Chitosan/Nanohydroxyapatite/Hydroxyethyl-cellulose-based printable formulations for local alendronate drug delivery in osteoporosis treatment

Osteoporosis is a silent bone disease and a growing health issue. Despite recent progress in diagnosis and treatment, effective therapeutic strategies are still needed. One of the possible solutions is the implantation of engineered drug-releasing scaffolds at the disease site. To boost this approach further, we aimed to develop printable materials (the inks) for the construction of patient-specific 3D scaffolds with drug-release capability. The inks were composed of chitosan – a natural osteoinductive polysaccharide, nanohydroxyapatite – a natural bone matrix ingredient improving mechanical properties, sodium alendronate – a bioactive drug, and hydroxyethyl-cellulose – a filler improving the printability. Printed scaffolds were crosslinked with citric acid or KOH. After coating with collagen and gelatin, they demonstrated biocompatibility with the adipose-derived mesenchymal stem cells and MG-63 cell line. They also showed a sustained release of alendronate for 50 days, causing a significant reduction in the expression of Cathepsin K, an osteoclast-specific gene marker, which indicates the osteoclast-inhibiting capacity of the coated scaffolds. This work demonstrates the potential of developed printable materials to find applications as cell and drug carriers for the treatment of osteoporosis.