Biocomposite Macrospheres Based on Strontium-Bioactive Glass for Application as Bone Fillers

Traditional bioactive glass powders are typically composedof irregularparticles that can be packed into dense configurations presentinglow interconnectivity, which can limit bone ingrowth. The use of novelbiocomposite sphere formulations comprising bioactive factors as bonefillers are most advantageous, as it simultaneously allows for packingthe particles in a 3-dimensional manner to achieve an adequate interconnectedporosity, enhanced biological performance, and ultimately a superiornew bone formation. In this work, we develop and characterize novelbiocomposite macrospheres of Sr-bioactive glass using sodium alginate,polylactic acid (PLA), and chitosan (CH) as encapsulating materialsfor finding applications as bone fillers. The biocomposite macrospheresthat were obtained using PLA have a larger size distribution and higherporosity and an interconnectivity of 99.7%. Loose apatite particleswere observed on the surface of macrospheres prepared with alginateand CH by means of soaking into a simulated body fluid (SBF) for 7days. A dense apatite layer was formed on the biocomposite macrospheres'surface produced with PLA, which served to protect PLA from degradation. In vitro investigations demonstrated that biocomposite macrosphereshad minimal cytotoxic effects on a human osteosarcoma cell line (SaOS-2cells). However, the accelerated degradation of PLA due to the degradationof bioactive glass may account for the observed decrease in SaOS-2cells viability. Among the biocomposite macrospheres, those composedof PLA exhibited the most promising characteristics for their potentialuse as fillers in bone tissue repair applications.

Automated summary

Traditional bioactive glass powders are typically composed of irregular particles that limit bone ingrowth due to low interconnectivity. Novel biocomposite macrospheres using Sr-bioactive glass, sodium alginate, polylactic acid (PLA), and chitosan (CH) as encapsulating materials were developed for bone fillers. The biocomposite macrospheres made with PLA exhibited higher porosity, interconnectivity, and protection from degradation, making them promising fillers for bone tissue repair applications.