Two-Photon Direct Laser Writing of 3D Scaffolds through C, H-Insertion Crosslinking in a One-Component Material System

The popularity of two-photon direct laser writing in biological research is remarkable as this technique is capable of 3D fabrication of microstructures with unprecedented control, flexibility and precision. Nevertheless, potential impurities such as residual monomers and photoinitiators remaining unnoticed from the photopolymerization in the structures pose strong challenges for biological applications. Here, the first use of high-precision 3D microstructures fabricated from a one-component material system (without monomers and photoinitiators) as a 3D cell culture platform is demonstrated. The material system consists of prepolymers with built- in crosslinker motieties, requiring only aliphatic C, H units as reaction partners following two-photon excitation. The material is written by direct laser writing using two-photon processes in a solvent-free state, which enables the generation of structures at a rapid scan speed of up to 500 mm s-1 with feature sizes scaling down to few micrometers. The generated structures possess stiffnesses close to those of common tissue and demonstrate excellent biocompatibility and cellular adhesion without any additional modification. The demonstrated approach holds great promise for fabricating high-precision complex 3D cell culture scaffolds that are safe in biological environments. The combination of C, H-insertion crosslinking photochemistry and two-photon direct laser writing technology presents an innovative avenue for fabricating biocompatible high-precision 3D microstructures. This approach enables rapid and flexible fabrication of 3D microstructures without the use of monomers and photoinitiators. The fabricated structures are successfully utilized as 3D cell culture platforms as exemplified in this study.image

Automated summary

The popularity of two-photon direct laser writing in biological research is remarkable, but impurities in the structures pose challenges for biological applications. This study demonstrates the first use of high-precision 3D microstructures fabricated from a one-component material system as a 3D cell culture platform, showing excellent biocompatibility and cellular adhesion.