Abstract
Optoelectronic tweezers (OET) are a microsystem actuation technology capable of moving microparticles at mm s-1 velocities with nN forces. In this work, we analyze the behavior of particles manipulated by negative dielectrophoresis (DEP) forces in an OET trap. A user-friendly computer interface was developed to generate a circular rotating light pattern to control the movement of the particles, allowing their force profiles to be conveniently measured. Three-dimensional simulations were carried out to clarify the experimental results, and the DEP forces acting on the particles were simulated by integrating the Maxwell stress tensor. The simulations matched the experimental results and enabled the determination of a new "hopping" mechanism for particle-escape from the trap. As indicated by the simulations, there exists a vertical DEP force at the edge of the light pattern that pushes up particles to a region with a smaller horizontal DEP force. We propose that this phenomenon will be important to consider for the design of OET micromanipulation experiments for a wide range of applications.
Highlights
Optoelectronic tweezers (OET) is an opto-electro-fluidic micromanipulation technology that uses light-induced dielectrophoresis (DEP) for touch-free actuation of micro-scale objects in physical, chemical and biomedical studies [1–5]
We analyze the behavior of particles manipulated by negative dielectrophoresis (DEP) forces in an OET trap
A user-friendly computer interface was developed to generate a circular rotating light pattern to control the movement of the particles, allowing their force profiles to be conveniently measured
Summary
Optoelectronic tweezers (OET) is an opto-electro-fluidic micromanipulation technology that uses light-induced dielectrophoresis (DEP) for touch-free actuation of micro-scale objects in physical, chemical and biomedical studies [1–5]. OET has been reported to manipulate micro particles at velocities of several mm s−1 propelled by forces of up to nano-Newton levels [14, 17, 18]. This suggests utility for OET as a microassembly tool, making it important to characterize its effectiveness to manipulate targeted objects in terms of the highest achievable positioning speed and accuracy. These properties are typically determined by measuring the viscous drag force imposed on a trapped object that causes it to escape the OET trap. There has been a lack of relevant studies concerning the mechanism of an object’s escape from an OET trap, a topic that will be important for users who wish to use OET for efficient manipulation of micro-objects in various conditions
Sign-in/Register to view highlights & summary 
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call