An in-situ gold growth self-catalytic signal amplification system enhanced hollow gold immunochromatography for ultrasensitive detection of p24 antigen in HIV infection

In recent years, the global public health landscape has faced unprecedented challenges, notably with the COVID-19 outbreak and the wide spread of HIV. The rapid spread and serious harm of the virus has highlighted the critical need for fast, accurate, and accessible diagnostic tools. These requirements make lateral flow immunochromatographic assay (LFIA) become the most prominent point-of-care testing (POCT) technology at present. In order to find the balance between sensitivity, ease of operation, detection speed and cost of LFIA, hollow gold nanoparticles (HGNPs) with stronger optical signal, stability and simple synthesis process were used as immune labeling materials to construct LFIA platform (HGNPs-LFIA). HGNPs exhibited elevated catalytic activity in relation to the reaction between chloroauric acid (HAuCl 4 ) and hydroxylamine hydrochloride (NH 2 OH-HCl). This heightened activity consequently resulted in the deposition of new gold nanoparticles on the surface of the original HGNPs. At lower analyte levels, a deepening of the colors of the test line and the control line can be observed with naked eyes. Utilizing this special catalytic activity, an in-situ gold growth method was further used to amplify the detection signal of HGNPs-LFIA by self-catalytic, signal amplified HGNPs-LFIA (sa-HGNPs-LFIA) platform for ultrasensitive and rapid detection of p24 antigen in serum was constructed. The platform struck a good balance between high sensitivity and low false positives, and was capable of detecting p24 antigen as low as 1 pg/mL in serum within 30–40 min, which is 10 times more sensitive than the original HGNPs-LFIA and 20 times more sensitive than the commercially available Alere test strips, and further shortened the window of detection for acute HIV infection.