We design and demonstrate multi-trap tug-of-war (TOW) optical tweezers with object-adapted optical potentials for trapping and manipulating asymmetric particles and biological samples such as mutant bacterial cells. While dual TOW tweezers can effectively trap rod-shaped objects and even stretch them laterally, triangular TOW tweezers enable in-plane trapping of larger asymmetric objects which do not necessarily have mirror symmetry. When trapping with the dual TOW tweezers, we previously demonstrated that they are more stable than Gaussian beam-based dual traps, and the strong lateral pulling forces from the TOW optical tweezers can stretch and even break apart cellular clusters. Here we show multi-trap TOW (with 3 and 4 arms) optical tweezers can be employed to control and manipulate mutant Sinorhizobium meliloti bacterial cells, which are typically multi-pronged. We discuss the advantage of such TOW beam-based optical tweezers over traditional Gaussian beam-based holographic tweezers, and the potential applications of these TOW tweezers in studying cellular viscoelasticity, biomechanics, motility, and intercellular interactions.
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