates offers remarkable advantages; however, their application in bone fixation is limited by their brittleness. Moreover, treatments tailored to patient conditions are needed in orthopedics. In this study, bone plates were fabricated with stereocomplex polylactic acid (scPLA) and the effects of poly(d-lactic acid) molecular weight and scPLA blending ratios were analyzed. Although modulus values of poly(l-lactic acid) (PLLA) and scPLA were similar, strain resistance improved at higher scPLA proportions. The enhanced elongation was owing to the presence of tie molecules within the scPLA as opposed to single PLA chains. The fabricated scPLA bone plates exhibited improved mechanical properties and transparency in the optical and near-infrared ranges. scPLA was characterized by a smaller crystallite size. These properties of scPLA combined with its biocompatibility indicate potential for various diagnostic and therapeutic orthopedic applications. Comparisons with commercial PLLA-based bone plates show no significant differences in in vivo bone-healing ability.