Mechano-responsive microfluidics based on fs-laser processed and selectively functionalised PDMS

Stimuli-adaptive microfluidics offer dynamic control over fluid transport and interfacial interactions, yet their integration into simple and cost-effective lab-on-a-chip platforms remains challenging. Here, we present a versatile fabrication strategy for mechano-responsive systems based on strain-dependent femtosecond laser processing and selective chemical functionalisation of highly elastic PDMS substrates. Reversible groove geometries are generated by laser ablation under defined tensile strain, enabling orientation-dependent opening and closing of microchannels upon mechanical deformation. Subsequent plasma oxidation and polyethylene glycol (PEG) grafting allow hydrophilisation of accessible surface regions, while shielded areas retain their intrinsic hydrophobicity. The combination of tunable topography and selective surface energy modification enables directional spreading, pump-free fluid transport and reaction of multiple liquids controlled by uniaxial mechanical deformation. This approach establishes a simple and scalable platform for flexible lab-on-a-chip applications with adaptive microfluidic functionality.