DNA aptamer selection and construction of an aptasensor based on graphene FETs for Zika virus NS1 protein detection

Zika virus (ZIKV) is a mosquito-borne virus that is phylogenetically close to other medically important flaviviruses with high global public health significance, such as dengue (DENV) and yellow fever (YFV) viruses. Correct diagnosis of a flavivirus infec-tion can be challenging, particularly in world regions where more than one flavivirus co-circulates and YFV vaccination is manda-tory. Acid nucleic aptamers are oligonucleotides that bind to a specific target molecule with high affinity and specificity. Because of their unique characteristics, aptamers are promising tools for biosensor development. Aptamers are usually obtained through a procedure called & ldquo;systematic evolution of ligands by exponential enrichment & rdquo; (SELEX). In this study, we select an aptamer (termed ZIKV60) by capillary electrophoresis SELEX (CE-SELEX) to the Zika virus non-structural protein 1 (NS1) and counterselection against the NS1 proteins of DENV (serotypes 1, 2, 3, and 4) and YFV. The ZIKV60 dissociation constant (Kd) is determined by en-zyme-linked oligonucleotide assay (ELONA) and the aptamer specificity is evaluated by quantitative real-time polymerase chain reaction. ZIKV60 shows a high binding affinity to the ZIKV NS1 protein with a Kd value of 2.28 +/- 0.28 nM. The aptamer presents high specificity for ZIKV NS1 compared to NS1 of DENV and YFV. Furthermore, graphene field-effect transistor devices functio-nalized with ZIKV60 exhibit an evident identification of NS1 protein diluted in human serum. These results point to the applicabili-ty of biosensors based on the ZIKV60 aptamer for the differential diagnosis of the Zika virus. Superscript/Subscript Available

Automated summary

In this study, an aptamer (ZIKV60) with high affinity and specificity to Zika virus NS1 protein was selected through CE-SELEX. The ZIKV60 aptamer showed a strong binding affinity to ZIKV NS1, and exhibited high specificity compared to NS1 from DENV and YFV. The functionalized graphene field-effect transistor devices with ZIKV60 demonstrated the potential for differential diagnosis of Zika virus.