title: Changes in type I collagen following laser welding.
abstract: Selection of ideal laser parameters for tissue welding is inhibited by poor understanding of the mechanism. We investigated structural changes in collagen molecules extracted from rat tail tendon (> 90% type I collagen) after tissue welding using an 808 nm diode laser and indocyanine green dye applied to the weld site. Mobility patterns on SDS-PAGE were identical in the lasered and untreated tendon extracts with urea or acetic acid. Pepsin incubation after acetic acid extraction revealed a reduction of collagen alpha and beta bands in lasered compared with untreated specimens. Circular dichroism studies of rat tail tendon showed absence of helical structure in collagen from lasered tendon. No evidence for covalent bonding was present in laser-treated tissues. Collagen molecules are denatured by the laser wavelength and parameters used in this study. No significant amount of helical structure is regenerated on cooling. We conclude that non-covalent interactions between denatured collagen molecules may be responsible for the creation of tissue welding.
authors.affiliation: Institute of Reconstructive Plastic Surgery, New York University Medical Center, New York City 10016.
authors.forename: L S
authors.initials: LS
authors.lastname: Bass
authors.forename: N
authors.initials: N
authors.lastname: Moazami
authors.forename: J
authors.initials: J
authors.lastname: Pocsidio
authors.forename: M C
authors.initials: MC
authors.lastname: Oz
authors.forename: P
authors.initials: P
authors.lastname: LoGerfo
authors.forename: M R
authors.initials: MR
authors.lastname: Treat
mesh_terms: D000818:Animals; D002942:Circular Dichroism; D003094:Collagen / Q000737:chemistry / Q000502:physiology* / Q000528:radiation effects; D003720:Densitometry; D004591:Electrophoresis, Polyacrylamide Gel; D053685:Laser Therapy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013623:Tail; D013710:Tendons / Q000378:metabolism / Q000601:surgery; D013718:Tensile Strength
chemical_list: D003094:Collagen