Research

Wound Healing

Wound healing is a complex tissue regeneration process that promotes the growth of new tissue to provide the body with the necessary barrier from the outside environment. In the class of non-healing wounds, diabetic wounds, and ulcers, dressing materials that are available clinically (e.g., gels and creams) have demonstrated only a slow improvement with current available technologies. Among all available current technologies, electrospun fibers exhibit several characteristics that may provide novel replacement dressing materials for the above-mentioned wounds. In addition, recent achievements in electrospun fibers allowed the incorporation of small molecule drugs, proteins and peptides, and gene vectors for wound healing applications. Furthermore, electrospun fibers provide an opportunity for multifunctional dressing materials, including those that are capable of achieving wound debridement and wound healing simultaneously as well as multi-drugs loading/types suitable for various stages of the healing process. Our goal is to design and develop advanced dressing materials from fibers to improve clinical treatment of non-healing wounds.

Polycaprolactone fibers made in Chou Biomaterials Lab. Scale bar = 10 um.

Thrombosis

Advances in nanotechnology and nanomaterials have enabled the development of functional biomaterials with surface properties that reduce the rate of the device rejection in injectable and implantable biomaterials. In addition, the surface of biomaterials can be functionalized with macromolecules for stimuli-responsive purposes to improve the efficacy and effectiveness in drug release applications. Furthermore, macromolecule-grafted surfaces exhibit a hierarchical nanostructure that mimics nanotextured surfaces for the promotion of cellular responses in tissue engineering. Owing to these unique properties, our research focuses on the grafting of macromolecules on the surfaces of various biomaterials (e.g., films, fibers, hydrogels, and etc.) to create nanostructure-enabled and macromolecule-grafted surfaces for biomedical applications, such as thrombosis prevention and wound healing. The macromolecule-modified surfaces can be treated as a functional device that either passively inhibits adverse effects from injectable and implantable devices or actively delivers biological agents that are locally based on proper stimulation. Our goal is to provide scientific understanding on nanostructure-enabled and macromolecule-grafted surfaces for biomedical applications.

Injectable and implantable biomedical device and their surface functionalization.

Porous Tissue Scaffolds

Porous scaffolds have potentials in low load-bearing applications as biomedical implants. These scaffolds, made from biocompatible and biodegradable polymers, are advantageous to provide structural support to the surrounding tissues, encapsulate and deliver agents (e.g., anti-inflammatory drugs or growth factors), and guide cell growth. Among all possible methods that are suitable for making porous scaffolds, freeze-drying is a powerful and versatile manufacturing route. It utilizes the growth of ice crystals to pattern the internal structure of a scaffold. The pore shape, size, and distribution allow the tunability of materials properties through freeze rates. To develop biomedical implants with anti-inflammatory responses, scaffolds are loaded with small molecule drugs (typically hydrophilic). Mechanics of the drug-loaded scaffolds is likely to decrease with increasing drug loading due to plasticizing effect. In addition, drug release rates dictate the level of losses in scaffolds mechanical properties. Our goal is to make specific observations on changes of scaffolds mechanical properties and drug release rates due to structural factor of the scaffold and drug loading.

10 wt% chitosan scaffold made in Chou Biomaterials Lab. Scale bar = 600 um.

Traumatic Brain Injury - Sleep Disorder - Gait Change

Traumatic brain injury (TBI) is one of the major health concerns among athletes, where types of head impacts determine stress distribution and deceleration in brain for potential development of TBI. An estimated number of 1.6 to 3.8 million sports-related TBI occurs annually in the US. Among them, collegiate athletes are the most vulnerable group to receive TBI due to the competitiveness of the sports (some may turn professional), lack of information/education on TBI prevention, and peer influence on their social and classroom life.

Empirical evidences show that athletes suffered from TBI are likely to experience symptoms in sleep disturbances and deterioration in lower extremity gaits. Sleep disturbances slow the recovery process of TBI patients. Mental distress is prevalent after TBI, which can further induce sleep disturbances. In addition, whether or not the TBI athletes develop sleep disturbances, they tend to exhibit an increased stiffness in their lower body extremity resulting in gait changes. Yet, the contributing factor of sleep disturbance on gait changes of TBI athletes is unknown.

We aim to establish a TBI gait database to further inform the rehabilitation process and the health of the athletes. Our findings will allow us to correlate sleep pattern and quality of student athletes with the TBI gait database to promote the health of athletes.

Simulation data on head impact and gait changes on control subjects (no TBI history).

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