Gradient Nanofiber Scaffold Libraries for Screening Cell Response to Poly(e-caprolactone)-Calcium Phosphate Composites
Carl G. Simon Jr., Limin Sun, Laurence C. Chow, William Miles, Christopher K. Tison, Kaushik Chatterjee, Marian F. Young, Vinoy Thomas, Murugan Ramalingam
A 2-spinnerette approach has been developed for fabricating nanofiber scaffold gradients for use as 1) scaffold libraries for screening the effect of nanofiber properties on cell response and 2) templates for generating graded tissue interfaces. Although previous approaches for rapid screening have used material libraries in the form of two-dimensional surfaces or films (2D) [1-6], biomaterials are commonly used in a three-dimensional scaffold format (3D), cells behave more physiologically when cultured in a 3D environment and cells are responsive to the topography presented by 3D scaffolds [7-11]. In addition, strategies for patterning cells and tissues are in high demand for replicating the hierarchical structures found in organs. Electrospun nanofiber scaffolds have shown promise because they mimic the nanotopography of native extracellular matrix [12-14]. For these reasons, we have developed a 2-spinneret approach for fabricating nanofiber scaffolds with property gradients. Nanofiber scaffolds containing gradients in a new preparation of amorphous calcium phosphate nanoparticles (A-CaP)  were fabricated to screen osteoblast response. For comparison, gradients in a crystalline CaP nanorparticle preparation (C-CaP) were also prepared. Osteoblast adhesion and proliferation were enhanced on nanofibers containing A-CaP but were not affected by presence of C-CaP. These results demonstrate that nanofiber gradients can be used for systematic screening of cell response, that nanofibers gradients can induce a graded cell response and that the new A-CaP nanoparticles enhance osteoblast proliferation when incorporated into nanofibers.