Real-time monitoring of two-photon photopolymerization for use in fabrication of microfluidic devices

摘要

We report an improved method for production of microfluidic device masters using two-photon photopolymerization of SU-8 negative photoresist,which relies on a two-photon microscope(TPM)commonly used in imaging of biological samples.The device masters serve as negative relief structures for polydimethylsiloxane-based microfluidic devices.We observed that not only did the two-photon excitation of the SU-8 photoresist initiate crosslinking of the material in the region of the focus of the near-infrared laser beam(as expected)but it also resulted in emission of fluorescence in the visible range.The detected emission of SU-8 photoresist undergoing two-photon excitation displayed a strong correlation with the size of the polymerized objects produced during the exposure;this allowed the progress of the microfluidic master production process to be monitored in real-time.We demonstrate the use of the fluorescence detection during two-photon photopolymerization in the production of microfluidic devices,which were designed to trap individual yeast cells to be imaged with the same TPM used for microfluidic master writing.