Abstract

Combining Magnetically-assisted Electrospinning with Photoconjugation to Create Multi-Gradient Biomaterials

Julianne Holloway, Assistant Professor of Chemical Engineering, Arizona State University

There have been significant advances within tissue engineering; nonetheless, translation has proven difficult with ongoing challenges regenerating complex tissues with a heterogeneous structure and multiple cell types. For example, the interfacial tissue between adjacent tissues (e.g. tendon-bone, ligament-bone, cartilage-bone) has complex gradients of structure, cell type, and chemical composition. Designing biomaterial scaffolds that mimic the heterogeneous properties of these interfacial tissues is vital for spatially controlling cell behavior and promoting functional tissue regeneration. Towards this aim, we have developed an innovative manufacturing technique to selectively and precisely control gradients in fiber alignment and chemistry. First, magnetically-assisted electrospinning was used to control fiber alignment. Electrospun fibers were highly aligned in the presence of a magnetic field and transitioned to randomly aligned fibers away from the magnetic field. Using different magnet configurations, we were able to spatially control the degree and direction of fiber alignment. Second, post-electrospinning photoconjugation was used to create gradients in fiber chemistry. To mimic the mineralization gradient present in the tendon-bone interface, we conjugated a calcium-binding peptide to the fibrous scaffold. Following incubation in simulated body fluid, mineralization selectively occurred only in areas where the calcium-binding peptide was present. Combined, these two techniques provide precise spatial control over fiber alignment and mineralization to create dual gradient fibrous scaffolds that mimic the tendon-bone interface.