Effects of surface curvature and surface characteristics of carbon-based nanomaterials on the adsorption and activity of acetylcholinesterase

Carbon-based nanomaterials (NM) are promising candidates for a myriad of applications ranging from drug delivery to biosensing platforms. In the physiological environment, proteins can be adsorbed onto the surface of NM that can alter their structure and function. Little is known of the effect of NM on larger proteins and enzymes and an attempt has been made in this study to investigate the effect of carbon-based NM such as carbon black (CB), graphene oxide (GO) and fullerene (C60) on the adsorption and activity of acetylcholinesterase (AChE), a key enzyme present in brain, blood and nervous system and a suitable neurotoxicity biomarker. Experimental and computational results showed that all the carbon-based NM tested adsorb AChE but they have different effects on the catalytic activity of the enzyme. The most efficient AChE inhibitor is CB. In contrast, AChE adsorbed on the GO surface retains its native conformation and most of its activity. As compared to GO and CB, C60 was found to be an inefficient adsorbent of AChE. The distinctive adsorption pattern of NM and their inhibitory potential could be related to the surface characteristics of NM. Our studies also demonstrate the potential of GO as a substrate for immobilization of AChE.