Graphene photothermal effect-induced microbubble for microparticle manipulation

Microbubbles have attracted widespread attention within the academic community, owing to their great potential for applications in microsystems. Considering practical applications, it is critical to use a simple method to generate a controllable microbubble without contaminating the target environment. In this paper, we propose a convenient and controllable method to generate a vapor microbubble using a monolayer graphene-assisted microfiber (GMF). When the light beam at a wavelength of 1.55 μm is coupled to GMF immersed in liquid, light energy can be converted into heat energy due to the photothermal effect of graphene, and thus a stable and controllable microbubble can be generated due to the existence of a temperature gradient around the GMF. This microbubble is used to capture microsphere particles such as polystyrene particles by means of the Marangoni Convection around it. Compared with bare microfiber, GMF has a higher fabrication tolerance for the purposes of generating microbubbles, and a lower threshold optical power due to the strong photothermal effect of graphene. Our proposed device, which demonstrates advantages such as ease of manufacture, simple structure, and biocompatibility, is a promising candidate for future applications in the fields of directional transport of drugs, biomedicine, biochemistry, microfluidics, etc.