Aptamer obtained by SELEX technology has drawn more and more interests because of its strong interaction between aptamer and target molecules. Compared with Enzyme-Linked Immunosorbent Assay (ELISA) via protein based on antibody-antigen protocol, aptamer is expected to replace ELISA technology in the future and becomes a promising generation for extensive applications of chemical and biological analysis, due to its high stability and selectivity.

Recently, Prof. WANG Jin and his co-workers from Institute of Intelligent Machines, Hefei Institutes of Physical Science, have utilized aptamer technology to fabricate plasmonic nanorod/nanoseeds superstructured nanosensor on the basis of gold nanorods/graphene oxide composites. The nanosensor can demonstrate ultrasensitive sensing of copper ions via the gold nanorod@nanoseed-SERS nanotags/graphene oxide.

Specifically, the researchers selected monodisperse gold nanorods on graphene oxide as nanocomposites and designed copper ions-recognition DNAzyme for aptamer-assembly.

Subsequently, they could assemble nanoseeds to nanorods/graphene oxide to form plasmonic nanorod@nanoseeds/graphene oxide superstructured nanoparticles.

Moreover, cleavage of DNAzyme-DNAsubstrate via copper ions could induce DNA dehybridization to yield dissociation of aptamer so as to realize reversible assembly of plasmonic nanorod@nanoseeds/graphene oxide superstructured nanoparticles.

As a result, considering the fact that gold nanoseeds have no SERS properties due to quite low Raman scattering cross section, the researchers prepared nanoseed-SERS nanotags and fabricated "on-off" graphene oxide SERS-aptamer sensor. With the aid of excellent SERS ability of gold nanorod@nanoseeds/graphene oxide, "turn-off" SERS sensing of copper ions can be achieved.

The research is supported by National Natural Science Foundation of China (Grant No. U1732122) and International cooperation researching project of Ministry of Science and Technology of People’s Republic of China (MOST-TEKES, Grant No. 2014DFG42290) funding.

Link to the paper: Gold nanorod@nanoparticle seed-SERSnanotags/graphene oxide plasmonic superstructured nanocomposities as an "on-off" SERS aptasensor

Schematic graph of fabricating A: AuNR@AuNPS-SERSnanotags/GO superstructured nanocomposities via DNA-prehybridization approach; B: AuNR@AuNPS-SERSnanotags/GO superstructured nanocomposities via DNA in-situ hybridization approach. (Image by TAO Gangqiang)

Contact:

ZHOU Shu

Hefei Institutes of Physical Science (http://english.hf.cas.cn/)

Email: zhous@hfcas.ac.cn