Fabrication of a layered microstructured polycaprolactone construct for 3-D tissue engineering.

Successful artificial tissue scaffolds support regeneration by promoting cellular organization as well as appropriate mechanical and biological functionality. We have previously shown in vitro that 2-D substrates with micrometer-scale grooves (5 microm deep, 18 microm wide, with 12 microm spacing) can induce cell orientation and ECM alignment. Here, we have transferred this microtopography onto biodegradable polycaprolactone (PCL) thin films. We further developed a technique to layer these cellularized microtextured scaffolds into a 3-D tissue construct. A surface modification technique was used to attach photoreactive acrylate groups on the PCL scaffold surface onto which poly(ethylene glycol)-diacrylate (PEG-DA) gel could be photopolymerized. PEG-DA serves as an adhesive layer between PCL scaffolds, resulting in a VSMC-seeded layered 3-D composite structure that is highly organized and structurally stable. The PCL surface modification chemistry was confirmed via XPS, and the maintenance of cell number and orientation on the modified PCL scaffolds was demonstrated using colorimetric and imaging techniques. Cell number and orientation were also investigated after cells were cultured in the layered 3-D configuration. Such 3-D tissue mimics fabricated with precise cellular organization will enable systematic testing of the effects of cellular orientation on the functional and mechanical properties of tissue-engineered blood vessels.