Near infrared laser-tissue welding using nanoshells as an exogenous absorber

• Published in: Lasers in surgery and medicine Vol. 37; no. 2; pp. 123 - 129
• Main Authors: Gobin, Andre M., O'Neal, D. Patrick, Watkins, Daniel M., Halas, Naomi J., Drezek, Rebekah A., West, Jennifer L.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-08-2005
• Subjects: Animals; Chickens; Gold - therapeutic use; Infrared Rays - therapeutic use; Laser Therapy - methods; laser tissue welding; Metals - therapeutic use; Models, Animal; nanoparticles; Nanostructures; nanotechnology; Phototherapy - methods; Rats; Skin - radiation effects; Tensile Strength - radiation effects; wound
• ISSN: 0196-8092; 1096-9101
• DOI: 10.1002/lsm.20206

Background and Objective
Gold nanoshells are a new class of nanoparticles that can be designed to strongly absorb light in the near infrared (NIR). These particles provide much larger absorption cross‐sections and efficiency than can be achieved with currently used chemical chromophores without photobleaching. In these studies, we have investigated the use of gold nanoshells as exogenous NIR absorbers to facilitate NIR laser‐tissue welding.
Study Design/Materials and Methods
Gold nanoshells with peak extinction matching the NIR wavelength of the laser being used were manufactured and suspended in an albumin solder. Optimization work was performed on ex vivo muscle samples and then translated into testing in an in vivo rat skin wound‐healing model. Mechanical testing of the muscle samples was immediately performed and compared to intact tissue mechanical properties. In the in vivo study, full thickness incisions in the dorsal skin of rats were welded, and samples of skin were excised at 0, 5, 10, 21, and 32 days for analysis of strength and wound healing response.
Results
Mechanical testing of nanoshell‐solder welds in muscle revealed successful fusion of tissues with tensile strengths of the weld site equal to the uncut tissue. No welding was accomplished with this light source when using solder formulations without nanoshells. Mechanical testing of the skin wounds showed sufficient strength for closure and strength increased over time. Histological examination showed good wound‐healing response in the soldered skin.
Conclusions
The use of nanoshells as an exogenous absorber allows the usage of light sources that are minimally absorbed by tissue components, thereby, minimizing damage to surrounding tissue and allowing welding of thicker tissues. © 2005 Wiley‐Liss, Inc.