Enhanced optical breakdown in KB cells labeled with folate-targeted silver-dendrimer composite nanodevices.

Unlabelled: Enhanced optical breakdown of KB tumor cells folate-targeted with silver-dendrimer composite nanodevices (CNDs) is described. CNDs [(Ag(0))(25)-PAMAM_E5.(NH(2))(42)(NGly)(74)(NFA)(2.

Penetration and precision of subsurface photodisruption in porcine skin tissue with infrared femtosecond laser pulses.

The surgical precision of photodisruption with ultrafast optical pulses depends on the accurate delivery of optical energy to sites of interest. As light penetration is limited in turbid tissues, localization and precision of subsurface breakdown highly depend on the interacting effects of increased power requirements and external focusing conditions. Infrared femtosecond breakdown extent in excised porcine skin tissue was investigated using a high-frequency ultrasonic technique which sensitively detected laser-induced bubbles.

Acoustic estimation of thermal distribution in the vicinity of femtosecond laser-induced optical breakdown.

Laser-induced optical breakdown (LIOB), or photo-disruption, can generate individual microbubbles in tissues for biomedical applications. We have previously developed a co-localized high-frequency ultrasound system to detect and characterize these laser-induced microbubbles. Because ultrasound speed varies with temperature, this system can also be used to directly estimate thermal effects in the vicinity of photodisruption.

Optical and acoustic detection of laser-generated microbubbles in single cells.

Acoustically monitored laser-induced optical breakdown (LIOB) has potential as an important tool to diagnose and treat living cells. Laser-induced intracellular microbubbles are readily detectable using high-frequency ultrasound, and LIOB can be controlled to operate within two distinct regimes. In the nondestructive regime, a single, short-lived bubble can be generated within a cell, without affecting its immediate viability.

Acoustic detection of controlled laser-induced microbubble creation in gelatin.

A high-frequency (85 MHz) acoustic technique is used to identify system parameters for controlled laser-induced microbubble creation inside tissue-mimicking, gelatin phantoms. Microbubbles are generated at the focus of an ultrafast 793-nm laser source and simultaneously monitored through ultrasonic pulse-echo recordings. Displayed in wavefield form, these recordings illustrate microbubble creation, and integrated backscatter plots provide specifics about microbubble characteristics and dissolution behavior.

Trapping cavitation bubbles with a self-focused laser beam.

We observed that laser-induced cavitation bubbles in water can be trapped in a self-focused laser beam. Both optical imaging and acoustic detection have been utilized to confirm bubble trapping. Transverse and longitudinal trapping forces were measured to be as large as 87 and 11 pN, respectively.

Lateral speckle tracking using synthetic lateral phase.

In traditional speckle tracking, lateral displacement (perpendicular to the beam direction) estimates are much less accurate than axial ones (along the beam direction). The accuracy of lateral tracking is very important whenever spatial derivatives of both axial and lateral displacements are required to give a full description of a two-dimensional (2-D) strain field. A number of methods have been proposed to improve lateral tracking by increasing the sampling rate in the lateral direction.