title: Enhancement of porcine skin graft adherence using a light-activated process.
abstract: BACKGROUND
  Skin grafts are widely used in plastic surgery, and burn and ulcer wound management. Rapid and sustained adherence, the ability to resist shear stress, and a void-free surface-to-surface contact are critical to the success of graft survival. Mechanical and adhesive fixation aids are currently used to achieve graft adherence and they are not free of problems. Photochemical tissue bonding (PTB) is an emerging laser technique with numerous applications in surgical specialties. In the current study, PTB was investigated as a means to bond and enhance the adherence of skin grafts.
  
  
  METHODS
  In this study, ex vivo porcine skin grafts treated with a photosensitizing dye, rose bengal (RB), were approximated dermis-to-dermis and irradiated with visible light from an argon laser at 514 nm. The adherence of the skin grafts was measured immediately after irradiation. Dose-response relationships between the light and the dye with adherence of the grafts were established. The surface temperature of the skin under irradiation was monitored and the viability of the skin cells in the grafts was also measured.
  
  
  RESULTS
  Results showed that the skin graft adherence was RB dose-dependent in a statistically significant manner with the concentration of RB reaching a plateau value of 0.1% (w/v) of RB. Graft adhesion also increased with laser fluence up to 504 J/cm(2) in the presence of 0.1% RB. No fluence dependence was observed in the absence of RB. Thermogram results showed that the maximal surface temperature during irradiation was less than 40 degrees C. Histological investigation and trypan blue exclusion assays demonstrated that skin grafts retained cell viability and collagen organization after PTB.
  
  
  CONCLUSIONS
  This ex vivo study demonstrates that PTB using argon laser irradiation and RB enhances skin graft adherence by forming dermal-dermal bonding. The increase in adherence is a function of the concentration of RB and the laser fluence. The results also suggest that the PTB is a potentially safe procedure because it is nonthermal in nature and does not significantly affect the skin cell viability.
authors.affiliation: Wellman Laboratories of Photomedicine, Department of Dermatology, Harvard Medical School, Massachusetts General Hospital, Boston 02114, USA.
authors.forename: Barbara P
authors.initials: BP
authors.lastname: Chan
authors.forename: Irene E
authors.initials: IE
authors.lastname: Kochevar
authors.forename: Robert W
authors.initials: RW
authors.lastname: Redmond
mesh_terms: D000818:Animals; D001128:Argon; D002470:Cell Survival / Q000528:radiation effects; D020405:Dermis / Q000166:cytology / Q000637:transplantation*; D005456:Fluorescent Dyes; D007834:Lasers; D010778:Photochemotherapy; D012395:Rose Bengal; D012881:Skin Temperature / Q000528:radiation effects; D016038:Skin Transplantation / Q000379:methods*; D013556:Swine, Miniature; D000267:Tissue Adhesions
chemical_list: D005456:Fluorescent Dyes; D012395:Rose Bengal; D001128:Argon