Modeling gold film fracture during a laser-assisted bioprinting process

Laser-assisted bioprinting (LAB) with gel microdroplets represents a promising method for biotechnology and medicine. In this printing process, nanosecond laser pulses are absorbed in a thin metal film deposited on a substrate with the surface bearing a layer of gel (e.g., hyaluronic acid solution, agar, etc.), which leads to heating and partial fracture of the film and to transfer of the gel microdroplets toward the acceptor substrate. We have studied the dynamics of 50-nm-thick metal (gold) film fracture under the LAB process conditions. It is established that, in excess of the film adhesion threshold, the laser radiation leads first to exfoliation of the gold film from a glass substrate. Further increase in the laser energy density leads to fracture and perforation of the film. The obtained results may be of use for developing LAB technologies.