Viscoelastic adhesive mechanics of aldehyde-mediated soft tissue sealants

Abstract

Soft tissue sealants generally sacrifice adhesive strength for biocompatibility, motivating the development of materials which interact with tissue to a predictable and controllable extent. Crosslinked hydrogels comprising aminated star polyethylene glycol and high molecular weight dextran aldehyde polymers (PEG:dextran) display aldehyde-mediated adhesion and readily tunable reactivity with soft tissue ex-vivo. Evaluation of PEG:dextran compositional variants revealed that the burst pressure of repaired intestinal wounds and the extent of material-induced tissue deformation both increase nonlinearly with formulation aldehyde content and are consistently within the desired range established by traditional sealants. Adhesive test elements featuring PEG:dextran and intestinal tissue exhibited considerable viscoelasticity, prompting use of a standard linear solid (SLS) model to describe adhesive mechanics. Model elements were accurately represented as continuous functions of PEG:dextran chemistry, facilitating prediction of adhesive mechanics across the examined range of compositional formulations. SLS models of traditional sealants were also constructed to allow general correlative analyses between viscoelastic adhesive mechanics and metrics of sealant performance. Linear correlation of equilibrium SLS stiffness to sealant-induced tissue deformation indicates dense adhesive crosslinking restricts tissue expansion, while correlation of instantaneous SLS stiffness to burst pressure suggests the adhesive stress relaxation capacity of PEG:dextran enhances their overall performance relative to traditional sealants.

Thermogelling bioadhesive scaffolds for intervertebral disk tissue engineering: Preliminary in vitro comparison of aldehyde-based versus alginate microparticle-mediated adhesion

“…Natural polysaccharides such as alginate [37] [38] [39] have been investigated as adhesives, since they form ionic and/or hydrogen bonds with matrix components, such as proteoglycan, in the tissue [40]. As a means of developing stronger adhesives, researchers have also functionalized these biological polymers with aldehyde groups that are capable to bond with amines in the tissue surface via a Schiff’s base reaction [41] [42] [43]. While aldehyde based bioadhesives demonstrate greater adhesive strength, they have been shown to elicit an inflammatory response from cells in contact with the adhesive [44] [45].…”

Characterization of Star Adhesive Sealants Based On PEG/Dextran Hydrogels

“…PEG/dextran tissue adhesive did not elicit inflammatory TNF-a release from macrophages, which suggests that this tissue adhesive is non-cytotoxic and non-inflammatory. [23] In addition, PEG/dextran adhesive was successful in sealing small intestinal puncture and corneal incisions to pressures higher than 100 and 500 mm Hg, [24] respectively, and was non-cytotoxic to bovine corneal endothelial cells. [25] The existing limitations of commercially available materials have highlighted the need for an alternative adhesive system with tunable adhesion and bioreactivity.…”

A two-component pre-seeded dermal–epidermal scaffold

“…The free aldehyde groups of the dermal hydrogel were intended to react covalently with amines of the PLL modified epidermal HA membrane layer. This chemistry has been applied to create glues which bind to tissue amines in situ [61, 62] or to crosslink cells with an aldehyde surface modification to amines on unmodified cells [63]. A piece of the composite with the approximate dimensions of 3 mm x 5 mm x 5 mm (H x L x W) was cut and imaged with the confocal microscope.…”