(12ad) Bacterial Biofilms: From the Built Environment to Human Diseases

Research Interests: Biofilms are communities of sessile microorganisms ubiquitously found in both natural and built environments, as well as numerous hosts including human. This mode of growth is preferred by bacteria for surviving in challenging environments because the unique structure of biofilms (e.g., extracellular polymeric substrates (EPS)) provide embedded bacteria with protection from harsh environmental factors such as antimicrobials. The enhanced resistance of biofilms against biocidal agents compared to free swimming bacteria (up to 1000 fold) is one of the leading causes of chronic infections in human and persistent biofouling in industrial settings. Although biofilm formation has become an important research topic in the past two decades, there is still a gap between fundamental knowledge obtained from experimental studies focusing on mono- or dual-species biofilms formed under controllable conditions and environmental studies based on multi-species biofilms in natural environments. This gap has severely hindered the mechanistic understanding of biofilm formation and the role of biofilms in human diseases, as well as the development of surfaces for biofilm prevention and removal. To control bacterial biofilms for public health, there is an urgent need to bridge the gap between experimental and environmental studies on biofilm formation and develop â??smartâ?? antifouling surfaces.

Motivated by the significance of biofilms, I set my long-term career goal to control biofilm formation through interdisciplinary research and teaching. To prepare for my career, I pursued my Ph.D. work with a focus on biofilm control using chemically modified surfaces to direct bacterial adhesion. This well-defined surface system was used to study biofilm formation and the development of biofilm-related high antibiotic resistance. The obtained results together with the effects of surface topography on bacterial adhesion were used to engineer â??smartâ?? antifouling surfaces via topographic surface modification. Engineering surface topography is a promising approach for biofilm control because it does not involve biocidal agents, and thus avoids the problem of antibiotic resistance. With my long-term goal to develop an academic career in the field of bacterial control, I extended my postdoctoral research to study biofilm formation and biofilm-associated high drug tolerance in built environments. People on average spend 90% of their time indoors. Surfaces in indoor environments such as air condition systems are all susceptible to colonization by microorganisms growing in biofilms, thus, it is critical to understand the physiology and virulence of biofilms formed by bacterial pathogens in the built environment, especially, in the hospital environment. Therefore, my postdoctoral research focuses on understanding the effects of environmental factors on bacterial biofilm formation and antibiotic resistance, so that the built environment can be better engineered for antifouling purposes. A well-defined surface system for studying the role of synergistic interaction between multispecies bacteria in biofilm formation and biofilm antibiotic resistance was also developed. The obtained results can help fill the gap between experimental and environmental studies on biofilm formation and design antifouling surfaces with enhanced and prolonged antifouling effects for environmental and medical applications.

In my faculty position, I plan to use my knowledge and skills of microbiology, engineering, material science, and chemistry to understand biofilm formation in built environments and the role of biofilms in environmental acquired chronic infections, especially those related to nosocomial infections. My doctoral and postdoctoral training has prepared me for building a successful independent research program that will make major contributions to the understanding and control of biofilms. Specifically, I will identify the microbial composition in biofilms formed in built environments and humans, as well as the transportation of microbes from environments to humans through human activities by following the â??footprintsâ?? of microbes. Meanwhile, the interaction between microbes from different species in the survival of surface attached communities under harsh environments is also a significant and interesting question to study. I also want to understand how biofilm pathogen and host interactions affect biofilm formation and biofilm antibiotic resistance in humans.

The results of environmental, in vitro, or in vivo studies can allow my research group to have a more comprehensive understanding of the role of biofilms in the transportation of bacterial pathogens from built environments to humans and inspire novel and ecofriendly strategies for biofilm control to effectively interrupt this process. The results of these studies can inform future epidemiological work on cystic fibrosis and microbial exposures in vulnerable populations such as patients with compromised immunity and bedridden elderly, as well as inform local or domestic health departments on the microbial composition in biofilms formed in built environments. Additionally, given the interdisciplinary nature of biofilm research and strong medical relevance, there are exciting opportunities to build collaboration with other fields, such as biostatistics, microbiology, architecture science/engineering, ecology and evolution, and immunology to pursue large multidisciplinary grants. Results from these studies also have the potential to inform industry stakeholders in the development of innovative antifouling products. Beyond research studies, the biofilm related problems are also suitable for integrating into engineering courses and for outreach with local K-12 students and teachers to promote STEM education and talent development.

Teaching Interests: With training in Chemical Engineering, I am comfortable to teach all core courses in this discipline and I am interested in developing new courses related to nano- or micro- techniques for cell manipulation, microbes and human life, and techniques for exploring cell microenvironments.