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Development of Flexible Microsystems for Bacterial Biofilm Management


Bacterial biofilms, a major cause of infection and environmental biofouling, are difficult to remove and contribute to the rapid increase in antibiotic-resistant bacterial strains. They often induce catastrophic consequences in an array of inaccessible environments with complex curved geometries, ultimately leading to persistent infections, implant failure, and systemic contamination. There is demand for viable methods to detect, prevent, and remove biofilms in locales including urinary catheters, prosthetic implants, and water systems, where currently effective methods do not exist to detect and eradicate biofilms. Advances in flexible device technology yield opportunities for feedback-driven biofilm management systems for operation in these vulnerable areas. The objective is to develop a paradigm enabling dynamic flexible sensor microsystems for detecting, monitoring, and inhibiting biofilms on multidimensional surfaces, in particular the cylindrical environment of a urinary catheter. The surface bacterial species, fluid conditions, and geometry are the basis for this approach, creating a guide for identifying methods of biofilm detection and prevention on demand. Successful monitoring and removal of biofilm will have a dramatic impact, improving quality of life for people of all demographics. These systems have the potential to reduce the spread of antibiotic-resistant and healthcare-acquired infections, and are particularly attractive for addressing these challenges in resource-poor regions. Moreover, the potential for low-cost manufacturing of these devices will enable their inclusion by high school teachers into laboratory-based STEM curricula.<br/><br/>To systematically develop this methodology, the objective of this proposal is divided into three tasks: 1) Optimization of microsystems for sensing and inhibiting biofilms in complex, 3D environments: Thin film electrodes will be selected as a simple and sensitive electrochemical impedance sensor, tested in a microfluidic system as a sensor and biofilm inhibitor via the bioelectric effect. Furthermore, the device will be optimized for biofilm detection via a computational model. The model will examine changes in the electric field of the sensor for the relevant geometry. 2) Manufacturing of integrated flexible devices for biofilms: appropriate materials and fabrication processes are determined by specific geometric and environmental requirements of each application, notably flexible substrates, such as polyimide, with gold as an inert electrode material. The flexible substrates will enable folding and scaling of the device as required to interface with the vulnerable complex curved surface. 3) Device testing using environmental model with data transmission and feedback control: A urinary catheter will serve as a test case. This will be developed considering the unique geometric, bacterial, and fluidic conditions. 3D-printed structures precisely recreate geometry interactions with biofilm, where sensor response and bioelectric treatment will be evaluated simultaneously. A wireless controlled (using Bluetooth or Wifi) electronic system will be developed to operate the impedance sensor and control the biofilm removal using the electrodes will be developed. Feedback-driven dynamic biofilm control will be developed, considering threshold impedance sensing values corresponding to biofilm biomass. The system will introduce a bioelectric effect treatment based on impedance sensor data indicating the formation of a biofilm in real-time. This project addresses the challenge of preventing, identifying, and removing biofilms on a complex surface. An interdisciplinary approach combining applied microbiology and engineering disciplines is required to overcome these problems. Complex interactions between flexible sensors, bacterial biofilms, and bioelectric treatment will be explored. Electrical reduction of biofilm enables remote programmability in vulnerable systems. The impact on system design of key parameters including bacterial species, surface geometry, and fluidic conditions will be clearly enumerated. The fundamental methodology developed here will enable further research to address biofilm monitoring and removal in areas of dire need.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Reza Ghodssi; William Bentley
University of Maryland - College Park
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