An　optical　biosensor　based　on　waveguided　metallic　photonic　crystals　(MPCs)　is　reported　for　the　sensitive　testing　of　biomolecular　interactions,　which　provides　practical　approaches　for　the　label-free　detection　of　specific　bioreactions.　The　enhancement　of　the　sensitivity　or　the　amplification　of　the　sensor　signal　by　the　coupling　between　the　waveguide　resonance　mode　and　particle-plasmon　resonance　(PPR)　breaks　through　the　bottle-neck　of　the　intrinsic　response　sensitivity　defined　by　the　spectral　shift　of　the　PPR.　The　success　of　this　sensor　is　demonstrated　by　sensing　the　specific　reaction　between　the　HIV-1　capsid　protein　(p24)　antigen　and　the　monoclonal　anti-p24　antibody,　where　the　dynamics　of　the　bioreactions　can　be　recorded　with　a　potentially　high　time　resolution.　This　new　sensor　stands　out　due　to　its　compact　design　and　its　new　physics,　compared　with　conventional　devices,　its　simple　operation,　the　simple　fabrication　of　the　MPC　chip　and　the　low　cost　of　the　whole　system.