3D Patterning For Cell Culture: Bioprinting and a Novel Microcontact Printing Device

Cells in vivo respond to a multiplicity of signaling molecules that influence their growth and behavior. In recent years, crucial developments in tissue engineering have come as the research focus has turned to methods that recreate complex 3D environments for cell culture. This work envisions two different approaches to patterning biomolecules in 3D space for cell culture: 3D bioprinting and microcontact printing. A literature review was conducted about bioprinted protein bioinks containing collagen, silk proteins, elastin, and fibrin. The review summarizes a vast range of physical, mechanical, and cell culture properties that have been attained using unique additives and printing techniques. A research project describes the favorable deformation properties of 9:1 RT 623 silicone rubber using a spring device to manually apply known forces. The shape deformation of an RT 623 stamp in response to applied forces is modeled. The compressive elastic modulus of 9:1 RT 623 cured at room temperature is estimated to be approximately 0.79-1.4 MPa. Though common on a larger scale in the pad printing industry, in this work a RT 623 stamp was used to innovatively transfer bioinks to the curved bottom of a microwell (~800μm diameter) to promote cell patterning. The feasibility of transferring a conductive ink to the curved HRC surface was also demonstrated. RT 623 is proposed as an attractive candidate material for microcontact printing inks on curved cell-culturing surfaces. Together, this research advances tissue engineering research about the precise patterning of cellular microenvironments to improve in vitro biological models.