Biofilms of chitosan-gold nanorods as a novel composite for the laser welding of biological tissue

Abstract

Gold nanorods (GNRs) exhibit intense localized plasmon resonances at optical frequencies in the near infrared (NIR), which is the window where the penetration of light into the body is maximal. Upon excitation with a NIR laser, a strong photothermal effect is produced, which can be exploited to develop minimally invasive therapies. Here we prove the use of chitosan-GNRs films as a novel NIR sensitive nanocomposite for the photothermal conversion of NIR laser light during surgical interventions of tissue welding. Chitosan is an attractive biomaterial due to its biodegradability, biocompatibility, hemostatic, antimicrobial and wound healing-promoting activity. Colloidal GNRs were embedded in chitosan based, highly stabilized, flexible and easy-to-handle films, which were stored in water until the time of surgery. The chitosan-GNRs films were first positioned on freshly explanted rabbit tendon samples. Then, by administration of single pulses ranging from 80 to 140 ms duration and 0.5 to 1.5 W power delivered by a 300-μm optic fiber coupled with a 810 nm diode laser, spots of local thermally-induced adhesion characterized by a tensile strength of ~ 10 kPa were obtained. The present results are encouraging toward the development of a novel minimally-invasive technology based on the application of bioderived nanoplasmonic materials to biomedical optics.