Fabrication of Organophosphorus Biosensor Using ZnO Nanoparticle-Decorated Carbon Nanotube–Graphene Hybrid Composite Prepared by a Novel Green Technique

In this work, we report a green synthesis procedure for preparing zinc oxide nanoparticle (NP)-decorated multiwalled carbon nanotube–graphene hybrid composite (ZnO–MWCNTs-sG) by using solar energy and its application as a transducer candidate for organophosphorus biosensor. This hybrid composite shows a good electrochemical activity due to large electrochemical active surface area in comparison to ZnONP-decorated graphene (ZnO-sG) prepared by the same root. This can be due to the presence of MWCNTs between the graphene layers, which effectively prevents its restacking, thereby increasing the accessible surface area. The fabricated biosensor using this composite as a transducer candidate shows a high affinity to acetyl cholinesterase (AChE) enzyme with a Michaelis–Menten constant (Km) value of 0.8 mM. Further, it exhibits a linear response for Paraoxon detection from 1 to 26 nM with a detection limit of 1 pM (S/N = 3). On the basis of the above synergetic electrochemical sensing and easy scale up green syn...