Effect of laser fluence in laser-assisted direct writing of human colon cancer cell

Purpose - The purpose of this paper is to study the effect of laser fluence on the post-transfer cell viability of human colon cancer cells (HT-29) during a typical biofabrication process, matrix-assisted pulsed-laser evaporation direct-write (MAPLE DW). Design/methodology/approach - The post-transfer cell viability in MAPLE DW depends on various operation conditions such as the applied laser fluence. HT-29 cell was selected as a model mammalian cell to investigate the effect of laser fluence on the post-transfer cell viability. MAPLE DW-based HT-29 cell direct writing was implemented using an ArF excimer laser under a wide range of laser fluence. Trypan blue dye-exclusion was used to test the post-transfer cell viability. Findings - It has been observed that: the HT-29 cell viability decreases from 95 to 78 percent as the laser fluence increases from 258 to 1,482 mJ/cm(2); and cell injury in this study is mainly due to the process-induced mechanical stress during the cell droplet formation and landing processes while the effects of thermal influence and ultraviolet radiation are below the level of detection. Research limitations/implications - This paper reveals some interesting relationships between the laser fluence and the post-transfer mammalian cell viability and injury, and the resulting knowledge of these process-related relationships helps the wide implementation of MAPLE DW-based biofabrication. Post-transfer cell injury reversibility and cell proliferation capacity need to be further elucidated. Practical implications - This paper will help the wide implementation of cell direct-write technologies including MAPLE DW to fabricate biological constructs as artificial tissues/organs and bio-sensing devices. Originality/value - The shortage of donor organs and the need of various bio-sensing devices have significantly prompted the development of various biological material-based direct-write technologies. Process-induced cell injury happens during fabricating of biological constructs using different direct-write technologies including MAPLE DW. The post-transfer cell viability is a key index to evaluate the feasibility and efficiency of any biofabrication technique. This paper has investigated the effect of laser fluence on the post-transfer HT-29 cell viability and injury. The knowledge from this study will help effectively and efficiently fabricate various biological constructs for organ printing and biosensor fabrication applications.