PDMS Liquid Mold	Weigh 40 g of the SYLGARD™ 184 elastomer base and 4 g of the SYLGARD™ 184 curing agent on a disposable plastic beaker at 10:1 weight ratio. NOTE: Different amounts of elastomer base can be used while maintaining the 10:1 ratio. The significance of using 40 g of the elastomer base and 4 g of the elastomer curing agent is to cover the entire surface area of the master mold and create a thickness of 5 mm PDMS mold. Use a cleaned glass rod (rinse with acetone and air dry it with compressed air) to thoroughly mix the two elastomers in a circular motion for 3 min, resulting in a completely white and opaque mixture.
PDL Solution	Weigh PDL powder at a ratio of 10 mg PDL per 20 microfluidic chips in a sterile 1.7 mL microcentrifuge tube. Add 1 mL sterile distilled water per 10 mg PDL to prepare 10 mg/mL solution and mix using a vortex mixer for 30 s. Filter sterilize the PDL solution with a 0.22 µm filter to remove any unwanted or insoluble particles. NOTE: If the insoluble particles are not removed, they may clog the chip microchannels, preventing liquid flow and incur leaks.
Phenol red with PBS	Dissolve 79.5 mg of Phenol red sodium salt in 500 mL of 10× phosphate buffered saline (PBS) using a vortex generator. This is required to make the collagen solution.
0.5 M Sodium hydroxide	Dissolve 5 g of NaOH tablets in 230 mL of sterile deionized water by stirring. CAUTION: The solution will become hot if more than 1 g of NaOH tablet is added, therefore, add less than 1 g to deionized water at a time. This is required to make the collagen solution.
Collagen solution, pH 7.4	Mix 20 µL of 10× PBS, 105 µL of type 1 collagen, 52.5 µL of deionized water, 20 µL of cell suspension to the solution, and 2.5 µL of NaOH. CAUTION: Keep all components in ice to avoid solidification of the collagen solution. Mix slowly but thoroughly and avoid creating bubbles.