Sensitive electrochemical detection of gp120 based on the combination of NBD-556 and gp120

As is known, the employment of molecular imprinting polymer (MIP) as specific sensing materials in sensors, namely MIP-based sensors. In this contribution, we devised a MIP electrochemical sensor for the detection of variable-format conformations protein gp120. The sensor was constructed by using a grapheme-like carbon nanfragment (CNF) and bismuth oxides composites (CNF-Bi) as decoration material, small-molecule entry inhibitor NBD-556 and gp120 conjugates NBD-556@gp120 instead of gp120 as the template, and pyrrole as an electropolymerization monomer. Cyclic voltammetry, differential pulse voltammetry, scanning electron microscopy and transmission electron microscope were used to characterize the preparation process of the sensor. Results showing that, under optimized conditions, the introduction of NBD-556 make the specific recognition and analytical properties of the MIP sensor towards gp120 more efficient. The response currents were proportional to the NBD-556@gp120 concentrations in the range of 0.0002 ng mL^-1 to 200 ng mL^-1 with the detection limit of 0.0003 ng mL^-1 based on S/N = 3. Meanwhile, the NBD-556@gp120 based MIP sensor also shows acceptable stability and reproducibility. When used for the detection of gp120 in human plasma, it also showed good accuracy. This research idea is in great promising for the early diagnosis of HIV-1 virus and can also be extended to the detection of other conformationally unstable proteins.