Ablation of cytoskeletal filaments and mitochondria in live cells using a femtosecond laser nanoscissor

Nan Shen, Dabajyoti Datta, Chris B. Schaffer, Philip LeDuc, Donald E.Ingber, Eric Mazur

Mechanics and Chemistry of Biosystems (2005)

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Analysis of cell regulation requires methods for perturbingmolecular processes within living cells with spatial discrimination on the nanometer-scale. We present a technique for ablating molecular structures in living cells using low-repetition rate, low-energy femtosecond laser pulses. By tightly focusing these pulses beneath the cell membrane, we ablate cellular material inside the cell through nonlinear processes. We selectively removed sub-micrometer regions of the cytoskeleton and individual mitochondria without altering neighboring structures or compromising cell viability. This nanoscissor technique enables non-invasive manipulation of the structural machinery of living cells with several-hundred-nanometer resolution. Using this approach, we unequivocally demonstrate that mitochondria are structurally independent functional units, and do not form a continuous network as suggested by some past studies.

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Femtosecond laser-drilled capillary integrated into a microfluidic device

Tyson N. Kim, Kyle Campbell, Alex Groisman, David Kleinfeld, and Chris B. Schaffer

Applied Physics Letters (2005)

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Recent growth in microfluidic technology is, to a large extent, driven by soft lithography, a high-throughput fabrication technique where polymer materials, such as polysdimethyld siloxane sPDMSd, are molded to form microscopic channel networks. Nevertheless, the channel architectures that can be obtained by molding are limited. We address this limitation by using femtosecond laser micromachining to add unmoldable features to the microfluidic devices. We apply laser ablation to drill microcapillaries, with diameters as small as 0.5 mm and aspect ratios as high as 800:1, in the walls of molded PDMS channels. Finally, we use a laser-drilled microcapillary to trap a polystyrene bead by suction and hold it against a shear flow

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