Drug delivery with microsecond laser pulses into gelatin

Shangguan, HanQun; Casperson, Lee W.; Shearin, Alan; Gregory, Kenton W.; Prahl, Scott A.

doi:10.1364/ao.35.003347

Cited by 33 publications

(22 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One possible explanation is that two processes, mass removal and drug delivery, occur simultaneously during photomechanical drug delivery. A shallower penetration may be as a result of the fact that more mass surrounding the ablation site is removed although the drug can be driven into targets more deeply with higher pressures [7]. We postulate that there is a threshold effect.…”

Section: Discussionmentioning

confidence: 85%

Enhanced laser thrombolysis with photomechanical drug delivery: An in vitro study

et al. 1998

Self Cite

View full text Add to dashboard Cite

Background and Objective: Current techniques for laser thrombolysis are limited because they can not completely clear thrombotic occlusions in arteries, typically leaving residual thrombus on the walls of the artery. The objective of this study was to investigate the possibility of using photomechanical drug delivery to enhance laser thrombolysis by delivering drugs into mural thrombus during laser thrombolysis. Study Design/Materials and Methods: Three experimental protocols were performed in vitro to quantitatively compare the effectiveness of thrombolysis by 1) constant infusion of drug, 2) laser thrombolysis, and 3) photomechanical drug delivery. A fiber‐optic flushing catheter delivered drug (a solution of 1 μm fluorescent microspheres) and light ( a 1 μs pulsed dye laser) into a gelatin‐based thrombus model. The process of laser‐thrombus interaction was visualized using flash photography and the laser‐induced pressure waves were measured using an acoustic transducer. Results Lumen sizes generated by mechanically manipulating the catheter through the thrombus were smaller than those generated by laser ablation. The microspheres could be driven several hundred microns into the mural thrombus. Conclusion Photomechanical drug delivery has potential for enhancement of laser thrombolysis. Two mechanisms seem to be involved in photomechanical drug delivery: 1) mural deposition of the drug at the ablation site and 2) increased exposure of the thrombus surface area to the drug. Lasers Surg. Med. 23:151–160, 1998. © 1998 Wiley‐Liss, Inc.

show abstract

Section: Discussionmentioning

confidence: 85%

Enhanced laser thrombolysis with photomechanical drug delivery: An in vitro study

et al. 1998

Self Cite

View full text Add to dashboard Cite

show abstract

“…More mass is removed although the drug can be driven into targets more deeply with higher pressures. 4 We postulate that there is a threshold effect. The maximum penetration can be achieved when the pressure is below the threshold, since the pressures can only remove a certain amount of the gelatin, so that more stained areas are left.…”

Section: Discussionmentioning

confidence: 97%

“…We have recently demonstrated that drug could be delivered into thrombus by use of hydrodynamic pressures following the laser-induced bubble expansion and collapse. 4 The bubbles were formed at the fiber tip due to the absorption of laser energy by the surrounding absorbing liquids. The spatial distribution of photomechanically delivered drug depended on parameters such as laser energy, absorption coefficient, fiber size, and material strength.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Penetration of fluorescent particles in gelatin during laser thrombolysis

et al. 1997

Self Cite

View full text Add to dashboard Cite

The use of pulsed laser energy to clear arteries obstructed by thrombus (blood clot) and plaque has emerged as a promising method for the treatment of cardiovascular diseases such as myocardial infarction and stroke. Current techniques for laser thrombolysis are limited because they cannot completely clear the clot in arteries, especially where a large volume clot is presented. Mural clot is a potent stimulus for reocclusion. We suggest that the combination of laser thrombolysis and localized intramural delivery of clot-dissolving drugs during the procedure may be a solution to this limitation.Ninety pulses of 30-70 mJ were delivered onto gelatin-based thrombus model with a flushing catheter. A solution of 1 µm fluorescent particles as a drug model was injected at a rate of 4mL/min in coincidence with the laser delivery. The controls were performed by injecting drug after laser thrombolysis. We measured the penetration of the particles in gelatin and the sizes of the lumen and stained areas. The results of this study demonstrated the possibility of enhancing laser thrombolysis by delivering drugs into thrombus. It was found that the particles could be driven several hundred micron in gelatin, and the lumen areas would be increased up to 25% if the areas were dissolved by the drugs.

show abstract

“…[1][2][3] A series of laser pulses were used to generate cavitation bubbles in a blood vessel due to the absorption of laser energy by targets (e.g., blood clots) or surrounding liquids (e.g., blood or saline). The hydrodynamic pressure arising from the expansion and collapse of cavitation bubbles forced drug into clot or vessel wall.…”

Section: Introductionmentioning

confidence: 99%

<title>Investigation of cavitation bubble dynamics using particle image velocimetry: implications for photoacoustic drug delivery</title>

et al. 1996

Self Cite

View full text Add to dashboard Cite

Photoacoustic drug delivery is a technique for delivering drugs to localized areas in the body. In cardiovascular applications, it uses a laser pulse to generate a cavitation bubble in a blood vessel due to the absorption of laser energy by targets (e.g., blood clots) or surrounding liquids (e.g., blood or injected saline). The hydrodynamic pressure arising from the expansion and collapse of the cavitation bubble can force the drug into the clots and tissue wall tissue. Time-resolved particle image velocimetry was used to investigate the flow of liquids during the expansion and collapse of cavitation bubbles near a soft boundary. A gelatin-based thrombus model was used to simulate the blood clot present during laser thrombolysis. An argon laser chopped by an acousto-optic modulator was used for illumination and photography was achieved using a CCD camera. The implications of this phenomenon on practical photoacoustic drug delivery implementation are discussed.

show abstract

Drug delivery with microsecond laser pulses into gelatin

Cited by 33 publications

References 17 publications

Enhanced laser thrombolysis with photomechanical drug delivery: An in vitro study

Enhanced laser thrombolysis with photomechanical drug delivery: An in vitro study

Penetration of fluorescent particles in gelatin during laser thrombolysis

<title>Investigation of cavitation bubble dynamics using particle image velocimetry: implications for photoacoustic drug delivery</title>

Contact Info

Product

Resources

About