Wound Healing Faculty Research Interests Dr. Gang Cheng Dr. Cheng’s lab focuses on designing and developing materials to address some key challenges in biomedical and biotech applications. The lab is interested in developing self-­‐
renewing antimicrobial coatings without microbes remaining on the coated surface using an integrated antimicrobial and nonfouling strategy. Microbial adhesion onto surfaces and subsequent formation of biofilm are critical issues for many biomedical and engineering applications. Antimicrobial coatings and non-­‐fouling coatings are two separate strategies to prevent the attachment and spreading of microorganisms onto implantable material surfaces. The major limitation of antimicrobial coatings is the continued attachment of dead microorganisms on antimicrobial coatings, which can trigger an immune response and inflammation, and block its antimicrobial functional groups. In addition, such antimicrobial coatings cannot fulfill the requirements of non-­‐fouling and biocompatibility as implantable biomaterials. Although non-­‐fouling zwitterionic coatings can reduce initial attachment and delay colonization of microbes on surfaces, there is a possibility of introducing pathogenic microbes into the patient during implantation operations and catheter insertions, resulting in the failure of implanted devices. It will be necessary to use antimicrobial agents to eliminate these microbes. Surface-­‐responsive materials have been developed for a broad spectrum of applications, but it is still a great challenge to develop materials bearing both antimicrobial and non-­‐fouling/biocompatibility capabilities. Dr. Alamgir Karim The Karim lab is interested in translating the nanotopology of polymer blends films into 3D tissue scaffolding. There is an abundance of information on how cells grow and proliferate on flat, film-­‐like surfaces. Many tissue engineering optimization trials are conducted on such 2D polymer surfaces because of the ease of fabrication and availability of analytical tools. However, it is uncertain if these 2D models provide accurate data for cell growth in more physiologically applicable 3D environments of scaffold materials. In addition, methods of 2D film preparation vary significantly from preparations of three-­‐dimensional constructs. It has been shown that the phase separation process of polymer blends induces nanotopology into the films on a roughness scale comparable to biological environment that promotes cell growth. However, the fragile 3D constructs are very difficult to analyze, thus the Karim lab developed and analyzed 2.5D constructs as approximation of the 3D scaffolds that allow surface evaluation. Three dimensions in scaffold design AFM scans of films surface prepared from biocompatible polymer blend system. Top row: height 3D representations. Bottom row: phase images Dr. Nic Leipzig The Leipzig lab is interested in the microenvironmental cues that modulate stem cell function and incorporating them into engineered systems. We are specifically studying how these cues can affect adult stem cell proliferation, adhesion, migration and differentiation. The lab is currently studying how biomaterial-­‐based scaffolds can be used for regenerative medicine with a focus on the nervous system and wound healing. A main specialty of our group is covalent immobilization of molecules to guide cell function. This includes growth factors (to control differentiation), guidance molecules (to steer axons, see below) and fluorocarbons (to modify local oxygen levels). Dr. Lingyun Liu The major research interests of the Liu lab are in the areas of biomolecular interfaces, biomaterials/tissue engineering, and biosensors. Biomolecular interfaces drive most biological processes both in vitro and in vivo. For example, they will determine the fate of implanted biomaterials and the limit of surface-­‐based detections. The development of nonfouling materials and surfaces is critical to many biomedical applications, such as biomaterials, tissue scaffolds, drug delivery carriers and biosensors. For example, a very low amount, at the scale of 1 ng/cm2, of protein adsorption to the synthetic blood vessel could lead to the platelet adhesion and accumulation, thrombosis, and therefore failure of the device. Several newly developed non-­‐fouling polymers are under investigation for their resistance to protein adsorption and cell adhesion. The goal is to develop tissue scaffolds and drug delivery carriers based on the novel nonfouling materials. Dr. Robert Weiss Wettability of surfaces plays an important role in many biological and industrial applications. Non-­‐wettable surfaces have important applications, for example in self-­‐
cleaning, anti-­‐sticking, stain resistance and anti-­‐contamination surfaces in technologies such as biomedical, transportation, textiles, electronics and coatings. The Weiss lab recently discovered a facile method for introducing nano-­‐ and micro-­‐scale roughness during the manufacture of thin polymer films. The goal of this research is to understand the mechanism of the roughness formation, which is thought to be a spinodal decomposition of the surface during solvent evaporation. The research involves experimental, theoretical, and computational components. Applications of this work that are being separately studied include manufacturing methods of forming superhydrophobic surfaces by solvent casting and the development of scaffolds for tissue engineering. Dr. Bi-­‐min Zhang Newby Dr. Zhang Newby’s lab is exploring both applied and fundamental research in the areas of surface modification, interfacial phenomena, and polymer thin films. One project involves biomaterial scaffolds for deep wound repairs. Deep wounds such as myocardial infarction are very different from superficial wounds. Deep wound repair requires delivery of cells deep into the wound to promote healing at all depths. In order to provide minimally invasive delivery of functional cells and retain the cells on the specific location, the group intends to devise aligned cells grown on microribbons/microtubular scaffolds. The currently unknown issues of what type of scaffold and/or matrix and/or biomaterial that will help retain cells and maintain their functionality will be investigated. Some basic minimally invasive delivery approaches (e.g. injection) will also be evaluated. Another project in the Zhang Newby lab involves preventing the formation of surgical adhesions. These adhesions, especially pelvic adhesions, represent a significant, costly morbidity typically expressed as pain and infertility in the patient. Availability of a reliable method to decrease occurrence of adhesions would constitute a beneficial advance in current surgical practice. However, the efficacy and utility in both open and laparoscopic surgery of currently approved standard adhesion barriers is limited. The goal of the proposed project is a delivery system that allows an initial burst of the anti-­‐adhesion agent, zosteric acid (ZA), followed by a sustained release of the agent. Zosteric acid, a natural product extracted from eelgrass Zostera Marina, shows an extremely low toxicity but effectiveness in preventing adhesion formation of various organisms. It will be directly integrated, along with its nanoparticle-­‐encapsulated form, into a thermo-­‐reversible gel made of Pluronic® F-­‐127 and Hydroxyl propyl methyl cellulose, which can then be easily applied in both open and laparoscopic surgeries to prevent adhesion development. Dr. Jie Zheng Superlow-­‐ or non-­‐fouling biomaterials (i.e. surface resistance to nonspecific protein adsorption) are very important for biomedical applications such as implanted devices, coating for drug carriers, and biomaterials and biosensors. The Zheng lab synthesized and characterized a series of polymethacrylate-­‐based brushes (polyHPMA, polyHEMA, and polyHEAA). Under optimal surface packing density and film thickness, all these polymer brushes exhibit high resistance to nonspecific protein adsorption from undiluted blood plasma and serum (< 5 ng/cm2), cell attachments, and bacterial adhesion in long incubation time.