The inhibition of neuronal calcium ion channels by trace levels of yttrium released from carbon nanotubes

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• 作者：Lorin M. Jakubek ; Spiro Marangoudakis ; Jesica Raingo ; Xinyuan Liu ; Diane Lipscombe ; Robert H. Hurt
• 关键词：Biocompatibility ; Nanoparticle ; Brain ; Metal ion release ; Ca_V2.2 ; Voltage-gated calcium channel
• 刊名：Biomaterials
• 出版年：2009
• 出版时间：October 2009
• 年：2009
• 卷：30
• 期：31
• 页码：6351-6357
• 全文大小：1062 K

文摘

Carbon nanotubes (CNTs) are used with increasing frequency in neuroengineering applications. CNT scaffolds are used to transmit electrical stimulation to cultured neurons and to control outgrowth and branching patterns of neurites. CNTs have been reported to disrupt normal neuronal function including alterations in endocytotic capability and inhibition of ion channels. Calcium ion channels regulate numerous neuronal and cellular functions including endo and exocytosis, neurite outgrowth, and gene expression. Strong CNT interactions with neuronal calcium ion channels would have profound biological implications. Here we show that physiological solutions containing CNTs inhibit neuronal voltage-gated calcium ion channels in a dose-dependent and CNT sample-dependent manner with IC50 as low as 1.2 μg/ml. Importantly, we demonstrate that the inhibitory activity does not involve tubular graphene as previously reported, but rather very low concentrations of soluble yttrium released from the nanotube growth catalyst. Cationic yttrium potently inhibits calcium ion channel function with an inhibitory efficacy, IC50, of 0.07 ppm w/w. Because of this potency, unpurified and even some reportedly “purified” CNT samples contain sufficient bioavailable yttrium to inhibit channel function. Our results have important implications for emerging nano-neurotechnology and highlight the critical role that trace components can play in the biological response to complex nanomaterials.