A novel amperometric biosensor based on gold nanoparticles anchored on reduced graphene oxide for sensitive detection of L-lactate tumor biomarker
In this work, a novel amperometric biosensor based on gold nanoparticles anchored on reduced graphene oxide (RGO-AuNPs) and L-lactate dehydrogenase (LDH) was developed for the sensing of Llactate. Firstly, the RGO-AuNPs modified screen printed electrodes were tested for NADH detection showing a wide dynamic range and a low detection limit. Next, the biosensor was constructed by incorporating both enzyme and RGO-AuNPs in a sol gel matrix derived from tetrametoxysilane and methyltrimetoxysilane. The enzyme loading, working pH, and coenzyme concentration were optimized. The biosensor linearly responded to L-lactate in the range of 10 μM - 5 mM and showed a good specific sensitivity of 154 μA/mM·cm2 with a detection limit of 0.13 μM. This was accompanied by good reproducibility and operational stability. Tests on artificial serum proved that L-lactate can be determined practically without interferences from commonly interfering compounds such as urate, paracetamol and L-ascorbate. Our LDH/RGO-AuNPs/SPCE based biosensor thus performs as electrochemical device for the detection of L-lactate as a viable early cancer bio-marker. ; This work was supported by Romanian National Authority for Scientific Research, grant PN-IIID- PCE-2011-3-0286 and FP7 Marie Curie PIRSES_GA_2012-318053: SMARTCANCERSENS. Ana M. Benito and Wolfgang K. Maser would like to thank the Spanish Ministry MINECO (Projects MAT2010-15026 and ENE2013-48816-C5-5-R), the Spanish National Research Council CSIC (Project 201080E124), and the regional Government of Aragon and the European Social Fund (Project DGA-ESF T66) for financial support. ; Peer reviewed