A novel and simple microcontact printing technique for tacky, soft substrates and/or complex surfaces in soft tissue engineering

Microcontact printing (μCP) has attracted much interest due to its simplicity and wide range of applications. However, when conventional μCP is applied to soft and/or tacky substrates, substrate sagging and difficulty in stamp removal cause non-conformance in the patterns. Moreover, it is almost impossible to apply conventional μCP on complex or wavy surfaces. In this study, we developed a novel yet simple trans-print method to create efficient micropatterning on soft and/or tacky substrates such as polydimethylsiloxane and polyacrylamide gel, and also on curved surfaces, by introducing polyvinyl alcohol film as a trans-print media. This technique is simple as it only involves one trans-print step and is also cost-effective. Most importantly, this technique is also versatile and we have proven this by printing various designs on more complex non-flat surfaces using various proteins as inks. The quality of the trans-printed pattern was excellent with high reproducibility and resolution as verified by immunostaining. Human mesenchymal stem cells cultured on these patterns displayed good conformance on the soft and tacky substrates printed using this technique. These results suggest that this novel trans-print technique can be extended to a potentially generic methodology for μCP of other proteins and biomolecules, other shapes and sizes, and cells, and will also be useful in three-dimensional micropatterning for soft tissue engineering.