Detection of HIV-1 antigen by quartz crystal microbalance using gold nanoparticles

• Recognition of HIV-1 antigen using quartz crystal microbalance is proposed.
• Streptavidin-functionalized gold nanoparticles act as signal enhancers.
• Size and shape of gold nanoparticles strongly affect the amplification of the signal.

In the current exploratory study, a quartz crystal microbalance (QCM) technique was employed to detect HIV-1 antigen at a very low concentration using gold nanoparticles (Au NPs) as a signal enhancer. Colloidal Au NPs were synthesized using a reduction method followed by streptavidin functionalization. HIV-1 antigen was captured by a polyclonal antibody on the QCM surface that had been previously treated with 11-mercaptoundecanoicacid (MUA) and streptavidin. The Au NPs with a high mass amplified the detection signal, making HIV-1 antigen detection possible even in the window period of HIV infection. In addition, the effect of Au NP size was also investigated to elucidate the optimal size of the enhancer. The signal performance is discussed in terms of mass effect and conjugate efficiency.