Abstract
Purpose :
To incorporate human corneal epithelial cells (HCECs) into a PDMS microfluidic chip fabricated with 3D printing for evaluating cytotoxicity of ophthalmic formulations.
Methods :
The moulds for the microfluidic chips were designed using CAD software and then 3D-printed using a commercial stereolithography (SLA) printer (FormLabs 3B+, FormLabs, Somerville, MA). The moulds were sanded and then coated with nail polish to smoothen the surface of the channels. PDMS (10:1 ratio of elastomer to curing agent) was then cast in the mould and cured at 120 oC for 2 hours. The resulting devices were sterilized by autoclaving and then coated with 0.01% polydopamine (PDA), a chemical that enhances the surface hydrophilicity, and 20μg/mL collagen. The surface wettability was evaluated using sessile drop contact angle. HCEC were cultured until ~80% confluency in standard polystyrene dishes with DMEM/F12 media. HCECs were subsequently dissociated from tissue culture dishes, and 3000 cells were collected and injected into the PDMS device using a syringe. The cells were allowed to grow for 18-36 hours in DMEM/F12 media at 37oC in a high humidity environment. HCECs were imaged by light microscopy, and viability was assessed by alamarBlue assays. The viability of HCEC cells were also evaluated under a flow rate of 1 μL/min.
Results :
The resulting devices were optically clear with channel dimensions of 100 mm. Coating the PDMS with PDA increased the surface wettability, from 110 degrees (without coating) to 75 degrees with a 0.01% PDA coating. HCEC grew significantly better on the PDA and collagen-coated chip than on the PDMS chip. The HCEC chips on these chips showed 60-90% metabolic activity as compared to standard tissue culture plates. The HCECs cultured in our devices were also capable of growth with fluid flow rates of up to 1 mm/s.
Conclusions :
This study showed that PDMS devices manufactured using a 3D printing method can be used in cell biological studies. Future studies will aim to further validate and optimize these devices with other biological assays for screening ophthalmic formulations.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.