Advancement of dengue virus NS1 protein detection by 3D-nanoassembly complex gold nanoparticles utilizing competitive sandwich aptamer on disposable electrode.

Signal amplification have been centralized in developing the highly reliable biosensor for analyte detection with a narrow detection window. We proposed an aptasensor to provide a highly sensitive early-stage diagnostic platform of dengue virus NS1 protein (DENV-NS1) by dual-approach - colorimetric and electrochemical detection. This work utilized two different aptamers specific to DENV-NS1: One conjugated to gold nanoparticles (AuNPs), forming AuNPs-Apt1 and its complementary sequence aptamer, forming AuNPs-Apt2. The unbound Apt1 of AuNPs-Apt1 by DENV-NS1 were to hybridize to AuNPs-Apt2 and induced a 3D-nanoassembled formation, resulting in DENV-NS1 concentration-dependent plasmonic color change. Occurrence of the hybridization of Apt1 and Apt2, the 3D-assembled hybridized aptamers of AuNPs was incubated with methylene blue (MB) solution, which intercalated a high number of MB molecules within the duplex structure of aptamers, and the complex was captured on the Apt2-conjugated disposable gold electrode (DGE). The developed aptamer-based biosensor showed high sensitivity with colorimetric response down to 1.28 pg/mL and electrochemical approach down to 30 fg/mL of DENV-NS1 with good selectivity. This work showcases an advanced utilization of aptamer and its complementary anti-sense aptamer in signal amplification and nanocarrier for biosensing.