The Wave-engineered platforms provide versatile mechanisms for manipulating acoustic and optical fields within compact lab-on-a-chip systems. Phononic crystals designed with pillar–cavity geometries generate tunable bandgaps and strong attenuation of Rayleigh waves, enabling stable pressure nodes that facilitate particle trapping and controlled transport inside microfluidic channels. This acoustic functionality offers a robust mechanical layer for precise sample handling. Complementing this, free-standing silicon membrane metasurfaces support high-Q guided-mode and quasi-BIC resonances, with spectral properties highly sensitive to refractive index changes and mid-infrared vibrational signatures. Their response can be tailored through membrane geometry and thermally tuned without moving components, enabling compact and high-resolution biochemical sensing. Combined, these phononic and photonic structures form an integrated wave-based platform that unifies acoustic manipulation with optical detection, advancing the capabilities of next-generation lab-on-a-chip technologies.