Drug Coated Clay Nanoparticles for Delivery of Chemotherapeutics

Purpose: Osteosarcoma (OSA) is the most common malignancy of bone in children and adolescents. Standard treatments include adjuvant chemotherapy, radiotherapy, hormone or biological therapy, and if OSA is refractory, surgical ablation of the primary tumor. Advancements in treatment modalities have led to increased rates of 'limb-sparing' surgeries, but patients are still threatened with the risk of recurrence. New chemotherapeutic delivery systems and strategies are needed to improve treatment options and patient outcomes. Methods: Halloysite nanotubes (HNTs) exhibit high levels of cytocompatibility and biocompatibility and have been show to be effective at sustained drug release. HNTs were coated with the polyelectrolytes (PE), polyvinylpyrrolidone and polyacrylic acid, and methotrexate (MTX) infused within the coating layers. MTX release and cytotoxicity studies were used to assess the effectiveness of the coatings in inhibiting osteosarcoma cell growth. Results: Polyelectrolyte coatings provided sustained release of MTX and, in an in-vitro study, were show to be effective in altering osteosarcoma cell morphology and reducing the rate of cell proliferation. We further show that MTX-coated halloysite nanotubes can be added to a polymer, Nylon-6; the MTX released, and still retain its ability to inhibit osteosarcoma cell growth. Conclusion: HNT/MTX encapsulated complexes inhibited osteosarcoma cell proliferation and show potential as a delivery vehicle for the prevention of tumor metastasis and/or tumor recurrence after surgery.