Microplate micromilling: A customizable platform to support the prototyping, development and testing of microphysiological culture models

The development of microphysiological cell culture models (MPMs) that align with the throughput demands of drug and chemical testing are needed to help reduce animal testing, aide in the discovery of new drugs, and identify harmful chemical exposures. To address this need, we have developed a process for rapid prototyping MPM devices using computer numerical control (CNC) micromilling of commercially available microplates. Microchannels are cut out of the existing microplate structure and ports are drilled into the bottom of the wells to interface the wells. To test versatility and benchmark to another rapid-prototyping approach, we manufactured common microfluidic features into microplates using four different CNC mills as well as a 3D printer. Cell viability was assessed for polystyrene (PS) well plates and two 3D printed resins (MED610 and VeroClear) with the PS showing >2.5-fold increase in cell growth after three days. Machines were tested on their ability to create common device features including a traditional microfluidic device as well as a custom design incorporating complex geometries. Features were measured by confocal microscopy. We found that features including 1000µm ports, 800µm microchannels, 200µm phase-guides, and 500µm post arrays were machined and the range of CVs for features were 1.02-4.42, 1.32-3.50, 2.34-16.58, 6.25-16.40 respectively, while the 3D printed features exhibited maximal CVs of 20.98, 11.68, 23.60, and 10.01 for the same features. Predictably, more expensive machines generally showed higher accuracy and lower variation, but many features could be created accurately and precisely by inexpensive (<$3000) machines facilitating the broader use of this technology to create a user customizable platform to support the prototyping, development, and testing of human relevant models with broad applications across the life sciences.