High-throughput fabrication of gray-level biomicrostructures via temporal focusing excitation and laser pulse control

A developed temporal focusing-based multiphoton excitation system with additional patterned excitation and local laser control can provide high-throughput fabrication of three-dimensional gray-level biomicrostructures via two-photon cross-linking with rose bengal (RB) as the photoactivator. Multiple bovine serum albumin (BSA) structures of different concentrations were simultaneously achieved by selecting different pulse numbers in the designated regions with an appropriate femtosecond laser power within a few seconds. Intensity of the RB two-photon excited fluorescence (TPEF) is correlated to the concentration of the fabricated cross-linked BSA microstructure. Hence, the fabricated BSA microstructure can be monitored online by utilizing the RB TPEF as contrast agent. It suggests that this approach with its unique capability of high-speed, gray-level, and online-inspection fabrication meets the requirements of the biomedical researches involved in extracellular matrix.