Adhesive curing through low-voltage activation

Abstract

Instant curing adhesives typically fall within three categories, being activated by either light (photocuring), heat (thermocuring) or chemical means. These curing strategies limit applications to specific substrates and can only be activated under certain conditions. Here we present the development of an instant curing adhesive through low-voltage activation. The electrocuring adhesive is synthesized by grafting carbene precursors on polyamidoamine dendrimers and dissolving in aqueous solvents to form viscous gels. The electrocuring adhesives are activated at −2 V versus Ag/AgCl, allowing tunable crosslinking within the dendrimer matrix and on both electrode surfaces. As the applied voltage discontinued, crosslinking immediately terminated. Thus, crosslinking initiation and propagation are observed to be voltage and time dependent, enabling tuning of both material properties and adhesive strength. The electrocuring adhesive has immediate implications in manufacturing and development of implantable bioadhesives.

Elastic Light Tunable Tissue Adhesive Dendrimers

“…The collagen surface layer of the tissue appears to be infiltrated by adhesive gel, which is expected due to the formation of covalent bonds at the interface. One product of UV‐induced free radical formation from conjugated diazirine is N 2 , which forms bubbles during UV irradiation . As the reaction occurs very rapidly even under relatively low UV power, these bubbles remained trapped after solidification of gel layer.…”

“…PBS (Gibco, Singapore) was used in all experiments. PAMAM‐g‐diazirine was synthesized by previously developed method . In brief, PAMAM solution in MeOH (0.5% w/v) was prepared and different amounts of diazirine were added directly into 5 mL of PAMAM solution (according to theoretical calculations) in order to obtain different diazirine conjugate percentages (Table S1, Supporting Information).…”

“…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.…”

Pulsed Laser Activation of Carbene Bioadhesive Boosts Bonding Strength

“…By grafting TAD onto G5 PAMAM dendrimer, a model system is easily synthesized in a one‐step reaction to explore photochemical and bioadhesive structure–activity relationships. Previous investigations have explored PDz with respect to grafting/solid content, voltage‐activation, and non‐aqueous formulations . Previous studies have also focused on biocompatibility and cytotoxicity behavior of the primary components.…”

Addressing Unmet Clinical Needs with UV Bioadhesives

“…We have functionalized poly(lactide-co-glycolide) (PLGA) thin films with diazirine that cross-link to tissue upon irradiation with 365 nm light at a dose of 300 mJ cm −2 in 10 min. 73 We have also functionalized poly(amido amine) (PAMAM) dendrimers with diazirine, as shown in Figure 4, for activation either by low-voltage electrical stimulation 74 or UV light. 21 Unlike free radical-mediated acrylate polymerization, carbene-mediated cross-linking allows control over both initiation and propagation; thus, adhesion, viscoelasticity, and modulus can be tuned via the UV dose.…”