Nanosurgery with femtosecond lasers

We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Subcellular surgery and nanosurgery

We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Subcellular surgery and nanosurgery

We use femtosecond laser pulses to selectively disrupt the cytoskeleton of a living cell and probe its mechanical properties. The nanosurgery setup is based on a home-built two-photon microscope. To image, we use a 80-MHz, 100-pJ/pulse laser beam, which is scanned across the sample; to cut, we introduce a second, 250-kHz, 1 to 5-nJ/pulse, laser beam and locally ablate sub-cellular structures. Simultaneous cutting and imaging allows us to study immediate cellular response with several hundred-nanometer spatial and less than 500-ms time resolution. We severed single actin bundles inside live... Read more about Sub-cellular nanosurgery in live cells using ultrashort laser pulses

We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Using short bursts of photons to manipulate biological matter at the nanoscale

We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Subcellular surgery and nanosurgery

We compare the potential of 100-fs and 200-ps laser pulses for photodisruptive surgery on the surface and in the bulk of turbid tissue. Water, human epidermis cultures, and pig skin were used as tissue models. In our technique, tightly-focused femtosecond and picosecond laser pulses are nonlinearly absorbed, vaporizing tissue in the focal volume. We find that there are several advantages in using femtosecond pulses for photodisruption. The breakdown threshold is lower and the energy deposition is more deterministic for 100-fs pulses compared to 200-ps pulses. In human skin culture we observe... Read more about Photodisruption in turbid tissue with 100-fs and 200-ps laser pulses

Using tightly-focused, 2-5 nJ femtosecond laser pulses we disrupt cellular material in the nematode worm C. elegans. Due to the nonlinear absorption of laser light, the dissection has submicrometer resolution, yielding surgery within the bulk of the worm without incision. The low energy of the pulses minimizes collateral damage. This technique permits subcellular surgery on live animals and opens a wide range of neurobiological questions to study in vivo.

We severed individual dendrites of a thermosensory neuron without damaging nearby neurons. Quantification of the resulting behavioral...

Read more about Single neuron dissection in C. elegans by femtosecond laser pulses

We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Subcellular surgery and nanosurgery

In eukaryotic cells, the spindle ensures the faithful segregation of the genetic material during cell division. In this study we use femtosecond nanosurgery to quantitatively measure parameters describing the metaphase spindle. We selectively cut microtubules of metaphase spindles assembled from Xenopus egg extracts. After the cut, microtubules depolymerize rapidly. Analysis of the time-lapse imaging reveals the depolymeration dynamics and allows determining the length distribution of the microtubules. We show that the average length of microtubules in metaphase spindles increases from the... Read more about Determining properties of spindle microtubules with femtosecond nanosurgery

We selectively disrupted the cytoskeletal network of a live bovine capillary endothelial cell using ultrashort laser pulses. We image the microtubules in the cytoskeleton of the cultured cells using green fluorescent protein. The cells are placed on a custom-built inverted fluorescence microscope setup, using a 1.4 NA oil-immersion objective to both image the cell and focus the laser radiation into the cell samples. The laser delivers 100-fs laser pulses centered at 800 nm at a repetition rate of 1 kHz; the typical energy delivered at the sample is 1–5nJ. The fluorescent image of the cell is... Read more about Nanosurgery in live cells using ultrashort laser pulses

We use femtosecond laser pulses to selectively disrupt the cytoskeleton of a living cell and probe its mechanical properties. Our nanosurgery setup is based on a home-built fluorescence microscope with an integrated femtosecond laser. We severed single actin bundles inside live cells to probe the local dynamics of the cytoskeleton and correlate it to global changes in cell shape. Simultaneous cutting and imaging allows us to study immediate cellular response with several hundred-nanometer spatial and less than 500-ms time resolution. The targeted actin bundle retracts rapidly after laser... Read more about Probing cell mechanics with femtosecond laser pulses

We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Manipulating cells using ultrashort laser pulses

We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Subcellular surgery and nanosurgery

Tightly focused femtosecond laser pulses can be absorbed nonlinearly inside biological materials, vaporizing tissue in the focal volume. High intensity is achieved at the focus with relatively low energy, minimizing collateral damage and unwanted heat deposition. We focus 100-fs laser pulses using a high numerical aperture microscope objective in the bulk of the skin tissue, disrupting micrometer-sized regions up to 100 mm beneath the sample surface. When the laser beam is focused even deeper into the sample, we observe the formation of filaments in the skin bulk rather than spherical sub-... Read more about Photodisruption in biological samples using femtosecond laser pulses