Novel On‐Demand Bioadhesion to Soft Tissue in Wet Environments

Abstract

Current methods of tissue fixation rely on mechanical-related technologies developed from the clothing and carpentry industries. Herein, a novel bioadhesive method that allows tuneable adhesion and is also applicable to biodegradable polyester substrates is described. Diazirine is the key functional group that allows strong soft tissue crosslinking and on-demand adhesion based on a free radical mechanism. Plasma post-irradiation grafting makes it possible to graft diazirine onto PLGA substrates. When the diazirine-PLGA films, placed on wetted ex vivo swine aortas, are activated with low intensity UV light, lap shear strength of up to 450 ± 50 mN cm(-2) is observed, which is one order of magnitude higher than hydrogel bioadhesives placed on similar soft tissues. The diazirine-modified PLGA thin films could be added on top of previously developed technologies for minimally invasive surgeries. The present work is focused on the chemistry, grafting, and lap shear strength of the alkyl diazirine-modified PLGA bioadhesive films.

Elastic Light Tunable Tissue Adhesive Dendrimers

“…The fat was removed and the tissue with endothelial (intima) side up was glued with cyanoacrylate adhesive onto a glass slide (25.4 × 76.2 mm, 1–1.2 mm thick, CLP, China). PLGA thin films were processed by a previously reported method . PLGA samples were cut into a 40 × 20 mm squares and glued onto glass slides with cyanoacrylate adhesive.…”

“…PLGA thin fi lms were processed by a previously reported method. [ 25 ] PLGA samples were cut into a 40 × 20 mm squares and glued onto glass slides with cyanoacrylate adhesive. PAMAM-gdiazirine in PBS (0.3 mL) with different concentrations and conjugation percentages were pipetted in between the swine artery surface and PLGA fi lm.…”

“…We have previously developed two different diazirine‐based adhesive systems: 1) diazirine grafted polymer films, and 2) electrocuring adhesive from diazirine grafted PAMAM dendrimer . In case of diazirine grafted films, relatively low adhesion strength was achieved (max.…”

“…[ 23,24 ] The design and control over mechanical modulus and adhesive strength of UVactivated PAMAM-g-diazirine bioadhesive is based on the following hypotheses: (i) the mechanical modulus and adhesive strength of crosslinked PAMAM-g-diazirine can be controlled by degree of grafted (conjugated) diazirine on PAMAM dendrimer periphery and the amount of PAMAM-g-diazirine dissolved in buffer; (ii) due to formation of carbene radicals capable of forming covalent bonds upon UV activation, irradiated PAMAM-g-diazirine enables rapid adhesion to tissue interfaces, even in aqueous environments. We have previously developed two different diazirinebased adhesive systems: 1) diazirine grafted polymer fi lms, [ 25 ] and 2) electrocuring adhesive from diazirine grafted PAMAM dendrimer. [ 6 ] In case of diazirine grafted fi lms, relatively low adhesion strength was achieved (max.…”

“…Rheometry analysis: A) schematic illustration of the setup for rheometry measurements with UV activation; B) storage modulus (G′) and loss modulus (G″) dynamics with UV activation of PAMAM-g-diazirine (50 wt% PBS, 15% conjugation); C) G′ and G″ dynamics upon UV activation with 15% conjugation for different concentrations(25, 50, and 75 wt%) in PBS, and; D) summary of G′ values for different diazirine conjugation percentages, concentrations and exposure times.…”