Electrical properties of osteoblasts cultured on carbon nanotubes

Abstract

A major goal in bone bioengineering is to produce artificial nanostructures with the capacity to increment or replace bone tissues. The purpose of this study is to further explore the use of carbon nanotubes (CNTs) as an adequate scaffold material for osteoblast proliferation and bone matrix formation. Ion channel activities were studied as an indirect measure of the ability of osteoblasts to carry out secretory functions. Chloride and calcium channels were measured in rat osteosarcoma 17/2.8 cells cultured on single-walled (SW) and multi-walled (MW) NTs. Osteoblasts grown on non-functionalised as prepared (AP-) and carboxyl (COOH)-modified SWNTs developed outwardly rectifying, non-inactivating voltage-gated Cl− currents that increased by 3-fold over 10 min because of mechanical stimulation. In addition, osteoblasts expressed inward Ba2+ currents through high voltage-activated L-type Ca2+ channels sensitive to the specific modulators, Bay K 8644 and nifedipine. In all cases, it was verified that COOH functionalisation of SW and MWNTs did not affect osteoblast ion channel activities. It is concluded that osteoblasts grown on AP- and COOH-modified SW and MWNTs retain electrical properties necessary for secretory activities involved in bone formation. These results confirm the suitability of NTs as a potential scaffold material in bone bioengineering.