Scaffold material sheds light on bone tumor therapy

Bone cancers are typically treated surgically but a few tumor cells can survive in the vicinity of defects and proliferate once again. Biomaterials that can both support bone regeneration and repair while suppressing tumor recurrence are highly desirable from a clinical point of view. Now researchers have devised just such a biomaterial based on nanoparticle-decorated bioactive glass that simultaneously provides a scaffold for bone regrowth and the capacity for photothermal treatment to target any remaining tumor cells [Dang et al., Biomaterials 160 (2018) 92].

Photothermal therapy (PTT) is an emerging treatment that harnesses absorbed near-infrared (NIR) light to generate heat locally, which destroys cancer cells in the vicinity. It is a promising approach because it can target cells in specific areas without systemic toxicity or long-lasting tissue damage while being cheap and minimally invasive.

The team, led by Chengtie Wu at the Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai Ninth People’s Hospital Affiliated Shanghai Jiao Tong University School of Medicine, and Queensland University of Technology in Australia, used three-dimensional printing to build porous scaffolds out of bioactive glass (BG), which is a well-recognized biocompatible material. Nanocrystals of the ternary chalcogenide CuFeSe₂ were grown on the BG surface using a simple solvothermal method. As a semiconductor, CuFeSe₂ has a narrow bandgap that makes it an ideal photothermal agent.

“We successfully prepared a bifunctional scaffold using three-dimensional printing technology in combination with in situ growth of CuFeSe₂ nanocrystals,” explains Wu. “The scaffold has high photothermal conversion efficiency and bioactivity, which can be used for bone tumor therapy and bone defect regeneration.”

The BG scaffolds functionalized with CuFeSe₂ nanocrystals (BG-CFS) absorb NIR radiation and convert it into heat very efficiently. The researchers report that their BG-CFS scaffolds can be rapidly heated up to 120°C in less than two minutes. Lower temperatures are achieved by simply controlling the laser power and duration. This capability can both effectively kill tumor cells in vitro and significantly inhibit bone tumor growth in vivo.

Moreover, the team demonstrates that the porous BG-CFS structure supports the attachment and proliferation of rabbit bone precursor cells (mesenchymal stem cells, rBMSCs), leading to the formation of new bone tissue after photothermal treatment.

“The main attractiveness of our scaffold is that it combines the photothermal performance of semiconducting CuFeSe₂ nanocrystals with the bone-forming activity of bioactive glass scaffolds,” says Wu. “We believe that this approach could offer a more extensive horizon for developing novel biomaterials with dual functions of bone tumor therapy and bone regeneration.”