High-topography surface functionalization based on parylene-C peel-off for patterned cell growth

This paper introduces a new technique for patterning functionalization layers on substrates with high-topography. The method is based on a parylene-C template shaped by a structured, sacrificial photoresist layer and attached to the substrate where functionalization is not intended. After photoresist removal and surface functionalization, the parylene layer is peeled off, leaving all areas initially covered by the sacrificial polymer functionalized. The technique has several advantages: (i) In contrast to microcontact printing, it allows surfaces with complex topographies to be functionalized; (ii) complex functionalization patterns are possible; (iii) the parylene structure can be reutilized. We successfully demonstrate the technique with the guided growth of neuron-like PC12 cells on honeycomb-shaped protein patterns on micropillars and microwells. The range and limits of the technique are analyzed and discussed in detail.