‘MAP’ping Microfluidic Devices Used for MAP Hydrogel Fabrication with Computational Fluid Dynamics Simulation

Microporous annealed particle (MAP) gel is a specific type of hydrogel with a capability to provide cellular channels for migration and integration with surrounding tissues1. The desirable functionality of MAP gel is made possible with microfluidic devices that produce particles of uniform size and shape. The differentiation in particle size affects the stiffness and porosity of the gel; components important for robust tissue regeneration2. The current design for step emulsification devices with channels smaller than 5um result in nonuniform particle size due to issues with fluid dynamics and pressure. The downstream negative effects of this are potentially a lack of biocompatibility and enhanced foreign body response in vivo. The primary objective of the capstone study is to identify issues associated with fluid movement with small channel size devices in order to propose design modifications for a novel device that improves the uniformity of particle sizes and effectiveness of MAP gels by ensuring consistent physicochemical properties. The study had two specific aims: (1) to identify fluid pressure issues that create non-uniform MAP gel particle sizes in the current design of microfluidic devices for MAP gel synthesis, and (2) to create a more effective novel microfluidic device design that improves device capability for optimal MAP gel production. The 19.7 and 5.6um versions of the device were recreated in CAD and simulated in COMSOL Multiphysics software to identify velocity and pressure profiles. The 5.6um channel device exhibited higher overall velocity compared to the 19.7um device, but experienced increased pressure in aqueous passages. Proposed device modifications included elongation of channels to decrease velocity and changes in geometry of the aqueous passages to decrease overall pressure. Future work includes further simulations to better understand the relationship these parameters have in MAP gel quality and later development of a novel device.

Keywords: Microporous annealed particle gel, microfluidic devices, particle size, simulation, physicochemical properties