Pulsed Laser Activation of Carbene Bioadhesive Boosts Bonding Strength

Light-activated tissue adhesives are limited to low light doses (50 J) and intensities (<1 W cm⁻²) due to photo-to-thermal heat generation. Low intensities have the disadvantage of limited penetration depths with retarded crosslinking kinetics, which impairs carbene-based crosslinking strategies that compete with nitrogen evolution and gas nucleation. These limitations are circumvented by a trade-off between high-intensity activation while reducing the exposure surface area. Continuous or pulsed activation by line scanning the carbene precursor adhesive allows curing a higher surface area/volume ratio while preventing localized heat generation. By optimizing irradiation with a pulsed laser scan, the adhesion strength is improved by 17-fold over ultraviolet A (UVA) light emitting diodes (LEDs) and is on par with bioadhesive gold standard of topical cyanoacrylates. Overall, this improved method of photo-activation applies to other industrial and clinical photocuring adhesives where limits on UVA dose constrain exposure intensities.