Figure 3.

(a) Intensity of test line for five independently synthesized batches of PtNCs (ca. 120 nm) for detection of 50 pg·mL^–1 p24 in FBS with 5 min development in CN/DAB and H₂O₂. Red line indicates average test line intensity for triplicate measurements across all batches. Coefficient of variation (n = 5) was 2.4%. (b) Intensity of test line (for detection of 500 pg·mL^–1 p24-spiked plasma) against days of test component aging at 44 °C or room temperature (RT). For the aging experiment, nanobody–biotin and either PtNC or HRP–antibody conjugates were lyophilized in appropriate buffers and incubated at specified temperature. At aging time points, spiked plasma was added to the vessel of freeze-dried components and flowed up the LFIA test strip followed by catalytic amplification.