Successful laser welding: Selecting necessary and sufficient parameters

Laser welding is thought to take place by a photothermal mechanism. The end-point for welding is likely to be protein denaturation. Several protein moieties have been implicated and these each have different denaturation temperatures. Preferred temperatures for laser welding can be predicted based on known denaturation of these proteins. Given this mechanism, the ultimate “tissue parameters” are peak temperature, time at temperature. The area of heating is also relevant. In selecting laser parameters for successful tissue welding, uniform heating of the full thickness of the tissue is desired. Pulse width, interval and spot size can be chosen to prevent thermal buildup and undesired collateral thermal injury. Power density can then be adjusted to allow heating to just the optimum endpoint of protein denaturation. At this point, cells at the target site are likely to be non-viable but no collateral cell death should have occurred. The wavelength selected effects the depth of penetration and therefore the heating profile at different depths in the tissue