Time of flight secondary ion mass spectrometry-A method to evaluate plasma-modified three-dimensional scaffold chemistry.

Biopolymers are used extensively in the manufacture of porous scaffolds for a variety of biological applications. The surfaces of these scaffolds are often modified to encourage specific interactions such as surface modification of scaffolds to prevent fouling or to promote a cell supportive environment for tissue engineering implants. However, few techniques can effectively characterize the uniformity of surface modifications in a porous scaffold. By filling the scaffold pores through polymer embedding, followed by analysis with imaging time-of-flight secondary ion mass spectrometry (ToF-SIMS), the distribution and composition of surface chemical species though complex porous scaffolds can be characterized. This method is demonstrated on poly(caprolactone) scaffolds modified with a low-fouling plasma-deposited coating from octafluoropropane via plasma enhanced chemical vapor deposition. A gradient distribution of CF+/CF3+ is observed for scaffolds plasma treated for 5 min, whereas a 20 min treatment results in more uniform distribution of the surface modification throughout the entire scaffold. The authors expect this approach to be widely applicable for ToF-SIMS analysis of scaffolds modified by multiple plasma processing techniques as well as alternative surface modification approaches.