Laser‐activated adhesive films for sutureless median nerve anastomosis

Abstract

A novel chitosan adhesive film that incorporates the dye 'Rose Bengal' (RB) was used in conjunction with a green laser to repair transected rat median nerves in vivo. Histology and electrophysiological recording assessed the impact of the laser-adhesive technique on nerves. One week post-operatively, the sham-control group (laser-adhesive technique applied on un-transected nerves) conserved the average number and size of myelinated fibres in comparison to its contralateral side and electrophysiological recordings demonstrated no significant difference with un-operated nerves. Twelve weeks after the laser-adhesive anastomoses, nerves were in continuity with regenerated axons that crossed the anastomotic site.

Nerve repair: toward a sutureless approach

“…The immediate tensile strength of rat median nerves repaired using PTB is comparable to the strength of direct end-to-end epineural (10-0 nylon) sutures and significantly stronger than LTW and soldering [2]. However, nerve tissue repaired by PTB is devoid of thermal injury seen in photothermal bonding, where temperatures never exceed 38°C [2].…”

“…In vivo PTB nerve repair in rats has been achieved integrating RB into epineural sleeves [26], human amniotic membranes [60] and chitosan bandages (Fig. 2a) [2]. The immediate tensile strength of rat median nerves repaired using PTB is comparable to the strength of direct end-to-end epineural (10-0 nylon) sutures and significantly stronger than LTW and soldering [2].…”

Gecko-inspired chitosan adhesive for tissue repair

“…The laser beam scanned the whole surface area of the adhesive several times in order to deliver~110 J cm − 2 , 19 during irradiation the adhesive temperature remained below 39°C. 17,18 The laser was coupled to a multimode optical fiber (core diameter = 200 μm and numerical aperture = 0.22) that was inserted into a hand-held probe to provide easy and precise beam delivery. The laser parameters are summarized in Table 1.…”

“…About 10% of the adhesive nanopillars presented some defects that can be corrected if the dry-casting technique is optimized, for example, exploring different materials for the master plate such as polydimethylsiloxane or Perspex. 6,37 The flat chitosan adhesive has been successfully used to repair rat median nerves in vivo, 18,19 showing repair strength comparable to sutures. Myelinated axons regenerated equally well either in rats operated with the flat chitosan adhesives or in sutured nerves; the laser-adhesive technique was nonetheless superior and less invasive than suturing when the functional recovery of nerves was tested 3 months postoperatively.…”

“…16 Our group has recently developed a biocompatible and sutureless adhesive for peripheral nerve repair; 17 this adhesive is based on chitosan and is bonded photochemically to tissue by a green laser without causing thermal damage. 18,19 In this study, we succeeded in modifying the adhesive surface with nanopillars to further enhance the strength of tissue bonding. A simple dry-casting technique is required to fabricate the nanostructured film and no coating is necessary to stabilize the bonding between adhesive and tissue in wet environment; this feature simplifies the fabrication process to a single step procedure.…”