Assistant Professor Duke University Durham, North Carolina, United States
Introduction: Systems in biofilm research are essential to isolate and understand strategies by which biofilms develop recalcitrance and cause pathogenic disease. Many of comorbidities related to biofilm recalcitrance are also correlated with immune dysfunction. Thus, investigation of the immune activity and potential dysfunction surrounding biofilm infection provides itself as an ideal opportunity to better understand the contribution of different comorbidities to biofilm infection and investigate immune dysfunction as a predictor of biofilm production. Current methods for biofilm research often focus on reliability and reproducibility of in vitro biofilm systems that involve biofilm adhesion to abiotic surfaces. However, these models fail to consider signaling phenomena that occur as a result of interactions between biofilms and eukaryotic hosts. These experiments propose an immunocompetent and vascularized full-thickness in vitro cell culture insert, representative of human skin. Increasingly complex models such as those developed and validated in this experiment provide new opportunities to investigate cellular communication and infection progression from biofilm-producing bacteria, revealing the underpinnings of poorly-understood clinical outcomes.
Materials and
Methods: Via 3D printing for the use of consistent vascular structure in a dermal component of a human skin equivalent in vitro, and use of THP-1 monocytes, an immunocompetent and vascularized 3D-printed skin model composed of dermal fibroblasts and keratinocytes will be developed. To validate immunocompetence, ELISA assays are preformed to analyze for IL-6 and IL-8 production in positive controls as well as in the presence of LPS.
Results, Conclusions, and Discussions: Current models in the field of tissue engineering, for the use of identifying response of skin to biofilms are underdeveloped. The existence of heterogenous structures throughout full-thickness skin constitute an environment that has significant importance on bacterial exposure to structures, cell types, and exposure to immune cells. By utilizing immunohistochemistry stains as well as histology stains and ELISA measurements, this study has been able to identify stratification of layers in the epidermal and dermal layers of a human skin equivalent both in the presence of THP-1 monocytes as well as vascularization. Standardization of physical methods to simulate vascular structure allow for direct and consistent observation of xenobiotic exposure and biofilm growth throughout different structures of the epidermis, improving research capability to represent infections in vivo. Furthermore, the standardization of this method through 3D bioprinting also increases throughput, improving the capability to infer on conditions involving immune dysfunction, such as psoriasis, while minimizing cost.
