Abstract
Achieving significant adhesion to soft tissues while
minimizing tissue damage poses a considerable clinical challenge.
Chemical-based adhesives require tissue-specific reactive chemistry, typically
inducing a significant inflammatory response. Staples are fraught with
limitations including high-localized tissue stress and increased risk of
infection, and nerve and blood vessel damage. Here inspired by the endoparasite
Pomphorhynchus laevis, which swells its proboscis to attach to its host’s
intestinal wall, we have developed a biphasic microneedle array that
mechanically interlocks with tissue through swellable microneedle tips,
achieving ~3.5-fold increase in adhesion strength compared with staples in skin
graft fixation, and removal force of ~4.5 N cm−2 from intestinal mucosal
tissue. Comprising a poly(styrene)-block-poly(acrylic acid) swellable tip and
non-swellable polystyrene core, conical microneedles penetrate tissue with
minimal insertion force and depth, yet high adhesion strength in their swollen
state. Uniquely, this design provides universal soft tissue adhesion with
minimal damage, less traumatic removal, reduced risk of infection and delivery
of bioactive therapeutics.