Nanowire Aptasensors for Electrochemical Detection of Cell-Secreted Cytokines.

ABSTRACT: Cytokines are small proteins secreted by immune cells in response to pathogens/infections; therefore, these proteins can be used in diagnosing infectious diseases. For example, release of a cytokine interferon (IFN)-? from T-cells is used for blood-based diagnosis of tuberculosis (TB). Our lab has previously developed an atpamer-based electrochemical biosensor for rapid and sensitive detection of IFN-?. In this study, we explored the use of silicon nanowires (NWs) as a way to create nanostructured electrodes with enhanced sensitivity for IFN-?. Si NWs were covered with gold and were further functionalized with thiolated aptamers specific for IFN-?. Aptamer molecules were designed to form a hairpin and in addition to terminal thiol groups contained redox reporter molecules methylene blue. Binding of analyte to aptamer-modified NWs (termed here nanowire aptasensors) inhibited electron transfer from redox reporters to the electrode and caused electrochemical redox signal to decrease. In a series of experiments we demonstrate that NW aptasensors responded 3× faster and were 2× more sensitive to IFN-? compared to standard flat electrodes. Most significantly, NW aptasensors allowed detection of IFN-? from as few as 150 T-cells/mL while ELISA did not pick up signal from the same number of cells. One of the challenges faced by ELISA-based TB diagnostics is poor performance in patients whose T-cell numbers are low, typically HIV patients. Therefore, NW aptasensors developed here may be used in the future for more sensitive monitoring of IFN-? responses in patients coinfected with HIV/TB.

SUBMITTER: Liu Y 

PROVIDER: S-EPMC7311073 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature