Thermo-optical tweezers based on photothermal waveguides

Abstract

Abstract Field-controlled micro-manipulation represents a pivotal technique in handling microparticles, yet conventional methods often risk physical damage to the targets. Here, we have discovered a completely new mechanism for truly non-contact manipulation through photothermal effect, called thermal-optical tweezers. we employing a laser-engraved photothermal waveguide for dynamic microparticle manipulation. This waveguide demonstrates superior photothermal conversion and precision control, generating a non-isothermal temperature field. The interaction of thermal convection and thermophoresis within this field creates a microfluidic potential well, enabling non-contact and non-destructive particle manipulation. By varying the path of photothermal waveguides in lithography and the manipulating laser loading modes, diverse manipulation strategies, such as Z-shaped migration, periodic oscillation, and directional transport, are achievable. Our innovative non-invasive micro-manipulation technology not only minimizes physical damage to target objects but also enables precise and diverse manipulation of micro-entities, opening up new avenues in photothermal control of cells and biomolecules.