Optical Fabrication Process And Biological Application Of Polydimethylsiloxane Microstructure

Corneal transplantation is a major hope patients with corneal blindness,but the scarcity of cornea is the biggest obstacle,and each person's cornea is different,corneal bio 3D printing with adequate and well-behaved cornea cells can generate a new cornea,the new cornea has a higher success rate and a better state,it also reduces the rejection after transplantation and promotes the recovery of the patient.Therefore,the cornea cells need to be cultured in vitro and ensure sufficient quality and quantity.However,the corneal endothelial cells are not suitable for the 3D printing of cornea due to deformation and endotheliall-mesenchymal transformation in vitro culture.Therefore,it is of great importance to prevent cells from deformation and endothelial-mesenchymal transition,and promote the transformation of mesenchymal-endothelial cell into endothelial cells which have normal phenotype in vitro culture.Studies have shown that flat polydimethylsiloxane substrate can effectively inhibit endothelial-to-mesenchymal transition,and micro-structure polydimethylsiloxane substrate can promote the mesenchymal-endothelial transformation.However,there is no systematic study on the effect of polydimethylsiloxane microstructure about corneal endothelial cells.Therefore,the polydimethylsiloxane microstructural parameters and fabrication methods are designed in this paper,and the micro-structure polydimethylsiloxane is successfully produced.The good growth of corneal endothelial cells on polydimethylsiloxane micro-structures was demonstrated,the phenotype and proliferation rate of cells was maintained,and the mesenchymal-endothelial transformation is promoted.There are various methods for fabricating PDMS microstructures,many of them are optical methods,and the most commonly method is optical lithography.However,there is no research on the fabrication of PDMS microstructures with femtosecond lasers,which have been widely studied and applied in optics in recent years.Because of small size,high precision of PDMS microstructure,high elasticity,heat resistance and chemical stability of PDMS,and high collimation,small spot and high instantaneous power of femtosecond laser,this paper proposes a new optical method to fabricate the PDMS microstructure,The femtosecond laser etching method.Then the feasibility of the femtosecond laser etching method was demonstrated.The specific research content and methods are as follows:1.PDMS microstructure parameters design and optimization.The PDMS microstructural parameters that were finally suitable for corneal endothelial cell culture were determined to be the groove width of 30?m,the groove pitch of 10?m,and the groove depth of 3?m.2.PDMS microstructure mold manufacturing methods.This paper proposes a new optical-based method,femtosecond laser etching method,The PDMS microstructure was made successfully by adjusting the femtosecond laser spot size,optical power,laser path and other parameters.At the same time,the common method of PDMS microstructures,lithography method,is used to make the same microstructure.Result shows that the PDMS microstructures produced by the two methods have the same effect,which proves the feasibility of the femtosecond laser etching method.3.PDMS microstructure hydrophilic modification and detection.Scanning electron microscopy and surface hydrophilicity modification were performed on the PDMS microstructures.Collagen IV was selected as the final modified material.The PDMS microstructure was tested for cell frame structure,survival rate and endothelial-to-mesenchymal transition.It is concluded that the optimized PDMS microstructure can maintain cell phenotype,rapidly proliferate and prevent endothelial-mesenchymal transition,and promote mesenchymal-endothelial transformation.The PDMS microstructure produced in this paper satisfies the need of endothelial cells in 3D printing.