Sealant processing requires isolation of silk from cocoons, creation of silk solution and addition of gold nanorods. The gold nanorods dispersed in the silk film are shown on the right. Source: Urie et al. Adv. Funct. Mater., 2018

Tissue repair is conventionally done with sutures, staples or surgical adhesives, all of which have inherent limitations and risks. Laser-activated nanosealants, which are under development at Arizona State University, may offer a more biocompatible option without the potential for collateral tissue damage.

The new approach embeds gold nanorods in silk fibroin polypeptide matrices. The silk sealant is activated as a laser heats the nanorods, after which the material forms a strong seal by integrating with tissue. The gold cools rapidly after the laser treatment, reducing the risk of damaging surrounding tissue.

A water-resistant sealant was designed to bond wet surgical environments. A good example would be surgery to excise a section of cancerous intestine, where the sealant must reattach the ends of intestine and prevent migration of bacteria into the bloodstream. When tested in the repair or porcine intestine, the sealant was effective in terms of burst pressure, and retained liquid under pressure better than sutures.

Another form of the laser-activated nanosealant creates a paste for direct application to superficial wounds on the skin, followed by laser activation. This type was tested on a mouse skin wound, and after two days demonstrated increased mechanical skin strength and faster repair relative to glue or sutures.

The researchers will next develop drug loading and release sealants with different timed-release profiles.