Development of conical soluble phosphate glass fibers for directional tissue growth

One of the challenges of tissue engineering is the regulation of vascularization and innervations of the implant by the host. Here, we propose that using soluble phosphate glass (SPG) fibers, incorporated in dense collagen constructs will allow us to control the rate and direction of tissue ingrowth. The idea here was to generate channels with tailored direction using conical phosphate glass fibers. The changing surface area-to-mass ratio of conical fibers will make them to dissolve faster from their narrow ends opening up channels in that direction ahead of any ingrowing cells. In this study, we show that SPG fibers can be manipulated to produce conical shape fibers using graded dissolution. Our result shows that 40 µm fibers of composition ratio 0.5 (P(2)O(5)):0.25 (CaO):0.25 (Na(2)O) and dissolution time of 8-10 h have a mean reduction in fiber diameter of 8.85 ± 2.8 µm over 19.5 mm fiber length, i.e., a mean rate of 0.5 µm/mm (n=20) change. These conically shaped fibers can also be manipulated and potentially used to promote uniaxial cell-tissue ingrowth for improved innervations and vascularization of tissue engineered constructs.