Gold nanorod@nanoparticle seed-SERSnanotags/graphene oxide plasmonic superstructured nanocomposities as an on-off SERS aptasensor

In order to prepare gold nanorods (AuNRs) with high purity and density on graphene oxide (GO), both two-step strategy of presythesis-postassembly and one-step strategy of in-situ growth have been explored, respectively. Observations of morphology and plasmonic bands reveal that both of the two approaches can yield AuNRs with high purity on GO; however, the former can generate more uniform-sized AuNRs on GO in contrast with the latter. Moreover, the AuNRs/GO and gold nanoparticle seed-SERSnanotags can be assembled to fabricate a large-scaled superstructured plasmonic nano-composities (AuNR@AuNPS-SERSnanotags/GO) through DNAzyme-DNA substrate prehybridization and in-situ hybridization, respectively, and disassembled via copper ions aided-DNAzyme-DNA substrate cleavage. As a result, an on-off aptasensor of DNA-AuNR@AuNPS-SERSnanotags/GO can be utilized as an ultrasensitive SERS substrate for detection of copper ions. (C) 2018 Elsevier Ltd. All rights reserved.