Spatial resolution in chitosan-based programmable biomolecular scaffolds

The polysaccharide chitosan is a versatile scaffold for assembly and conjugation of biomolecules, including nucleic acids, proteins, and viruses. It provides unique value in bioMEMS in that it can be electrodeposited on demand at specific locations in closed microfluidic systems, enabling spatial and temporal programmability of biomolecular binding and reaction sites in bio-microfluidic networks. In anticipating the scaling of such systems to smaller dimensions, we have investigated the spatial resolution which the chitosan electrodeposition process can achieve, using micron-scale electrode patterns coupled with fluorescence and Raman microscopies to assess the fidelity and edge sharpness of the resulting chitosan patterns. These show that electrodeposited chitosan scaffolds can be defined to an edge sharpness of 0.5–1.0 mm, compatible with the vast majority of microfluidics and bioMEMS applications, where microfluidic channel dimensions in the range of 10s or 100s of micrometers are common.