Label-free determination and multiplex analysis of DNA and RNA in tumor tissues

Determination of the total content of nucleic acids constitutes an important part of medicinal diagnosis. This determination is typically performed using a combination of spectrophotometry and polymerase chain reaction, where multi-step and complex sample pretreatment is generally required. To simplify the analysis, we present a nanosensor for the multiplex determination of DNA and RNA. This nanosensor consists of a magnetic Fe3O4@Ag nanocomposite functionalized by a low molecular selector from the family of alkylating agents, chlorambucil. The sensor allows selective isolation of nucleic acids based on the magnetic properties of integrated Fe3O4 nanoparticles and consecutive determination of their content via magnetically assisted surface-enhanced Raman spectroscopy (MA-SERS). Limits of detection of 3.0 ngL(-1) and 3.8 ngL(-1) are achieved for DNA and RNA, respectively. The enhanced selectivity of the developed sensor, owing to the presence of the alkylating agent, allows multiplexed analysis of DNA and RNA with low relative errors (<10%) of determination. (C) 2017 Published by Elsevier Ltd.