Hydrogels with the precise three-dimensional configuration (3D hydrogels) have played important roles in the fields of tissue engineering and drug delivery, which will help to mimic the behavior of bio-inspired systems. Thus, the improvement of the spatial resolution on both the microscopic and the nanometric scale has been urgently demanded. There are some developed techniques to fabricate the 3D microstructures, however, these techniques require either high energy, strict operation environment or expensive mask.
As a promising maskless and flexible photolithography technique, two-photon polymerization (TPP) is a promising protocol to achieve 3D hydrogels. However, TPP of 3D hydrogels has been hindered due to the lack of high efficient water-soluble photoinitiator. In this presentation, the development of water soluble TPP photoinitiator of high initiating efficiency, as well as its fabrication capability and the resolution will be illustrated. The high resolution of 92 nm has been achieved benefiting from the high efficency of the developed photoinitiators and the optimized optical parameters. Furthermore, the microstructures with high accuracy such as those simulating the morphology of adenovirus and red blood cell have been fabricated, demonstrating the promising fabrication capability for achieving arbitrary architectures. The design of the photoinitiators, and the TPP fabrication technique mentioned in this study would provide high potential for the futher application in the research fields of cell imaging and tissue engineering.