Three-Dimensional Biomaterials with Spatiotemporal Control for Regenerative Tissue Engineering.

Abstract

At Morehouse College, one of the nation's top liberal arts historically black colleges and universities (HBCU) for African American men, research experiences are used to enhance the liberal arts educational experience. Securing research funding to train HBCU students is highly competitive and challenging due to the review process that is typically vetted by scientists from research-intensive universities who may not be familiar with the HBCU enterprise that may be comprised of insolvent infrastructures. In this Account, the synthesis and preparation of synthetic polymeric biomaterials that are used to facilitate or support changes in biological processes, enhance mechanical properties, and foster tissue growth in three dimensions (3D) under disease conditions will be discussed. The use of biomaterials to help control biological processes in disease states is limited. Hence, the fabrication of 3D scaffolds with chemical variability to grow or repair damaged tissues by inhibiting molecular pathways shows promise by controlling the cellular response to recapitulate 3D tissues and organs. The Mendenhall laboratory at Morehouse College uses 3D biomaterials to solve biological problems by probing cellular mechanistic pathways using natural products and nanoparticles. Toward this end, we have fabricated and manufactured 3D biomaterial scaffolds using chemical strategies to mitigate biological processes to help restore pristine tissue properties. Hydrogels are 3D polymeric matrixes that swell in aqueous environments and support cell growth that later infuriates the 3D matrix to create new tissue(s). In contrast, electrospun fibers use high electric fields to create porous 3D polymeric structures that can be used to create 3D tissue molds.The synergistic use of 3D biomaterial templates that can inhibit cellular damage while providing a mechanically strong scaffold to support regenerative tissue growth is essential to creating the next generation of biomaterials. This approach will require foresight using tools from synthetic biology, molecular biology, autonomous processes, advanced biomanufacturing, and machine learning (ML). The use of several biomaterials has been explored by the Mendenhall laboratory to design, prepare, fabricate, characterize, and evaluate 3D electrospun fibers and hydrogels containing hybrid compositions of polylactic acid (PLA), poly(n-vinylcaprolactam) (PVCL), cellulose acetate (CA), and methacrylated hyaluronic acid (meHA). This work contributed to the newly fabricated PVCL-CA fibers with morphological changes and nanoscale fiber hydrophobic surface properties. While the use of electrospun fibers can create hierarchal scaffolds for bone tissue engineering, the use of injectable gels for nonporous tissues such as articular cartilage presents another compelling biomaterial challenge. Using graft polymerization, we prepared PVLC-graft-HA and studied the effect of lower critical solution temperatures (LCSTs), gelation temperatures, and mechanical properties using temperature-controlled rheology. Additionally, we reported that articular cartilage (chondrocyte) cells seeded in PVCL-g-HA gels and incubated at hypoxia 1% O2 produced a 10-fold increase in extracellular matrix proteins (collagen) after 10 days. This work supported exploring new approaches to protecting chondrocyte cells under hypoxia using a 3D scaffold technology.