Combining Gold Nanoparticles with Real-Time Immuno-PCR for Analysis of HIV p24 Antigens

We have improved real-time immuno-PCR (IPCR) with nanoparticle based amplification. Gold magnetic particles were functionalized with antibodies against the HIV capsid protein p24 and gold nanoparticles were functionalized with both oligonucleotide barcodes and antibodies against a non- overlapping region of the cognate p24. In the presence of p24, the gold magnetic particles and the gold nanoparticles form sandwiched structures that are magnetically separated from mixture. After dehybridization of the barcode DNA on the gold nanoparticle, the released barcodes are quickly identified by realtime PCR. The limit of detection was 100 copies of p24 antigens. Results show that the real-time IPCR through nanoparticle based barcode amplification offers an disruptive approach to p24 detection and quantification, thus may potentially shorten the window of HIV-1 diagnosis, and might be valuable to monitor the response to anti-retroviral treatment when RNA copy number is very below.