Microchannels are an architectural cue that promotes integration and vascularization of silk biomaterials in vivo

Functional integration of implanted biomaterials and bioengineered tissues in vivo requires effective and timely vascular ingrowth. While many vascularization strategies rely on delivery of angiogenic growth factors or endothelial cells to promote vascular ingrowth, the effect of physical and architectural features of biomaterials on the vascularization process is less well understood. Microchannels are a simple, accessible architectural feature frequently engineered into 3D biomaterials to promote mass transfer. In this study, the effect of microchannels on the integration and vascularization of 3D porous silk scaffolds was explored over a 14 week period. An array of 508 µm diameter microchannels spanning the length of critically-sized, porous silk scaffolds significantly improved tissue ingrowth into the constructs. At week 6, all silk scaffolds (n=8) with microchannels showed complete tissue infiltration throughout the construct, while only one of eight (12.5%) did so in the absence of microchannels. T...