Cell lysis servesas an essential role in the sample preparationfor intracellular material extraction in lab-on-a-chip applications.However, recent microfluidic-based cell lysis chips still face severaltechnical challenges such as reagent removal, complex design, andhigh fabrication cost. Here, we report highly efficient on-chip photothermalcell lysis for nucleic acid extraction using strongly absorbed plasmonicAu nanoislands (SAP-AuNIs). The highly efficient photothermal celllysis chip (HEPCL chip) consists of a PDMS microfluidic chamber anddensely distributed SAP-AuNIs with large diameters and small nanogaps,allowing for broad-spectrum light absorption. The SAP-AuNIs inducephotothermal heat, resulting in a uniform temperature distributionwithin the chamber and rapidly reaching the target temperature forcell lysis within 30 s. Furthermore, the localized plasmonic heatingof SAP-AuNIs expeditiously triggers phase transition and photoporationin the directly contacted lipid bilayer of the cell membrane, resultingin rapid and highly efficient cell lysis. The HEPCL chip successfullylysed 93% of PC9 cells at 90 & DEG;C for 90 s without nucleic aciddegradation. This on-chip cell lysis offers a new sample preparationplatform for integrated point-of-care molecular diagnostics.