Using a low receptor density regime to emulate an ideal distribution of analyte capture across a large capture area, dose-response studies were conducted to evaluate the optimal surface area of printed PSA when eliciting signal amplification in 'capture-andrelease' AmpliFold assays (Figure ). In dose-response studies, serially diluted samples of HER2 antigen were run up assays and test line signal were measured in order to determine the minimum concentration of antigen, or the limit-of-detection (LOD), that is detectable either a traditional or AmpliFold LFA system.