Stephen Sloan Receives a TL1 Training Award

Stephen received a TL1 Training Award from Cornell’s Clinical and Translational Science Center for the proposal titled “Repair Strategies for Treating Intervertebral Disc Degeneration.” The goal of the TL1 Training Award is to support career development among pre- and early post-doctoral trainees by providing advanced degree training and practical skills to conduct translational team research across disciplines and institutions. Congrats, Stephen!

Stephen Sloan Publishes an Article in Tissue Engineering, Part B

Stephen published an article entitled Biologic Annulus Fibrosus Repair: A Review of Preclinical In Vivo Investigations in Tissue Engineering, Part B.

Lower back pain, the leading cause of workplace absences and disability, is often attributed to intervertebral disc (IVD) degeneration in which nucleus pulposus (NP) herniates through lesions in the annulus fibrosus (AF) and impinges on the spinal cord and surrounding nerves. Surgeons remove extruded NP via discectomy when indicated by local/radicular pain supported by radiographic evidence, however current interventions do not alter the underlying disease or seal the AF. The reported rates of recurrent herniation or pain following discectomy cases range from 5-25%, which has pushed spine research in recent years towards annular repair and closure strategies.  Synthetic implants designed to mechanically seal the AF have been subject to large animal and clinical trials, with limited success in preventing recurrent herniation. Like gold standard interventions, purely mechanical devices fail to promote tissue integration, long term healing, or restore native biomechanical function to the spine. Biological repair strategies utilizing principles of tissue engineering have demonstrated success in overcoming the inadequacies of current interventions and mechanical implants, yet none have reached clinical or proof-of-concept trials in humans. In this review, we will discuss annular repair strategies promoting biological healing that have been implemented in small and large animal models in vivo, and ways to enhance the efficacy of these treatments.

Rebecca Irwin Receives the GAANN Fellowship

Rebecca Irwin was awarded a Gradaute Assistance in Areas of National Need (GAANN) fellowship. Cornell received the GAANN grant from the US department of Education and provides funding for multi-scale biomedical engineering. The focus of the GAANN program is to train US students to conduct research and teaching in biomedical engineering that will satisfy the increased demands for biomedical engineers who can make explicit and quantitative connections between phenomenon occurring at different scales and use that information to improve human health.

Jill Middendorf Publishes a Paper in the Journal of Biomechanics

Tissue engineered cartilage has been implanted into the knees of hundreds of people to fix articular cartilage defects. These implants increase joint function and reduce pain. To understand why these implants improve joint function, many researchers examine the mechanical properties of tissue engineered cartilage. The initial cell seeded scaffold contributes significantly to the mechanics of the implant. As the implant grows the cells produce more matrix which changes the mechanical properties. However, this matrix deposition is heterogeneous and the local mechanical properties do not change uniformly. Therefore, this paper examined changes in the microscale mechanical properties that occur due to increased matrix deposition in human tissue engineered cartilage. Like many engineered cartilage implants, these implants begin as a 3D scaffold prone to buckling at low strains. As matrix is deposited on the scaffold, the implants show resistance to buckling. This study suggests the importance of in vitro culture of constructs prior to implantation to prevent microscale scaffold buckling.

Alexander Boys and Mary Clare McCorry Publish an Article in MRS Communications

Alexander Boys and Mary Clare McCorry published an article in MRS Communications.

Next generation tissue engineering of orthopedic soft tissue-to-bone interfaces 

This article reviews current strategies for tissue engineering soft tissue-to-bone interfaces, specifically the enthesis of tendons, ligaments, and the meniscus. The tissue engineering process is broken down into three sections: Materials processing methods, Cellular contributions, and Biochemical factors. These processes can be concurrently applied to produce a tissue engineered construct. Such a construct then undergoes maturation by stimulation through mechanical and chemical means before developing into an implantable construct. The review culminates in an outline of future challenges for the interfacial tissue engineering field.

Bonassar Lab Travels to the 2017 BMES Annual Meeting

The Bonassar lab is traveling to the 2017 BMES Annual Meeting in Phoenix, Arizona. We will be presenting four abstracts. See below for details:
Jorge Santiago is presenting Total Cervical Disc Replacement with Tissue-Engineered Intervertebral Discs Assisted by Resorbable Stabilization System in a Canine Spine Model on Thursday, October 12 at 8:15AM
Ben Cohen is presenting Extensively Passaged Human Auricular Chondrocytes Retain the Capacity to Generate Auricular Cartilage In Vivo on Thursday, October 12 at 3:45PM
In collaboration with Dr. Jason Spector, work from Ben Cohen and Dr. Bonassar will be presented Custom 3D-Printed External Biocompatible Cage Mitigates Contraction During Maturation of Human Auricular Cartilage Scaffolds on Thursday, October 12 at 4:15PM
Stephen Sloan is presenting Cell-Laden Annulus Fibrosus Repair in an In Vivo Ovine Lumbar Spine Model on Thursday, October 12 at 4:15PM

Stephen Sloan Publishes an Article in Acta Biomaterialia

Stephen Sloan recently published an article in the journal Acta Biomaterialia entitled: Initial Investigation of Individual and Combined Annulus Fibrosus and Nucleus Pulposus Repair Ex Vivo.


Intervertebral disc degeneration affects an estimated 90% of individuals throughout their life, and is a candidate pathology for tissue engineered repair. The current standard of clinical care reduces spinal articulation and leads to further degeneration along the spine, hence great interest in a regenerative medicine therapy. Lit- erature studies focused on biomaterial repair strategies for treating degenerated discs have partially restored native disc function, however no studies have reported the use of combined therapies to address multiple aspects of disc degeneration. This initial investigation screened injectable biomaterial repair strategies ex vivo, and through complementary outcome measures showed a combined therapy restores disc function better than individual approaches. This study is the first of its kind to address multiple aspects of disc degeneration, using clinically-oriented biomaterials in a well-established animal model.

Nicole Diamantides Publishes a Paper in Biofabrication

Nicole Diamantides published a paper in Biofabrication entitled, Correlating rheological properties and printability of collagen bioinks: the effects of riboflavin photocrosslinking and pH.

Collagen has shown promise as a bioink for extrusion-based bioprinting, but further development of new collagen bioink formulations is necessary to improve their printability. The goal of this work was to determine the effects of riboflavin photocrosslinking and pH on collagen bioink rheology before, during, and after gelation and directly correlate these findings to the printability of each bioink formulation.  We found that riboflavin photocrosslinking and pH levels above physiologic resulted in improved collagen bioink printability and that printability was most strongly correlated with rheological properties of the bioink during extrusion.  These findings will allow for the more rapid screening of new collagen bioink formulations.