A major focus for the lab is the development of implantable devices that are more effective, and with lower exclusion criteria, than those currently available for cardiovascular diseases. Our approach is to design and fabricate devices that are highly conformable to the anatomy of a patient by one or both of these methods: i) Patient-specific design, which uses CT imaging and 3D printing to design devices with geometries that match that of the target anatomy; and, ii) Elastomeric materials, which enable devices to be highly conformable to the irregular structure of the patient's anatomy. Since our approach uses unconventional manufacturing and deployment methods, the lab also develops novel methods to prevent device thrombosis, and aid in the alignment of these asymmetric devices during transcatheter delivery. Many of the ongoing projects utilize principles from the enabling technologies listed below.
Soft robots use the non-linear properties of elastomers to perform sophisticated tasks that would otherwise be impossible or very complex and expensive to do with traditional hard robotic components. The use of these “smart” materials allows the fabrication of robotic systems with fewer auxiliary sensors and feedback loops. One class of soft robotic actuators are elastomeric structures powered by pressurized fluids. These soft fluid-actuators are of particular interest for biomedical applications because they are lightweight, distribute forces easily, inexpensive, easily fabricated, and can provide non-linear motion with simple inputs. We believe soft robotics will have a significant impact in surgical tools, implantable devices, and rehabilitation therapy.
Microfluidics is a technology that enables precise spatial and temporal control over small volumes of fluids, and displays unique behaviors not seen in macro-scale systems. Self-contained microfluidic devices (i.e., lab-on-a-chip technology) allow for sophisticated processing of biological fluids for diagnostic and therapeutic applications. Our lab aims to develop novel microfluidic devices with embedded fluidic controls that enable true lab-on-a-chip devices by eliminating the need for off-chip control systems. These devices will utilize a novel design concept, referred to as integrated microfluidic circuits (IMC), which are networks of elastomeric valves that provide self-control of the timing of fluidic switching within the device, reminiscent of integrated circuits for electronic devices. The IMC technology will be useful for many applications of microfluidics, including combinatorial chemistry, point-of-care diagnostics, organs-on-chip cell culture, and other biomedical applications. In addition, this technology is applicable to other fields using fluidic actuation, such as soft robotics, medical/surgical tools, and energy harvesting systems.
3D Cell Culture
Our lab aims to develop novel 3D culture systems that recapitulate cues from the microenvironment of tissues, in a form factor that allows for easy analysis and control of the system parameters. Our lab will use both microfluidic technologies and a novel multi-layer stacking system to achieve these goals. The multi-layered stacking system is a paper-based technology, which utilizes the inherent properties of paper—wicking of liquids and stacking of sheets. The wicking property allows hydrogel solutions containing cells to be positioned within the thickness (~40-200 µm) of a sheet of paper. The stackability of paper allows layer-by-layer construction of thick constructs at the resolution of the thickness of each layer. The cells within these constructs are able to communicate, migrate, and remodel the ECM in a manner that captures the 3D environment of tissues in the body. Furthermore, the construct can be separated back into its individual layers, allowing for easy isolation and analysis of living subpopulations of cells; typical procedures for analysis of thick tissues require complicated procedures that include killing the cells for analysis. This system is particularly useful for creating nutrient-specific (i.e., oxygen and glucose) gradients, to mimic pathological conditions such as ischemia in tumors and cardiac tissue. Additionally, this system allows easy isolation of cells within particular regions of the stack; a capability that enables the use of cells in these systems for cell therapies and diagnostics (e.g., cancer stem cells, directing stem cell differentiation, and screening for pharmaceutical drugs).