The researchers have developed a platform that allows for automated and multistep immunoassays on paper-based microfluidic devices through smart fluid manipulation with automatically controlled paper valves. The platform comprises an integrated paper-based microfluidic system with SMP-actuated fluid valves that are capable of automated colorimetric enzyme-linked immunosorbent assays (ELISAs). The system has been designed as a single-layer microfluidic paper-based analytical device (μPAD) that stores all the necessary reagents on the chip and sequentially transfers them to a paper test zone following a specific ELISA protocol.