Custom Multiwell Plate Design for Rapid Assembly of Photopatterned Hydrogels

The extracellular matrix provides both mechanical support and biochemical cues that influence cellular behavior. Matrix stiffness, in particular, has been found to regulate cellular morphology, motility, proliferation, differentiation, and drug responses among other behaviors. Thus, biomaterial platforms that exhibit wide range of stiffness and are available in a semi high-throughput format such as a multiwell plate would be useful for elucidating cell-substrate relationships. Polyacrylamide (PA) gels have been widely used as cell platforms since they span a range of stiffness between 0.3 and 300 kPa in Young's modulus, which encompasses all soft tissues. However, PA gels are time consuming and labor intensive to prepare, and are not amenable to a multiwell plate format. In this study, we present a novel custom multiwell plate design that allows for a one-step stiffness assay assembly that reduces preparation time and labor intensity by several fold. Gel stiffness is controlled by ultraviolet light intensity and exposure time to achieve a wide stiffness range from a single gel precursor solution. The geometry of the gels is defined by a custom photomask and gel thickness is controlled by spacers. A multiwell plate upper structure is designed similar to a regular multiwell plate such that a gel fits in each well and cells and media are added on top. The upper structure design allows for adequate gas exchange and minimum evaporation. Comparison between cell behaviors seeded in the custom and a standard multiwell plate demonstrated the suitability of the design as a cell culture platform. In summary, we describe and validate a novel custom design for an easy and rapid assembly of photopolymerizable PA-based stiffness assay.