LAUSR

Abstract This work reports a new and easy-to-use methodology for construction of screen-printed electrodes (SPE) based on carbon ink and its modification with 4-aminothiophenol (4-ATP) and gold nanoparticles for detection of HIV RNA. Morphological analysis for SPE/4-ATP/AuNps+DNA probe showed increased roughness indicating that 4-ATP monolayer works as a network for connection of functionalized gold nanoparticles with specific oligonucleotide probe to the RNA target. The biosensor response was monitored by indirect electrodetection using ethidium bromide as indicator of duplex formation. The peak current response of ethidium bromide was linear related to the logarithm of concentration of HIV RNA, detecting up to 6 copies/mL and linear range of 6 to 11000 copies/mL of RNA, covering the clinically relevant concentration range (50-200 copies/mL). The biosensor discriminates negative and positive samples, making it possible to quantify the viral load, a crucial factor for the development of biosensors for the early detection of HIV.