Hybrid nanocomposite films for laser-activated tissue bonding.

We report new advancements in the biomedical exploitation of plasmonic nanoparticles as an effective platform for the photothermal repair of biological tissue. Chitosan films are loaded with gold nanorods with intense optical absorption in the "therapeutic window" of deepest light penetration through the body, and then activated by near infrared laser excitation to give adhesion with adjacent connective tissues. The adhesion consists of 0.07 mm(2) welds of ~20 kPa tensile strength at the film/tissue interface, which are obtained by administration of pulses with duration in the hundreds of millisecond timescale from a diode laser at ~130 J cm(-2). We investigate the adhesive effect as a function of pulse power and duration and identify an optimal operative window to achieve effective and reproducible welds with minimal detrimental superheating. These results may prove valuable to standardize laser bonding techniques and meet current needs for new knowledge which is urged by the penetration of nanotechnology into biomedical optics.