Occlusion or blockage of
silicone shunts utilized in the treatment of
hydrocephalus is a major challenge that is currently addressed by multiple shunt replacements. Shunt occlusion is caused by the adhesion and proliferation of reactive cells, such as glial and vascular cells, into the lumen of the
catheter and on valve components. This in vitro study describes how the adhesive behavior of four human cell types on
poly(dimethylsiloxane) (PDMS) surfaces can be suppressed by functionalization with
trypsin, a
proteolytic enzyme. The covalently conjugated
trypsin retained its proteolytic activity and acted in a dose-dependent manner.
Trypsin-modified PDMS surfaces supported significantly lower adhesion of normal human astrocytes, human microglia, human dermal fibroblasts, and human umbilical vein endothelial cells compared to unmodified PDMS surfaces (p < 0.0001). Immunofluorescence imaging of cellular
fibronectin and quantitative adsorption experiments with serum components indicated that the PDMS surfaces immobilized with
trypsin inhibited surface remodeling by all cell types and resisted
protein adsorption. The impact of this work lies in the recognition that the well-known proteolytic characteristics of
trypsin can be harnessed by covalent surface immobilization to suppress cell adhesion and
protein adsorption.