Fabrication of microfluidic chip using 3D printing for ocular cell studies

Purpose: This thesis aimed to create a polydimethylsiloxane (PDMS) microfluidic chip utilizing low-cost commercial 3D printers and to integrate human corneal epithelial cells (HCEC) into the fabricated chip. Methods: The purpose of the first experimental chapter (Chapter 3) of this thesis was to develop PDMS devices from 3D printed moulds of two commercially available 3D printers: the Formlabs Form 3B+, which employs Stereolithography (SLA) technology, and the AnyCubic D2 DLP, which utilizes Digital Light Processing (DLP) technology. The fabrication of PDMS from 3D printed moulds can be achieved by introducing three simple post-processing steps: heating, sanding, and nail polish coating. A biomaterial coating was applied to the surfaces of the PDMS devices to render their surfaces hydrophilic. The second experimental chapter (Chapter 4) centred on incorporating HCEC into the PDMS device fabricated using the method described in Chapter 3. Results: Both 3D printers could generate optically clear PDMS devices with smaller channel dimensions of 100 µm, with faster print times and higher accuracy for the DLP 3D printer. Heating the 3D printed moulds produced fully cured PDMS chips with perfect channel edges. The sanding and nail polish coating of the mould produced optically transparent and smooth PDMS devices. Coating the PDMS surface with polydopamine (PDA) improved its surface wettability from 110° to 75°. On the PDA and collagen-coated device, HCEC exhibited significantly better growth than on the untreated PDMS device. HCEC cultured on these PDA/collagen-coated PDMS devices demonstrated 80% cell viability compared to conventional tissue culture plates. Conclusion: This study demonstrated that SLA and DLP printers can be used to produce PDMS microfluidic chips quickly and affordably. Notably, the DLP printer offered better accuracy and faster printing time than the SLA printer. The fabricated PDMS chips were transparent and capable of incorporating HCEC.