Nitrogen-doped porous carbon-based fluorescence sensor for the detection of ZIKV RNA sequences: fluorescence image analysis.

Many studies have demonstrated that metal-organic frameworks (MOFs) are universal fluorescence quenchers for DNA/RNA detection. Nevertheless, the structural stability of many MOFs is relatively weak, which limits their practical applications. Thus, it remains a great interest to develop constitutionally stable nano biosensor suitable for application in the complex environment. Herein, a new angle of nitrogen-doped porous carbon (NPC) obtained from MOFs-based precursors by virtue of a simple method was applied as a nano biosensor for the fluorescence detection of Zika virus (ZIKV) RNA sequences. The fluorescence signal capturing was carried out by using a charge-coupled device (CCD)-based imaging system. The NPC could adsorb TAMRA-tagged ZIKV RNA probe (P-DNA) to form P-DNA@NPC complex accompanied by substantial fluorescence quenching. Upon adding the complementary target RNA (T-RNA), the P-DNA could release from NPC by forming a double-stranded hybrid and induce the fluorescence recovery. The P-DNA@NPC complex was valid and reliable for ZIKV RNA sequences assay with a limit of detection (LoD) at 0.23 nM, which is superior to many of the previously reported fluorescent DNA sensors. Moreover, it could distinguish mismatched RNA and was effective in detecting ZIKV RNA sequences spiked in the human saliva sample. We envision that this study would offer an interesting new angle on the potential integrating application of carbon nanomaterials and CCD-based fluorescence imaging platform in the field of nucleic acid assay.