One-step fabrication of a self-driven point-of-care chip by femtosecond laser direct writing and its application in cancer cell H2O2 detection via semiconductor-based SERS

Self-driven microfluidic systems have attracted significant attention and demonstrated great potential in the field of point-of-care (POC) testing due to their device simplicity, low power consumption , increased portability, and reduced sample consumption. To develop POC detection chips with diverse characteristics that meet different requirements, there is a strong demand for feasible strategies that enable easy operation and reduce processing time. Here, a one-step processing approach using femtosecond laser direct writing technology was proposed to fabricate a capillary-actuated POC microfluidic chip. The driving force of the chip is highly dependent on its surface wettability , which can be easily adjusted by changing the laser processing parameters . This POC microfluidic chip allowed for the detection of intracellular H 2 O 2 through a catalytic reaction system that incorporated 5-aminosalicylic acid -sensitized colloidal TiO 2 nanoparticles and horse radish peroxidase , with integrating semiconductor-based surface-enhanced Raman scattering (SERS) quantitative technique. The concentration of H 2 O 2 was determined by the SERS signal of the catalytic products in the microfluidic chip, resulting in rapid detection with minimal sample consumption. Our method provides a simple, feasible, and alternative strategy for POC testing of H 2 O 2 , with a linear range of 10 −2 ∼10 −6  M and a limit of detection of 0.55 μM. This approach was successfully applied to rapid detection of intracellular H 2 O 2 in MCF-7 breast cancer cells with high sensitivity and minimal sample consumption. Additionally, this study not only demonstrates the exceptional advantages of femtosecond laser processing technology in fabricating diverse microfluidic chips for various applications, but also presents an efficient POC testing strategy for detecting cell signaling molecules .