Design of aptamer-based sensing platform using gold nanoparticles functionalized reduced graphene oxide for ultrasensitive detection of Hepatitis B virus

In the present work, electrochemical aptasensor for earlier detection of Hepatitis B virus infection was developed. First, the surface of a glassy carbon electrode was modified with gold nanoparticles functionalized reduced graphene oxide, then thiol-terminated aptamer specifically recognizes (HBsAg) was covalently linked to Nano-platform via strong gold-sulfur affinity. Subsequently, an electrochemical indicator Methylene Blue (MB) was intercalated into the aptamer structure through electrostatic interaction between MB and guanine bases. The function of the aptasensor relies on the specific binding between the aptamer and (HBsAg). In the absence of HBsAg, a strong electrochemical signal was observed. If the HBsAg was added, The MB- intercalated aptamer can be forced to release of MB from the sensing interface after HBsAg triggered structure switching of the aptamer. Hence, the electrochemical signal of cyclic voltammetry was linearly declined with the concentration of HBsAg over a range of 0.125-2.0 fg/mL with a limit of detection (at 3 sigma/slope) equivalent to 0.0014 fg/mL. To the best of our knowledge the developed aptasensor recount one of the lowest limit of detection for determination HBsAg recently reported in the literature. The selectivity of this electrochemical aptasensor was investigated, the peak current was slightly decreased even then the high concentration of interfering reagents was added. The aptasensor was applied for determining HBsAg in spiked human serum samples. The method was ultrasensitive, highly selective, good stability, and a wide analytical performance range.

Automated summary

An electrochemical aptasensor was developed for earlier detection of Hepatitis B virus infection. It demonstrated high sensitivity, selectivity, and stability, with one of the lowest reported limits of detection for HBsAg in the literature. The sensor was successfully applied to spiked human serum samples for HBsAg determination.