Micropatterning biomacromolecules on aldehyde-enriched polyester surfaces by a microtransfer technique

A modified microtransfer technique was introduced to create micropatterns of biomacromolecules on activated polyester surfaces. Briefly, a recessed poly(dimethylsiloxane) stamp was first coated with a biomacromolecule solution. After drying the solution and selectively removing the biomacromolecules on the ridges, the stamp was stored at low temperature and high humidity to form a condensed water layer. The stamp was subsequently pressed onto the activated polyester surfaces to yield the biomacromolecular patterns. The notable feature of this method is that the reaction between the biomacromolecules and the polymer surface could be performed at a comparable speed to that in solution. Using this method, albumin and chitosan were micropatterned onto aldehyde-enriched polycaprolactone or poly(L-lactic acid) surfaces. Observations under confocal laser scanning microscopy confirmed that the albumin or chitosan patterns formed by this microtransfer technique had higher contrast and good stability. The amount of water condensed on the stamp surface had significant influence on the quality of the resultant patterns. Deficient water produced rimming patterns, while excessive water caused the contamination of the patterns because of the overflow of the condensed water. This technique will be especially useful to those systems with lower reaction activity in the absence of solvent and hence can be applied widely to create patterns of biomacromolecules on polymer surfaces.