This　work　demonstrated　a　pressure-based　biosensor　integrated　with　a　flexible　pressure　sensor　and　an　electrochromic　device　for　visual　detection.　Initially,　a　sandwich-type　immunoreaction　for　target　carcinoembryonic　antigen　(CEA,　as　a　model　analyte)　was　carried　out　using　the　capture　antibody　(cAb)　and　platinum　nanoparticles-labeled　detection　antibody　(PtNPs-dAb)　in　a　reaction　cell.　The　added　hydrogen　peroxide　(H2O2)　could　be　catalyzed　by　the　PtNPs　to　generate　oxygen　(O2).　In　a　sealed　chamber,　the　pressure　increased　with　the　overflowing　O2.　Meanwhile,　a　skin-inspired　flexible　pressure　sensor　with　excellent　sensing　performance　was　fabricated　to　monitor　the　pressure　change　in　real　time.　Thus,　the　electrical　signal　of　the　pressure　sensor　could　reveal　the　target　concentration.　Moreover,　a　voltage-regulated　electrochromic　device　based　on　polyaniline　(PANI)　and　tungsten　oxide　(WO3)　was　integrated　into　the　platform　to　provide　a　visualized　readout.　According　to　the　electrical　signal　of　the　pressure　sensor,　the　electrochromic　device　would　change　its　color　from　green　to　blue,　which　also　revealed　the　target　concentration　and　could　be　observed　by　the　naked　eye.　Under　optimal　conditions,　the　biosensor　presented　a　high　sensitivity　for　CEA　in　a　detectable　range　of　0.2-50　ng/mL.　The　limit　of　detection　(LOD)　was　94　pg/mL.　The　selectivity,　reproducibility,　and　accuracy　were　also　satisfying.　Furthermore,　this　immunoassay　gives　a　path　for　developing　visualized　biosensors　in　point-of-care　settings.　©