Abstract: Systems and methods are provided for immobilizing nucleic acid amplicons and protein antigens on a test device. Amplicons comprising a synthetic binding unit and a detectable label are generated and immobilized at predetermined locations on a test device by specific binding interactions between the synthetic binding unit and a synthetic capture unit located at the predetermined locations. The synthetic binding unit may include a unique design such that during amplification, a region of the synthetic binding unit is not subject to the amplification reaction, and thus the amplicon remains single stranded and available for binding to the synthetic capture unit during the capture process. In certain embodiments, the synthetic binding unit and a synthetic capture unit include synthetic nucleic acid analogs that do not interact with native nucleic acids or enzymes that act thereon. In one embodiment the synthetic binding unit and synthetic capture unit comprises puranosyl RNA (pRNA).