Micropatterning of micro/nanospheres on PDMS by using layer-by-layer self-assembly

Recently, microcontact printing has been used as a new method for building complex patterns. Unlike patterning self-assembled monolayers, we introduced a method to pattern micro/nano structures on PDMS without the help of metal thin film coating and alkanethiol solution. In this study, polycation poly(ethylenimine) and polyanion poly(styrenesulfonate) were used as ink solution to form an ultrathin film on PDMS stamp through electrostatic layer-by-layer self-assembly. The multilayer film of (PEI/PSS)₃/PEI was assembled with a thickness of 12 nm. Then negatively charged 4.5-μm microspheres or 45-nm fluorescence nanospheres were adsorbed on the precursor film through the LbL technique. Finally, microspheres or nanospheres were patterned on PDMS substrate through contact printing. Positively charged poly-D-lysine was adsorbed on patterned microspheres through electrostatic interaction. Then bovine coronary arterial endothelial cells were seeded on micropatterns of PDL. In conclusion, charged polyions could be used as an ink solution for PDMS stamps in micropatterning of micro/nanospheres on PDMS substrate