The Wei Laboratory

Research

Overview

The Wei laboratory emphasizes the integration of current engineering science with emerging fields of engineering applications and processes. Our research focuses on the development of novel biomaterials for tissue repair and regeneration. Due to the nature of our research, students work on multidisciplinary, team-based research projects, which involve scientists from disciplines including Materials Science, Polymer Science, Biology, Animal Science, Computer Science as well as Industry Partners.

Current Projects

1. Fabrication of novel tissue engineering scaffolds for osteochondral repair
   In a high percentage of patients, damages to the articular cartilage surface and the underlying subchondral bone can easily progress to joint degeneration, especially osteoarthritis, which is the leading cause of disability in the United States. To help the disabled patients to resume their lost activities, extensive efforts have been made in osteochondral defect treatment, but there is still no widely accepted method which produces consistent, satisfactory results. The long-term aim of the current project is to use the newly emerging tissue engineering approach to generate articular cartilage with excellent functionality and long-term stability. The specific aim of the project is to use a combination of our novel graded tissue engineering scaffold and articular-specific chondrocytes to generate articular cartilage. (Funded by NSF)
2. Dense apatite-polymer fiber absorbable composites for medium- and high-load bearing skeletal applications:
   The objective of this project is to achieve a fundamental understanding of the effect of apatite/fibrous polymer composite constructions on the mechanical properties, degradation rate and bone formation rate of the material. In the last two decades, there has been tremendous interest in the fabrication of apatite/polymer composites. Such composites have stable bone/implant interfaces, excellent biocompatibility, and low risk of stress-shielding. Despite the success in apatite/polymer composite studies, the existing composites have relatively poor mechanical properties, which restrict their use in many applications, such as a skeletal implant in load-bearing situations. Rational materials design and precise engineering of the composites are becoming increasingly important in the development of a new generation of materials for broader orthopedic applications. (Funded by NSF)
3. Establishment of in vivo time-lapsed imaging platform for in situ visualization of cell-scaffold interplay during dynamic new bone formation and remodeling
   Tissue engineering of skeletal tissue is rapidly approaching the stage for human application despite the fact that rigorous preclinical testing aimed at understanding the cellular and environmental determinants of success or failure has not been developed. Traditional histological and molecular markers of tissue formation do not indicate the degree of bone formation. However, knowledge of the proliferative and migratory properties of the progenitor cells that invest the scaffold and the relative host and donor contribution to the repair are generally not appreciated. This information is extremely important and to a great extend determines the final outcome of bone tissue engineering. Thus, the primary objective of this project is to establish an in vivo assessment platform to visualize the real-time cell/scaffold/new bone interplay (4D) at a mouse calvarial site using two-photon microscopy. (Funded by NIH)
4. Biomimetic apatite and apatite/collagen coatings for bone repair and drug delivery:
   Over 10 million Americans are currently carrying at least one major implanted medical device in their body.  More than forty percent involves the use of metallic implants. Especially, Ti and Ti alloys have been widely used in orthopedic and dental applications due to their superior mechanical properties and good biocompatibility. Unfortunately, nearly all metallic implants are bioinert, so they are consequently not osteoconductive leading to no surface continuity.  Therefore, there is a pressing need to identify a coating system with excellent osteoconductivity, strong bonding to the metal substrate, good cell signaling property on the surface, and capable of carrying drugs or proteins to simulate bone formation. Thus, the aim of this project is to produce gradient bioactive apatite and apatite/collagen coatings which have a dense structure adjacent to the substrate to facilitate a strong bond and a porous surface to enhance cell attachment and new bone ingrowth. These coatings can also be used as a carrier for controlled release of drugs and growth factors. (Funded by NSF and Teleflex Medical Inc.)
5. 3D Bioprinting of alginate hydrogels for bone tissue regeneration
   The practice of individualized medicine has recently shaped the progression of leading research and innovative technology in the field of bone tissue engineering. Specifically, 3D printing of versatile biomaterials, such as hydrogels, has recently been implemented to produce tissue substitutes as allows for a repaired model of damaged tissue to be constructed from a patient’s CT scan or MRI and printed within 24 hours. Thus, the patient can receive an individualized, biocompatible tissue that is of the identical size and geometry which can support incorporation of the patient’s own cells to better promote healing and acceptance in vivo. Hydrogel systems have a great capacity for encapsulating cells and supporting cell life as the structural network comprised of mostly water closely resembles that of the natural extracellular matrix. Alginate hydrogels are ideal candidates for 3D printing as its gelation rate can be easily controlled , thereby enabling the materials properties to be easily tailored. Additionally,  alginate has been extensively researched as a cell encapsulation medium for 3D printing as its gradual gelation process is gentle and not harmful to cells. Thus, the goal of this project is to develop an alginate hydrogel suitable for 3D bioprinting of MC3T3 cells and capable of promoting proliferation and early signs of bone regeneration in vitro. (Funded by NSF)