Single-walled carbon nanohorns modulate tenocyte cellular response and tendon biomechanics

Subfailure ligament and tendon injury remain a significant burden to global healthcare. Here, we present the use of biocompatible single-walled carbon nanohorns (CNH) as a potential treatment for the repair of sub-failure injury in tendons. First, in vitro exposure of CNH to human tenocytes revealed no change in collagen deposition but a significant decrease in cell metabolic activity after 14 days. Additionally, gene expression studies revealed significant downregulation of collagen Types I and III mRNA at 7 days with some recovery after 14 days of exposure. Biomechanical tests with explanted porcine digitorum tendons showed the ability of CNH suspensions to modulate tendon biomechanics, most notably elastic moduli immediately after treatment. in vivo experiments demonstrated the ability of CNH to persist in the damaged matrix of stretch-injured Sprague Dawley rat Achilles tendon but not significantly modify tendon biomechanics after 7 days of treatment. Although these results demonstrate the early feasibility of utility of CNH as a potential modality for tendon subfailure injury, additional work is needed to further validate and ensure clinical efficacy.