Sticking with the Pattern for a Safer Glue

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Science Translational Medicine  02 Oct 2013:
Vol. 5, Issue 205, pp. 205ec161
DOI: 10.1126/scitranslmed.3007663

A variety of synthetic materials such as sutures and staples are routinely used to close surgical wounds and repair injured tissue. These materials have greatly improved surgical care but are often cumbersome to apply and are associated with a risk of leakage from the suture line, which can lead to undesired postoperative complications. Adhesive materials considerably expand the resources available for wound repair and surgical interventions by providing mechanical support to the friable tissue while sealing the wound and preventing leakage from the incision site. However, commercially available materials such as fibrin glue and cyanoacrylate (CA) often require a choice between adequate adhesion and biocompatibility. Now, Pereira et al. combine surface patterning and reactive chemistry to maximize tissue adhesion while reducing toxicity.

Medical-grade CA adheres strongly to tissue; however, it is also associated with toxicity. Nonspecific interactions between CA and functional groups on tissue surfaces, the heat produced by the bonding reaction, and the toxic degradation products all pose drawbacks to the use of this material, despite its adequate adhesion and sealing characteristics. To reduce material toxicity, the authors used only a thin film of the medical-grade adhesive. To improve the degree of adhesion, the authors employed microtextured patches of CA-coated substrate to provide a larger surface area for interaction with tissue surfaces. Spin-coating of cyanoacrylate onto a polycaprolactone (PCL) substrate helped maintain the topographical features of the substrate. Spin-coating also reduced the amount of glue applied to the tissue interface and hence the amount of toxic products released during degradation. Ex vivo pull-off adhesion tests against wet intestine tissue confirmed the enhanced adhesion force on patterned patches as compared to that of flat substrates. Subcutaneous implantation of CA-coated PCL patches in rats also showed reduced inflammation and fibrotic capsule formation for the spin-coated CA samples, as evidenced by hematoxylin and eosin and antibody-to-CD68 staining. Statistically significant differences in adhesion strength between patterned and nonpatterned surfaces were confirmed in rat models subjected to colon or stomach punctures.

Harnessing the synergy between surface topography and reactive chemistry may expand the clinical applications that use CA-based materials beyond external use. Follow-up studies should examine the extent to which patterning alone improves adhesion and whether it can be used to enhance the effectiveness of other adhesive materials that are more biocompatible.

M. J. N. Pereira et al., Combined surface micropatterning and reactive chemistry maximizes tissue adhesion with minimal inflammation. Adv. Healthcare Mater., published online 18 September 2013 (10.1002/adhm.201300264). [Abstract]

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