It is critically important to study head and neck squamous cell carcinoma tumorigenic mechanisms in order to gain a better understanding of tumor development, progression, and treatment. Unfortunately, a representative three-dimensional (3D) model for these evaluations has yet to be developed. The purpose of this study was to replicate tumor extracellular matrix (ECM) morphology utilizing electrospinning technology. First, the tumor ECM was evaluated by decellularizing tumor samples and analyzing the fibrous structure of the ECM by scanning electron microscopy. Cryogenic electrospun silk scaffolds were then fabricated to mimic the tumor ECM, and were found to be similar in fiber orientation and fiber dimensions to the native tumor ECM. Tumor cells were cultured on these ECM mimicking scaffolds and compared to an in vivo model of the same derivative human tumor in terms of proliferation and differentiation. The tumor cells in the 3D model show similar phenotypes to those found in vivo, contrasting to the same cells grown in two-dimensional (2D) culture. The sensitivity of the tumor cells to paclitaxel was compared between 2D culture and 3D culture. The results indicate that increased drug concentrations, orders of magnitude higher than the IC90 for 2D culture, had minimal effects on HN12 cell viability in the 3D model. In conclusion, an in vitro tumor model has been developed that will allow for a better understanding of tumor biology and aid chemotherapeutic drug development and accurate evaluation of drug efficacy.

Regenerative ligament and tendon repair scaffolds have been highly researched, yet few match the mechanical properties of native tissue, while fewer drugs have been explored for enhancing cell infiltration into the damaged tissue. Here a nanofiber scaffold of silk fibroin (SF)-collagen blend is explored as a biologically enhanced matrix, along with a therapeutic agent (bone morphogenetic protein-13, [BMP-13]) for connective tissue regeneration. SF and collagen were blended and electrospun to form fibrous scaffolds with 1.15±0.08 μm diameter fibers. These scaffolds were crosslinked with either methanol or ethanol. Crosslinking with methanol resulted in significantly higher mechanical strength compared to ethanol treated scaffolds (2.92±0.21 MPa versus 1.13±0.08 MPa, respectively). Adipose-derived stem cells showed robust cell attachment and proliferation on SF-collagen scaffolds, with confocal imaging suggesting cellular alignment and spreading. BMP-13 growth factor is further shown to promote cell migration into SF-collagen scaffolds. In all, electrospun SF with telocollagen produces a regenerative matrix with enhanced tensile strength. BMP-13 improves cellular infiltration into electrospun SF-collagen scaffolds and may prove a potent chemotactic agent for enhancing ligament and tendon repair. RECEIVED

Approximately 800, 000 surgical repairs are performed annually in the U.S. for debilitating injuries to ligaments and tendons of the foot, ankle, knee, wrist, elbow and shoulder, presenting a significant healthcare burden. To overcome current treatment shortcomings and advance the treatment of tendon and ligament injuries, we have developed a novel electrospun Tissue ENgineered Device (TEND), comprised of type I collagen and poly(D,L-lactide) (PDLLA) solubilized in a benign solvent, dimethyl sulfoxide (DMSO). TEND fiber alignment, diameter and porosity were engineered to enhance cell infiltration leading to promote tissue integration and functional remodeling while providing biomechanical stability. TEND rapidly adsorbs blood and platelet-rich-plasma (PRP), and gradually releases growth factors over two weeks. TEND further supported cellular alignment and upregulation of tenogenic genes from clinically relevant human stem cells within three days of culture. TEND implanted in a rabbit Achilles tendon injury model showed new in situ tissue generation, maturation, and remodeling of dense, regularly oriented connective tissue in vivo. In all, TEND’s organized microfibers, biological fluid and cell compatibility, strength and biocompatiblility make significant progress towards clinically translating electrospun collagen-based medical devices for improving the clinical outcomes of tendon injuries.

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